Textile carbon network with enhanced areal capacitance prepared by chemical activation of cotton cloth

Flexible all-solid-state supercapacitors are emerging as one of the most gratifying energy storage devices in the application of portable and wearable electronics. The design and fabrication of high-performance and flexible electrodes are crucial for an all-solid-state supercapacitor. Herein we report a free-standing textile carbon network composed of activated textile carbon (aTC) by thermal annealing of cotton cloth, followed by chemical activation with KOH. The aTC fibers remain the unique features of surface wrinkles and hollow tubular structure of the natural cotton fibers, together with the abundant micropores introduced by further chemical activation, making the specific surface area of the aTC-3 fibers reach 1075 m² g^-1 with a high electrical conductivity of 1506 S m^-1. When served as the supercapacitor electrode, the aTC-3 exhibits a specific capacitance as high as 1026 mF cm^-2 with a capacitance retention of 85% at 100 mA cm^-2 (868 mF cm^-2), which is far superior to commercial carbon cloth. More interestingly, the long-range continuous structure enables aTC as electrode of solid-state supercapacitor, which delivers an outstanding mechanical flexibility without noticeable change of capacitive performance when folded at maximal angle of 180° over 200 cycles. This work may benefit the low-cost mass production of carbon-based flexible electrodes for developing wearable electrochemical energy storage systems.