@article {1140, title = {Formation of 6H-Ba3Ce0.75Mn2.25O9 During Thermochemical Reduction of 12R-Ba4CeMn3O12: Identification of a Polytype in the Ba(Ce,Mn)O3 Family}, journal = {Inorganic Chemistry}, volume = {61}, year = {2022}, month = {4}, keywords = {analytical chemistry, inorganic, layered perovskite, organic, oxide, physical, polytype, STCH, thermochemistry}, doi = {10.1021/acs.inorgchem.2c00282}, author = {Strange, Nicholas A. and Park, James Eujin and Goyal, Anuj and Bell, Robert T. and Trindell, Jamie A. and Sugar, Joshua D. and Stone, Kevin H. and Coker, Eric N. and Lany, Stephan and Shulda, Sarah and Ginley, David S.} } @article {1143, title = {Mechanistic understanding of pH effects on the oxygen evolution reaction}, journal = {Electrochimica Acta}, volume = {405}, year = {2022}, pages = {139810}, abstract = {The oxygen-evolution reaction (OER) is pivotal in many energy-conversion technologies as it is an important counter reaction to others that convert stable chemicals to higher-value products using electrochemistry. The local microenvironment and pH for the anode OER can vary from acidic to neutral to alkaline depending on the system being explored, making definitive mechanistic insights difficult. In this paper, we couple experiments, first-principles calculations based on density functional theory, microkinetics, and transport modeling to explore the entire pH range of the OER. At low current densities, neutral pH values unexpectedly perform better than the acidic and alkaline conditions, and this trend is reversed at higher current densities (> 20~mA cm-2). Using multiscale modeling, this switch is rationalized by a change from a dual-reaction mechanism to a single rate-determining step. The model also shows how the alkaline reaction rates dominate in the middle to high pH range. Furthermore, we explore that the local pH for near-neutral conditions is much different (e.g., 2.4 at the reaction surface vs. 9 in the bulk) than the pH extremes, demonstrating the criticality that transport phenomena plays in kinetic activity.}, keywords = {Electrochemistry, Microkinetics, Oxygen evolution reaction}, issn = {0013-4686}, doi = {https://doi.org/10.1016/j.electacta.2021.139810}, url = {https://www.sciencedirect.com/science/article/pii/S0013468621020934}, author = {Julie C. Fornaciari and Lien-Chun Weng and Shaun M. Alia and Cheng Zhan and Tuan Anh Pham and Alexis T. Bell and Tadashi Ogitsu and Nemanja Danilovic and Adam Z. Weber} } @article {1146, title = {Predicting Oxygen Off-Stoichiometry and Hydrogen Incorporation in Complex Perovskite Oxides}, journal = {Chemistry of Materials}, volume = {34}, year = {2022}, pages = {510-518}, keywords = {charge transfer resistance, Hydrogen Incorporation, Oxygen evolution reaction, Perovskite, Perovskite Oxides, Stoichiometry}, doi = {10.1021/acs.chemmater.0c04765}, url = {https://doi.org/10.1021/acs.chemmater.0c04765}, author = {Millican, Samantha L. and Deml, Ann M. and Papac, Meagan and Zakutayev, Andriy and O{\textquoteright}Hayre, Ryan and Holder, Aaron M. and Musgrave, Charles B. and Stevanovi{\'c}, Vladan} } @article {1152, title = {A mini-review on proton conduction of BaZrO 3 -based perovskite electrolytes}, journal = {Journal of Physics: Energy}, volume = {3}, year = {2021}, month = {07}, pages = {032019}, keywords = {ceramics, dopant, electrolyte, electrolytic cell, energy conversion, fuel cell, hydration, interaction, mobility, oxide, proton, proton conduction}, doi = {10.1088/2515-7655/ac12ab}, author = {Vera, Clarita and Ding, Hanping and Peterson, David and Gibbons, William and Zhou, Meng and Ding, Dong} } @article {1160, title = {Modeling Electrokinetics of Oxygen Electrodes in Solid Oxide Electrolyzer Cells}, journal = {Journal of The Electrochemical Society}, volume = {168}, year = {2021}, month = {11/2021}, pages = {114510}, abstract = {A microscale model is presented in this study to simulate electrode kinetics of the oxygen electrode in a solid oxide electrolyzer cell (SOEC). Two mixed ionic/electronic conducting structures are examined for the oxygen producing electrode in this work: single layer porous lanthanum strontium cobalt ferrite (LSCF), and bilayer LSCF/SCT (strontium cobalt tantalum oxide) structures. A yttrium-stabilized