Dual-network hydrogel electrolytes based on carboxymethyl cellulose/tannic acid physical network and covalently crosslinked polyacrylic acid for flexible interdigital zinc-ion hybrid supercapacitors.

A rigid-flexible interpenetrating dual-network gel polymer electrolyte (GPE) is designed by integrating a reversible physically crosslinked network of carboxymethyl cellulose (CMC) and tannic acid (TA) - formed via dynamic hydrogen bonds and coordination interactions - with a covalently crosslinked polyacrylic acid (PAA) network via UV-initiated in-situ polymerization. The resulting electrolyte exhibits high stretchability (elongation at break of ~900%), strong adhesion (shear strength 24.02 kPa), room-temperature self-healing, and flame retardancy. When assembled with an electrodeposited polyaniline (PANI) cathode and zinc foil anode into a flexible interdigital zinc-ion hybrid supercapacitor, the device achieves a specific capacitance of 245.8 F g-1, an energy density of 18.74 Wh kg-1, and a power density of 527.36 W kg-1, while maintaining stable electrochemical performance under various bending radii and external pressures. The dual-network design effectively ensures interfacial contact and ion transport under dynamic deformation, offering a promising approach for flexible energy storage systems.