活化和表面改性对碳纳米管超级电容器性能的影响

用KOH为活化剂对碳纳米管（CNTs）进行活化；用浓硝酸为氧化剂对活化CNTs进行表面改性.通过TEM、BET和IR对经过活化和表面改性的CNTs进行了分析,并运用循环伏安和恒流充放电测试研究了活化和表面改性对CNTs超级电容器性能的影响.结果表明,通过活化使CNTs的比表面积增大,从而使其比电容从未活化时的43 F•g－1提高到73 F•g－1；通过表面改性引进赝电容,使电容器的比电容进一步提高到94 F•g－1.

Effect of Activation and Surface Modification on the Properties of Carbon Nanotubes Supercapacitors

To increase the specific capacitance of supercapacitors based on carbon nanotubes (CNTs),activation and surface modification were carried out by using KOH and concentrated nitric acid respectively. The materials were analyzed by transmission electron microscopy (TEM), N2 adsorption and infrared spectra (IR). The effect of activation and surface modification on the performance of the CNTs supercapacitors was also studied by cyclic voltammetry and galvanostatic charge/discharge. The results showed that activation enlarged the BET specific surface area of the CNTs and hence increased the specific capacitance of the supercapacitors from 43 F•g－1 to 73 F•g－1.By surface modification, large quantities of electroactive functional groups were adsorbed on the surface of the CNTs, thus pseudocapacitance was induced and the specific capacitance was further increased to 94 F•g－1.