Safety-Enhanced Flexible Polypropylene Oxide-ZrO2 Composite Solid Electrolyte Film with High Room-Temperature Ionic Conductivity

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 x 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.

Automated summary

In this study, a flexible polypropylene oxide-based solid electrolyte film with high ionic conductivity, excellent mechanical and thermal properties, and good inhibiting ability for lithium dendrites was successfully prepared. The cross-linking reaction of BSPPO oligomer initiated by lithium bis(oxalate)borate significantly improved the ionic conductivity of the solid electrolyte. The composite solid electrolyte film showed promising potential for use in high-performance solid-state lithium batteries, providing enhanced safety and stable cycling performance.