碳气凝胶的结构重整及其电化学行为

Restructured Carbon Aerogels and Their Electrochemical Performances

将碳气凝胶(CAs)在金属钠熔体中于800°C加热3h,制得结构重整的碳气凝胶(RCAs),并研究了它们的电化学行为.采用X射线粉末衍射(XRD)、激光散射拉曼(Raman)光谱、气体的吸附与脱附(BET法)、透射电子显微镜(TEM)以及电化学阻抗谱(EIS)等手段,对CAs和RCAs样品分别进行了表征.结果表明:无定形态的碳单质微粒在金属钠作用下发生结构重排;所得RCAs的比表面积比CAs的大约增加48%;RCAs中孔径在2和4nm尺寸处,呈现比较集中的分布,孔径小于10nm以下的孔体积占其总孔容的30%,是CAs的3倍.CAs和RCAs样品的电化学测试结果表明:RCAs内部接触电阻约为CAs的45%,并保持了明显的电容特性.

Restructured carbon aerogels （RCAs） were obtained by annealing carbon aerogels （CAs） in sodium melt at 800 ℃ for 3 h and the differences in electrochemical performance between the resultant CAs and RCAs were studied. X-ray diffraction （XRD）, Raman scattering spectra, gas physisorption （BET）, transmission electron microscopy （TEM）, and electrochemical impedance spectroscopy （EIS） were used to probe the structures of CAs and RCAs. The studies indicated that the amorphous carbon particles were rearranged in sodium melt, in which the surface area of the resultant RCAs was 48% larger than that of CAs. Two concentrated pore distributions were observed at the apertures of 2 and 4 nm in RCAs. The pore volume at apertures below 10 nm is 30% of the total volume in RCAs, which is 3 times as many as that in CAs. Electrochemical performances of both CAs and RCAs were investigated and the results indicate that the inner resistance of RCAs is only 45% of that in the sample of CAs. The results also indicate that RCAs display good performance in capacitance characteristics.