Improved Composite Solid Electrolyte through Ionic Liquid-Assisted Polymer Phase for Solid-State Lithium Ion Batteries

Abstract

Organic-inorganic solid-state composite electrolyte is of great promise to support the high-performance and safe energy storage applications. Herein we developed an ionic liquid-assisted PEO-LAGP-EMITFSI composite electrolyte (PLE) for advanced solid-state lithium ion batteries (LIBs). The EMITFSI ionic liquid was employed as the plasticizer to effectively lower the crystallinity of the composite and thus significantly enhance the ionic conductivity up to 8.85 × 10−4 S cm−1 at 60°C. Combined with its good electrochemical stability and decent ion transference selectiveness, the optimized PLE electrolyte contributed to an excellent battery performance in LiFePO4/PLE/Li configuration with high capacity retention of 114.7 mAh g−1 after 120 cycles and good rate capability of 112.2 mAh g−1 at 1C, indicating its great potential in developing high-performance solid-state LIBs.