Preparation of Eco-Friendly High-Performance Manganese Dioxide Supercapacitors by Linear Sweep Voltammetry

In this paper, the non-polluting, non-toxic, and eco-friendly material-MnO2 electrodes were deposited on threedimensional porous nickel (Ni) foam by linear sweep voltammetry, and the entire electrodeposition process did not require sintering of the material, which was fast and convenient while avoiding unnecessary energy consumption and thus was environmentally friendly. Scanning electron microscopy (SEM) and transmission electron microscopy were used to examine the surface and microscopic characteristics of each sample (TEM). Chronoamperometry (CA), cyclic voltammetry (CV), galvanostatic charge/discharge (GCD), and electrochemical impedance spectroscopy (EIS) were then used to determine the electrochemical characteristics of the manufactured samples. The result suggests that the MnO2-sv80 electrode sample at a scan rate of 80 mV/s???1 has excellent performance for the supercapacitor electrode. The specific capacitance was as high as 531.4 F g???1 at a current density of 1 A g???1 and remained at 223.2 F g???1 at an ultra-high current density of 20 A g???1, with capacitance retention of 42%.