3D glass fiber cloth reinforced polymer electrolyte for solid-state lithium metal batteries

Substituting solid electrolyte for liquid electrolyte in lithium batteries is not only safe but also improves battery performance. Here, we successfully prepared solid polymer electrolytes (SPEs) by filling poly(ethylene oxide) (PEO), LiTFSI and ionic liquids (ILs) into the 3D glass fiber cloth (GFC) framework (electrolyte is recorded as PEO@GFC-x% ILs). This unique 3D SPEs has a robust network structure, which guarantees that GFC is evenly distributed in the PEO matrix. The thermal stability, mechanical strength, ionic conductivity, electrochemical stability, and lithium ion migration number of PEO@GFC-x% ILs electrolyte is higher than the original PEO electrolyte. Benefiting from good structural features, the Li symmetrical battery shows stable cyclability during 2000 h cycle. Solid-state lithium metal batteries (SSLMBs) assembled based on LiCoO₂ and LiFePO₄ cathode materials and PEO@GFC-25% ILs electrolyte can obtain specific capacities of 128.3 mA h g⁻¹ and 155.2 mA h g⁻¹, respectively (0.2C, 100 cycles). In addition, the solid-state LiFePO₄/PEO@GFC-25% ILs/Li battery can provide a reversible capacity of 152.0 mA h g⁻¹ after 150 cycles at a current density of 0.5C. This research proposes a simple and easy way to realize SPEs with 3D structure, and provides a new idea for the design of high-performance SSLMBs.