Advanced Electrolyte Materials Design for High-Energy Lithium Metal Batteries Beyond 500 Wh Kg^-1

The development of high-energy lithium metal batteries (LMBs) is crucial for advancing next-generation energy storage and electric vehicle technologies. However, the realization of energy densities beyond 500 Wh kg^-1 remains hindered by the intrinsic limitations of conventional electrolyte chemistry and unfavorable interfacial dynamics. These limitations induce Li dendrite formation, cathode structural degradation, continuous electrolyte decomposition, and progressive interphase deterioration, ultimately compromising the electrochemical reversibility, stability, and safety of LMBs. In this review, we summarize the fundamental challenges limiting LMBs and delineate the essential characteristics of ideal electrolyte chemistry and interfacial stability. Building upon these foundations, recent advances in diverse electrolyte systems are systematically discussed to elucidate how rational electrolyte design dictates solvation structures and interfacial dynamics, which in turn govern ion transport, interphase stability, and the overall electrochemical and practical performance of LMBs. Furthermore, this review highlights the integration of AI-driven electrolyte discovery, in situ characterization, and further summarizes recent progress in their practical validation in high-energy pouch cells and battery devices, thereby accelerating electrolyte design and deepening mechanistic understanding. Finally, electrolyte design principles and future perspectives are outlined to promote the development of practical, safe, and high-energy batteries.