Orientation-dependent electrochemical reduction and proton evolution in the oxygen-deficient perovskite SrFeO_2.5+y

Abstract Electrochemical reactions with insertions of ions in solids depend on crystallographic orientations. We investigated electrochemical responses (100), (110) and (111)-oriented oxygen-deficient perovskite SrFeO 2.5+ y epitaxial films electric-field-effect transistor structures the proton-conducting electrolyte Nafion as a gate insulator. found that only (100)-oriented exhibit changes associated gate-voltage-induced reductions. Furthermore, elastic recoil detection analysis shows electrochemically reduced (100) can accommodate protons, forming proton-containing oxide H 0.11 . Our results show oxygen vacancies form preferentially along {100} axes ion diffusion occurs dominantly directions