A Highly Elastic and Fatigue‐Resistant Natural Protein‐Reinforced Hydrogel Electrolyte for Reversible‐Compressible Quasi‐Solid‐State Supercapacitors

Compressible solid‐state supercapacitors are emerging as promising power sources for next‐generation flexible electronics with enhanced safety and mechanical integrity. Highly elastic and compressible solid electrolytes are in great demand to achieve reversible compressibility and excellent capacitive stability of these supercapacitor devices. Here, a lithium ion‐conducting hydrogel electrolyte by integrating natural protein nanoparticles into polyacrylamide network is reported. Due to the synergistic effect of natural protein nanoparticles and polyacrylamide chains, the obtained hydrogel shows remarkable elasticity, high compressibility, and fatigue resistance properties. More significantly, the supercapacitor device based on this hydrogel electrolyte exhibits reversible compressibility under multiple cyclic compressions, working well under 80% strain for 1000 compression cycles without sacrificing its capacitive performance. This work offers a promising approach for compressible supercapacitors.