Ultra-Thin, High-Performance Composite Solid Electrolytes for Lithium Metal Batteries: Progress and Prospects

Abstract

Significant progress has been made in recent years in the development of high-performance lithium batteries, which are critical to meeting the growing demands for next-generation energy storage systems, wide range of electronic devices and technological applications. Solid-state lithium metal batteries (SSLMBs) are considered as one of the most promising alternatives to state-of-the-art lithium-ion batteries (LIBs) due to their potential for higher energy density and the ability to address safety concerns associated with traditional LIBs that use flammable liquid electrolytes. Despite their promise, SSLMBs still face significant challenges that hinder their practical application, particularly in terms of Li⁺ conductivity, Li⁺ transference number, thickness, machinability, mechanochemical stability, and interfacial compatibility. This review comprehensively examined the specific properties of practical solid-state electrolytes (SSEs) based on current applications and summarized the opportunities and challenges in designing high-performance SSEs with high Li⁺ conductivity, high Li⁺ transference number, and ultra-thin structures (referred to as HCTSEs). Furthermore, the advantages and limitations of various design strategies were discussed and evaluated. The performance improvements of SSLMBs enabled by HCTSEs were summarized, and new perspectives on the design of HCTSEs were proposed to facilitate the large-scale application of SSLMBs in the future.