Direct Growth of Birnessite-Type MnO2 on Activated Carbon Cloth for a Flexible Supercapacitor

Abstract

A piece of commercially-available carbon cloth (CC) was treated using a simple wet method and then served as a substrate for the direct growth of MnO2 via an electrochemical process. The treated CC electrode allowed the deposition of a large amount of MnO2 while maintaining its electrochemical utilization efficiency. The optimal mass loading of MnO2 was determined to be 4.27 mg cm-2, a level that gave an areal capacitance of 568 mF cm-2 at a scan rate of 2 mV s-1. This MnO2/CC piece was employed in conjunction with an activated carbon-coated CC section as the positive and negative electrodes, respectively, in a solid-state asymmetric supercapacitor.