Robust Succinonitrile-Based Gel Polymer Electrolyte for Lithium-Ion Batteries Withstanding Mechanical Folding and High Temperature

Fabrication of a gel polymer electrolyte containing succinonitrile (GPE-SN) with high mechanical strength is quite challenging because the SN electrolyte always suppresses the formation of polymer networks during in situ polymerization. In this work, a mechanically robust GPE-SN was successfully prepared by using a solution immersion method. During fabrication, the paste-like SN electrolyte was transformed into a liquid SN electrolyte with low viscosity by heating at 50 °C and then infiltrated into the UV-cured highly cross-linked polyurethane acrylate (PUA) skeleton. The resulted GPE-SN film exhibits superior tensile strength (6.5 MPa) compared to the one (0.5 MPa) prepared by in situ polymerization (GPE-SN-IN). The high mechanical strength of the GPE-SN-IM film enables the LiCoO2/Li4Ti5O12 film battery to withstand 100-cycle folding without electrolyte damage and capacity loss. Besides, the GPE-SN presents a high ionic conductivity (1.63 × 10–3 S·cm–1 at 25 °C), which is comparable to GPE with a commerc...