Constructing high performance dry-processing oxide composite electrolyte via interfacial interactions for durable solid-state lithium batteries

Composite solid electrolytes (CSEs) have considerable combination properties, which have been considered as the most promising choice for realizing advanced solid-state lithium batteries. Yet the ionic conductivity of CSEs fails to meet the practical requirements. Herein, we develop a dry-processing CSEs based on Li1.5Al0.5Ge1.5(PO4)3 (LAGP) and succinonitrile (SN) through polytetrafluoroethylene fibrillation. On the one hand, SN can enable fast ion transport in ceramic network and serve as high-speed conducive path. On the other hand, the strong affinities of LAGP towards SN and anions can significantly improve the conductive behavior and restrict side reactions at electrolyte/Li interface. Under such regulations, the composite electrolyte exhibits high ionic conductivity (0.64 mS cm−1 at 30 °C), high transference number (0.50), and high oxidation potential (>5.0V vs. Li+/Li). The assembled lithium metal batteries demonstrate excellent stability over 300 cycles at 1.0C. This work demonstrates the ion migration mechanism and the interactions at the heterogeneous interface for SN enhanced CSEs, contributing to the development of durable solid lithium metal batteries with extended lifespan. This contribution reports a composite electrolyte based on Li1.5Al0.5Ge1.5(PO4)3 (LAGP) and succinonitrile (SN) through polytetrafluoroethylene fibrillation. High ionic conductivity is achieved due to the interconnecting ceramic network and continuous SN phase. Besides, surface interaction between LAGP and SN/anions can modify the ion transport behavior. [Display omitted] •High performance oxide composite electrolyte is developed by polytetrafluoroethylene fibrillation.•Interactions between Li1.5Al0.5Ge1.5(PO4)3 (LAGP), succinonitrile and anions were revealed.•Reliable solid Li metal battery was realized by the obtained composite electrolyte.