High‐Performance PVA/PEDOT:PSS Hydrogel Electrode for All‐Gel‐State Flexible Supercapacitors

Abstract Flexible supercapacitors are widely favored because they can provide a stable energy supply under different deformations. However, how to avoid the delamination of flexible matrix and electroactive materials under high deformation and balance mechanical durability and electrochemical performance is still an urgent problem to be overcome. Here, a hybrid polyvinyl alcohol/poly(3,4‐ethylenedioxythiophene): polystyrene sulfonate (PVA/PEDOT:PSS) hydrogel electrode with 3D interpenetrated network structure is prepared by the freeze–thaw crosslinking and solution immersion method. Due to the strong intermolecular force between PVA and PEDOT:PSS, coupling with the use of liquid phase mixing, this hybrid hydrogel electrode shows uniform interconnectivity and robust mechanical properties. The all‐gel‐state flexible supercapacitor based on the PVA/PEDOT:PSS hydrogel is fabricated to demonstrate its excellent mechanical durability of which capacitance retention retains 98.1% after 1000 bending cycles as well as excellent electrochemical performance whose areal specific capacitance is 128.9 mF cm⁻² and energy density is up to 11.46 μWh cm⁻². Moreover, it can continuously power the liquid‐crystal display (LCD) watch in bending, compression, and low‐temperature environments. The outstanding comprehensive performance of this supercapacitor indicates that it has the potential to be used in a new generation of flexible energy storage devices.