zirconia (YSZ) electrolyte separates the hydrogen and oxygen electrodes, as well as a gadolinium doped-ceria (GDC) buffer layer on the oxygen electrode side. Electrochemical reactions occurring at the two-phase boundaries (2PBs) and three-phase boundaries (3PBs) of single-layer LSCF and bilayer LSCF/SCT oxygen electrodes are modeled under various SOEC voltages with lattice oxygen stoichiometry as the key output. The results reveal that there exists a competition in electrode kinetics between 2PBs and 3PBs, but 3PBs are the primary reactive sites for single-layer LSCF oxygen electrode under high voltages. These locations experience the greatest oxygen stoichiometry variations and are therefore the most likely locations for dimensional changes. By applying an active SCT layer over LSCF, the 2PBs become activated to compete with the 3PBs, thus alleviating oxygen stoichiometry variations and reducing the likelihood of dimensional change. This strategy could reduce lattice structural expansion, proving to be valuable for electrode-electrolyte delamination prevention and will be the focus of future work.}, keywords = {Barium zirconate, Defect transport, electrode-electrolyte delamination prevention, Faradaic efficiency, lattice oxygen stoichiometry, microscale model, o-SOEC, oxygen electrode, solid oxide electrolyzer cell}, doi = {10.1149/1945-7111/ac35fc}, url = {https://doi.org/10.1149/1945-7111/ac35fc}, author = {Korey Cook and Jacob Wrubel and Zhiwen Ma and Kevin Huang and Xinfang Jin} } @article {1161, title = {Multiple Reaction Pathways for the Oxygen Evolution Reaction May Contribute to IrO2 (110){\textquoteright}s High Activity}, journal = {Journal of The Electrochemical Society}, volume = {168}, year = {2021}, month = {02/2021}, pages = {024506}, abstract = {Density functional theory calculations in conjunction with statistical mechanical arguments are performed on the rutile IrO2 (110) facet in order to characterize multiple reaction pathways on the surface at the highest active limit (the stoichiometric surface with all metal sites available) and at the lowest active limit (the oxygen-terminated surface). Alternative pathways to the oxygen evolution reaction (OER) are found, with multiple pathways determined at each step of the four proton-coupled electron transfer reaction. Of particular interest is the detailed characterization of a co-adsorption pathway utilizing neighboring, adsorbed O, OH species in order to evolve oxygen; activation energies of this pathway are <0.5 eV and therefore easily surmountable at the high operating potentials of OER. We also determined that surface Ir atoms can potentially participate in deprotonating an OOH* intermediate; the activation energy to this is 0.67 eV on the oxygen-terminated surface. These theoretical findings explain in part the high activity present in iridium oxide catalysts and also provide insight into the mechanistic pathways available on metal oxide catalysts, which may require the concerted interaction of nearest neighbor co-adsorbates to produce chemicals of interest.}, keywords = {DFT modeling, Iridium oxide, Oxygen evolution}, doi = {10.1149/1945-7111/abdeea}, url = {https://doi.org/10.1149/1945-7111/abdeea}, author = {Mai-Anh Ha and Ross E. Larsen} } @article {1120, title = {Outstanding Properties and Performance of CaTi0.5Mn0.5O3{\textendash}δ for Solar-Driven Thermochemical Hydrogen Production}, journal = {Matter}, volume = {4}, year = {2021}, pages = {688-708}, keywords = {inorganic perovskite, oxygen non-stoichiometry, phase transition, solar fuel, thermo-kinetic limit, thermochemical hydrogen production, thermodynamic properties}, doi = {https://doi.org/10.1016/j.matt.2020.11.016}, author = {X. Qian and J. He and E. Mastronardo and B. Baldassarri and W. Yuan and C. Wolverton and S. M. Haile} } @article {1166, title = {The oxygen partial pressure in solid oxide electrolysis cells with multilayer electrolytes}, journal = {Acta Materialia}, volume = {213}, year = {2021}, pages = {116928}, abstract = {A number of degradation mechanisms have been observed during the long-term operation of solid oxide electrolysis cells (SOEC). Using an electrolyte charge carrier transport model and a diffuse interface treatment for a multilayer electrolytes, we