Vitaliy Robert Yurkiv

Interests

Research

Multi-physics modeling and machine learning calculation of energy storage and conversion technologies.Ab-initio density functional theory (DFT) calculations. Thermal measurements of cylindrical and pouch batteries.

Teaching

ThermodynamicsEnergy storage and conversionRechargeable batteriesElectric vehicles (EVs)

Courses

Scholarly Contributions

Journals/Publications

• AbdiSobbouhi, Y., Alahmad, Q., Kingston, T. A., & Yurkiv, V. (2025).

  Standardizing Battery Safety Testing Protocols: Enhancing Reliability and Global Regulatory Alignment for Lithium-Ion Batteries

  . Electrochemical Society, MA2025-01(8), 858.
• AbdiSobbouhi, Y., Das, G., Alahmad, Q., Kingston, T. A., & Yurkiv, V. (2025).

  Multiphysics Modeling of Commercial Batteries for Predicting Thermal Behavior Under Variable Environmental and Operational Conditions

  . Electrochemical Society, MA2025-01(8), 817.
• Borshon, I. Z., Jabbari, V., Kingston, T. A., Shahbazian-Yassar, R., & Yurkiv, V. (2025). Deep Learning Analysis of Solid-Electrolyte Interphase Microstructures in Lithium-Ion Batteries. Advanced Materials Interfaces, 12(21), e00558.
• Borshon, I. Z., Jabbari, V., Kingston, T. A., Shahbazian-Yassar, R., & Yurkiv, V. (2025). Deep Learning Analysis of Solid-Electrolyte Interphase Microstructures in Lithium-Ion Batteries. Advanced Materials Interfaces, 12(Issue). doi:10.1002/admi.202500558
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  A comprehensive understanding of the solid-electrolyte interphase (SEI) in lithium-ion batteries is crucial for improving energy efficiency, battery performance, and safety. In this study, a transformer-based instance segmentation framework, integrating deep convolutional neural networks is introduced with a feature pyramid network (FPN), to quantitatively analyze High-Resolution Transmission Electron Microscopy (HRTEM) images and explain the complex microstructural features of the SEI. The model is trained on a dataset of simulated HRTEM images generated using Density Functional Theory (DFT)-optimized grain boundary (GB) structures and calibrated with experimental microscope parameters. The model achieves robust segmentation performance, with training and validation mean intersection over union (mIOU) values of 0.98 and 0.96, respectively. On unseen test data, the model attains mean area match (AM) scores of 91.4% for GBs, 92.3% for Li2CO3, 91.7% for LiF, 88.7% for LiOH, and 88.6% for Li2O. These quantitative results highlight the model's high fidelity and its ability to capture subtle variations in crystallographic orientations and material contrasts. By enabling detailed, statistically grounded segmentation of SEI components, the approach offers valuable insights into ion transport and degradation mechanisms, paving the way for more resilient and efficient energy storage solutions.
• Granda, R., Plog, J., Yurkiv, V. R., Mashayek, F., & Yarin, A. L. (2025). Electro-Stretching and Electro-Coalescence of Sessile Drops of Conducting Polymer Solutions with and without Surfactant and Dielectric Particles. Langmuir : the ACS journal of surfaces and colloids, 41(39), 26798-26811.
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  The present study explores electrically driven stretching of individual conducting polymer drops and electro-coalescence of drop pairs on a dielectric surface under a strong electric field of 10 kV. Conducting PEDOT:PSS and PEDOT:PSS-PEO [poly(3,4-ethylenedioxythiophene):polystyrenesulfonate-poly(ethylene oxide)] drops were tested with and without a nonionic surfactant (Silwet L-77) and dispersed titanium dioxide (TiO) particles. The surfactant dramatically reduced the solution's surface tension from ∼70 to ∼20 mN/m, and PEO doping increased viscosity and imparted shear-thinning behavior. Under the applied field, drops stretched between the electrodes and spread much wider than without voltage. This pronounced stretching is driven by electrostatic Maxwell stress overcoming capillarity (the electric capillary number Ca ∼ 0.9-2.3). The surfactant further enhanced deformation by lowering surface tension, and polarizable TiO particles introduced dielectrophoretic forces that also eased stretching. Furthermore, in surfactant-free cases, two initially separate drops underwent rapid electro-coalescence: upon field activation, finger-like protrusions formed within ∼2-5 ms from each drop to meet and create a narrow liquid bridge, which then expanded to merge the drops into one over a few seconds. However, drops containing surfactant (and TiO) failed to coalesce, as strong Marangoni flow from surfactant-induced surface tension gradients dominated the Maxwell stress-driven attraction. Such surfactant-laden drops instead developed dendrite-like patterns at their trailing edges, with only a brief (∼millisecond) "handshake" contact and no full merging. These findings clarify how solution composition and interfacial and electrohydrodynamic mechanisms govern drop deformation and merging, providing insights for controlling drop behavior in coating processes. Moreover, the present experiments with drops of solutions of the conducting polymer with a surfactant (a superspreader SILWET L-77) and particles added reveal a novel phenomenon─a competition of the concentration-gradient Marangoni flow with electro-coalescence driven by the electric Maxwell stresses, which causes a noncoalescence even at a very high applied voltage.
• Granda, R., Plog, J., Yurkiv, V. R., Mashayek, F., & Yarin, A. L. (2025). Electro-Stretching and Electro-Coalescence of Sessile Drops of Conducting Polymer Solutions with and without Surfactant and Dielectric Particles. Langmuir, 41(Issue 39). doi:10.1021/acs.langmuir.5c03475
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  The present study explores electrically driven stretching of individual conducting polymer drops and electro-coalescence of drop pairs on a dielectric surface under a strong electric field of 10 kV. Conducting PEDOT:PSS and PEDOT:PSS–PEO [poly(3,4-ethylenedioxythiophene):polystyrenesulfonate–poly(ethylene oxide)] drops were tested with and without a nonionic surfactant (Silwet L-77) and dispersed titanium dioxide (TiO2) particles. The surfactant dramatically reduced the solution’s surface tension from ∼70 to ∼20 mN/m, and PEO doping increased viscosity and imparted shear-thinning behavior. Under the applied field, drops stretched between the electrodes and spread much wider than without voltage. This pronounced stretching is driven by electrostatic Maxwell stress overcoming capillarity (the electric capillary number CaE∼ 0.9–2.3). The surfactant further enhanced deformation by lowering surface tension, and polarizable TiO2particles introduced dielectrophoretic forces that also eased stretching. Furthermore, in surfactant-free cases, two initially separate drops underwent rapid electro-coalescence: upon field activation, finger-like protrusions formed within ∼2–5 ms from each drop to meet and create a narrow liquid bridge, which then expanded to merge the drops into one over a few seconds. However, drops containing surfactant (and TiO2) failed to coalesce, as strong Marangoni flow from surfactant-induced surface tension gradients dominated the Maxwell stress-driven attraction. Such surfactant-laden drops instead developed dendrite-like patterns at their trailing edges, with only a brief (∼millisecond) “handshake” contact and no full merging. These findings clarify how solution composition and interfacial and electrohydrodynamic mechanisms govern drop deformation and merging, providing insights for controlling drop behavior in coating processes. Moreover, the present experiments with drops of solutions of the conducting polymer with a surfactant (a superspreader SILWET L-77) and particles added reveal a novel phenomenon─a competition of the concentration-gradient Marangoni flow with electro-coalescence driven by the electric Maxwell stresses, which causes a noncoalescence even at a very high applied voltage.
• Mostafavi, A., Ranjbar, M., Yurkiv, V., Yarin, A. L., & Mashayek, F. (2025). MOOSE-based finite element framework for mass-conserving two-phase flow simulations on adaptive grids using the diffuse interface approach and a Lagrange multiplier. Journal of Computational Physics, 527, 113755.
• Mostafavi, A., Ranjbar, M., Yurkiv, V., Yarin, A. L., & Mashayek, F. (2025). MOOSE-based finite element framework for mass-conserving two-phase flow simulations on adaptive grids using the diffuse interface approach and a Lagrange multiplier. Journal of Computational Physics, 527. doi:10.1016/j.jcp.2025.113755
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  A numerical framework capable of simulating incompressible laminar two-phase flows has been developed within the Multiphysics Object-Oriented Simulation Environment (MOOSE). The fully-coupled and fully-implicit-in-time methodology relies on the continuous Galerkin finite element discretization of the coupled Cahn-Hilliard Navier-Stokes (CHNS) equations. Despite the computational advantages of adaptive mesh refinement (AMR), mass-conserving interpolation schemes do not exist for transferring the solution to a newly adapted mesh. This paper introduces a new time-dependent scalar Lagrange multiplier to ensure mass conservation on adaptive grids while efficiently handling the interpolation errors involved in mesh coarsening. To assess the accuracy of the numerical implementation, several two-phase flow benchmark problems have been studied and validated against reference solutions. The comparisons demonstrate the accuracy of the code and the overall methodology. The proposed method can be effectively applied to any 2D, 2D axisymmetric and 3D complex immiscible two-phase flows, leveraging conservative AMR without compromising conservation principles.
• Mostafavi, A., Ranjbar, M., Yurkiv, V., Yarin, A. L., & Mashayek, F. (2025). On the energy analysis of two-phase flows simulated with the diffuse interface method. Physics of Fluids, 37(Issue 7). doi:10.1063/5.0276045
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  The phase-field method (PFM) is employed to simulate two-phase flows with the fully coupled Cahn-Hilliard-Navier-Stokes equations governing the temporal evolution. The methodology minimizes the total energy functional, accounting for diffusive and viscous dissipations. A new perspective is presented by analyzing the interplay between kinetic energy, mixing energy, and viscous dissipation using the temporal evolution of the total energy functional. The classical surface energy is approximated with mixing energy under specific conditions, and the accuracy of this substitution is rigorously evaluated. The energy-based surface tension formulation derived from the Korteweg stress tensor demonstrates exceptional accuracy in capturing variations in the mixing energy. These concepts are demonstrated by considering two benchmark problems: droplet oscillation and capillary thread breakup. Key findings include validating mixing-energy theory for highly deformed interfaces, as well as the discovery of distinct energy dissipation patterns during thread breakup and droplet oscillations. The results highlight the robustness of the free energy-based PFM in accurately capturing complex interfacial dynamics, while maintaining energy conservation.
• Tamadoni Saray, M., Yurkiv, V. R., & Shahbazian-Yassar, R. (2025). In Situ TEM Studies on the Formation of High-Entropy Alloy Nanoparticles from Mixed Metal-Salt Precursors. Langmuir, 41(Issue 23). doi:10.1021/acs.langmuir.5c00528
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  Understanding the nucleation and growth mechanisms of high-entropy alloy (HEA) nanoparticles is crucial for developing functional nanocrystals with tailored properties. This study investigates the thermal decomposition of mixed metal salt precursors (Fe, Ni, Pt, Ir, Ru) on reduced graphene oxide (rGO) using in situ transmission electron microscopy (TEM) when heated to 1000 °C at both slow (20 °C min-1) and fast (103 °C s-1) heating/cooling rates. Slow heating to 1000 °C revealed the following: (1) The nanoparticles' nucleation occurred through multistage decomposition at lower temperatures (250-300 °C) than single metal salt precursors (300-450 °C). (2) Pt-dominant nanocrystals autocatalytically reduced other elements, leading to the formation of multimetallic FeNiPtIrRu nanoparticles. (3) At 1000 °C, the nanoparticles were single-phase with noble metals enriched compared to transition metals. (4) Slow cooling induced structural heterogeneity and phase segregation due to element diffusion and thermodynamic miscibility. (5) Adding polyvinylpyrrolidone (PVP) suppressed segregation, promoting HEA nanoparticle formation even during slow cooling by limiting atomic diffusion. Under fast heating/cooling, nanoparticles formed as a solid solution of fcc HEA, indicating kinetic control and limited atomic diffusion. The density function theory (DFT) calculations illustrate that the simultaneous presence of metal elements on rGO, as expected by the fast heating process, favors the formation of an fcc HEA structure, with strong interactions between HEA nanoparticles and rGO enhancing stability. This study provides insights into how heating rates and additives like PVP can control phase composition, chemical homogeneity, and stability, enabling the rational design of complex nanomaterials for catalytic, energy, and functional applications.
• Tamadoni Saray, M., Yurkiv, V. R., & Shahbazian-Yassar, R. (2025). TEM Studies on the Formation of High-Entropy Alloy Nanoparticles from Mixed Metal-Salt Precursors. Langmuir : the ACS journal of surfaces and colloids, 41(23), 14727-14742.
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  Understanding the nucleation and growth mechanisms of high-entropy alloy (HEA) nanoparticles is crucial for developing functional nanocrystals with tailored properties. This study investigates the thermal decomposition of mixed metal salt precursors (Fe, Ni, Pt, Ir, Ru) on reduced graphene oxide (rGO) using transmission electron microscopy (TEM) when heated to 1000 °C at both slow (20 °C min) and fast (10 °C s) heating/cooling rates. Slow heating to 1000 °C revealed the following: (1) The nanoparticles' nucleation occurred through multistage decomposition at lower temperatures (250-300 °C) than single metal salt precursors (300-450 °C). (2) Pt-dominant nanocrystals autocatalytically reduced other elements, leading to the formation of multimetallic FeNiPtIrRu nanoparticles. (3) At 1000 °C, the nanoparticles were single-phase with noble metals enriched compared to transition metals. (4) Slow cooling induced structural heterogeneity and phase segregation due to element diffusion and thermodynamic miscibility. (5) Adding polyvinylpyrrolidone (PVP) suppressed segregation, promoting HEA nanoparticle formation even during slow cooling by limiting atomic diffusion. Under fast heating/cooling, nanoparticles formed as a solid solution of HEA, indicating kinetic control and limited atomic diffusion. The density function theory (DFT) calculations illustrate that the simultaneous presence of metal elements on rGO, as expected by the fast heating process, favors the formation of an HEA structure, with strong interactions between HEA nanoparticles and rGO enhancing stability. This study provides insights into how heating rates and additives like PVP can control phase composition, chemical homogeneity, and stability, enabling the rational design of complex nanomaterials for catalytic, energy, and functional applications.
• Yurkiv, V., AbdiSobbouhi, Y., Alahmad, Q., & Kingston, T. A. (2025).

