Fluorine-Containing Phase-Separated Polymer Electrolytes Enabling High-Energy Solid-State Lithium Metal Batteries

Abstract

Solid-state lithium (Li) metal batteries (LMBs) have been developed as a promising replacement for conventional Li-ion batteries due to their potential for higher energy. However, the current solid-state electrolytes used in LMBs have limitations regarding mechanical and electrochemical properties and interfacial stability. Here, a fluorine (F)-containing solid polymer electrolyte (SPE) having a bi-continuous structure of F-containing elastomers and plastic crystals is reported. The trifluoroethyl acrylate-based SPE (T-SPE) exhibits high ionic conductivity over 10−3Scm−1, superior mechanical elasticity, and robust LiF-rich interphases at both the Li metal anode and the LiNi0.83Mn0.06Co0.11O2 cathode. Full cells with thin T-SPEs and low negative/positive capacity ratios below 0.5 at the high-operating voltage of 4.5V demonstrate a high specific energy of 538Whkganode+cathode+electrolyte−1 and maintain 393Whkg−1 at a high specific power of 804W kganode+cathode+electrolyte−1. The F-containing phase-separated SPE system provides a powerful strategy for achieving high-energy and -power solid-state LMBs. © 2024 Wiley-VCH GmbH.