High performance electrochemical capacitors based on MnO2/activated-carbon-paper

Abstract

In this research, the surface of commercial carbon paper was firstly activated with potassium dichromate lotion and then MnO₂ nanoribbons were anchored onto the activated carbon paper (denoted as ACP) through an electrodeposition route. The as-prepared composite MnO₂/ACP possessed a specific capacitance as high as 640.8 F g⁻¹ calculated from the discharge curve with a current density of 10.0 A g⁻¹ and this observation was deemed to originate from its enlarged specific surface area and improved electronic conductivity. Accordingly, the specific capacitances calculated from cyclic voltammograms were 617.0 and 395.0 F g⁻¹ at a potential scan rate of 20 and 50 mV s⁻¹, which kept 81.5% and 52.2% specific capacitance at 10 mV s⁻¹ (757.0 F g⁻¹). This indicated that the composite MnO₂/ACP possessed good rate capability as an active electrode material for pseudo-capacitors. In a word, for the first time the composite MnO₂/ACP has been reported as a promising electrode material for efficient supercapacitors.