Potassium-conducting solid electrolytes in the K3 − 2x Cd x PO4 system

New potassium-conducting solid electrolytes of the K3 − 2x Cd x PO4 system are synthesized and studied. A wide range of solid solutions reaching x ≈ 0.35 with the structure of high-temperature modification of potassium orthophosphate forms in the system. An addition of cadmium ions leads to an abrupt increase in the K3PO4 conductivity due to the formation of potassium vacancies. The highest conductivity is approximately 10−2 S cm−1 at 300°C and above 10−1 S cm−1 at 700°C.