Solvent-Assisted Hopping Mechanism Enables Ultrafast Charging of Lithium-Ion Batteries
Xiaoteng Huang, Ruhong Li, Chuangchao Sun, Haikuo Zhang, Shuo‐Qing Zhang, Ling Lv, Yiqiang Huang, Li‐Wu Fan, Lixin Chen, Malachi Noked, Xiulin Fan
Abstract
Fast charging is regarded as one of the most coveted technologies for commercial Li-ion batteries (LIBs), but the lack of suitable electrolytes with sufficient ionic conductivity and effective passivation properties hinders its development. Herein, we designed a mixed-solvent electrolyte (1 M LiPF6 in fluoroethylene carbonate/acetonitrile, FEC/AN, 7/3 by vol.) to overcome these two limitations by achieving an FEC-dominated solvation structure and an AN-rich environment. The specific AN-assisted Li+ hopping transport behavior shortens the Li+ diffusion time, doubling the ionic conductivity to 12 mS cm–1, thus endowing the graphite anode with >300 mAh g–1 at 20C and reversible (de)intercalation over a wide temperature range (from −20 to +60 °C). Furthermore, the designed electrolyte triples the capacity of the 1 Ah graphite||LiNi0.8Mn0.1Co0.1O2 (NMC811) pouch cells at 8C in comparison with the commercial electrolyte. The solvent-assisted hopping mechanism maximizes the fast-charging capability of the electrolytes, which motivates further research toward viable next-generation high-energy LIBs.