Preparation of Gel Electrolyte for Lithium Metal Solid-State Batteries and Its Failure Behavior at Different Temperatures

The stability of the electrolyte is very important for the development of high-performance all-solid-state lithium batteries. To improve the stability of electrolyte performance, it is essential to first understand the causes of its deterioration. Physically speaking, the degradation of electrolyte performance is mainly due to interface degradation. PAN-PVDF-HFP-LiClO4-Li6.4La3Zr1.4Ta0.6O12 (LLZTO) gel polymer electrolyte was prepared by the UV curing method and assembled into a solid-state battery. The electrochemical properties of solid-state batteries were tested at −20 °C, 30 °C, and 60 °C. The test results show that the gel polymer electrolyte exhibits good electrochemical performance in this temperature range. (The ionic conductivities of the gel polymer electrolyte at −20 °C and 60 °C were 3.95 × 10−4 S·cm−1 and 5.04 × 10−4 S·cm−1, respectively.) At a current density of 0.2 C, the battery exhibited high initial specific discharge capacities of 122 mAh g−1 and 151.6 mAh g−1 at −20 °C and 60 °C. The gel polymer electrolyte before and after working at different temperatures was characterized, and the ion transport was analyzed to explore the physical reasons for the degradation of the gel polymer electrolyte membrane interface. Therefore, this work provides a certain theoretical basis for improving the stability of solid-state lithium-ion batteries.