Effects of Cr2O3 doping on crystallization behavior and electrochemical properties of Li2O–Al2O3–TiO2–P2O5–SiO2 glass-ceramics

Abstract

Bulk glass-ceramic solid electrolytes of the Li2O–Al2O3–TiO2–P2O5–SiO2 system were prepared by melt-quenching and one-step heat treatment method in this work. The effects of the gradual substitution of Al3+ by Cr3+ and the elevation of the heat treatment temperature on the phase composition, microstructure, and ionic conductivity of the solid electrolytes were systematically investigated. The results show that the major crystalline phase is LiTi2(PO4)3, and the conductivity of the glass-ceramics initially enhances and then decreases as the Cr2O3 content increases from 0 mol% to 3 mol%. The highest conductivity is obtained when the Cr2O3 content is 2 mol%, measuring 4.45 × 10−4 S/cm at 25 °C. Additionally, the mechanism of the surface exfoliation of the glass-ceramics and the enhancement achieved by doping with Cr3+ are explained according to microstructure analysis. This work provides a simple method to enhance the electrical conductivity and physical properties of LATP glass-ceramic solid electrolytes, which is of great significance for the design of lithium-ion solid electrolytes.