Electrochemical responses from the chemical properties of activated carbons by gaseous phase treatment

摘要

In order to discuss the effect of functional groups of activated carbon on electric double-layer characteristics, as-prepared activated carbon with various amounts of functional groups were thermally treated by gaseous phase. The structure and chemical properties of obtained samples were examined through nitrogen porosimetry, element analysis (EA), X-ray photoelectron spectroscopy (XPS). And the electrochemical performances, especially pseudocapacitance between the ions of the electrolyte and functional groups, were evaluated in KOH aqueous solution using a three-electrode cell by cyclic voltammetry and galvanostatic charge/discharge cycling. The changes in the electrochemical behavior were considered in relation to the surface chemistry properties. The surface functional groups can enhance the capacitance and wettability, and also exhibit asymmetric capacitive behavior in negative and positive electrodes. The electrochemical impedance spectroscopy was applied to reveal the change of inner resistance owing to existed heteroatoms.