High-temperature and composite proton-conducting electrolytes

Abstract

This paper presents a continuation of a review of research on proton-conducting solid electrolytes. We consider high-temperature proton-conducting materials based on mixed oxides of polyvalent elements whose structure contains a high concentration of oxygen vacancies. Their interaction with water vapor leads to the formation of two OH groups with a highly mobile proton. Conduction in such materials is not unipolar: proton conduction in them is usually accompanied by oxygen-ion conductivity and, often, by electron transport. The proton conductivity of acid salts can be raised using their composites with fine particles of polyvalent element oxides. Their large surface area and its high activity lead to an increase in defect density in the ionic salt near interfaces owing to sorption processes. A similar approach, involving the formation of hybrid systems through the incorporation of oxide nanoparticles, is used to increase the conductivity of ion exchange membranes, but the effect is achieved due to a transformation of the system of pores and channels.