Affiliation:
1. State Key Laboratory of Materials Processing and Die & Mould Technology School of Materials Science and Engineering Huazhong University of Science and Technology Wuhan Hubei 430074 P. R. China
2. State Key Laboratory of Advanced Electromagnetic Technology School of Electrical and Electronic Engineering Huazhong University of Science and Technology Wuhan Hubei 430074 P. R. China
3. GuSu Laboratory of Materials Suzhou Jiangsu 215123 P. R. China
Abstract
AbstractLithium‐ion batteries (LIBs) suffer from energy loss and safety hazards under high‐rate conditions, because of the sluggish electrochemical kinetics and unstable interfacial passivation. Herein, a PC‐based electrolyte using weakly solvated solvent ethyl trifluoroacetate is developed to improve interfacial kinetics and stability in LIBs. A microsolvating competition is revealed in the bulk electrolyte, forming a loose Li+ coordination configuration with benign Li+ affinity and high ionic conductivity. Furthermore, an inorganic‐rich interphase is constructed on a graphite anode, affording smooth Li+ desolvation and reliable passivation. Consequently, the NCM622/graphite cell in PC‐based electrolyte shows improved cycling stability (82.2% after 200 cycles) and rate capability (83% at 4C compared to 0.1C) at a high‐voltage of 4.5 V, much better than those of EC‐based electrolyte (76.2% after 200 cycles and 74% at 4C). Additionally, the PC‐based electrolyte affords reversible operation at –40 °C while the EC‐based electrolyte fails at –40 °C. This work highlights the potential of solvation structure engineering for low‐energy‐barrier electrolyte.
Funder
National Basic Research Program of China