Rigid support–molecular regulation–interface reinforcement synergistic strategy enables PEO-based electrolytes for solid-state lithium batteries

Abstract

Poly(ethylene oxide) (PEO)-based solid polymer electrolytes have broad application prospects due to their flexibility, high lithium salt solubility, and low cost. However, low ionic conductivity, low Li⁺ transference number, poor electrochemical stability, and inadequate mechanical strength restrict their application in solid-state lithium batteries (SSLBs). Herein, a composite solid-state electrolyte (CSE), PEO@GFC-15, is prepared using a simple and scalable solution casting method, incorporating glass fiber cloth (GFC) and Li_6.4Al_0.1La₃Zr_1.7Ta_0.3O₁₂ (LALZTO) particles. LALZTO can enhance Li⁺ transport kinetics by increasing the amorphous region, constructing a Li–O–C dynamic coordination network, and providing more free Li⁺. It can also promote the decomposition of lithium salt to generate abundant LiF and fix TFSI⁻, enhancing interface stability, with the oxidation potential increasing to 5.2 V. The high elastic modulus of GFC and the strong hydrogen bond network endow PEO@GFC-15 with good flexibility. Additionally, the three-dimensional rigid network and non-flammable inorganic LALZTO particles improve its thermal stability. Therefore, the Li plating/stripping stability and electrochemical performance of SSLBs are effectively enhanced by the rigid support–molecular regulation–interface reinforcement synergistic modification strategy. This work provides practical insights for the development of high-performance SSLBs.