A comparative study of electrocapacitive properties of manganese dioxide clusters dispersed on different carbons Original Research Article

Manganese dioxide (MnO2) clusters were directly grown on different carbons, including reduced graphene oxide (RGO), multi-wall carbon nanotubes (CNTs), and carbon black (Vulcan XC-72), via a chelation-mediated aqueous solution method. The electrocapacitive properties of the composite materials were evaluated by using cycle voltammetry, electrochemical impedance spectroscopy (EIS), and charge/discharge techniques. The composite electrode consisting of RGO and MnO2 performed the best among the composite electrodes studied with a specific capacitance as high as 260 F/g at a current density of 0.3 A/g. EIS data revealed the smallest charge transfer resistance in electrode. The results suggest that two-dimensional (2D) RGO sheets are an excellent support for pseudocapacitive MnO2. This study provides fundamental insights into the role of a carbon support in carbon–transition-metal-oxide composite electrodes for supercapacitors.