Sol–gel synthesis and electrical properties of sodium ion conducting solid electrolyte with Na5YSi4O12-type structure

Abstract Sodium ion conductor with the composition of Na4.0Y0.6P0.2Si2.8O9 was prepared using a sol-gel method (polymerized complex method). The homogeneous gel was prepared by dissolving citric acid and ethylene glycol in mixtures of water solutions of metal salts. Drying the gel provides the uniform precursor. The sintered pellet obtained from the precursor had a single crystalline phase of Na5YSi4O12-type structure and exhibited ionic conductivity of 3.7 × 10−2 S/cm at 300 °C.