Rational Design of Electrochemical Iodine-based Redox Mediators for Water-Proofed Flexible Fiber Supercapacitors

Flexible supercapacitors based on electrostatic double-layer capacitors as next-generation energy storage systems hold great promise for wearable and flexible electronic devices owing to their high flexibility and electrochemical cyclability. However, the challenge of low charge storing ability still remains as electronic devices require a high charge storage capability. As one of advanced strategies for enhancing charge storing ability in flexible supercapacitors, the introduction of a redox mediator (RM) into a gel electrolyte has recently attracted great interest. Here, we present a fiber-based flexible energy storage system (f-FESS) integrated with iodine-based chemical species as a novel RM, carbon fiber-based electrodes, and a solid-state polymer gel-electrolyte to enhance the charge storage capability of flexible supercapacitors. The as-prepared f-FESS-RM exhibits the enhanced charge storage capabilities of up to 461.8 F L-1 and 64.14 mWh L-1, which are 3.6 times higher than those of f-FESS without...