Optimization of Self-Healing Components in the UPY-PETEA-LAGP Composite Electrolyte for Solid-State Lithium Batteries

Abstract Solid-state electrolytes with self-healing capability to prevent mechanical damage can enhance the safety and prolong service life for solid-state lithium metal batteries (SSLMBs). However, the self-healing components inside polymer electrolyte remain largely unexplored. In this work, a novel self-healing composite electrolyte of UPY-PETEA-LAGP was obtained by way of a simple thermal polymerization method. This self-healing composite electrolyte is composed of the self-healing component with quadrupole hydrogen bonds, lithium salt complex, and lithium-conductor particles. The optimized electrolyte exhibits a room temperature ionic conductivity of 7.01×10-4 S cm-1, an electrochemical window of 4.75 V and a thermal decomposing temperature of 324°C. Coupling this electrolyte with LiFePO4 cathode, the full battery retains a high discharge capacity of 119.8 mAh g-1 at 0.2 C after 100 cycles, with a high capacity retention rate of 75.1%. The electrolyte can achieve self-healing process after cutting in 4 hours at 60°C. The batteries assembled with the healed UPY-PETEA-LAGP electrolyte reveals a similar cyclic performance after 50 cycles at 0.2 C. This work offers new tactics to explore high-performance self-healing composite electrolytes for solid-state lithium batteries.