超级电容器用碳纳米管的室温活化时间与电容量的依赖关系研究

Effect of Activated Time on the Supercapacitive Performance of Carbon Nanotubes

报道了铬酸洗液室温活化多壁纳米管的方法,室温活化后的碳纳米管构筑的超级电容器储能性能有显著提高。该方法是采用铬酸洗液室温处理碳纳米管,改变了其表面拓扑结构,在碳纳米管表面引入了羟基(—OH),羰基(>C=O)和羧基(—COOH)等亲水基团。这些基团的引入使得活化后的碳纳米管构筑的超级电容器展示出优异的电容特性。随着活化时间的增加,比电容呈上升趋势,但增幅减小,结果表明铬酸洗液室温活化碳纳米管20 min后具有最佳性能。

In this paper, a facile method by potassium dichromate lotion to activate surfaces of carbon nanotubes （CNTs） at room temperature leading to enhanced electrochemical capacitances was reported. Surface hydrophilicity of the treated CNTs en- hanced due to the generation of hydrophilic groups such as hydroxyl （--OH） , carbonyl （ 〉 C = O） and carboxyl （--COOH） and they act as strong polar sites to absorb water molecules. With the effect of hydrophilic groups, the treated CNTsprovide high specific capacitance. With the increase of activation time, specific capacitance of treated CNTs is on the rise, but the growth rate decreases. Activation time is up to 20 minutes, the supercapacitiveperformanceis to achieve the best. The capacitance decay for CNT-4over 3000 cycles is as low as 1.4 %, implying its excellent long- term capacitive stability.