High-performance carbon-fiber-based supercapacitors: Enhanced performance through the porosity modification of electrodes containing a redox mediator

[Display omitted] •Carbon-fiber-based supercapacitors with micro-meso porous carbon fibers electrodes.•Increase in the number of electrochemically active sites by dehydrogenation of polymer.•Reversible faradaic reactions involving redox mediators.•Redox reactions comprising VO2+/VO2+ with hydroxyl and carbonyl groups.•Additional pseudo-capacitive contribution from reversible faradaic redox reactions. Carbon-fiber-based supercapacitors (CFS) are emerging as a prospective option for innovative wearable energy storage devices by reason of their safety, environmental compatibility, and high power density. However, the limited practical application of CFS is attributed to its poor energy storage performance, which is caused by the carbon fiber electrode's limited specific surface area and low wetting ability. To address this, this study developed a CFS with micro-meso porous carbon fibers electrodes and a redox additive electrolyte (CFS-MMRE). The CFS-MMRE showed exceptional energy storage capaability, high specific capacitance of 876 mF cm−2 at 70 μA cm−2, respectively, cycling stability over 5,000 cycles with 70 % capacitance retention at 400 μA cm−2. Moreover, CFS-MMRE possesses mechanical pliability, high achievability, and remarkable energy storage performance, which make them a viable choice for wearable electronic devices.