Robust and Highly Ion-Conducting Gel Polymer Electrolytes with Semi-Interpenetrating Polymer Network Structure

Here we report gel polymer electrolytes (GPEs) formed by the film casting of the solution containing poly(ethylene glycol) methyl ether methacrylate (PEGMA) and trimethylolpropane ethoxylate triacrylate (ETPTA) with poly(vinylidene fluoride-co-hexafluoropropylene (PVDF-HFP), followed by the thermal radical polymerization and liquid electrolyte absorption. The resulting GPEs show a semi-interpenetrating polymer network (SIPN) structure that provides film robustness which is investigated by morphological, structural, and electrochemical studies. Particularly, the GPE prepared by the composition of 98 mol% PEGMA and 2 mol% ETPTA in the presence of 40 wt% of PVDF-HFP (relative to total amount of PEGMA and ETPTA) manifests large ionic conductivity (1.46 × 10−3 S cm−1) and tensile strength (6.28 MPa at elongation at break of 156%) at a room temperature due to large uptake of the liquid electrolyte (up to 267%) and SIPN structure. We also verify that the GPE is electrochemically stable up to 4.7 V (vs. Li/L+), suggesting it holds the great promise of a polymer electrolyte membrane for energy storages such as rechargeable batteries or supercapacitors.