Design and Preparation of Self‐Adaptive and Robust Solid‐State Elastomeric Electrolyte for Lithium Metal Battery Inspired by Rubber Tire

The development of safe, high-performance solid-state electrolytes remains a central challenge for advancing lithium metal batteries (LMBs) toward practical deployment. Inspired by the durable, deformable nature of rubber tires, we report the design and preparation of a self-adaptive solid-state elastomeric electrolyte containing a deep eutectic electrolyte, termed PMEC, which integrates molecular-level plasticizer dispersion, mechanical flexibility, and interfacial adaptivity. The PMEC membrane exhibits high ionic conductivity (2.37 mS cm^-1 at 30 °C), a high Li⁺ transference number (0.64), excellent elasticity, and robust interfacial adhesion (36.34 J m^-2). Structural characterizations confirm its amorphous and homogeneously mixed nature, while micro-Raman and XPS/TOF-SIMS analyses reveal uniform component distribution and the formation of an organic-inorganic gradient SEI layer on lithium. These features enable exceptional electrochemical performance in both symmetric and full batteries, including over 2000 h of stable cycling and >800 cycles at 0.5 C in LFP|PMEC|Li batteries with >88% capacity retention. Moreover, PMEC-based pouch batteries maintain functionality under severe mechanical abuse. This tire-inspired electrolyte design offers a generalizable platform for high-safety and high-performance solid-state lithium batteries.