Silicon Substituted Lithium Stannum Phosphate Ceramic Electrolytes: Structural, Electrical and Electrochemical Properties

Abstract

Structural, electrical, and electrochemical properties of silicon (Si) substituted NASICON-structured lithium stannum phosphate, Li₁+_ySn₂P₃-ySi_yO₁₂ with 0 < y < 1 that was prepared by the low-temperature waterbased sol-gel method has been investigated. From the structural analysis, all samples in the system from y = 0.1 to 0.5 displayed R_3c rhombohedral symmetry. The electrical analysis showed that the total ionic conductivity, was increased with the increase of silicon content, y. A high ionic conductivity value of 6.05 × 10^-5 Scm^-1 exhibited at y = 0.5 with a temperature of 500 °C. Linear sweep voltammetry analysis of the highest conducting sample showed that the sample was electrochemically stable up to 5.1 V. Meanwhile, the ionic transference number value of the sample was 0.99, suggesting that the majority of mobile charge carriers were predominantly due to ions. Thus, from these results, it indicated that silicon substitution in LiSn₂P₃O₁₂ ceramic electrolytes is significantly enhanced the electrical and electrochemical properties.