Anion Coordination Strength: A Unified Descriptor for Low-Temperature Fast-Charging Performance of Lithium-Ion Batteries.

Low-temperature fast-charging performance of lithium-ion batteries is fundamentally limited by sluggish graphite lithiation kinetics and lithium plating, arising from an imbalance between Li+ supply and consumption at the graphite interface. Here, we treat bulk Li+ transport, interfacial desolvation, and solid electrolyte interphase (SEI) transport as sequential and coupled kinetic processes with a common molecular origin in the Li+ primary solvation sheath. Anion coordination strength is identified as a unified molecular descriptor linking solvation structure, transport kinetics, interfacial reactions, and SEI evolution. Accordingly, electrolyte strategies, including high-concentration systems, localized high-concentration electrolytes, composition tuning, and anion design, can be viewed as approaches to regulate coordination strength. This perspective provides a descriptor-guided strategy for rational electrolyte design toward safe and high-performance fast charging at low temperatures for graphite-anode lithium-ion batteries with suppressed lithium plating.