Preparation and Properties of Carbon Coated Manganese Dioxide Electrode Materials
Chinese Journal of Materials Research. 2019, 33 (
Manganese dioxide powders were firstly prepared
via electric pulse assisted redox method with KMnO 4 and MnSO 4 as raw material, then MnO 2/C composite materials coated with different amounts of carbon were fabricated via liquid phase sintering with glucose as a carbon source. The effect of amount of coated carbon on the morphology, structure and electrochemical properties of the MnO 2/C materials were investigated. Results show that the coated carbon could induce the transformation of crystallographic structure of MnO 2 from γ-type into α-type. Under heating conditions glucose decomposed and coated on the surface of MnO 2 particles, which could inhibit the grain growth and thus refine grains. When the preparation with the process parameters: glucose concentration was 1.5 g/L and the current density was 2 A·g -1, the prepared MnO 2/C material presented the specific capacitance of MnO 2 of 722.2 F·g -1, in other words, the carbon coating could increase the specific capacitance by 80%, in comparison with that of the blank ones. Furthermore, after 4000 charge-discharge cycles, the capacitance retention rate could still maintain 74.72%, displayed good electrochemical performance and cycling performance.
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