碳气凝胶的孔结构及其对电化学超级电容器性能的影响

通过改变碳气凝胶的溶胶-凝胶制备条件和炭化活化工艺,实现了对碳气凝胶纳米孔洞结构的控制.采用扫描电子显微镜(SEM)和氮气等温气体吸附法对碳气凝胶和KOH活化碳气凝胶的形貌和孔结构进行了表征和分析,并且使用循环伏安法(CV),恒流充放电,电化学阻抗谱(EIS)等检测技术评价了电化学性能.结果表明:发达的三维纳米网络结构与合理的孔径分布是影响碳气凝胶电化学超级电容器性能的关键因素.经适度活化后的碳气凝胶材料含有丰富的介孔,比表面积可达1480m2·g-1.在6mo·lL-1的KOH溶液中,在100mV·s-1的扫描速率下其比电容量高达216F·g-1.通过拟合发现,碳气凝胶类材料的大孔和介孔拥有更高的单位面积比电容量.

Pore Structures of Carbon Aerogels and Their Effects on Electrochemical Supercapacitor Performance

Control of the pore structures of carbon aerogels(CAs)was investigated by changing the sol-gel polymerization and activation conditions.The morphologies and physical properties of the CAs and KOH activated carbon aerogels(ACAs)were characterized by scanning electron microscopy(SEM)and N2 adsorption isotherms.The electrochemical performances of the CAs and ACAs as electrode materials were characterized using cyclic voltammetry(CV),a galvanostatic charge-discharge test,and electrochemical impedance spectroscopy(EIS).The results showed that the well developed three- dimensional nano-network structures and the reasonable pore size distributions of the CAs have great effect on their electrochemical performance in supercapacitors.Because of abundant mesopores and a high specific surface area(1480m 2·g-1 ),the specific capacitance of a ACA electrode in 6 mo·lL-1 KOH electrolyte was approximately 216F·g-1 at a scan rate of 100 mV·s-1 .A simple model was used to investigate the role of the pores in electrochemical performance.