In Situ Construction of Fluorinated Graphene-Modified Gel Polymer Electrolyte for Lithium Metal Batteries

Abstract

Compared to traditional lithium metal batteries (LMBs) with liquid electrolytes, solid-state lithium metal batteries (SSLMBs) utilizing gel polymer electrolytes (GPEs) present improved energy density and enhanced safety stability, positioning them as promising candidates for the next generation of energy storage systems. This study focuses on the synthesis and modification of a fluorinated graphene-modified GPE (FG-GPE) through in-situ polymerization. The FG-GPE exhibits efficient channels for Li+ transport through Li+--O=C/O-C and Li+--NH interactions, resulting in a high ionic conductivity of 4.74 × 10-3 S cm-1 at 30 ℃. Furthermore, due to its excellent ability to form a stable cathode-electrolyte interface (CEI) enriched with LiF, the assembled NCM811|FG-GPE|Li batteries exhibit exceptional cycling stability. After undergoing 400 cycles at 3C, an impressive capacity retention rate of 80.0% is achieved, and even after experiencing 200 cycles at 5C, an equally remarkable capacity retention rate of 80.5% is maintained. This study aims to present a novel strategy for the development of GPEs in LMBs.

Keywords: In situ polymerization, fluorinated graphene, LiF-rich interphase, Li metal batteries