In-situ generation of high performance thiol-conjugated solid polymer electrolytes via reliable thiol-acrylate click chemistry

Abstract A kind of high performance thiol-conjugated solid polymer electrolytes is in situ generated via a facile thiol-acrylate Michael addition reaction between ethylene glycol dimethacrylate (EGDMA) and 3,6-dioxa-1,8-octane dithiol (DODT) without UV irradiation or thermal initiation. The resulting amorphous linear polymer P(EGDMA-DODT) has a high average molecular weight of 47,000 Da with a low glass transition temperature of −50 °C. The in-situ generated P(EGDMA-DODT) solid polymer electrolyte exhibits room temperature ionic conductivity up to 2.7 × 10 −5 S cm−1 with a high lithium ion transference number above 0.40 and electrochemical stability window up to 4.3 V vs. Li/Li+. Advantages of longer C–S bond length (1.81 A), lower electronegativity (2.58) and moderate coordination facilitate the segment motion and contribute to higher room temperature ionic conductivity. It is demonstrated that the all-solid-state LiFePO4/Li cells using the in-situ generated P(EGDMA-DODT) electrolytes delivers considerable specific capacities, rate capability and excellent cyclic performance at room temperature. These results demonstrate that this thiol-acrylate click chemistry without UV irradiation or thermal initiation is a facile and intriguing strategy for in-situ preparing high performance solid polymer electrolytes.