  (Invited) Thermal Runaway Prediction in Li-Ion Batteries: Combining Experimental Insights with Multiphysics and Transformer-Based Models

  . Electrochemical Society, MA2025-01(8), 822.
• Amiri, A., Yurkiv, V., Phakatkar, A. H., Shokuhfar, T., & Shahbazian-Yassar, R. (2024). Insights Into Formation and Growth of Colloidal Multielement Alloy Nanoparticles in Solution through In Situ Liquid Cell TEM Study. Advanced Functional Materials, 34(Issue 19). doi:10.1002/adfm.202304685
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  The nucleation and growth of nanoparticles are critical processes determining the size, shape, and properties of resulting nanoparticles. However, understanding the complex mechanisms guiding the formation and growth of colloidal multielement alloy nanoparticles remains incomplete due to the involvement of multiple elements with different properties. This study investigates in situ colloidal synthesis of multielement alloys using transmission electron microscopy (TEM) in a liquid cell. Two different pathways for nanoparticle formation in a solution containing Au, Pt, Ir, Cu, and Ni elements, resulting in two distinct sets of particles are observed. One set exhibits high Au and Cu content, ranging from 10 to 30 nm, while the other set is multi-elemental, with Pt, Cu, Ir, and Ni, all less than 4 nm. The findings suggest that, besides element miscibility, metal ion characteristics, particularly reduction rates, and valence numbers, significantly impact particle composition during early formation stages. Density functional theory (DFT) simulations confirm differences in nanoparticle composition and surface properties collectively influence the unique growth behaviors in each nanoparticle set. This study illuminates mechanisms underlying the formation and growth of multielement nanoparticles by emphasizing factors responsible for chemical separation and effects of interplay between composition, surface energies, and element miscibility on final nanoparticles size and structure.
• Borshon, I. Z., Ragone, M., Phakatkar, A. H., Long, L., Shahbazian-Yassar, R., Mashayek, F., & Yurkiv, V. (2024). Predicting column heights and elemental composition in experimental transmission electron microscopy images of high-entropy oxides using deep learning. npj Computational Materials, 10(1), 275.
• Borshon, I., Ragone, M., Phakatkar, A., Long, L., Shahbazian-Yassar, R., Mashayek, F., & Yurkiv, V. (2024). Predicting column heights and elemental composition in experimental transmission electron microscopy images of high-entropy oxides using deep learning. npj Computational Materials, 10(1). doi:10.1038/s41524-024-01461-w
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  A novel approach is presented by integrating images-driven deep learning (DL) with high entropy oxides (HEOs) analysis. A fully convolutional neural network (FCN) is used to interpret experimental scanning transmission electron microscopy (STEM) images of HEO of various sizes. The FCN model is designed to predict column heights (CHs) and elemental distributions from single, experimentally acquired STEM images of complex (Mn, Fe, Ni, Cu, Zn)3O4 HEO nanoparticles (NPs) at atomic resolution. The model’s ability to predict elemental distributions was tested across various crystallographic zones. It was found that the model could effectively adapt to different atomic configurations and operational conditions. One of the significant outcomes was the identification of substantial elemental inhomogeneities in all experimental NPs, which highlighted the random and complex nature of element distribution within HEOs. The developed FCN DL method can be applied to assist experimental HEO and beyond NP analysis in various operating conditions.
• Das Goswami, B., Abdisobbouhi, Y., Du, H., Mashayek, F., Kingston, T., & Yurkiv, V. (2024). Advancing battery safety: Integrating multiphysics and machine learning for thermal runaway prediction in lithium-ion battery module. Journal of Power Sources, 614(Issue). doi:10.1016/j.jpowsour.2024.235015
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  The safety concerns associated with lithium-ion batteries (LIBs) have led to the development of a novel framework combining advanced machine learning (ML) techniques with multiphysics modeling. Herein, we report an ML framework aiming to predict the occurrence of thermal runaway (TR) in the LIB module by employing a multiphysics model that incorporates thermal, electrochemical, and degradation sub-models. The focus of this research lies in understanding the degradation phenomenon associated with the breakdown of the solid electrolyte interface (SEI) on the negative electrode, which can trigger TR. The developed multiphysics model enables the investigation of electrochemical and degradation processes within batteries under various conditions, including constant charge/discharge and driving cycles. To capture the spatio-temporal temperature change, a graph neural network (GNN) for spatial change is coupled with a Long Short-Term Memory (LSTM) network for temporal evolution to form an integrated framework. The results demonstrate the high accuracy of the ML model in predicting battery temperatures in a module based on spatial and temporal temperature data obtained from temperature sensors attached to the batteries, hence, offering a means to detect TR before it occurs by identifying potential thermal hotspots.
• Das, G., Abdisobbouhi, Y., Du, H., Mashayek, F., Kingston, T. A., & Yurkiv, V. (2024). Advancing battery safety: Integrating multiphysics and machine learning for thermal runaway prediction in lithium-ion battery module. Journal of Power Sources, 614, 235015.
• Das, G., Mastrogiorgio, M., Ragone, M., Jabbari, V., Shahbazian-Yassar, R., Mashayek, F., & Yurkiv, V. (2024). A combined multiphysics modeling and deep learning framework to predict thermal runaway in cylindrical Li-ion batteries. Journal of Power Sources, 595, 234065.
• Ghorbani, A., Yurkiv, V., Gon??alves, J. M., Amiri, A., Ritter, T. G., Tamadoni, S. M., & Shahbazian-Yassar, R. (2024). Role of CO2 and Glycerol in the Formation of Urchin-Like Strontium Carbonate Particles. ACS Sustainable Chemistry & Engineering, 12(8), 3185-3195.
• Granda, R., Yurkiv, V., Mashayek, F., & Yarin, A. (2024). Impact of drops of epoxy resin and hardener, silicone and turpentine oils onto balsa wood and polypropylene substrates. Physics of Fluids, 36(5). doi:10.1063/5.0208144
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  Electrowetting and wettability-driven spreading of liquids on porous and nonporous substrates was investigated using impact of drops of epoxy resin, epoxy hardener, and epoxy resin and hardener, as well as silicone and turpentine oils with oil-soluble aniline dyes onto balsa wood and polypropylene surfaces. The experimental results revealed that the electric field stretched drops of epoxy resin, epoxy hardener, and epoxy resin and hardener after impact on polypropylene substrate in the long-term. The spreading of drops of epoxy resin and turpentine oil with dyes after impact onto porous balsa wood under the action of a 10 kV applied voltage was relatively weak. In addition, the measured footprint areas corresponding to drops of epoxy resin, epoxy hardener, and epoxy resin and hardener demonstrated a significant increase in the wetted areas driven by the applied voltage of 10 kV on polypropylene substrate, whereas on balsa wood, the footprint is practically unaffected by the electric field. Furthermore, it was determined that surface wettability was the main mechanism of spreading of epoxy resin, as well as silicone and turpentine oils with aniline dyes on porous balsa without the electric field applied. On the other hand, insufficient concentration of ions and counterions in silicone oil was responsible for the absence of electrohydrodynamic effects after impact of such drops onto porous balsa substrate subjected to high potentials of 7 and 10 kV. Hence, wettability-driven spreading with imbibition on balsa wood was the only reason for an increase in the wetted area in the case of silicone oil.
• Granda, R., Yurkiv, V., Mashayek, F., & Yarin, A. L. (2024). Impact of drops of epoxy resin and hardener, silicone and turpentine oils onto balsa wood and polypropylene substrates. Physics of Fluids, 36(5), 053312.
• Ritter, T. G., Il, K. Y., Bezerra, D., Wang, X., Pan, Y., Yurkiv, V., Yarin, A. L., & Shahbazian-Yassar, R. (2024). Composite PEDOT:PSS-PEO Layers for Improving Lithium Batteries. ChemElectroChem, 11(20), e202400458.
• Ritter, T., Il Kim, Y., Bezerra De Souza, B., Wang, X., Pan, Y., Yurkiv, V., Yarin, A., & Shahbazian-Yassar, R. (2024). Composite PEDOT:PSS-PEO Layers for Improving Lithium Batteries**. ChemElectroChem, 11(20). doi:10.1002/celc.202400458
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  This work investigates the application of poly(3,4-ethylenedioxythiophene) polystyrenesulfonate (PEDOT:PSS) with polyethylene oxide (PEO) in lithium batteries (LIBs). This composite film comprising PEDOT:PSS and PEO was 3D printed onto a carbon nanofiber (CNF) substrate to serve as a layer between the polypropylene (PP) separator and the lithium anode in LIBs. The resulting CNF-PEDOT:PSS-PEO film exhibited superior mechanical and thermal properties compared to conventional PP separators. Mechanical tests revealed a high Young's modulus and puncture strength for the composite film. Thermal stability tests indicated that the CNF-PEDOT:PSS-PEO film remained stable at higher temperatures compared to the commercial PP separator, and combustion tests confirmed its superior fire-resistance properties. In terms of conductivity, the composite film maintained comparable ionic conductivity to the commercial PP separator. Electrochemical tests demonstrated that LIBs incorporating the CNF-PEDOT:PSS-PEO film exhibited slight improvement in cycling performance, with a 7.9 % increase in long-term cycling capacity compared to LIBs using only the commercial PP separator. These findings indicate that the developed CNF-PEDOT:PSS-PEO composite film holds promise to improve safety, while maintaining the electrochemical performance of LIBs by reducing dendrite formation and enhancing thermal stability.
• Yurkiv, V., Wang, X., Kim, Y., Pan, Y., Mashayek, F., & Yarin, A. (2024). Ab initio modeling and experimental analysis of electronic conductivity in PEDOT:PSS-PEO films for extrusion-based manufacturing. Journal of Colloid and Interface Science, 674(Issue). doi:10.1016/j.jcis.2024.06.148
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  In this study, a combination of ab initio modeling and experimental analysis is presented to investigate and elucidate the electronic conductivity of films composed of conducting polymer blend PEDOT:PSS-PEO. Detailed density functional theory (DFT) calculations, aligned with experimental data, aided at profound understanding of the chemical composition, band structure, and the mechanical behavior of these composite materials. Systematic evaluation across diverse ratios of PEDOT, PSS, and PEO revealed a pronounced transformation in electronic properties. Specifically, the addition of PEO into the polymer matrix remarkably changes the band gap, with a marked alteration observed near a PEO concentration of 52 wt-%. This adjustment led to a substantial enhancement in the electrical conductivity, exhibiting an increase by a factor of approximately 20, compared to the original PEDOT:PSS polymer. The present investigation determined the crucial role of the PEDOT to PSS ratio in band gap determination, emphasizing its significant impact on the material's electrical conductivity. Concurrently, the mechanical property analysis unveiled a consistent increase in Young's modulus, reaching up to 765.93 MPa with increased PEO content, signifying a notable mechanical stiffening of the blend. The obtained combined theoretical and experimental insights illustrate a detailed perspective on the conductivity anomalies observed in PEDOT:PSS-PEO systems, establishing a robust framework for designing highly conducting and mechanically stable polymer blends. This comprehensive approach elucidates the interplay between chemical composition and electronic behavior, offering a strategic pathway for extrusion-based manufacturing techniques such as Direct Ink Writing (DIW).
• Yurkiv, V., Wang, X., Kim, Y., Pan, Y., Mashayek, F., & Yarin, A. L. (2024). Ab initio modeling and experimental analysis of electronic conductivity in PEDOT:PSS-PEO films for extrusion-based manufacturing. Journal of Colloid and Interface Science, 674, 128-138.
• Amiri, A., Ghildiyal, P., Phakatkar, A. H., Shahbazian-Yassar, R., Shokuhfar, T., Sorokina, L. V., Wang, Y., Yurkiv, V., & Zachariah, M. R. (2023).

