Electrochemical stability of a NASICON solid electrolyte from the lithium aluminum germanium phosphate (LAGP) series

Li1.5Al0.5Ge1.5(PO4)3 glass-ceramics from NASICON series was synthesized using two different methods: single heat treatment and glass sintering with concurrent crystallization of a pressed pellet, which exhibit ionic conductivity of 4.15 × 10−4 S cm−1. The electrochemical stability window was investigated by cyclic voltammetry, utilizing a mixture of powder solid electrolyte, carbon, and binder as the working electrode, resulting in the Li/LAGP/LAGP+C/Au configuration. As a comparison, conventional set-up for cyclic voltammetry was also used, resulting in the Li/LAGP/Au setup. An electrochemical stability window around 3.5 V was found.