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以甲烷作为碳源气体,块体锰作为原料,采用一种简单的直流电弧等离子体法成功制备了Mn_7C_3@C核壳型纳米粒子,用于高性能超级电容器的电极材料.所制备的Mn_7C_3@C核壳型纳米粒子平均直径为30~35nm.拉曼光谱结果显示石墨碳壳具有良好的导电性.通过循环伏安、恒电流充放电及电化学交流阻抗谱对Mn_7C_3@C核壳型纳米粒子电极材料进行电化学性能分析,结果表明其具有高比电容、快速充放电等优异的电化学性能.在扫描速率为1mV/s时,比电容最高可达185.8F/g.同时具有良好的循环稳定性,在100mV/s扫描速率下1 000次循环伏安测试后,比电容仍保持为最初的88%,与单纯Mn_7C_3(79%)相比,有明显提高.Mn_7C_3@C核壳型纳米粒子电极材料优异的电化学性能归因于其良好的核壳结构,富缺陷碳层具有良好的导电性,有助于离子的传输和结构的稳定,而内核Mn_7C_3主要产生赝电容,在C和Mn_7C_3的协同作用下产生双电层和赝电容双模式储能机制.
Mn_7C_3 @ C core-shell nanoparticles were prepared successfully by using a simple DC arc plasma method with methane as carbon source gas and bulk manganese as raw materials for the electrode material of high performance supercapacitor.Mn_7C_3 @ C core-shell nanoparticles average diameter of 30 ~ 35nm Raman spectroscopy results show that graphite carbon shell has good conductivity by cyclic voltammetry, constant current charge-discharge and electrochemical impedance spectroscopy of Mn_7C_3 @ C core-shell nano Electrochemical analysis of the particle electrode material showed that it has excellent electrochemical performance such as high specific capacitance, fast charge and discharge, etc. The maximum specific capacitance of 185.8F / g at a scanning rate of 1mV / s, Cyclic stability: After 1 000 cycles of voltammetry at 100 mV / s, the specific capacitance still maintained the initial 88%, which was significantly higher than that of pure Mn_7C_3 (79%). The Mn_7C_3 @ C core- The excellent electrochemical performance of the nanoparticle electrode material is attributed to its good core-shell structure. The defect-rich carbon layer has good conductivity and contributes to the ion transport and structural stability. The main Mn_7C_3 core produces pseudocapacitance, And Mn_7C_3 Generating an electric double layer capacitor and a pseudo-dual-mode storage under the same action mechanism.