  In Situ Microscopic Studies on the Interaction of Multi-Principal Element Nanoparticles and Bacteria

  . ACS Nano, 17(6), 5880-5893. doi:10.1021/acsnano.2c12799
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  Multi-principal element nanoparticles are an emerging class of materials with potential applications in medicine and biology. However, it is not known how such nanoparticles interact with bacteria at nanoscale. In the present work, we evaluated the interaction of multi-principal elemental alloy (FeNiCu) nanoparticles with Escherichia coli (E. coli) bacteria using the in situ graphene liquid cell (GLC) scanning transmission electron microscopy (STEM) approach. The imaging revealed the details of bacteria wall damage in the vicinity of nanoparticles. The chemical mappings of S, P, O, N, C, and Cl elements confirmed the cytoplasmic leakage of the bacteria. Our results show that there is selective release of metal ions from the nanoparticles. The release of copper ions was much higher than that for nickel while the iron release was the lowest. In addition, the binding affinity of bacterial cell membrane protein functional groups with Cu, Ni, and Fe cations is found to be the driving force behind the selective metal cations’ release from the multi-principal element nanoparticles. The protein functional groups driven dissolution of multielement nanoparticles was evaluated using the density functional theory (DFT) computational method, which confirmed that the energy required to remove Cu atoms from the nanoparticle surface was the least in comparison with those for Ni and Fe atoms. The DFT results support the experimental data, indicating that the energy to dissolve metal atoms exposed to oxidation and/or the to presence of oxygen atoms at the surface of the nanoparticle catalyzes metal removal from the multielement nanoparticle. The study shows the potential of compositional design of multi-principal element nanoparticles for the controlled release of metal ions to develop antibacterial strategies. In addition, GLC-STEM is a promising approach for understanding the nanoscale interaction of metallic nanoparticles with biological structures.
• Das Goswami, B. R., Jabbari, V., Shahbazian-Yassar, R., Mashayek, F., & Yurkiv, V. (2023).

  Unraveling Ion Diffusion Pathways and Energetics in Polycrystalline SEI of Lithium-Based Batteries: Combined Cryo-HRTEM and DFT Study

  . The Journal of Physical Chemistry C, 127(45), 21971-21979. doi:10.1021/acs.jpcc.3c05395
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  The solid-electrolyte interphase (SEI) in lithium-based batteries has been extensively studied regarding its composition, structure, and formation mechanisms. However, an understanding of the ion transport through the SEI remains incomplete. Revealing the underlying ion diffusion processes across the SEI holds great potential for enhancing battery performance and improving safety. In this study, we present the outcomes of first-principles density functional theory (DFT) calculations based on cryogenic high-resolution transmission electron microscopy (cryo-HRTEM) imaging, which elucidate the dominant diffusion pathways, energetics, and diffusion coefficients associated with lithium (Li) diffusion through the polycrystalline SEI. Specifically, we focus on Li diffusion through the grain boundaries (GBs) formed by the three primary inorganic components of the SEI, namely, Li2O, LiF, and Li2CO3. Our findings reveal that Li diffusion primarily occurs through numerous open channels created by the GBs. The energetics and potential barriers reveal significant variations depending upon the structural characteristics of these channels, with a distinguished trend being faster Li diffusion within the GB compared to neighboring crystalline regions within the grain interiors. The analysis of the charge density in GBs revealed that Li dendrite formation occurs in GBs with less Li diffusion kinetics.
• Jabbari, V., Yurkiv, V., Ghorbani, A., Mashayek, F., & Shahbazian-Yassar, R. (2023).

  Fast rate lithium metal batteries with long lifespan enabled by graphene oxide confinement

  . Energy Advances, 2(5), 712-724. doi:10.1039/d3ya00083d
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  Dendritic growth of lithium (Li) is hindering potential applications of Li-metal batteries, and new approaches are needed to address this challenge. The confinement effect of two-dimensional materials triggered by strong molecular interactions between parallelly-aligned graphene oxide (GO) at Li metal interface is proposed here as a new strategy to suppress the dendritic growth of Li. The effectiveness of aligned GO for Li-metal cells is shown for two different polymer separator cells:liquid electrolytes with porous propylene (PP) separators and solid polyethylene oxide (PEO) electrolytes. For the case of liquid electrolytes, PP separators were modified with plasma treatment to induce the alignment of GO layers. The Li‖Li cells with aligned GO illustrate a stable Li platting/stripping (up to 1000 cycles). The Li‖lithium iron phosphate (LFP) battery cells with aligned GO could cycle at 5C for 1000 cycles (∼90% capacity retention). For solid polymer electrolyte (SPE) cells, GO–Li confinement effect is also effective in Li dendrites suppression enhancing the stability and lifespan of Li-metal batteries. The Li‖LFP cell with the GO-modified SPE showed ∼85% capacity retention after 200 cycles at 1C. Such combined high rate capability and number of cycles exceeds the previously reported performances for both liquid and SPE-based Li‖LFP cells. This points to a new opportunity for utilizing the confinement effect of two-dimensional materials for the development of next generation, fast rate rechargeable Li batteries.
• Ragone, M., Shahabazian-Yassar, R., Mashayek, F., & Yurkiv, V. (2023).

  Deep learning modeling in microscopy imaging: A review of materials science applications

  . Progress in Materials Science, 138, 101165. doi:10.1016/j.pmatsci.2023.101165
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  The accurate analysis of microscopy images representing various materials obtained in scanning probe microscopy, scanning tunneling microscopy, and transmission electron microscopy, is in general time consuming as it requires the inspection of multiple data bases for the correct interpretation of the observed crystal structures. This task is especially demanding in microscopy video analysis involving a vast amount of image data. The recent development of deep learning (DL) algorithms has paved the way for cutting-edge microscopy studies in materials science, often outperforming conventional image analysis methods. This paper reviews the state-of-the-art in DL-based synthetic data generation, materials structure identification, three-dimensional structural reconstruction, and physical properties evaluation for different types of microscopy images. First, the fundamental concepts of DL relevant to materials science applications are reviewed. Subsequently, the combined experimental measurements and numerical simulations for preparing dedicated microscopy image for DL analysis are discussed. Then, the review concentrates on the core topic of the paper, that is the critical assessment of DL advances in materials’ structural and physical properties evaluation. We believe that the future development and deployment of DL for practical microscopy data analysis will rely on the progress and improvement of advanced algorithms and innovative methods for training data generation.
• Saray, M. T., Yurkiv, V., & Shahbazian‐Yassar, R. (2023).

  Role of Kinetics and Thermodynamics in Controlling the Crystal Structure of Nickel Nanoparticles Formed on Reduced Graphene Oxide: Implications for Energy Storage and Conversion Applications

  . ACS Applied Nano Materials, 6(12), 10033-10043. doi:10.1021/acsanm.2c05528
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  Ultrafast heating has emerged recently to speed up the synthesis processes of nanoparticles and control their morphology. However, it is not clear how the heating rate affects the formation of metal nanoparticles, particularly those formed on substrates. Here, we explored the formation of nickel (Ni) nanoparticles on graphene oxide (GO) substrates under slow (20 °C/min) and ultrafast (103 °C/s) heating rates. The experiments were performed in situ on heating microchip devices using an aberration-corrected transmission electron microscope. Interestingly, the GO structure was the most effective in controlling the stability of nanoparticles when ultrafast heating was employed, leading to a hexagonally close-packed Ni phase (hcp-Ni) because of less lattice mismatch with the graphitic substrate. On the contrary, fcc-Ni nanoparticles formed under a slow heating process where no strong correlation with the GO crystal structure was observed. Additionally, ultrafast heating resulted in smaller-size nanoparticles which could be ascribed to rapid reduction, nucleation rate, and higher diffusion barrier of hcp-Ni crystals on rGO. Nevertheless, the stability of the crystal structure of the nickel nanoparticles remains unaffected by their size. These results indicate the crucial role of the substrate on crystal structure during the nonequilibrium processing of materials and the competing effects of thermodynamics versus kinetics in creating novel phases of materials for energy storage and conversion applications.
• Tamadoni Saray, M., Yurkiv, V., & Shahbazian‐Yassar, R. (2023).

