An In Situ Polymeric Electrolyte with Low Interfacial Resistance on Electrodes for Lithium-Ion Batteries

Due to their high energy density and safety, polymer electrolytes are considered a promising alternative to the commercial liquid electrolytes used in lithium-ion batteries (LIBs). However, in practical application, polymer electrolytes are limited by the high interface resistance between electrodes and electrolyte, leading to low ionic conductivity at room temperature (RT). In the present work, an in situ cationic ring-opening technique is introduced using LiFSI as an initiator to address the issue of interfacial contact between electrolyte and electrodes in LIBs. Herein, a series of in situ poly(siloxane-epoxy)-based polymer electrolytes (PSEPEs) are synthesized, which present good thermal stability (158 degrees C), low glass transition temperature (T-g) (-42 degrees C), high ionic conductivity of 1.16 x 10(-4) S cm(-1), and good t(Li)(+) of 0.61 at RT. The PSEPEs also show a wide electrochemical window (>4.7 V vs Li/Li+), and excellent compatibility with the lithium anode with an assembled LiFePO4/ PSEPEs /Li cell. This work contributes to developing a new polymer electrolyte fabricated by in situ cationic polymerization, and its effects on the reduction of the interfacial resistance of electrodes-electrolyte.