Recent advances in electrolyte engineering, electrode design, and separator optimization for lithium-ion batteries operating under extreme temperatures

Lithium-ion batteries (LIBs) are the predominant electrochemical energy storage technology, yet their reliable operation is confined to a narrow temperature window of approximately −20 to 60 °C, severely limiting deployment in extreme environments. In contrast to previous reviews that focus on a single thermal regime or an individual cell component, this review provides a comprehensive and unified analysis of the challenges and strategies associated with low temperature, high temperature, and wide temperature LIB operation. We first elucidate the fundamental degradation mechanisms at both thermal extremes, including sluggish ion transport, elevated desolvation energy barriers, lithium plating, cathode structural collapse, electrolyte decomposition, and interfacial instability. We then critically survey recent advances in liquid electrolyte engineering, encompassing solvent design, lithium salt selection, functional additives, solvation structure regulation, and high-concentration and localized high-concentration electrolyte architectures. Electrode material modification through surface coating, element doping, nanostructuring, and alternative active materials is also discussed, along with separator functionalization and thermal management strategies. Particular emphasis is placed on wide temperature electrolyte design, where weak solvation engineering, anion-enriched coordination structures, and multi-component synergistic formulations have progressively expanded the operational window from below −60 °C to above 120 °C. Finally, current limitations and future directions toward commercially viable all-climate LIBs are outlined.