Tough and self-healing all-in-one supercapacitor enabled by triple-network redox carrageenan and sodium carboxymethylcellulose reinforcing gel polymer electrolyte

Flexible supercapacitors have recently gained great attention in the field of wearable electronics due to their long cycle life, and high efficiency. Herein, an all-in-one flexible supercapacitor is fabricated by in-situ polymerization of PANI on the surface of a fully physical cross-linking polyacrylamide/κ-carrageenan-K ⁺/sodium carboxymethylcellulose-Al ³⁺ triple network gel polymer electrolyte (GPE). By designing multiple interpenetrating networks and bimetallic ions cross-linking, the GPE displays outstanding mechanical performance. Meanwhile, owing to the dynamic interactions (hydrogen bond, ion coordination and thermoreverisible transition of KC) among different polymer chains, the GPE exhibits remarkable self-healing properties. Additionally, the all-in-one configuration accelerates ion transport at electrode-electrolyte interface and provides extremely low interface resistance, which endows the supercapacitor with excellent capacitance performance (254.58 mF/cm ²) and energy density (59.81 μWh/cm ²). Thanks to the unique integrated structure, the device avoids the slippage among multilayers and shows splendid electrochemical stability even under various physical deformations. More importantly, the all-in-one supercapacitor displays superior safety, self-healing and low temperature properties (85 % capacitance retention after 8 cutting/healing cycles even at −20 °C) due to the multi-function GPE. This simple and versatile strategy for constructing the all-in-one supercapacitors will offer broad prospects for designing energy storage devices in wearable electronics.