Organic Microemulsion Electrolytes for Advanced Metal Secondary Batteries

Current carbonate electrolytes encounter a bottleneck for high-performance lithium rechargeable batteries due to their potential safety issues, narrow operating temperature range, limited electrochemical windows, and chemical instability. Herein, advanced organic microemulsion electrolytes (OMEs) are developed by emulsifying the high-molar-ratio electrolytes to decrease the viscosity and molarity with nonpolar solvents and surfactants. The as-prepared nonflammable LiFSI-TMP/TFEP/PFPN OME shows intrinsic safety and high stability toward the graphite anode and LiCoO₂ cathode. The pouch cells with this OME demonstrate long-term cycling stability of 200 cycles, along with excellent low-temperature performance, and meanwhile pass the nail penetration safety test. Moreover, the concept of "OME" can be extended to prepare other electrolyte systems with compatible electrochemical properties for different battery systems at extreme conditions, which opens a new avenue in electrolyte development by extending the choice of solvents for broadening the application fields of advanced rechargeable batteries.