Weakly Binding Molecules‐Based Fast Charging Li‐Ion Batteries

Abstract

AbstractFast charging of Li‐ion batteries (LIBs) beyond standard 0.3 C (charged in 3.3 h) are desperately pursued but hindered by sluggish desolvation kinetics of ethylene carbonate‐based traditional electrolyte, and Li‐plating and dendrites growth at graphite anode and fire hazard. Herein, a new class of weakly binding all linear molecules‐based nonflammable electrolyte (WNLE) is reported, comprising 1 m LiPF6 in ethyl methyl carbonate and 2,2,2‐trifluoroethyl acetate with additives for 10–20 times faster charging LIBs than traditional ones. The critical benefits of WNLE are 44% lower viscosity, 62% higher Li+ diffusion coefficient, 20% higher Li+ transference number, and 17% lower desolvation energy, which promotes diffusion kinetics and desolvation kinetics of Li+ in the vicinity of graphite anode enabling dendrites‐free LIB, along with nonflammability. Under 3 C (charged in 20 min), WNLE‐based industrial 800 mAh graphite//LiNi0.8Mn0.1Co0.1O2 (high active mass 13 mg cm−2) Li‐ion pouch battery achieves outstanding 700 cycles, delivering 82% capacity retention and high Coulombic efficiencies ≈100%. Robust solid electrolyte interphase layers formed at the anode and cathode mitigate interfacial failures, making fast charge to 7 C and longer cycle‐life. This new class of electrolyte formulation is a promising solution and a new opportunity to realize safe and long operation of fast‐charging LIBs for practical applications.