Abstract: Mn₇C₃@C core-shell nanoparticles were successfully prepared by a simple DC arc plasma method using methane as the carbon source gas and bulk manganese as the raw material for the electrode material of high performance supercapacitor. The average diameter of Mn₇C₃@C core-shell nanoparticles is 3035nm, and the Raman spectrum shows that graphite carbon shell has good conductivity. The electrochemical properties of Mn₇C₃@C core-shell nanoparticles were analyzed by cyclic voltammetry, constant current charge/discharge and electrochemical AC impedance spectroscopy, and the results showed that the electrochemical properties such as high specific capacitance and fast charge/discharge were excellent. The specific capacitance was up to 185.8 F/g at a scan rate of 1 mV/s. Also, the specific capacitance remained at 88% of the initial capacitance after 1,000 cycles of voltammetric testing at 100 mV/s, which was a significant improvement compared with that of Mn₇C₃ alone (79%). is attributed to its good core-shell structure, where the defect-rich carbon layer has good electrical conductivity, which contributes to ion transport and structural stability, while the core Mn₇C₃ mainly generates pseudocapacitance, which produces a dual-layer and pseudocapacitance dual-mode energy storage mechanism under the synergistic effect of C and Mn₇C₃.

https://doi.org/10.15541/jim20160276