Growth of Polyaniline on Hollow Carbon Spheres for Enhancing Electrocapacitance
Growth of Polyaniline on Hollow Carbon Spheres for Enhancing Electrocapacitance
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DOI：
10.1021/jp1084026
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发表时间：
2010-11-25
影响因子：
3.7
通讯作者：
Zhao, X. S.
中科院分区：
文献类型：
--
作者：
Lei, Zhibin;Chen, Zhongwei;Zhao, X. S.
以二茂铁为碳前驱体，硅胶球为模板，采用化学气相沉积法制备了比表面积高达2239 m2/g的空心碳球。在HCS存在下，苯胺的化学氧化聚合产生具有聚苯胺层（PAN！）沉积在HCS的外表面上。采用循环伏安法、恒电流充放电和电化学阻抗谱技术研究了不同PANI含量的复合材料（HCS-PANI）的电容性能。结果表明，聚苯胺涂层之前和之后的HCS的比电容分别为268和525 F/g的硫酸水溶液电解质，这几乎是两倍增强。在0.1A/g的放电电流密度下，HCS-PANI电极实现了17.2Wh/kg的最大能量密度。然而，具有较高PANI含量（> 65wt%）的HCS-PANI电极的能量密度随着功率密度的增加而迅速下降。使用该复合材料作为正极和HCS作为负极的非对称超级电容器显示出良好的电化学稳定性，在1.0A/g的电流密度下，在1000次循环后保持了73%的电容、75%的能量密度和几乎100%的功率密度。
Hollow carbon spheres (HCS) with specific surface areas as high as 2239 m(2)/g were prepared by chemical vapor deposition with ferrocene as the carbon precursor and colloidal silica spheres as the template. Chemical oxidative polymerization of aniline in the presence of the HCS yielded composite materials with a layer of polyaniline (PAN!) deposited on the external surface of the HCS. The electrocapacitive properties of the composite materials (HCS-PANI) with different PANI contents were evaluated using cyclic voltammetry, galvanostatic charge discharge, and electrochemical impedance spectroscopy techniques. Results showed that the specific capacitances of the HCS before and after PANI coating were, respectively, 268 and 525 F/g in an aqueous H2SO4 electrolyte, which is almost doubly enhanced. A maximum energy density of 17.2 Wh/kg was achieved for the HCS-PANI electrode at a discharge current density of 0.1 A/g. However, the energy density of the HCS-PANI electrodes with higher PANI contents (>65 wt %) declined quickly as the power density increased. An asymmetric supercapacitor using the composite material as the positive electrode and HCS as the negative electrode showed good electrochemical stability, with 73% of the capacitance, 75% of the energy density, and almost 100% of the power density being retained after 1000 cycles at a current density of 1.0 A/g.