Electrolytes for low-temperature lithium metal batteries: An evolution-based framework for solvation, interfaces, and phase regulation

Lithium metal batteries (LMBs) have attracted extensive attention due to their ultrahigh energy density and strong potential for next-generation high-performance energy storage. However, under low-temperature conditions, electrolyte-related limitations emerge as critical bottlenecks that severely restrict the practical deployment of LMBs. These challenges primarily arise from suppressed ionic conductivity, increased Li⁺ desolvation energy barriers, sluggish interfacial reaction kinetics, and exacerbated lithium dendrite growth accompanied by elevated safety risks. Addressing these issues requires a comprehensive design framework that goes beyond isolated parameter optimization and instead captures the intrinsic evolution behavior of electrolyte systems under low-temperature conditions. In this review, we establish an evolution-oriented design framework based on the chain-like and hierarchical degradation mechanisms of low-temperature electrolytes. Guided by this perspective, we systematically summarize and analyze recent progress in electrolyte design strategies for low-temperature LMBs from multiple interconnected dimensions, including fluidity-oriented regulation, solvation-structure modulation, interfacial stability engineering, and phase-state reconstruction. The emerging roles of artificial intelligence and high-throughput simulations in accelerating electrolyte discovery and enabling data-driven optimization are also discussed. Finally, key scientific challenges and future research directions are outlined, highlighting the need for synergistic regulation across solvation, interfacial, and phase-state domains to realize safe, high-performance, and wide-temperature-operable LMBs.