  In Situ Thermolysis of a Ni Salt on Amorphous Carbon and Graphene Oxide Substrates

  . Advanced Functional Materials, 33(28). doi:10.1002/adfm.202213747
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  Abstract Understanding the thermal decomposition of metal salt precursors on carbon structures is essential for the controlled synthesis of metal‐decorated carbon nanomaterials. Here, the thermolysis of a Ni precursor salt, NiCl 2 ·6H 2 O, on amorphous carbon (a‐C) and graphene oxide (GO) substrates is explored using in situ transmission electron microscopy. Thermal decomposition of NiCl 2 ·6H 2 O on GO occurs at higher temperatures and slower kinetics than on a‐C substrate. This is correlated to a higher activation barrier for Cl 2 removal calculated by the density functional theory, strong Ni‐GO interaction, high‐density oxygen functional groups, defects, and weak van der Waals using GO substrate. The thermolysis of NiCl 2 ·6H 2 O proceeds via multistep decomposition stages into the formation of Ni nanoparticles with significant differences in their size and distribution depending on the substrate. Using GO substrates leads to nanoparticles with 500% smaller average sizes and higher thermal stability than a‐C substrate. Ni nanoparticles showcase the fcc crystal structure, and no size effect on the stability of the crystal structure is observed. These findings demonstrate the significant role of carbon substrate on nanoparticle formation and growth during the thermolysis of carbon–metal heterostructures. This opens new venues to engineer stable, supported catalysts and new carbon‐based sensors and filtering devices.
• Yurkiv, V., Rasul, G., Phakatkar, A. H., Mashayek, F., & Jabbari, V. (2023).

  In situ formation of stable solid electrolyte interphase with high ionic conductivity for long lifespan all-solid-state lithium metal batteries

  . Energy Storage Materials, 57, 1-13. doi:10.1016/j.ensm.2023.02.009
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  Parasitic reactions inevitably occur at the interface of lithium (Li) metal and polymer electrolytes due to ultrahigh Li reducibility coupled with poor interfacial stability or ionic conductivity. This leads to significant capacity loss and inferior lifespan of Li metal batteries (LMBs). Herein, we engineered a stable solid electrolyte interphase (SEI) layer at the interface of Li metal and polyethylene oxide (PEO) electrolyte via incorporation of phosphazene molecules. The phosphazene-solid polymer electrolyte (P-SPE) shows a significantly higher long-term stability against Li metal anode when compared with non-modified SPE. Using cryogenic transmission electron microscopy (cryo-TEM) and X-ray photon spectroscopy (XPS), Li3N, LiF, Li3P and Li3PO4 nanocrystals were identified in the SEI layer. The Li|Li cell with P-SPE cycle for 1800 cycles at 0.2 mA cm‒2. The Li||LFP cells with P-SPE deliver a specific capacity of ∼150 mAh g−1 and ∼120 mAh g−1 at 1C and 2C charge/discharge rates, respectively, with up to 80% capacity retention after 500 and 1000 cycles, respectively. Critical role of phosphazene-modified SEI in improving electrochemical performance is further investigated by density function theory (DFT) and ab-initio molecular dynamic (AIMD) calculations. This study offers a promising approach for engineering a stable and ion-conductive Li|polymer electrolyte interface for long lifespan LMBs.
• Halder, S., Granda, R., Wu, J., Sankaran, A. N., Yurkiv, V., Yarin, A. L., & Mashayek, F. (2022).

