A high ionic conductive PDOL/LAGP composite solid electrolyte film for Interfacial Stable solid-state lithium batteries

Abstract

High ionic conductivity for solid electrolyte and stable electrode/electrolyte interface have always been the main requirements for solid-state lithium batteries. Herein, a high ionic conductive composite solid electrolyte (CSE) film was prepared by combining 1.3-dioxolanes (DOL) capable of in-situ polymerization with high ionic conductive Li1.5Al0.5Ge1.5(PO4)3 (LAGP)ceramic fillers. The CSE film also shows high interface compatibility and stability with lithium metal. The optimized poly-DOL (PDOL)-30% LAGP CSE exhibits a desirable dense and uniform structure, which endows the CSE with a high ion conductivity of 4.63 × 10−4 S cm−1, a high ion migration number up to 0.73 and a wide electrochemical stability window of 5.1 V. The assembled high-voltage NCM622/PDOL-30%LAGP CSE/Li solid-state cell exhibits good rate and cycle performances with a capacity of 125 mAh/g at 2 C and a capacity retention of 76% at 0.5C after 400 cycles with an average Coulomb efficiency of 99.7%. The PDOL-30%LAGP CSE also possesses a high inhibition ability of lithium dendrites owing to the dense and uniform structure and the stable electrolyte/lithium electrode interface including Li–Ge, LiF and CF3 components. The Li/CSE/Li cell maintains a relatively stable voltage up to 650 h at a current density of 0.1 mA/cm2. This high ionic conductive composite solid electrolyte film shows a good application prospect in high-voltage solid-state lithium batteries.