Advanced asymmetric supercapacitors based on two-step activated carbon cloth with long cycle life

A simple and efficient method is developed to activate commercial carbon cloth by creating a large number of hierarchical pores on the surface of carbon cloth and introducing numerous pseudocapacitance oxygencontaining functional groups to achieve excellent electrochemical performance for supercapacitors. The obtained active carbon cloth (AECC) shows core-shell structural with high surface area and abundant functional groups. Benefiting from these fascinating properties, the AECC displays an areal specific capacitance of 1.06 F cm(-2) at 1 mA cm(-2) and the rate capability of 40.8 % (from 1 to 32 A cm(-2)). More impressively, after 10,000 time charge/discharge cycles, AECC still maintains 100 % of the initial capacitance, indicating its superior cycle stability. The asymmetric supercapacitor with AECC as anode and MnO2/CC as cathode delivers a high energy density of 139.7 mWh cm(-2) at 1 W cm(-2) and excellent cyclic stability (100 % after 10,000 cycles at 16 mA cm(-2)). This work may provide a reference for exploring and designing high-performance carbon electrodes.