  Air bubble entrapment during drop impact on solid and liquid surfaces

  . International Journal of Multiphase Flow, 149, 103974. doi:10.1016/j.ijmultiphaseflow.2022.103974
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  The phase-field modeling (PFM) of water drop impact onto a dielectric hydrophobic parafilm surface is performed to explore air entrapment and its influence on deposition and rebound phenomena. Local and global characteristics of the drop impact are taken into account by using the combined Cahn-Hilliard and Navier-Stokes equations. The modeling results of water drop impact are directly compared with our experimental measurements in terms of maximum spreading distance, and air bubble size. The simulation results reveal that air can be trapped under the liquid drop during the initial impact as well as during the retraction phase at the center of the drop due to the closure of the liquid layer above a cavity. It is found that the drop diameter and the impact velocity play significant roles in the air entrapment phenomena. The probability of air bubble formation is higher at lower impact velocity and for larger drop size. The model is also capable of simulating the case of drop impact onto a water surface, and the results are validated using prior literature data. In addition, the influence of the phase-field variables and the mesh adaptation scheme on the PFM is studied and discussed. Thus, our findings provide new qualitative and quantitative insights into the influence of air entrapment on drop deposition onto hydrophobic and liquid surfaces.
• Jabbari, V., Yurkiv, V., Rasul, M. G., Saray, M. T., Rojaee, R., Mashayek, F., & Shahbazian-Yassar, R. (2022). An efficient gel polymer electrolyte for dendrite-free and long cycle life lithium metal batteries. Energy Storage Materials, 46. doi:10.1016/j.ensm.2022.01.031
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  Lithium metal batteries (LMBs) are plagued with non-uniform and dendritic electrodeposition of Li when used with liquid electrolytes, resulting in poor cycle life and Coulombic efficiency, and safety hazards. Herein, we report a novel gel polymer electrolyte (GPE) for LMBs enabling uniform and nondendritic Li electrodeposition, long cycle life, and high Columbic efficiency. The GPE is made by immobilization of liquid electrolytes within a crosslinked polymer matrix. At ambient temperature, the GPE shows a Li ion conductivity of 1.5 mS cm−1. Topology and morphology of the electrochemically deposited Li in the GPE were studied by operando optical microscopy and scanning electron microscopy (SEM). Cryogenic transmission electron microscopy (cryo-TEM) and X-ray photon spectroscopy (XPS) characterizations indicate that the solid electrolyte interphase (SEI) layer at the Li/GPE interface is a thin and LiF-rich while the SEI layer is thick and LiF-poor at the Li/liquid electrolyte interface. Density functional theory (DFT) calculations show that LiF crystals facilitate and regulate Li ions transport. Lithium|lithium iron phosphate (Li|LFP) cells with our GPE deliver an initial specific capacity of ∼130 mAh g−1 and ∼70% capacity retention after 1000 cycles at 2C charge/discharge rate. This study offers a promising approach for engineering a stable and conductive Li/polymer electrolyte interface for dendrite-free LMBs.
• Jabbari, V., Yurkiv, V., Rasul, M., Cheng, M., Griffin, P., Mashayek, F., & Shahbazian-Yassar, R. (2022). A Smart Lithium Battery with Shape Memory Function. Small, 18(4). doi:10.1002/smll.202102666
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  Rapidly growing flexible and wearable electronics highly demand the development of flexible energy storage devices. Yet, these devices are susceptible to extreme, repeated mechanical deformations under working circumstances. Herein, the design and fabrication of a smart, flexible Li-ion battery with shape memory function, which has the ability to restore its shape against severe mechanical deformations, bending, twisting, rolling or elongation, is reported. The shape memory function is induced by the integration of a shape-adjustable solid polymer electrolyte. This Li-ion battery delivers a specific discharge capacity of ≈140 mAh g-1 at 0.2 C charge/discharge rate with ≈92% capacity retention after 100 cycles and ≈99.85% Coulombic efficiency, at 20 °C. Besides recovery from mechanical deformations, it is visually demonstrated that the shape of this smart battery can be programmed to adjust itself in response to an internal/external heat stimulus for task-specific and advanced applications. Considering the vast range of available shape memory polymers with tunable chemistry, physical, and mechanical characteristics, this study offers a promising approach for engineering smart batteries responsive to unfavorable internal or external stimulus, with potential to have a broad impact on other energy storage technologies in different sizes and shapes.
• Mashayek, F., Shahbazian-Yassar, R., Tamadoni, M., Yurkiv, V., Long, L., & Ragone, M. (2022). "Deep Learning for Mapping Element Distribution of High-Entropy Alloys in Scanning Transmission Electron Microscopy Images". Computational Materials Science, 201, 110905. doi:https://doi.org/10.1016/j.commatsci.2021.110905
• Mashayek, F., Yarin, A. L., Yurkiv, V., Sankaran, A., Wu, J., Granda, R., & Halder, S. (2022). “Air Bubble Entrapment during Drop Impact on Solid and Liquid Surfaces”. International Journal of Multiphase Flow, 149, 103974. doi:https://doi.org/10.1016/j.ijmultiphaseflow.2022.103974
• Mashayek, F., Yurkiv, V., Granda, R., & Yarin, A. L. (2022). Paint drop spreading on wood and its enhancement by an in-plane electric field. Physics of Fluids, 34(12), 122112. doi:10.1063/5.0130871
• Cheng, M., Ramasubramanian, A., Rasul, M. G., Jiang, Y., Yuan, Y., Foroozan, T., Deivanayagam, R., Tamadoni Saray, M., Rojaee, R., Song, B., Yurkiv, V. R., Pan, Y., Mashayek, F., & Shahbazian-Yassar, R. (2021). Direct Ink Writing of Polymer Composite Electrolytes with Enhanced Thermal Conductivities. Advanced Functional Materials, 31(Issue 4). doi:10.1002/adfm.202006683
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  Proper distribution of thermally conductive nanomaterials in polymer batteries offers new opportunities to mitigate performance degradations associated with local hot spots and safety concerns in batteries. Herein, a direct ink writing (DIW) method is utilized to fabricate polyethylene oxide (PEO) composite polymers electrolytes (CPE) embedded with silane-treated hexagonal boron nitride (S-hBN) platelets and free of any volatile organic solvents. It is observed that the S-hBN platelets are well aligned in the printed CPE during the DIW process. The in-plane thermal conductivity of the printed CPE with the aligned S-hBN platelets is 1.031 W −1 K−1, which is about 1.7 times that of the pristine CPE with the randomly dispersed S-hBN platelets (0.612 W −1 K−1). Thermal imaging shows that the peak temperature (°C) of the printed electrolytes is 24.2% lower than that of the CPE without S-hBN, and 10.6% lower than that of the CPE with the randomly dispersed S-hBN, indicating a superior thermal transport property. Lithium-ion half-cells made with the printed CPE and LiFePO4 cathode displayed high specific discharge capacity of 146.0 mAh g−1 and stable Coulombic efficiency of 91% for 100 cycles at room temperature. This work facilitates the development of printable thermally-conductive polymers for safer battery operations.
• Granda, R., Plog, J., Li, G., Yurkiv, V., Mashayek, F., & Yarin, A. L. (2021). Evolution and Shape of Two-Dimensional Stokesian Drops under the Action of Surface Tension and Electric Field: Linear and Nonlinear Theory and Experiment. Langmuir, 37(Issue 39). doi:10.1021/acs.langmuir.1c01015
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  The creeping-flow theory describing evolution and steady-state shape of two-dimensional ionic-conductor drops under the action of surface tension and the subcritical (in terms of the electric Bond number) electric field imposed in the substrate plane is developed. On the other hand, the experimental data are acquired for drops impacted or softly deposited on dielectric surfaces of different wettability and subjected to an in-plane subcritical electric field. Even though the experimental situation involves viscous friction of drops with the substrates and wettability-driven motion of the contact line, the comparison to the theory reveals that it can accurately describe the steady-state drop shape on a non-wettable substrate. In the latter case, the drop is sufficiently raised above the substrate, which diminishes the three-dimensional effects, making the two-dimensional description (lacking the no-slip condition at the substrate and wettability-driven motion of the contact line) relevant. Accordingly, it is demonstrated how the subcritical electric field deforms the initially circular drops until an elongated steady-state configuration is reached. In particular, the surface tension tends to round off the non-circular drops stretched by the electric Maxwell stresses imposed by the electrodes. A more pronounced substrate wettability leads to more elongated steady-state configurations observed experimentally than those predicted by the two-dimensional theory. The latter cases reveal significant three-dimensional effects in the electrically driven drop stretching. In the supercritical electric fields (corresponding to the supercritical electric Bond numbers), the electrical stretching of drops predicted by the present linearized two-dimensional theory results in splitting into two separate droplets. This scenario is corroborated by the predictions of the fully nonlinear results for similar electrically stretched bubbles in the creeping-flow regime available in the literature as well as by the present experimental results on a substrate with slip.
• Granda, R., Yurkiv, V., Mashayek, F., & Yarin, A. L. (2021). Metamorphosis of trilobite-like drops on a surface: Electrically driven fingering. Physics of Fluids, 33(Issue 12). doi:10.1063/5.0065378
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  The experimental evidence reveals that sessile drops on a dielectric horizontal substrate subjected to sub-critical in-plane electric field acquire steady-state configurations where a balance between the pulling-outwards electric Maxwell stresses and the restoring surface tension has been attained. On the other hand, the experiments show that in supercritical electric field the Maxwell stresses become dominant and not only stretch the drop as a whole but also trigger growth of multiple fingers crawling toward electrodes on both sides of the drop. This makes the drops with fingers stretched along the electric field lines similar to some trilobites known from their imprints in petrified sediments studied in paleontology. It is shown experimentally and theoretically that fingers are triggered during the encounters of the spreading drop outlines with minor surface imperfections. Such surface defects (existing originally or pre-notched on purpose) result in fingers which can grow being directed by the electric-field lines. The present work details multiple experimental observations of the trilobite-like fingering with several types of commercially available paints (colloidal dispersions) and also provides a theoretical framework for this novel type of fingering.
• Jiang, B., Yuan, Y., Wang, W., He, K., Zou, C., Chen, W., Yang, Y., Wang, S., Yurkiv, V., & Lu, J. (2021). Surface lattice engineering for fine-tuned spatial configuration of nanocrystals. Nature Communications, 12(Issue 1). doi:10.1038/s41467-021-25969-7
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  Hybrid nanocrystals combining different properties together are important multifunctional materials that underpin further development in catalysis, energy storage, et al., and they are often constructed using heterogeneous seeded growth. Their spatial configuration (shape, composition, and dimension) is primarily determined by the heterogeneous deposition process which depends on the lattice mismatch between deposited material and seed. Precise control of nanocrystals spatial configuration is crucial to applications, but suffers from the limited tunability of lattice mismatch. Here, we demonstrate that surface lattice engineering can be used to break this bottleneck. Surface lattices of various Au nanocrystal seeds are fine-tuned using this strategy regardless of their shape, size, and crystalline structure, creating adjustable lattice mismatch for subsequent growth of other metals; hence, diverse hybrid nanocrystals with fine-tuned spatial configuration can be synthesized. This study may pave a general approach for rationally designing and constructing target nanocrystals including metal, semiconductor, and oxide.
• Mashayek, F., Yurkiv, V., Ramasubramanian, A., Ragone, M., & Kashir, B. (2021). "Application of Fully Convolutional Neural Networks for Feature Extraction in Fluid Flow". Journal of Visualization, 24, 771-785. doi:https://doi.org/10.1007/s12650-020-00732-0
• Ragone, M., Yurkiv, V., Ramasubramanian, A., Kashir, B., & Mashayek, F. (2021). Data driven estimation of electric vehicle battery state-of-charge informed by automotive simulations and multi-physics modeling. Journal of Power Sources, 483. doi:10.1016/j.jpowsour.2020.229108
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  State-of-charge (SOC) estimation in a lithium-ion battery (LIB) is a crucial task of the battery management system (BMS) in battery electric vehicle (BEV) applications. In this work, we propose a modeling framework for SOC estimation using different machine learning (ML) methods, i.e. support vector regressor (SVR), artificial neural network (ANN), and long-short term memory (LSTM) network. The necessary training data have been developed using Matlab/Simulink automotive simulations of BEV, integrated with an electrochemical Comsol Multiphysics model of LIBs. The developed multi-physics model of BEV and LIBs operation allows to investigate the effect of driving conditions on the electrochemical and degradation (i.e., the solid electrolyte interphase – SEI – formation and decomposition) processes occurring inside batteries of different chemistries adopted in the Tesla S and Nissan Leaf BEVs. Our study remarks also the importance of taking into account the different components of BEV in the development of informative datasets, which are required for the implementation of learning algorithms for SOC evaluation. Thus, the proposed work establishes a basis for the generation of realistic training data based on simulations of BEV and LIBs dynamic response, which allows a more precise SOC estimation based on data-driven approaches.
• Sankaran, A., Wu, J., Granda, R., Yurkiv, V., Mashayek, F., & Yarin, A. L. (2021). Drop impact onto polarized dielectric surface for controlled coating. Physics of Fluids, 33(Issue 6). doi:10.1063/5.0054077
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  Control of surface wettability by means of electrowetting-on-dielectric (EWOD) is among the most effective methods of active enhancement of surface wettability. Here, electrohydrodynamics of drop impact onto a dielectric surface with electrodes embedded in the dielectric (or aligned and attached to it) is experimentally investigated. Drop impact of different liquids (water, n-butanol, and motor oil) onto different substrates (stretched Teflon, parafilm, and polypropylene) is studied. Water drop impact onto stretched Teflon (the only Teflon which revealed significant electrowetting) and un-stretched parafilm surfaces is studied in detail. The results for water drop impact indicate that drop spreading on such non-wettable surfaces can be significantly enhanced by the electric field application. In particular, water drop rebound can be suppressed by the electric force. Furthermore, impact dynamics and spreading of hydrocarbon liquids with electric field are explored. Partial suppression of splash phenomena was also observed with the application of the electric field in addition to enhancement of spreading. In addition, the experimental results for water drops are compared with the Cahn−Hilliard−Navier−Stokes (CHNS) simulations for static contact angles and drop impact dynamics, and the results are in close agreement for water drops. This study demonstrates that electrowetting-on-dielectric holds great promise for coating and spraying technologies.
• Shahbazian-Yassar, R., Mashayek, F., Griffin, P., Cheng, M., Rasul, M. G., Yurkiv, V., & Jabbari, V. (2021). “A Smart Lithium Battery with Shape Memory Function”. Small. doi:https://doi.org/10.1002/smll.202102666
• Yurkiv, V., Wu, J., Halder, S., Granda, R., Sankaran, A., Yarin, A. L., & Mashayek, F. (2021). Water interaction with dielectric surface: A combined ab initio modeling and experimental study. Physics of Fluids, 33(Issue 4). doi:10.1063/5.0046587
