Tailoring High-Elasticity Cross-Linked Polymer Electrolytes to Harmonize Flexible Solid-State Lithium–Oxygen Batteries

Abstract

Solid-state lithium-oxygen (Li-O₂) batteries (SSLOBs) are promising for next-generation energy storage due to their high theoretical energy density. However, their development is hindered by the lack of competent solid-state electrolytes (SSEs). This study develops cross-linked SSEs with controlled ultraviolet crosslinking polymerization. This advanced molecular architecture provides high ionic conductivity (8.35 × 10⁻⁴ S cm⁻¹ at 25 °C), an extended electrochemical window (0–5.4 V vs Li/Li⁺), and a high lithium-ion transference number (0.76). The engineered elastomer exhibits exceptional mechanical resilience with an elongation rate of 1824.7%, minimal energy dissipation, and efficient strain recovery. This enables over 4000 h of stable lithium plating/stripping at 0.1 mA cm⁻². Additionally, SSLOBs show excellent cycling performance (106 cycles), and the electrolyte's geometric adaptability supports pouch-type flexible batteries, with enhanced safety. This work offers insights into stress-mitigation strategies in electrolyte matrices and sets a framework for designing next-generation flexible lithium-air batteries.