(557a) Solid State Battery Based on PEO/PVDF-HFP Solid Polymer Electrolyte

In this work, a solid polymer electrolyte (SPE) was synthesized by complex of PEO, PVDF-HFP, and LiTFSI. The SPE has high thermal stability and can be used in high temperature working environment. Solid-state lithium batteries based on SPE, lithium metal, and LiFePO₄ were assembled. At 70 °C and 120 °C, the obtained lithium batteries demonstrated excellent electrochemical performance, indicating that the tailor-made SPE has a wide working temperature range and it is suitable for high-performance solid-state batteries. A symmetrical Li/SPE/Li battery operated at 120 °C for 1,300 h with low polarization voltage and without any short circuit, indicating that the interface compatibility between lithium metal and SPE film was good and could effectively suppress the formation of lithium dendrites. The superior performance of the resulting SPE was mainly due to high thermal stability of the SPE, the interaction between the lithium salt and the host polymer, as well as weak interaction between PEO and PVDF-HFP, which reduced the crystallinity of PEO, thereby significantly improving the Li⁺ migration ability and improving the battery's cycle life.