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  A combined ab initio modeling and experimental study of water adsorption on a dry hydrophobic dielectric surface is presented. This is an important phenomenon for controlled droplet deposition in various technological applications. The ab initio density functional theory calculations are performed to reveal the dominant water adsorption sites, energetics, and the electron density profile on Teflon and parafilm surfaces. Several surface states such as stretched, nondefective, and defective are considered for water adsorption studies. It is revealed that stretching of nondefective surface leads to weaker water adsorption compared to an unstretched surface. Accordingly, such stretching makes the surface more hydrophobic as revealed by the electron density profile. The introduction of random defects into Teflon and parafilm surfaces results in an increase in water adsorption energy leading, in some cases, to practically hydrophilic interactions. These findings are in good agreement with the present measurements of static contact angle on prestretched Teflon and parafilm samples, where stretching not only elongates interatomic bonds but also changes the surface roughness. Thus, the present combined modeling and experimental study allows for a mechanistic interpretation of the reasons behind the change of wettability of dry hydrophobic surfaces.
• Cheng, M., Ramasubramanian, A., Rasul, M. G., Jiang, Y., Yuan, Y., Foroozan, T., Deivanayagam, R., Tamadoni Saray, M., Rojaee, R., Song, B., Yurkiv, V., Pan, Y., Mashayek, F., & Shahbazian-Yassar, R. (2020). “Direct Ink Writing of Polymer Composite Electrolytes with Enhanced Thermal Conductivities”. Advanced Functional Materials, 31(4), 2006683. doi:http://doi.org/10.1002/adfm.202006683
• Lu, J., Shahbazian-Yassar, R., Mashayek, F., Song, B., Liu, T., Yurkiv, V., Yao, W., & Yuan, Y. (2020). “Beyond volume variation: anisotropic and protrusive lithiation in bismuth” . ACS Nano, 14(11), 15669-15677. doi:http://doi.org/10.1021/acsnano.0c06597
• Mashayek, F., Shahbazian-Yassar, R., Paoli, R., Sharifi-Asl, S., Ragone, M., Ramasubramanian, A., Foroozan, T., & Yurkiv, V. (2020). "The Mechanism of ZN Diffusion Through ZnO in Secondary Battery: A Combined Theoretical and Experimental Study”. Journal of Physical Chemstry, 124(29), 15730-15738. doi:http://doi.org/10.1021/acs.jpcc.0c03514
• Mashayek, F., Shahbazian-Yassar, R., Ragone, M., Foroozan, T., Yurkiv, V., & Ramasubramanian, A. (2020). "Stability of Solid-Electrolyte Interphase on Lithium Metal Surface in Lithium Metal Batteries". ACS Applied Energy Materials, 3(11), 10560-10567. doi:http://doi.org/10.1021/acsaem.0c01605
• Mashayek, F., Shahbazian-Yassar, R., Ramsubramanian, A., Song, B., Yurkiv, V., & Ragone, M. (2020). “Atomic Column Heights Detection in Metallic Nanoparticles Using Deep Learning”. Computational Material Science, 180, 109722. doi:http://doi.org/10.1016/j.commatsci.2020.109722
• Shahbazian-Yassar, R., Ganesan, V., Mashayek, F., Pan, Y., Son, S., Cheng, M., Phakatkar, A. H., Sharifi-Asl, S., Rasul, M. G., Foroozan, T., Deivanayagam, R., Yurkiv, V., Wheatle, B. K., Mogurampelly, S., Cavallo, S., & Rojaee, R. (2020). “Highly-Cyclable Room-Temperature Black Phosphorene Polymer Electrolyte Composites for Li Metal Batteries”. Advanced Functional Materials, 1910749. doi:http://doi.org/10.1002/adfm.201910749
• Sharifi-Asl, S., Yurkiv, V., Gutierrez, A., Cheng, M., Balasubramanian, M., Mashayek, F., Croy, J., & Shahbazian-Yassar, R. (2020). Revealing Grain-Boundary-Induced Degradation Mechanisms in Li-Rich Cathode Materials. Nano Letters, 20(Issue 2). doi:10.1021/acs.nanolett.9b04620
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  Despite their high energy densities, Li- A nd Mn-rich, layered-layered, xLi2MnO3·(1-x)LiTMO2 (TM = Ni, Mn, Co) (LMR-NMC) cathodes require further development in order to overcome issues related to bulk and surface instabilities such as Mn dissolution, impedance rise, and voltage fade. One promising strategy to modify LMR-NMC properties has been the incorporation of spinel-type, local domains to create "layered-layered-spinel" cathodes. However, precise control of local structure and composition, as well as subsequent characterization of such materials, is challenging and elucidating structure-property relationships is not trivial. Therefore, detailed studies of atomic structures within these materials are still critical to their development. Herein, aberration corrected-scanning transmission electron microscopy (AC-STEM) is utilized to study atomic structures, prior to and subsequent to electrochemical cycling, of LMR-NMC materials having integrated spinel-type components. The results demonstrate that strained grain boundaries with various atomic configurations, including spinel-type structures, can exist. These high energy boundaries appear to induce cracking and promote dissolution of Mn by increasing the contact surface area to electrolyte as well as migration of Ni during cycling, thereby accelerating performance degradation. These results present insights into the important role that local structures can play in the macroscopic degradation of the cathode structures and reiterate the complexity of how synthesis and composition affect structure-electrochemical property relationships of advanced cathode designs.
• Yurkiv, V., Foroozan, T., Ramasubramanian, A., Ragone, M., Shahbazian-Yassar, R., & Mashayek, F. (2020). Understanding Zn Electrodeposits Morphology in Secondary Batteries Using Phase-Field Model. Journal of the Electrochemical Society, 167(6). doi:10.1149/1945-7111/ab7e91
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  Zinc (Zn) aqueous rechargeable batteries (ZBs) have shown a tremendous success in various applications due to their environmental friendliness, multi-electron capacity, high abundance, safety and low cost; however, analogous to their Li-ion battery counterparts, they suffer from the dendrite formation leading to decrease in capacity and eventual failure. Despite many studies reporting a good performance and partial dendrites suppression, there have been little theoretical systematic studies of Zn electrodeposits morphology analysis in ZBs. In the current work, we present the results from phase-field modeling (PFM) of Zn electrodeposition at different current densities. Different Zn morphologies, such as boulders, mossy and dendritic shape are modeled. The computational model predicts two-dimensional distribution of Zn electrodeposits, Zn2+ ions concentration, electrostatic potential, stress and equivalent plastic strain. It was found that the stress has a major influence on the electrodeposition, and vice versa the Zn electrodeposits growth is found to affect the stress distribution significantly. The plastic yielding occurs preferentially at the node of the boulders and through the filaments and mossy structures. The results also provide a basis for development and design of novel strategies against unwanted Zn dendrites formation.
• Mashayek, F., Shahbazian-Yassar, R., Khounsary, A., Najafi, A., Nie, A., Yurkiv, V., & Ramasubramanian, A. (2019). “A Numerical Study on Striped Lithiation of Tin Oxide Anodes”. International Journal of Solids and Structures, 159, 163-170. doi:https://doi.org/10.1016/j.ijsolstr.2018.09.027
• Mashayek, F., Shahbazian-Yassar, R., Ragone, M., Foroozan, T., Yurkiv, V., & Ramasubramanian, A. (2019). “Lithium Diffusion Mechanism through Solid-Electrolyte Interphase (SEI) in Rechargeable Lithium Batteries”
  . Journal of Physical Chemstry, 123(16), 10237-10245. doi:https://doi.org/10.1021/acs.jpcc.9b00436
• Shahbazian-Yassar, R., Lu, J., Amine, K., Mashayek, F., Friedrich, C. R., Long, F., Bi, X., Yurkiv, V., Cheng, M., Liu, C., Tan, G., Yuan, Y., & Yao, W. (2019). “Tuning Li₂O₂ Formation Routes by Facet-engineering of MnO2 Cathode Catalysts”. Journal of the American Chemical Society, 141(32), 12832-12838. doi:https://doi.org/10.1021/jacs.9b05992
• Shahbazian-Yassar, R., Mashayek, F., Rojaee, R., Sharifi-Asl, S., Yurkiv, V., & Foroozan, T. (2019). “Non-Dendritic Zn Electrodeposition Enabled by Zincophilic Graphene Substrates”. ACS Applied Materials & Interfaces, 11(47), 44077-44089. doi:https://doi.org/10.1021/acsami.9b13174
• Subramanian, A., Vasudevamurthy, G., Harris, C. T., Yoo, J., Maksud, M., Ramasubramanian, A., Shikder, M. R., Yurkiv, V., & Mashayek, F. (2019). “Plastic Recovery and Self-healing in Longitudinally Twinned SiGe Nanowires”. Nanoscale, 11(18). doi:https://doi.org/10.1039/C9NR02073J
• Unocic, R. R., Shahbazian-Yassar, R., Veith, G. M., Mashayek, F., Yurkiv, V., Shin, D., Sang, X., Baggetto, L., & Gutierrez-Kolar, J. S. (2019). “Interpreting Electrochemical and Chemical Sodiation Mechanisms and Kinetics in Tin Antimony Battery Anodes using in situ TEM and Computational Methods”. ACS Applied Engineering, 2(5), 3578-3586. doi:https://doi.org/10.1021/acsaem.9b00310
• Costa, R., Han, F., Szabo, P., Yurkiv, V., Semerad, R., Cheah, S., & Dessemond, L. (2018). Performances and Limitations of Metal Supported Cells with Strontium Titanate based Fuel Electrode. Fuel Cells, 18(3). doi:10.1002/fuce.201700117
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  In this contribution, we report investigation of metal supported cells with a La0.1Sr0.9TiO3–α (LST) based fuel electrode. The cells are prepared on a substrate made of a porous NiCrAl metal foam infiltrated with NiO and LST materials. The functional anode layer, consisting of LST mixed with a Gd0.1Ce0.9O2–α (GDC), is produced by screen printing. Nickel metal is infiltrated in the backbone to enhance electronic and catalytic properties. The electrolyte made of an 1 μm + 0.5µm thick Zr0.84Y0.16O2–α (YSZ) layer followed by a 2 μm thick GDC layer, is fabricated by wet ceramic processing and electron beam physical vapor deposition (EB-PVD), respectively. La0.6Sr0.4Co0.2Fe0.8O3–α (LSCF) is employed as a cathode material. All cells are electrochemically characterized. At 750 °C and at a cell voltage of 0.7 V, the typically achieved power density value is up to 0.40 W cm−2. With less than 2% variation for 50 cycles, the OCV showed an excellent stability as a function of redox cycles, demonstrating that an electrolyte as thin as 3 µm maintains its integrity, despite the harsh operating conditions. This highlights the potential of perovskite based fuel electrodes in metal supported cells, and paves the way to the next generation of cells' design.
• Foroozan, T., Soto, F. A., Yurkiv, V., Sharifi-Asl, S., Deivanayagam, R., Huang, Z., Rojaee, R., Mashayek, F., Balbuena, P. B., & Shahbazian-Yassar, R. (2018). Synergistic Effect of Graphene Oxide for Impeding the Dendritic Plating of Li. Advanced Functional Materials, 28(Issue 15). doi:10.1002/adfm.201705917
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  Dendritic growth of lithium (Li) has severely impeded the practical application of Li-metal batteries. Herein, a 3D conformal graphene oxide nanosheet (GOn) coating, confined into the woven structure of a glass fiber separator, is reported, which permits facile transport of Li-ions thought its structure, meanwhile regulating the Li deposition. Electrochemical measurements illustrate a remarkably enhanced cycle life and stability of the Li-metal anode, which is explained by various microscopy and modeling results. Utilizing scanning electron microscopy, focused ion beam, and optical imaging, the formation of an uniform Li film on the electrode surface in the case of GO-modified samples is revealed. Ab initio molecular dynamics (AIMD) simulations suggest that Li-ions initially get adsorbed to the lithiophilic GOn and then diffuse through defect sites. This delayed Li transfer eliminates the “tip effect” leading to a more homogeneous Li nucleation. Meanwhile, CC bonds rupture observed in the GO during AIMD simulations creates more pathways for faster Li-ions transport. In addition, phase-field modeling demonstrates that mechanically rigid GOn coating with proper defect size (smaller than 25 nm) can physically block the anisotropic growth of Li. This new understanding is a significant step toward the employment of 2D materials for regulating the Li deposition.
• Gondolini, A., Mercadelli, E., Constantin, G., Dessemond, L., Yurkiv, V., Costa, R., & Sanson, A. (2018). On the manufacturing of low temperature activated Sr0.9La0.1TiO3-δ-Ce1-xGdxO2-δ anodes for solid oxide fuel cell. Journal of the European Ceramic Society, 38(Issue 1). doi:10.1016/j.jeurceramsoc.2017.07.035
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  Lanthanum doped strontium titanate–gadolinium doped cerium oxide (LST-GDC) anodic layers are sintered in air and further reduced in-situ at low temperature (750 °C) avoiding usually performed pre-reduction treatment at high temperature. The influence of various milling techniques and of powders with different specific surface area, on the microstructures of screen-printed anodes, is investigated. The combination of milling and sonication processes is efficient in reducing aggregation of the anode powders. The anode performance is improved when a planetary milling step is involved in the preparation of the screen printing inks. The use of gadolinium doped cerium oxide with high specific surface area decreases the polarization resistance. The rate of hydrogen oxidation is also enhanced by increasing porosity.
• Ji, H., Trevino, J., Tu, R., Knapp, E., McQuade, J., Yurkiv, V., Mashayek, F., & Vuong, L. T. (2018). Long-Range Self-Assembly via the Mutual Lorentz Force of Plasmon Radiation. Nano Letters, 18(Issue 4). doi:10.1021/acs.nanolett.8b00269
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  Long-range interactions often proceed as a sequence of hopping through intermediate, statistically favored events. Here, we demonstrate predictable mechanical dynamics of particles that arise from the Lorentz force between plasmons. Even if the radiation is weak, the nonconservative Lorentz force produces stable locations perpendicular to the plasmon oscillation; over time, distinct patterns emerge. Experimentally, linearly polarized light illumination leads to the formation of 80 nm diameter Au nanoparticle chains, perpendicularly aligned, with lengths that are orders of magnitude greater than their plasmon near-field interaction. There is a critical intensity threshold and optimal concentration for observing self-assembly.
• Mashayek, F., Shahbazian-Yassar, R., Ramasubramanian, A., Foroozan, T., & Yurkiv, V. (2018). “The Influence of Stress Field on Li Electrodeposition in Li-metal Battery” . MRS Communications, 8, 1285-1291. doi:https://doi.org/10.1557/mrc.2018.146
• Mashayek, F., Yarin, A. L., & Yurkiv, V. (2018). “Modeling of Droplet Impact onto Polarized and Non-polarized Dielectric Surfaces”. Langmuir, 34(34), 10169-10180. doi:https://doi.org/10.1021/acs.langmuir.8b01443
• Yurkiv, V., Foroozan, T., Ramasubramanian, A., Shahbazian-Yassar, R., & Mashayek, F. (2018). Phase-field modeling of solid electrolyte interface (SEI) influence on Li dendritic behavior. Electrochimica Acta, 265. doi:10.1016/j.electacta.2018.01.212
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  This paper reports a phase-field modeling (PFM) study of lithium (Li) electrodeposition process in Li‒metal battery (LMB) to explain its physics and morphology. Three regimes are investigated: Li filaments evolution, Li bush-like structure evolution and the transition between Li filaments and bush-like morphologies. The model takes into consideration the effect of solid electrolyte interface (SEI) on Li electrodeposits evolution. Also, an important new element of the model is the capability to represent the directional diffusion of Li by implementing diffusion tensor of Li-ions in the electrolyte, thus, allowing to simulate Li filaments root growth. In addition, an elastic deformation energy of the Li solid phase is included in the free energy functional of the PFM, which allows for monitoring the stress field and its influence on Li filaments/bush-like structure evolution. In particular, a significant stress is observed at the root of the Li electrodeposits, which can support the development of the experimental strategies to suppress their formation by lowering the stress field. Thus, the present study, in addition to improving the fidelity of the PFM of Li electrodeposition, identifies critical regimes of Li filaments growth and splitting, allowing for a more profound understanding of their influence on battery performance.
• Ramasubramanian, A., Yurkiv, V., Najafi, A., Khounsary, A., Shahbazian–Yassar, R., & Mashayek, F. (2017). A comparative study on continuum-scale modeling of elasto-plastic deformation in rechargeable ion batteries. Journal of the Electrochemical Society, 164(Issue 13). doi:10.1149/2.1911713jes
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  Continuum-scale modeling techniques are frequently used to simulate the elasto–plastic deformation of rechargeable battery’s electrode materials during intercalation. The primary objective of this paper is to explore and compare the mathematical formulations, the ease of implementations and parametrization of two such techniques that are extensively used to represent the physics of ions intercalation in rechargeable battery electrodes. The first technique is a finite element coupled diffusion/structure mechanics (CDSM) model, and the second is a phase-field model (PFM). In the present work, the two models are compared quantitatively utilizing an example based upon lithiation of silicon. It is observed that the two models provide essentially similar results; however, their implementations and parameters clarification are significantly diverse. The detailed discussion in the paper identifies the merits and limitations of each model in the context of the assumptions in their theoretical formulations and their influence on the physics of diffusion/intercalation and deformation. Hence, the paper delivers new insights regarding the ranges of applicability and helps to understand similarities and differences between the two models.
