A novel thioctic acid-functionalized hybrid network for solid-state batteries

The development of solid electrolytes for solid-state metal batteries is challenging and limited due to low ionic conductivity, poor interface stability, and accompanying side reactions. Herein, a novel thioctic acid-functionalized solid electrolyte based on hybrid heterogeneous 3D cross-linked network covalently tethering thioctic acid is designed and synthesized. Thioctic acid makes soft PEGDA polymerized in hard P(VDF-HFP) matrix to form tough hybrid heterogeneous 3D cross-linked network without initiator, which simultaneously enhances the ion transport and regulates the lithium deposition on the lithium metal surface. Moreover, the C-S bonds formed by polymerization can increase the migration rate of Li+, and this initiator-free polymerization process eliminates residual free radical side reactions and by-products, effectively improving the compatibility of the solid electrolyte with lithium anode. Due to the rational design, the thiotic acid-functionalized hybrid network electrolyte exhibits high ionic conductivity of 0.11 mS cm(-1) at ambient temperature. The symmetrical Li//Li cells enable over 1800 h cycling, and the LiFePO4//Li full solid-state batteries deliver high capacity retention (> 80%) over 300 cycles at 0.5 C at 25 degrees C. This work demonstrates a rational design of thicotic acid-functionalized hybrid network with greatly improved ionic conductivity and stability for high performance solid-state batteries.

Automated summary

A novel thioctic acid-functionalized solid electrolyte was designed and synthesized in this study, which improves the ion transport and lithium deposition on the lithium metal surface. The electrolyte exhibits high ionic conductivity and stability, and shows long cycling life and high capacity retention in experiments.