ANOMALOUS CAPACITANCE PROPERTIES OF NITROGEN DOPED CARBONS PREPARED BY REPLICATION

摘要

In the present work, it has been proved that templated carbons with an interconnected network of micro/mesopores are perfect reference carbons for a detailed study of capacitance properties in aqueous medium. A series of carbons with almost identical ultramicroporosity has been produced. These carbons differ only by the content of supermicropores and small mesopores. Such a well sized nanotexture allows the narrow micropores, where ions with a distorted solvation shell closely approach the electrode surface, to be efficiently used. It has been shown that the presence of heteroatoms in the carbon network can greatly affect the electrochemical performance of the electrodes through pseudo-faradic reactions of nitrogenated and oxygenated groups as well as an accelerated sorption of ions in the regions of locally modified electronic structure. Capacitance values of total capacitors vary from 145 F/g to 210 F/g, however, a great difference can be observed for single electrodes. Generally, the negative electrodes supply higher values of capacitance. It is anticipated that asymmetric systems with a negative electrode preferably from nitrogen-rich carbon and a positive electrode from a material with oxygen in-built in the carbon network would be an optimal solution.