• Riegraf, M., Yurkiv, V., Costa, R., Schiller, G., & Friedrich, K. A. (2017). Evaluation of the Effect of Sulfur on the Performance of Nickel/Gadolinium-Doped Ceria Based Solid Oxide Fuel Cell Anodes. ChemSusChem, 10(Issue 3). doi:10.1002/cssc.201601320
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  The focus of this study is the measurement and understanding of the sulfur poisoning phenomena of Ni/gadolinium-doped ceria (CGO) based solid oxide fuel cells (SOFC). Cells with Ni/CGO10 and NiCu5/CGO40 anodes were characterized by using impedance spectroscopy at different temperatures and H2/H2O fuel ratios. The short-term sulfur poisoning behavior was investigated systematically at temperatures of 800–950 °C, current densities of 0–0.75 A cm−2, and H2S concentrations of 1–20 ppm. A sulfur poisoning mitigation effect was observed at high current loads and temperatures. The poisoning behavior was reversible for short exposure times. It was observed that the sulfur-affected processes exhibited significantly different relaxation times that depend on the Gd content in the CGO phase. Moreover, it was demonstrated that the capacitance of Ni/CGO10 anodes is strongly dependent on the temperature and gas-phase composition, which reflects a changing Ce3+/Ce4+ratio.
• Sharifi-Asl, S., Soto, F. A., Nie, A., Yuan, Y., Asayesh-Ardakani, H., Foroozan, T., Yurkiv, V., Song, B., Mashayek, F., Klie, R. F., Amine, K., Lu, J., Balbuena, P. B., & Shahbazian-Yassar, R. (2017). Facet-Dependent Thermal Instability in LiCoO2. Nano Letters, 17(Issue 4). doi:10.1021/acs.nanolett.6b04502
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  Thermal runaways triggered by the oxygen release from oxide cathode materials pose a major safety concern for widespread application of lithium ion batteries. Utilizing in situ aberration-corrected scanning transmission electron microscopy (STEM) and electron energy loss spectroscopy (EELS) at high temperatures, we show that oxygen release from LixCoO2 cathode crystals is occurring at the surface of particles. We correlated this local oxygen evolution from the LixCoO2 structure with local phase transitions spanning from layered to spinel and then to rock salt structure upon exposure to elevated temperatures. Ab initio molecular dynamics simulations (AIMD) results show that oxygen release is highly dependent on LixCoO2 facet orientation. While the [001] facets are stable at 300 °C, oxygen release is observed from the [012] and [104] facets, where under-coordinated oxygen atoms from the delithiated structures can combine and eventually evolve as O2. The novel understanding that emerges from the present study provides in-depth insights into the thermal runaway mechanism of Li-ion batteries and can assist the design and fabrication of cathode crystals with the most thermally stable facets.
• Yurkiv, V., Gutiérrez-Kolar, J. S., Unocic, R. R., Ramsubramanian, A., Shahbazian-Yassar, R., & Mashayek, F. (2017). Competitive ion diffusion within grain boundary and grain interiors in polycrystalline electrodes with the inclusion of stress field. Journal of the Electrochemical Society, 164(Issue 12). doi:10.1149/2.0121713jes
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  Herein, we present a phase-field model (PFM) representing ions diffusion/intercalation into polycrystalline battery electrodes and its coupling to mechanics equations. Electrochemical free energy functions, considering ions diffusion within the grains and the grain boundary (GB), along with the elastic stress field associated with ions intercalation, are considered. The phase-field GB model is used to generate thin film grain structures and subsequently to study their evolution during the ions diffusion. The partial differential equations, representing ions concentration progress and the GB evolution, are solved computationally using the finite element method. In order to validate and to demonstrate capabilities of the model, we use examples of SnSb thin film sodiation. The results showed that the generated stress upon Na diffusion tends to slow down diffusion kinetics. In order to assess the effects of various model parameters on the sodium diffusion and the GB evolution, a sensitivity analysis was performed by calculating the sodiation rate. The present paper, in addition to the development of the coupled grain boundary to concentration field phase-field model, provides new insights concerning the influences of Na diffusion on the SnSb thin film performance.
• Yurkiv, V., Sharifi-Asl, S., Ramasubramanian, A., Shahbazian-Yassar, R., & Mashayek, F. (2017). Oxygen evolution and phase transformation in LCO cathode: A phase-field modeling study. Computational Materials Science, 140. doi:10.1016/j.commatsci.2017.09.007
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  Despite the tremendous success of Li-ion battery based upon liquid electrolytes and oxide positive electrodes, their widespread application is limited due to the safety concerns originated from the oxygen release. Consequently, the oxygen release causes phase transformation, which also leads to the mechanical failure of a battery. Thus, this paper presents a detailed multiphase-field model (PFM) to predict chemo-mechanical properties of oxide based battery electrodes. The PFM considers the chemical composition change, the associated phase transformation and the stress generation in the bulk as well as at the surface of the electrode. This model is applied to capture the development and evaluation of phase transformation mechanism, which occurs at elevated temperatures in the partially delithiated Li0.45CoO2 (LCO) material. Our results indicate that the major oxygen concentration change occurs in the narrow region between the phases, and the compressive stress is generated inside the bulk LCO, whereas tensile stress is observed within the LCO-gas phase interface. In addition, an important contribution of this work is the derivation of a new set of thermodynamic and kinetic data of the oxygen release. The modeling results allow for a direct comparison with the in-situ transmission electron microscopy (TEM) measurements reported by Sharifi-Asl et al. [Nano Letters, 17(4), 2165, 2017]. Thus, our findings provide new qualitative and quantitative understandings of the LCO phase transformations and the kinetics of oxygen release.
• Riegraf, M., Schiller, G., Costa, R., Friedrich, K. A., Latz, A., & Yurkiv, V. (2015). Elementary kinetic numerical simulation of Ni/YSZ SOFC anode performance considering sulfur poisoning. Journal of the Electrochemical Society, 162(Issue 1). doi:10.1149/2.0471501jes
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  An elementary kinetic model is developed and applied to explore the influence of sulfur poisoning on the behavior of solid oxide fuel cell (SOFC) anodes. A detailed multi-step reaction mechanism of sulfur formation and oxidation at Ni/YSZ anodes together with channel gas-flow, porous-media transport and elementary charge-transfer chemistry is established for SOFCs operating on H2/H2O mixtures with trace amounts of hydrogen sulfide (H2S). A thermodynamic and kinetic data set is compiled from various literature sources. The derived chemical model, validated against sulfur chemisorption isobars taken from literature, is used to analyze performance drops of SOFCs working under typical fuel cell operating conditions. Electrochemical results show that at relatively low H2S concentrations SOFC button-cell performance can be interpreted using chemical sulfur formation. However, when the concentration is sufficiently high, the inclusion of second stage degradation and triple-phase boundary reconstruction is necessary to describe the performance decrease. Additionally, it is shown that the sulfur surface coverage increases with increasing current density. In order to shed more light on advanced fundamental understanding of cell poisoning, sensitive analyses toward total anode resistance and sulfur coverage for different operating conditions were performed.
• Riegraf, M., Yurkiv, V., Schiller, G., Costa, R., Latz, A., & Friedricha, K. A. (2015). The influence of sulfur formation on performance and reforming chemistry of SOFC anodes operating on methane containing fuel. Journal of the Electrochemical Society, 162(Issue 12). doi:10.1149/2.0291512jes
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  This paper presents a detailed analysis of the influence of sulfur formation on performance and efficiency of Solid Oxide Fuel Cells (SOFC) operating on methane containing fuels. Our previously developed multi-step reaction mechanism of sulfur formation and oxidation is coupled with a complex heterogeneous mechanism of methane reforming, channel gas-flow, porous-media transport and elementary kinetic charge transfer and is used to describe sulfur-induced degradation and performance drops of Ni/YSZ anodes. Experimental literature data is used to validate the model and to interpret important aspects of cell performance degradation. Comparisons of the model predictions to the experiments illustrate that the developed model, without any modifications, reproduces the observed voltage decrease well and is able to capture the changes in fuel conversion and selectivity for different gas mixtures. It is shown that atomically adsorbed sulfur significantly influences heterogeneous reforming chemistry, causing substantial voltage degradation. At constant current densities, cell voltage decreases in a non-linear way with faster recovery than in H2/H2O mixtures.
• Yurkiv, V., Constantin, G., Hornes, A., Gondolini, A., Mercadelli, E., Sanson, A., Dessemond, L., & Costa, R. (2015). Towards understanding surface chemistry and electrochemistry of La0.1Sr0.9TiO3-α based solid oxide fuel cell anodes. Journal of Power Sources, 287(Issue). doi:10.1016/j.jpowsour.2015.04.039
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  In the present contribution, we combine modeling and experimental study of electrochemical hydrogen oxidation at an alternative perovskite based mixed-conducting SOFC anode. Composite electrodes were produced by conventional wet ceramic processing (screen printing - spraying) and sintering on YSZ electrolytes (La0.1Sr0.9TiO3-α-Ce1-xGdxO2-α|YSZ) with different compositions and microstructure, and were electrochemically characterized using symmetrical button-cells configuration. An elementary kinetic model was developed and applied to explore the performance of LST based SOFC anode. A detailed multi-step heterogeneous chemical and electrochemical reaction mechanism was established taking into account transport of ions in all ionic phases, and gas transport in channel and porous media. It was found that heterogeneous chemistry at LST surface has capacitive behavior that alters the impedance spectra. In addition, surface charge-transfer reaction, which describes partial oxygen ionization, caused impedance feature and is rate-limiting at high temperature. The gas transport in the supply chamber (gas conversion) is significant only at moderate temperatures.
• Yurkiv, V. (2014). Reformate-operated SOFC anode performance and degradation considering solid carbon formation: A modeling and simulation study. Electrochimica Acta, 143(Issue). doi:10.1016/j.electacta.2014.07.136
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  An elementary kinetic model is established to represent the coupled behavior of (electro)-chemistry, transport and degradation processes in the porous Ni/YSZ anode of solid oxide fuel cells (SOFC). This model is applied to support the development and evaluation of solid carbon formation mechanisms at Ni/YSZ anodes. The simulation of cells, operated on partially reformed hydrocarbons, show that performance and degradation are influenced significantly by the operation temperature and applied potential. Specifically at OCV and high temperature (>1000 K), a surface carbon layer is formed which covers Ni surface and Ni/YSZ/gas-phase three-phase boundary, blocking heterogeneous and charge-transfer reactions. However, at lower temperature (
• Yurkiv, V., Costa, R., Ilhan, Z., Ansar, A., & Bessler, W. G. (2014). Impedance of the surface double layer of LSCF/CGO composite cathodes: An elementary kinetic model. Journal of the Electrochemical Society, 161(Issue 4). doi:10.1149/2.070404jes
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  We present a combined modeling and experimental study of electrochemical oxygen reduction at mixed-conducting composite LSCF/CGO solid oxide fuel cell (SOFC) cathodes. The developed kinetic model incorporates elementary heterogeneous chemistry and electrochemical charge-transfer processes at two different electrochemical double layers, transport in the porous composite electrode (ionic and electronic conduction, multi-component porous diffusion and convection) as well as gas supply. A full set of thermodynamic and kinetic parameters is developed. Experimentally, La0.6Sr0.4Co0.8Fe0.2O3-δ/Ce0.9Gd0.1O2-α composite electrodes embedded into a symmetrical cell with CGO electrolyte were characterized via electrochemical impedance spectroscopy. The model shows good agreement with experimental impedance data over the complete range of investigated conditions (temperature range 775 K-1075 K, frequency range 10 mHz-100 kHz). This allows a mechanistic interpretation of the origin of the three observed impedance features: (i) low frequency: transport in the gas supply (gas conversion), (ii) intermediate frequency: charge transfer and surface double layer at the LSCF/air interface, (iii) high frequency: charge transfer and electrical double layer at the LSCF/CGO interface.
• Yurkiv, V., Gorski, A., Bessler, W. G., & Volpp, H. R. (2012). Density functional theory study of heterogeneous CO oxidation over an oxygen-enriched yttria-stabilized zirconia surface. Chemical Physics Letters, 543(Issue). doi:10.1016/j.cplett.2012.06.057
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  The reaction mechanism of heterogeneous CO oxidation on yttria-stabilized zirconia (YSZ), frequently used as electrolyte in solid oxide fuel cell (SOFC) composite anodes, was investigated employing density functional theory (DFT). The results demonstrate the possibility for an Eley-Rideal type CO oxidation reaction on the electrolyte surface without the need for a metallic catalyst if the vacant sites of YSZ are filled by externally supplied oxygen, either by dissociative adsorption of gaseous O 2 or via bulk oxygen atoms delivered by the SOFC cathode. Our results are consistent with the findings of recent experiments [J. Electrochem. Soc. 158 (2011) B5]. © 2012 Elsevier B.V. All rights reserved.
• Yurkiv, V., Utz, A., Weber, A., Ivers-Tiffée, E., Volpp, H. R., & Bessler, W. G. (2012). Elementary kinetic modeling and experimental validation of electrochemical CO oxidation on Ni/YSZ pattern anodes. Electrochimica Acta, 59(Issue). doi:10.1016/j.electacta.2011.11.020
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  Carbon monoxide (CO) is a major component in typical feed gases for solid oxide fuel cells (SOFC). This paper presents a combined modeling and experimental analysis of electrochemical CO oxidation on Ni/YSZ patterned model anodes. A computational model representing the coupled behavior of heterogeneous chemistry and electrochemistry in terms of elementary reactions is developed, which allows for a quantitative description of electrochemical impedance spectra and current-voltage behavior. Excellent agreement between model and experiment was achieved for the complete experimental data set, which covers a wide range of CO/CO 2/N 2 gas compositions (4.0 × 10 2 Pa ≤ pCO ≤ 5.1 × 10 4 Pa and 9.5 × 10 2 Pa ≤ pCO 2 ≤ 9.2 × 10 4 Pa) and operating temperatures (973 K ≤ T ≤ 1073 K). In the framework of the presented model a direct mechanistic interpretation of the experimentally observed electrochemical characteristics is obtained. © 2011 Elsevier Ltd. All Rights Reserved.
• Yurkiv, V., Starukhin, D., Volpp, H. R., & Bessler, W. G. (2011). Elementary reaction kinetics of the CO/CO2 /Ni/YSZ electrode. Journal of the Electrochemical Society, 158(Issue 1). doi:10.1149/1.3505296
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  Results of combined experimental and theoretical investigations of elementary chemical reaction processes of CO-C O2 gas mixtures at nickel/yttria-stabilized zirconia (Ni/YSZ) solid oxide fuel cell (SOFC) model anode systems are presented. Temperature-programmed desorption and reaction measurements were performed in order to determine adsorption/desorption kinetic data as well as thermodynamic parameters for the CO/C O2 /Ni and CO/C O2 /yttria-stabilized zirconia (YSZ) heterogeneous reaction systems. From these data, an elementary kinetic reaction mechanism of the electrochemical CO oxidation at Ni/YSZ anodes was developed. Numerical simulations were performed for three different spillover mechanisms. Steady-state polarization curves and electrochemical impedance spectra were calculated, allowing for a direct comparison with experiments performed by Lauvstad [J. Electrochem. Soc., 149, E506 (2002)]. Best agreement with the experimental data was obtained when assuming two consecutive charge-transfer steps from YSZ- O2- via YSZ- O- to Ni-O, the second step being accompanied by oxygen spillover over the three-phase boundary. © 2010 The Electrochemical Society.

