Solid rubidium-conducting electrolytes in the Rb3–3xMxPO4 (M = Y, La, Nd) systems

Abstract

New solid electrolytes with a high rubidium-cation conductivity, which are based on Rb₃PO₄ with partial substitution of three-charged yttrium, lanthanum, and neodymium cations for Rb⁺ cations, are synthesized and studied. Introduction of M³⁺ cations leads to an abrupt increase in the conductivity of rubidium orthophosphate due to the formation of cationic vacancies and stabilization of high-temperature cubic β-modification of Rb₃PO₄. In all systems, the highest conductivity is observed in the single-phase region of β-phase existence: it is ~10^–1 S cm^–1 at 700°C and above 10^–2 S cm^–1 at 400°C. The factors, which have an effect on the transport properties of studied electrolytes, are considered.