Solvation sheath reorganization enables fast ion transfer kinetics in lithium-ion battery

Abstract The limitations of ion transport kinetics in conventional electrolytes, particularly under extreme operating conditions, arise from suboptimal solvation structures and inefficient charge carrier utilization. Here, we present strategic electrolyte design that reconfigures Li⁺ coordination geometry by modulating intermolecular interactions and solvent molecule volume, fundamentally overcoming these transport constraints. By incorporating an optimized moderator with a low dipole moment and small molecular size, extensive anion aggregation is effectively disrupted into compact ion conduction domains, simultaneously increasing the number of free charge carriers and enhancing ion mobility. Guided by this principle, the designed electrolyte with dichloromethane (85.11 Å, 2.36 Debye) exhibits rapid Li+ hopping between adjacent coordination sites (152.3 ps for acetonitrile and 115.7 ps for FSI-). This electrolyte enables stable cycling of 1.0 Ah 4.5 V graphite (3.13 mAh cm-2)||LiNi0.8Mn0.1Co0.1O2 (2.85 mAh cm-2) pouch cells, delivering 0.87 Ah at −40 °C, surpassing commercial carbonate-based electrolytes, which fail to retain reversible capacity at this temperature. This study establishes fundamental principles for fast ion-transport electrolytes, paving the way for next-generation Li-ion batteries under extreme scenarios.