Safety-Enhanced Flexible Polypropylene Oxide–ZrO<sub>2</sub> Composite Solid Electrolyte Film with High Room-Temperature Ionic Conductivity
Huimin Xu, Mao‐xiang Jing, Jie Li, Zhen-hao Huang, Tengfei Wang, Weiyong Yuan, Bowei Ju, Xiangqian Shen
Abstract
High ionic conductivity, excellent mechanical and thermal properties, and good inhibiting ability for lithium dendrites are essential requirements for polymer solid electrolytes (SEs). In this work, a flexible polypropylene oxide-based SE film was prepared by combining the bis[3-(methyldimethoxysilyl)]-terminated polypropylene oxide (BSPPO) high polymer with ZrO2 fillers, the succinonitrile (SN) plasticizer, and the cellulose membrane framework. The cross-linking reaction of the BSPPO oligomer initiated by lithium bis(oxalate)borate at the addition of SN and ZrO2 improves the ionic conductivity of the prepared SE as high as 9.619 × 10–4 S cm–1 at room temperature with a high ion migration number of 0.8 and a high potential window of 5 V. The excellent mechanical strength, thermal stability, and good lithium dendrite inhibition ability greatly enhance the safety of the electrolyte in the use of lithium batteries. The assembled NCM622/SE/Li solid-state batteries can be stably cycled at a current density of 0.1–1 C. This safety-enhanced rigid-flexible BSPPO–ZrO2 composite SE film with high ionic conductivity is expected to be widely used in high-performance solid-state lithium batteries.