Activated carbon clothes for wide-voltage high-energy-density aqueous symmetric supercapacitors

Mild air calcination endows carbon cloth (CC) with three orders of magnitude increase in specific capacitance. A 2.0 V activated CC based symmetric supercapacitor achieves high volumetric (7.62 mW h/cm3) and gravimetric (18.2 Wh/kg) energy densities. [Display omitted] Commercial carbon clothes have the potential to be utilized as supercapacitor electrodes due to their low cost and high conductivity. However, the negligible surface area of the carbon clothes serves as a serious impediment to their utilization. Herein, we report a facile calcination activation method for carbon cloths to realize remarkable comprehensive electrochemical performance. The activated carbon cloths deliver a high areal capacitance (1700 mF/cm2), good rate capability, and stable cycling performance up to 20,000 cycles. Owing to the stability in the wide potential window, a designed symmetric capacitor can function in a cell voltage of 2.0 V and delivers high volumetric and gravimetric energy densities of 7.62 mWh/cm3 and 18.2 Wh/kg, respectively. The remarkable electrochemical performance is attributed to rich microporosity with high surface area, superior electrolyte wettability, and stability in wide potential window.