quantify the oxygen potentials across the electrolyte and thereby provide insights into these degradation mechanisms. Our model describes the transport of charge carriers in the electrolyte when the oxygen partial pressure is extremely low by accounting for the spatial variation of the concentration of oxygen vacancies in the electrolyte which is closely related to the degradation of the SOEC near the interface of hydrogen electrode and electrolyte. Moreover, we identify four quantities that characterize the distribution of oxygen partial pressure in the electrolyte, which are directly related to the degradation mechanisms in the electrolyte as well, and give analytical estimates for them. These analytical expressions provide guidance on the parameters that need to be controlled to suppress the degradation observed in the electrolyte.}, keywords = {Diffuse interface model, Multilayer electrolyte, Oxygen partial pressure, solid oxide electrolysis cell}, issn = {1359-6454}, doi = {https://doi.org/10.1016/j.actamat.2021.116928}, url = {https://www.sciencedirect.com/science/article/pii/S1359645421003086}, author = {Qian Zhang and Qin-Yuan Liu and Beom-Kyeong Park and Scott Barnett and Peter Voorhees} } @article {1164, title = {Regulation of Cathode Mass and Charge Transfer by Structural 3D Engineering for Protonic Ceramic Fuel Cell at 400 {\textdegree}C (Adv. Funct. Mater. 33/2021)}, journal = {Advanced Functional Materials}, volume = {31}, year = {2021}, pages = {2170244}, abstract = {3D Engineering In article number 2102907, Wei Wu, Meng Zhou, Dong Ding, and co-workers develop a 3D engineered cathode to enhance oxygen reduction reaction kinetics on a proton-conducting fuel cell at <600 {\textdegree}C. The results demonstrate remarkable cell performance at 400{\textendash}600 {\textdegree}C by effectively regulating the mass and charge transfer through the electrode and across the interface of electrolyte and electrode.}, keywords = {3D engineering, charge transfer, mass transfer, oxygen reduction reaction, p-SOEC, protonic ceramic fuel cells}, doi = {https://doi.org/10.1002/adfm.202170244}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/adfm.202170244}, author = {Bian, Wenjuan and Wu, Wei and Gao, Yipeng and Gomez, Joshua Y. and Ding, Hanping and Tang, Wei and Zhou, Meng and Ding, Dong} } @article {1177, title = {Thin film growth effects on electrical conductivity in entropy stabilized oxides}, journal = {Journal of the European Ceramic Society}, volume = {41}, year = {2021}, pages = {2617-2624}, abstract = {Entropy stabilization has garnered significant attention as a new approach to designing novel materials. Much of the work in this area has focused on bulk ceramic processing, leaving entropy-stabilized thin films relatively under-explored. Following an extensive multi-variable investigation of polycrystalline (Mg0.2Co0.2Ni0.2Cu0.2Zn0.2)O thin films deposited via pulsed laser deposition (PLD), it is shown here that substrate temperature and deposition pressure have strong and repeatable effects on film texture and lattice parameter. Further analysis shows that films deposited at lower temperatures and under lower oxygen chamber pressure are \~{}40{\texttimes} less electrically resistive than otherwise identical films grown at higher temperature and pressure. Annealing these films in an oxygen-rich environment increases their electrical resistivity to match that of the films grown at higher temperatures and pressures. Because of this, the electric conductivity is hypothesized to be the result of polaron hopping mediated by transition metal valence changes which compensate for oxygen off-stoichiometry.