A caddisfly larva case-mimicked gel polymer electrolyte with high toughness and enhanced ion transport for safe lithium metal batteries.

Liu, Quan; Liang, Xin; Liu, Bing; Yuan, Yuan; Wang, Kang; Xia, Yuxin; Li, Bingbing; Liu, Huakun et al. · Sci Adv · 2026

basic_science · Level V

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Abstract

Lithium (Li) metal batteries (LMBs) promise higher energy density than Li-ion cells but face a trade-off between ionic conductivity and mechanical strength in gel polymer electrolytes (GPEs). Inspired by caddisfly larvae cases, which assemble silk with particles for toughness and permeability, we develop a caddisfly larva case-mimicked gel polymer electrolyte (CLC GPE) with high toughness and enhanced ion transport. It integrates an electrospun polyvinylidene fluoride-hexafluoropropylene scaffold with shear thickening fluid. CLC GPE achieves a high ionic conductivity (2.80 × 10<sup>-3</sup> siemens per centimeter), a Li<sup>+</sup> transference number of 0.89, superior toughness (7.29 megajoules per cubic meter), and a puncture energy of 49.69 millijoules, which can resist thermal abuse (150°C), flame, and bullet impact (225 kilometers per hour). Symmetric Li||Li cells exhibit stable cycling over 800 hours, while Li||LFP (LiFePO<sub>4</sub>) full cells maintain 97.6% capacity after 700 cycles at 0.5C. This design couples mechanical robustness with fast ion transport, offering a scalable route to safer, high-performance LMBs.