多壁碳纳米管与氧化石墨对活性炭电化学性能影响

Influences of multi-walled carbon nanotubes and graphite oxide on electrochemical performances of activated carbon

以石油焦制得活性炭(AC)作为超级电容器的电极材料,在此AC中分别加入5%多壁碳纳米管(MWCNTs)或5%氧化石墨(GO),借助氮吸附分析仪、循环伏安测试(CV)和电化学交流阻抗谱分析(EIS),比较MWCNTs与GO对改进AC电化学性能作用影响。实验结果显示:MWCNTs和GO的吸附等温线具有多段特征,而AC呈现含丰富中孔的微孔炭特征。CV测试显示,在低扫描速率下,加入MWCNTs和GO可使响应电流略有增加。EIS揭示加入MWCNTs和GO可提高AC电极的导电性、频率响应和快速充放电性能,同时提高AC电极的的充放电容量。倍率放电性能和1000次循环测试也表明加入MWCNTs和GO可提高AC电极的放电容量。

Activated carbon is prepared from petrol coke as the electrode material of electric double-layer ca- pacitors （ECs）. Multi-walled carbon nanotubes （MWCNTs） and graphite oxide （GO） are used to mix with ac- tivated carbon as electrode material of ECs, where the amounts of MWCNTs and GO inside AC electrodes are all the weight percentage of 5%. The nitrogen adsorption analysis, the cyclic voltammogram （CV） and elec- trochemical impedance spectroscopy （EIS） are applied to compare the influences of MWCNTs and GO on electrochemical performances of activated carbon. The results show that the isotherms of MWCNTs and GO present the characteristics of the hybrid of multi-type isotherms. However, AC represents the feature of the mi- croporous carbon with the abundant mesopores. The response current densities are slightly enhanced through the cyclic voltammery test at the small scan rates, when MWCNTs and GO of 5% are added in AC elec- trodes. Meanwhile, the EIS demonstrates that the conductivity, frequency response, the quick charge-dis- charg capability and capacitance. Furthermore, the power charge-discharge property and the cycling perfor- mance of 1 000 cycles are also improved.