}, keywords = {electrical conductivity, Entropy, oxide, Phase, Polycrystalline oxide thin films, Pulsed laser deposition, STCH, Thin film}, issn = {0955-2219}, doi = {https://doi.org/10.1016/j.jeurceramsoc.2020.12.021}, url = {https://www.sciencedirect.com/science/article/pii/S0955221920309900}, author = {V. Jacobson and D. Diercks and B. To and A. Zakutayev and G. Brennecka} } @article {1170, title = {Emergent Degradation Phenomena Demonstrated on Resilient, Flexible, and Scalable Integrated Photoelectrochemical Cells}, journal = {Advanced Energy Materials}, volume = {10}, year = {2020}, pages = {2002706}, abstract = {Abstract Photoelectrochemical (PEC) water splitting provides a pathway to generate sustainable clean fuels using the two most abundant resources on Earth: sunlight and water. Currently, most of the successful models of PEC cells are still fabricated on small scales near 1 cm2, which largely limits the mass deployment of solar-fuel production. Here, the scale-up to 8 cm2 of an integrated PEC (IPEC) device is demonstrated and its performance compared to a 1 cm2 IPEC cell, using state-of-the-art iridium and platinum catalysts with III{\textendash}V photoabsorbers. The initial photocurrents at 1 sun are 8 and 7 mA cm-2 with degradation rates of 0.60 and 0.47 mA cm-2 day-1, during unbiased operation for the 1 and 8 cm2 devices, respectively. Evaluating under outdoor and indoor conditions at two U.S. National Laboratories reveals similar results, evidencing the reproducibility of this design{\textquoteright}s performance. Furthermore, the emerging degradation mechanisms during scale-up are investigated and the knowledge gained from this work will provide feedback to the broader community, since PEC device durability is a limiting factor in its potential future deployment.}, keywords = {durability, on-sun testing, PEC cell scale-up, reproducibility, water splitting}, doi = {https://doi.org/10.1002/aenm.202002706}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/aenm.202002706}, author = {Kistler, Tobias A. and Zeng, Guosong and Young, James L. and Weng, Lien-Chun and Aldridge, Chase and Wyatt, Keenan and Steiner, Myles A. and Solorzano Jr., Oscar and Houle, Frances A. and Toma, Francesca M. and Weber, Adam Z. and Deutsch, Todd G. and Danilovic, Nemanja} } @article {1129, title = {A First-Principles-Based Sub-Lattice Formalism for Predicting Off-Stoichiometry in Materials for Solar Thermochemical Applications: The Example of Ceria}, journal = {Advanced Theory and Simulations}, volume = {3}, year = {2020}, keywords = {off-stoichiometric materials, sub-lattice models, thermodynamic modeling}, doi = {https://doi.org/10.1002/adts.202000112}, author = {G. Sai Gautam and E. B. Stechel and E. A. Carter} } @article {1185, title = {Ferritic stainless steel interconnects for protonic ceramic electrochemical cell stacks: Oxidation behavior and protective coatings}, journal = {International Journal of Hydrogen Energy}, volume = {44}, year = {2019}, pages = {25297-25309}, abstract = {Protonic ceramic fuel or electrolysis cells (PCFC/PCEC) have shown promising performance at intermediate temperatures. However, these technologies have not yet been demonstrated in a stack, hence the oxidation behavior of the metallic interconnect under relevant operating environments is unknown. In this work, ferritic stainless steels 430 SS, 441 SS, and Crofer 22 APU were investigated for their use as interconnect materials in the PCFC/PCEC stack. The bare metal sheets were exposed to a humidified air environment in the temperature range from 450~{\textdegree}C to 650~{\textdegree}C, to simulate their application in a PCFC cathode or PCEC anode. Breakaway oxidation with rapid weight gain and Fe outward diffusion/oxidation was observed on all the selected stainless steel materials. A protective coating is deemed necessary to prevent the metallic interconnect from oxidizing. To mitigate the observed breakaway oxidation, state-of-the-art protective coatings, Y2O3, Ce0.02Mn1.49Co1.49O4, CuMn1.8O4 and Ce/Co, were applied to the stainless steel sheets and their oxidation resistance was investigated. Dual atmosphere testing further validated the effectiveness of the protective coatings in realistic PCFC/PCEC environments, with a hydrogen gradient across the interconnect. Several combinations of metal and coating material were found to be viable for use as the interconnect for PCFC/PCEC stacks.}, keywords = {Dual atmosphere, Interconnect oxidation, Oxidation, Protective coatings, Protonic ceramic electrolysis cell, Protonic ceramic fuel cell}, issn = {0360-3199}, doi = {https://doi.org/10.1016/j.ijhydene.2019.08.041}, url = {https://www.sciencedirect.com/science/article/pii/S0360319919329581}, author = {Ruofan Wang and Zhihao Sun and Jung-Pyung Choi and Soumendra N. Basu and Jeffry W. Stevenson and Michael C. Tucker} }