A Comprehensive Review of Liquid Electrolyte Engineering for High−Energy Lithium Metal Batteries

Lithium metal batteries (LMBs) represent the frontier of high−energy−density energy storage, promising gravimetric energy densities exceeding 400 Wh kg−1 and volumetric densities exceeding 1000 Wh L−1, substantially outperforming conventional lithium−ion batteries, which are constrained by the graphite anode. Despite growing interest in solid−state chemistries, liquid electrolytes remain central to near−term LMB development due to their superior ionic conductivity and compatibility with existing manufacturing infrastructure. However, practical commercialization requires solving several fundamental electrolyte design challenges, such as ensuring compatibility with both Li metal anodes and high−voltage Ni−rich cathodes, suppressing uncontrolled lithium deposition and dendrite formation, and maintaining compatibility with existing Li−ion manufacturing infrastructure. This review synthesizes advanced strategies in liquid electrolyte design that address these challenges, including solvent−family selection, fluorination and concentration engineering, and solvent−functionality engineering. Emphasis is placed on landmark studies demonstrating practical high−voltage, long−life−cycle LMB architectures with thin lithium anodes and lean electrolyte loadings, thereby establishing emerging benchmarks for commercial viability.