Tough and safe integrated supercapacitor based on physically crosslinked double network gel polymer electrolyte with dual-role Co2+

To meet the demands of wearable electronics, flexible supercapacitors based on gel polymer electrolyte (GPE) have attracted significant interest. Herein, a physically cross-linked double network polyvinyl alcohol-sodium alginate-CoSO₄ GPE was developed. The multivalence ion Co²⁺ was utilized as charge carrier for the first time, resulting in exceptional conductivity (3.7 S/m). On the other hand, Co²⁺ functioned as an ion crosslinker, constructing a double network structure, endowing the GPE with outstanding mechanical properties. Furtherly, polyaniline was in-situ synthesized on the GPE surface to fabricate an integrated supercapacitor. The integrated configuration provided a seamless electrode/electrolyte interface, significantly reducing interface resistance and improving specific capacitance (169 mF/cm²) and energy density (60 μWh/cm²). Notably, benefiting from this unique structure, the supercapacitor exhibited remarkable deformation adaptability and security without slippage and delamination among multilayers. This GPE and integrated supercapacitor offered a novel preparation strategy for wearable energy storage devices, demonstrating application potential in flexible electronics.