New Complex Phosphate Cation-Conducting Materials in Ternary System Li3PO4-Na3PO4-InPO4

Abstract

Phase equilibrium in ternary system Li3PO4–Na3PO4–InPO4 and formation of heterovalent Zr‐substituted solid solutions (up to 15 mol%) for In3+ in Li3In2(PO4)3 and Na3In2(PO4)3 complex phosphates were studied by the cross‐section method at 950°C. Samples obtained were investigated by X‐ray powder diffraction and impedance spectroscopy. Ionic conductivity of Na3In2(PO4)3 and Li3In2(PO4)3 complex phosphates is about 10−2 S/cm at 300°C. Heterovalent substitution was performed according to the scheme: In3+=Zr4++v, where v is a vacancy in cationic sublattice. Zr‐substituted (15 mol%) Na3In2(PO4)3 and Li3In2(PO4)3 have ionic conductivity of about 10−1 S/cm at 300°C.