Simultaneously Catalyze 1,3-Dioxolane Polymerization and Construct a Hybrid Protection Layer on Lithium Anode by InF3 Catalyst

The emerging approach of in-situ polymerization of solid polymer electrolytes based on 1,3-dioxolane (DOL) possesses the advantage of low interfacial impedance and relatively high Coulombic efficiency. However, the DOL monomer conversion (C%) under Lewis acid catalysts needs to be further improved, besides their alloying ability with lithium metal to generate protective interfacial layer has been ignored. Here, the above two aims are simultaneously achieved by Indium Trifluoride (InF3) catalyst. It is demonstrated that the highest C% is up to 94% with 15 mg of InF3 in the 1 mL electrolyte (1 M LiTFSI/DOL). The optimized ionic conductivity and lithium-ion transfer number are 8.9 x 10(-5) S/cm (30 degrees C) and 0.42, respectively. The stable interface between poly-DOL and lithium metal anode could be proved by the stable over-potential (156mv, 900 h) at current density of 2.0 mA cm(-2). X-ray diffraction results confirm the presence of In and In-Li alloy peaks. After 300 cycles at 1C, the assembled Li/PDI15/LiFePO4 cells deliver a 125.2mAh/g, 90% capacity retention and Coulombic efficiency of 99.75%, respectively. This innovative and facile strategy of dual functional InF3 on the in-situ polymerization of DOL and solid electrolyte interphase formation provides new ideas for design poly-DOL based solid polymer electrolytes.