Lamellar confined ionic liquid electrolytes with advanced performance for Li-ion batteries

Ionic liquids are promising to rival traditional organic solvent to develop safe electrolytes for Li-ion batteries. However, the ionic liquid-based electrolytes still suffered from issues of inferior performance and potential leakage. Here, non-ionic surfactant Brij58 was introduced into ionic liquid electrolytes (BMPTFSI/LiTFSI) consisting of 1-butyl-1-methylpyrrolidinium bistriflimide (BMPTFSI) and LiTFSI salt to construct solid-state lyotropic liquid crystals (LLCs). Self-assembly of Brij58 in ionic liquid electrolytes constructed lamellar nanostructures, which confined the ionic liquid electrolytes to form layered conducting channels. The nanoscale layered conducting channels in solid-state LLC electrolytes endowed liquid-like ion conductivity and significantly improved Li-ion transfer. Although the LLC electrolytes only consumed 50 wt % BMPTFSI/LiTFSI, the discharge capacities and rate performance of the Li-ion batteries based on LLC electrolytes was much improved comparing to that containing pristine BMPTFSI/LiTFSI. Also, the flame-retardant feature retained within the lamellar LLC electrolytes. The work paved new way for optimizing the conducting performance of IL electrolytes by constructing lamellar lyotropic LLC nanostructures. [Display omitted] •Solid-state lamellar electrolytes are developed as beyond IL electrolytes for LIBs.•LLC electrolytes are simply prepared by lamellar assembly of brij58 in IL solutions.•Lamellar regulation of ILs enable superior ion conductivity for efficient LIBs.•LLC electrolytes retain inherent stability of ILs for durable applications of LIBs.•The work demonstrates a new way for optimization of IL electrolytes for LIBs.