Proceedings Publications

• Ji, H., Trevino, J., Tu, R., Knapp, E., Mashayek, F., Yurkiv, V., & Vuong, L. T. (2018). Long-range Laser-induced Self-assembly via Plasmon Radiative Interactions and the Lorentz Force. In 2018 Conference on Lasers and Electro-Optics, CLEO 2018, 2018.
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  We report on the light-induced formation of gold-nanoparticle chains as long as 200um, aligned perpendicular to the illuminating linear polarization. The long-range self-assembly is shown to arise from plasmon radiation and the Lorentz force.
• Riegraf, M., Zekri, A., Yurkiv, V., Costa, R., Schiller, G., & Friedrich, K. A. (2017). Assessment of sulfur poisoning of Ni/CGO-Based SOFC anodes. In Symposium on Solid-Gas Electrochemical Interfaces 2, SGEI 2017 - 231st ECS Meeting 2017, 77.
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  The presence of fuel impurities, such as hydrogen sulfide, siloxane and phosphine, in biogas, diesel and natural gas can cause Solid Oxide Fuel Cell (SOFC) degradation due to surface poisoning of Ni-containing anodes. In this regard, Ni/CGO anodes have shown higher sulftir tolerance than Ni/YSZ anodes and a comparable high performance. In order to allow for a more profound understanding of the processes underlying sulfur poisoning, this study presents an extensive experimental investigation of commercial Ni/CQO-based SOFC operating on H2/H2O fuel gases and reformate fuel mixtures with trace amounts of hydrogen sulfide (HiS). The short-term poisoning behavior of high-performance electrolyte-supported Ni/CGO 10-based cells was systematically investigated by means of transient voltage stability experiments and electrochemical impedance measurements for a wide range of operating conditions. The effects of temperature (800 -950 °C) and current density (OCV - 0.75 A cm"2) on the extent of sulfur poisoning (1-20 ppm H2S) was evaluated. The poisoning behavior was shown to be completely reversible for short exposure times in all cases. The chemical capacitance of Ni/CGOIO anodes was demonstrated to be strongly dependent upon temperature and gas phase composition reflecting a changing Ce3+/Ce4+ ratio in the CGO phase. Using a model reformate as fuel gas, it was shown that CO can still be electrochemically converted under sulfur exposure. Furthermore, long-term experiments of 1500 h were conducted at 900 °C and 0.5 Acm-2 with and without sulfur exposure and the degradation progress was monitored by impedance spectroscopy.
• Riegraf, M., Schiller, G., Costa, R., Friedrich, K., Latz, A., & Yurkiv, V. (2015). Lifetime and performance prediction of SOFC anodes operated with trace amounts of hydrogen sulfide. In 14th International Symposium on Solid Oxide Fuel Cells, SOFC 2015; held as part of the Electrochemical Society, ECS Conference on Electrochemical Energy Conversion and Storage, 68.
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  An elementary kinetic model is developed to predict the influence of sulfur on Ni/YSZ anodes of solid oxide fuel cells (SOFC) performance. A multi-step reaction mechanism describing the formation and oxidation of sulfur on the Ni surface is coupled with gas transport in the channel and porous phase, and charge-transfer processes. A thermodynamic and kinetic data set of sulfur formation and oxidation is derived based upon various literature sources including a coverage-dependent description of the enthalpy of surface-adsorbed sulfur. The validity of the model is demonstrated on two SOFC operation modes, namely H2/H2O/H2S and CH4/H2/H2O/H2S fuel mixtures, at different operating conditions using various electrochemical literature experiments. The first concern is the influence of adsorbed sulfur on chargetransfer processes and the second concern is the effect of adsorbed sulfur on complex methane reforming chemistry. The results reveal that sulfur surface coverage increases with current density demonstrating a low sulfur oxidation rate.
• Gorski, A., Yurkiv, V., Bessler, W. G., & Volpp, H. R. (2011). Combined theoretical and experimental studies of H 2and CO oxidation over YSZ surface. In 12th International Symposium on Solid Oxide Fuel Cells, SOFC-XII - 219th ECS Meeting, 35.
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  The mechanism of H 2 and CO adsorption and oxidation on yttria-stabilized zirconia, frequently used as electrolyte in solid oxide fuel cell composite anodes, was investigated employing temperature-programmed spectroscopy (TPS) and density functional theory (DFT). In agreement with theory, the experimental results show that interaction of gaseous H 2O with YSZ results in dissociative adsorption leading to strongly bound OH surface species. In the interaction of gaseous H 2 with an oxygen-enriched YSZ surface (YSZ+O), similar OH surface species are formed as reaction intermediates in the H 2 oxidation. In contrast, the interaction of CO with an oxygen-enriched YSZ leads to direct formation of gaseous CO 2 via an Eley-Rideal type reaction that was also confirmed by TPS measurements. ©The Electrochemical Society.
• Weber, A., Utz, A., Joos, J., Ivers-Tiffée, E., Störmer, H., Gerthsen, D., Yurkiv, V., Volpp, H. R., & Bessler, W. G. (2011). Electrooxidation of reformate gases at model anodes. In 12th International Symposium on Solid Oxide Fuel Cells, SOFC-XII - 219th ECS Meeting, 35.
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  This paper summarizes the experimental and modeling results concerning the electrooxidation of hydrogen and carbon monoxide, the main oxidizable compounds in reformates, at patterned nickel anodes on polycrystalline yttria stabilized zirconia electrolytes. The line specific resistance of the three phase boundary was evaluated within a wide range of gas compositions and temperature. The investigations showed that microstructural stability, impurities, accelerated degradation and reversible dynamic changes are key issues which have to be considered. Elementary kinetic models, parameterized with literature data, temperature-programmed desorption and reaction and quantum chemical calculation results were in excellent agreement with the experimental data. For the first time it could be shown that the line specific resistance values evaluated by means of patterned anodes are applicable in homogenized and space resolved models for cermet anodes. ©The Electrochemical Society.
• Yurkiv, V., Yurkiv, V., Utz, A., Utz, A., Weber, A., Weber, A., Ivers-Tiffée, E., Ivers-Tiffée, E., Volpp, H. R., Volpp, H. R., Bessler, W. G., & Bessler, W. G. (2011). Elementary kinetic numerical simulation of electrochemical CO oxidation on NI/YSZ pattern anodes. In 12th International Symposium on Solid Oxide Fuel Cells, SOFC-XII - 219th ECS Meeting, 35.
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  Results of a numerical simulation analysis of recent experimental data obtained in a comprehensive study of electrochemical CO oxidation on well-defined Ni/YSZ patterned model anodes [Utz et al. J. Power Sources, doi:10.1016/j.powsour.20.10.056 (2010)] are presented. A computational model representing the coupled behavior of heterogeneous chemistry and electrochemistry in terms of elementary reactions was developed, which allows for a quantitative description of the complete experimental data set, which covers a wide range of CO/CO 2 gas compositions (4.0·10 2 Pa ≤ pCO ≤ 5.1·10 4 Pa and 9.5·10 2 Pa ≤ pCO 2 ≤ 9.2·10 4 Pa) and operating temperatures (973 K ≤ T ≤ 1073 K). In the framework of the presented model a direct mechanistic interpretation of the experimentally observed electrochemical characteristics is obtained. ©The Electrochemical Society.

Presentations

• Yurkiv, V. R., Phakatkar, A., Shahbazian-Yassar, R., Ragone, M., & Mashayek, F. (2022, December).

  Combined machine learning and density functional theory approach to predict element distribution of high-entropy alloys in scanning transmission electron microscopy images

  . 2022 MRS Meeting. Boston: NSF.