b'A fundamental investigationNewly developed computational framework decouples various of the current leakagefundamental chemical and physical processes occurring in harsh mechanism and relevantenvironmental conditions relevant to emerging energy applications.harsh environmentalT he proton-conducting solid oxide electrolysis cell produces hydrogen and oxygen simultaneously via the water splitting reaction at intermediate chemistries in solidtemperatures (400600C), which is near the temperatures of nuclear power plants. Although proton-conducting solid oxide electrolysis cell technology oxide materials shows great promise, commercialization suffers from various scientific limitations, including unresolved fundamental solid oxide material chemistries that limit the design and development of solid oxide electrolyte materials and relevant harsh environmental processes and eventually compromise the technical feasibility of such technology when compared with the conventional oxide-ion conducting solid oxide electrolysis cells. Our project aimed to add to the existing fundamental knowledge PROJECT NUMBER:of solid oxide electrolysis cell electrolyte material chemistries at intermediate 21A1050-131FP temperatures and set the stage to simulate complex zero voltage (electrons absent) and non-zero voltage effects (electrons present) in solid oxide electrolysis cells. TOTAL APPROVED AMOUNT:We developed a computational framework that captures the quantum mechanical $899,000 over 3 years behavior of solid oxide electrolysis cell electrolyte material very well. This unique PRINCIPAL INVESTIGATOR:computational framework enabled us to study both electron and oxygen vacancy Gorakh Pawar migration pathways in complex multi-metal oxides at length and time scales that can relate to experiments.CO-INVESTIGATORS:Hanping Ding, INL Oxygen vacancies could play a pivotal role in surface chemistries, electron Meng Li, INL conductivity, and solid oxide electrolysis cell Faradaic efficiency. Therefore, we studied oxygen vacancy migration and evolution aspects because novel material COLLABORATOR: design and optimization strategies can be used to enhance the electrocatalytic Pennsylvania State Universityactivity of solid oxide electrolytes and make hydrogen production more efficient. Consequently, we used the computational framework to investigate oxygen vacancy evolution as a function of oxygen vacancy abundance and operational temperature. We also explored localization and migration of explicitly modeled electrons as a function of oxygen vacancy concentration and doping of yttrium with zirconium in a representative barium zirconate doped with 20 mol% of yttrium (BZY20) solid oxide material. We discovered that oxygen vacancies are essential for electron migration in BZY20. Further, oxygen vacancies incline to settle between yttrium and zirconium atoms. Also, oxygen vacancies migrate toward the surface during their dynamic evolution and increase the surface oxygen vacancy concentration by 10% in the present work. Also, yttrium has a significant impact on electron migration because yttrium restricts the electron mobility in BZY20 and functions as an electron trapping site. In contrast, zirconium accelerates the electron mobility and migration in BZY20. Overall, such insights could allow an advancement of theoretical calculations to understand the electron conductivity as a function of various doping and its effects on the electrochemical performance of solid oxide electrolysis cells.82'