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

Abstract

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 oxygen-containing 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.