Engineering the Structural Uniformity of Gel Polymer Electrolytes via Pattern-Guided Alignment for Durable, Safe Solid-State Lithium Metal Batteries

Ultrathin and super-toughness gel polymer electrolytes (GPEs) are the key enabling technology for durable, safe, and high-energy density solid-state lithium metal batteries (SSLMBs) but extremely challenging. However, GPEs with limited uniformity and continuity exhibit an uneven Li⁺ flux distribution, leading to nonuniform deposition. Herein, a fiber patterning strategy for developing and engineering ultrathin (16 µm) fibrous GPEs with high ionic conductivity (≈0.4 mS cm⁻¹) and superior mechanical toughness (≈613%) for durable and safe SSLMBs is proposed. The special patterned structure provides fast Li⁺ transport channels and tailoring solvation structure of traditional LiPF₆-based carbonate electrolyte, enabling rapid ionic transfer kinetics and uniform Li⁺ flux, and boosting stability against Li anodes, thus realizing ultralong Li plating/stripping in the symmetrical cell over 3000 h at 1.0 mA cm⁻², 1.0 mAh cm⁻². Moreover, the SSLMBs with high LiFePO₄ loading of 10.58 mg cm⁻² deliver ultralong stable cycling life over 1570 cycles at 1.0 C with 92.5% capacity retention and excellent rate capacity of 129.8 mAh g⁻¹ at 5.0 C with a cut-off voltage of 4.2 V (100% depth-of-discharge). Patterned GPEs systems are powerful strategies for producing durable and safe SSLMBs.