Tough, highly adaptable and self-healing integrated supercapacitor based on double network gel polymer electrolyte

Flexible supercapacitor has been proved a promising candidate for wearable electronics due to its high power density, fast charge/discharge rates and long life cycle. Gel polymer electrolyte (GPE), an important component of supercapacitor, combines high ionic conductivity of liquid electrolyte and great safety of solid electrolyte. To satisfy the practical application of wearable flexible devices, the GPE should possess outstanding mechanical properties. Herein, a fully physical cross-linked polyacrylamide/κ-carrageenan double network GPE is prepared, in which κ-carrageenan with double-helix structure is used as the first network and polyacrylamide acts as the second network. The double network GPE shows outstanding mechanical properties, including high tensile strength (0.33 MPa), elongation (1143%) and preeminent self-recovery performance. Moreover, owing to thermoreversible characteristic of κ-carrageenan and reversible hydrogen bonds, the GPE exhibits excellent self-healing performance. Furtherly, an integrated supercapacitor is fabricated by in-situ growing polyaniline on the GPE surface. Different from conventional sandwich-like structure of supercapacitor, this seamless connection between electrode and electrolyte layers can significantly lower interfacial resistance, and avoid displacement and separation under deformations. Meanwhile, this supercapacitor also demonstrates splendid self-healing performance and high adaptability during harsh conditions. This flexible self-healing supercapacitor with superior security has broad application prospects in portable and wearable electronics.