Correlation between Capacitance and Porosity in Microporous Carbon Monoliths

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• 作者：A. Garcia-Gomez ; V. Barranco ; G. Moreno-Fernandez ; J. Iba帽ez ; T. A. Centeno ; J. M. Rojo
• 刊名：Journal of Physical Chemistry C
• 出版年：2014
• 出版时间：March 13, 2014
• 年：2014
• 卷：118
• 期：10
• 页码：5134-5141
• 全文大小：382K
• 年卷期：v.118,no.10(March 13, 2014)
• ISSN：1932-7455

文摘

Specific capacitance of carbons in aqueous KOH electrolyte seems to have two contributions, a double-layer capacitance and a pseudocapacitance. Moreover, the specific capacitance increases as the specific surface area does. Here, we report that the pseudocapacitance is associated with the K⁺ ion and the double-layer capacitance with both K⁺ and OH^{鈥?/sup> ions. The former ion dominates the capacitance of a real two-electrode supercapacitor. Two microporous carbon monoliths with surface areas similar for micropores below 0.63 nm but different for larger micropores are chosen. There is a correlation between the double-layer capacitance due to those ions and the surface areas due to micropores with sizes above a certain value. It provides information on the size of those ions as they are electroadsorbed at the double layer. The dielectric permittivity associated with the K+ and OH鈥?/sup> ion is discussed in relation to the confinement of these electroadsorbed ions in the micropores.}