Gel polymer electrolyte based on hydrophilic–lipophilic TiO 2 -modified thermoplastic polyurethane for high-performance Li-ion batteries

Due to the advantages of high energy density and improved safety properties, Li metal batteries with gel polymer electrolyte (GPE) have drawn much attention in recent years. Herein, a novel gel thermoplastic polyurethane (TPU) electrolyte filled with ultrafine hydrophilic–lipophilic TiO2 nanoparticles was successfully prepared by using a phase separation technology. The gel electrolyte can protect the battery against the leakage of liquid electrolyte by means of its strong interaction with Li+ and solvents. This kind of GPE shows an ionic conductivity of 1.59 mS cm−1 and an electrochemical window of 4.3 V (vs. Li/Li+) at room temperature. Robust TiO2 nanoparticles embedded into TPU matrix can effectively block dendrite puncture and, besides, greatly improve the thermal stability of GPE. The cycling performance, rate capability and mechanical properties guarantee the reliability of the as-prepared GPE in Li-ion batteries.