Mixed Ionic Electronic Conducting Quaternary Perovskites: Materials by Design for Solar Thermochemical Hyrdogen

Mixed Ionic Electronic Conducting Quaternary Perovskites: Materials by Design for Solar Thermochemical Hyrdogen Mixed Ionic Electronic Conducting Quaternary Perovskites: Materials by Design for Solar Thermochemical Hydrogen The current proposal aims to contribute to materials discovery for improved STCH materials, through fundamental quantum mechanics investigations into an exciting class of redox active, mixed ionic electronic conducting metal oxides, which can stably exist over a range of oxygen stoichiometries. By characterizing key thermodynamic properties and stability, we aim to offer strategies to boost solar to hydrogen thermal efficiency, as well as to provide experimentalists with crucial input to synthesize, validate, and perform further tests on promising candidates. Project Goal: The project goal is four-fold. 1. To adapt and apply computational materials design capability, developed in the Carter group, to calculate and validate chemical potentials for complex off-stoichiometric redox-active mixed ionic electronic conducting (MIEC) perovskite metal oxides with open metal d- and f-shells and with disorder: AyA'1-yBzB'1-zO3-x-d or (A,A')(B,B')O3-x-d. 2. To relate the calculated solid-state chemical potentials to materials thermodynamics, enthalpy and entropy of reduction and the equilibrium off-stoichiometry as a function of gas phase operating conditions. 3. To relate the thermodynamics to theoretical and expected performance, noting that performance is a function of operating variables (obtainable via an exergy analysis) and a key driver of cost. 4. To identify promising candidates that should perform better than the state-of-the-art (or at least best studied,) material ceria and meet the target efficiency (solar-to-hydrogen thermal efficiency (>30%) and the potential for meeting the ultimate production cost goal of < $2/kg H2.)