Super-tough and self-healable all-cellulose-based electrolyte for fast degradable quasi-solid-state supercapacitor.

Recyclable and degradable supercapacitors have promising applications for a sustainable energy storage industry. Herein, we prepare a dual-physical crosslinking (DP) carboxymethyl cellulose (CMC) hydrogel with high-toughness, healability, and electric conductivity by integrating abundant ions into the matrix. The prepared hydrogel displays a maximum compressive fracture stress of 4.42 MPa, fast healing in five seconds, and full degradation within eight days. Moreover, the fabricated supercapacitor shows high specific capacitance (309 F g) and volumetric capacitance (2.60 F cm). The supercapacitor achieves a healing efficiency of 93.9 % after five cuttings, and exhibits a cycling stability of 84.6 % capacitance retention after 1000 cycles. These merits ensure that the all-cellulose-based supercapacitor can operate in case of sudden collision and deformation, which contribute to reducing the environmental hazards from supercapacitor's preparation to its abandonment.