Synthesis of mesoporous carbon composite and its electric double-layer formation behavior
Synthesis of mesoporous carbon composite and its electric double-layer formation behavior
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DOI：
10.1016/j.micromeso.2006.02.017
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发表时间：
2006-07
影响因子：
5.2
通讯作者：
C. Hsieh;Yitong Lin
中科院分区：
文献类型：
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作者：
C. Hsieh;Yitong Lin
本研究采用热化学气相沉积法制备了以多孔碳为基体的碳纳米纤维（CNFs）介孔碳复合材料作为电化学电容器的电极材料。场发射扫描电子显微镜和透射电子显微镜观察表明，多孔碳表面生长了大量的CNF，平均直径为8- 15 nm。氮气吸附实验表明，与原始炭相比，生长态炭具有相似的比表面积，但孔径分布不同。密度泛函理论分析也表明，炭复合材料具有较大比例的中孔，其孔径分布集中在中孔尺寸。在两种电解液中，使用1 M KOH和2 M Et 4 NBF 4，研究了用碳制造的电容器的电化学行为。实验结果表明，与原始碳相比，碳复合材料在两种电解液中的电容都有增加的趋势。这表明，由CNFs的生长贡献的电容增强起着重要的作用，不仅降低了电解质迁移的阻力，但也促进了双电层形成的孔隙可达性。这种影响变得更加重要，特别是对于具有较大分子尺寸的有机电解质。
The present study investigated that, by using an efficient thermal chemical vapor deposition technique, the mesoporous carbon composite containing carbon nanofibers (CNFs) grown on porous carbon was prepared to serve as an electrode material for electrochemical capacitors. Field-emission scanning electron microscopy and transmission electron microscopy observations showed that a large amount of CNFs with an average diameter of 8–15nm were grown onto the porous carbon. Experiments of nitrogen adsorption reflected that the as-grown carbons have a similar surface area but different pore size distributions, compared with the original carbon. Density functional theory analysis also demonstrated that the carbon composite possessed a greater proportion of mesopores and its pore size distribution was centered at mesopore size. Electrochemical behavior of the capacitors fabricated with the carbons was investigated in two kinds of electrolytes, using 1M KOH and 2M Et4NBF4. Experimental results showed that compared with the original carbon, an increasing trend of capacitance for the carbon composite was found in both electrolytes. It suggested that the capacitance enhancement contributed from the growth of CNFs plays an important role not only to lower the resistance for electrolyte migration, but also to promote the pore accessibility for double-layer formation. This influence becomes more vital especially for the organic electrolyte that has a larger molecular size.