Thermoplastic polyurethane/poly(methyl methacrylate)/titania gel electrolyte film with high voltage and coulombic efficiency for lithium-ion battery

Polymer films composed of thermoplastic polyurethane (TPU), poly (methyl methacrylate) (PMMA), and titania were developed by solution-casting method. Accordingly, gel polymer electrolytes (GPEs) were prepared by soaking the films in commercial liquid electrolytes for 8 h. The prepared GPEs could fix the liquid electrolytes inside and kept the shape stable. The hybrid GPEs exhibited a maximum ionic conductivity of 3.9 × 10 −3  S‌‌‍ cm −1 at room temperature, with an electrochemical stability of up to 4.8 V versus Li + /Li. The compatibility test demonstrated that the introduction of PMMA and TiO 2 improved the interfacial compatibility between lithium and GPEs. In battery test, the Li/GPE/LiFePO 4 cell delivered the first discharge capacity of 169.2 mAh g −1 at 0.1 C and stable cycle performance (the retention of capacity is nearly 92% after 60 cycles) with high coulombic efficiency. All results demonstrated that the hybrid GPE was promising to satisfy the application in the future.