Fabricating of MnO 2 /CNTs Nanocomposite by Hydrothermal-Assisted Chemical Oxidation for Application as Cathode Materials in Mg Batteries

In this paper, MnO 2 /CNTs composite materials have been studied and fabricated by hydrothermal-assisted chemical oxidation. Oxidation reactions of KMnO 4 with MnSO 4 and CNTs to form the composites were carried out at 140°C for 20 h. The obtained materials were morphologically observed by FESEM, analyzed for elemental composition by EDX, phase composition by XRD, and thermogravimetric analysis. Results show that the materials were composite of rod-shaped α-MnO 2 crystals, diameter from 20 to 30 nm, about 1 μm long, with scattered CNTs. The electrochemical properties of the materials were studied by cyclic voltammetry (CV) and chronopotentiometry (CP) methods. CNTs have improved electrochemical properties of the materials, the discharge rate increased two times and the specific capacity increased 20% higher compared to α-MnO 2 with the same fabricated conditions. The MnO 2 /CNTs 1% material has the best properties, the specific capacity reaches 113 mAh/g, the electrode can still work well after 100 charge-discharge cycles.