Oxygen group-containing activated carbon aerogel as an electrode material for supercapacitor

• Activated carbon aerogel (ACA) was prepared by activating carbon aerogel with CO2.
• Modified ACAs (MACA-X, X = 3, 6, 9, and 12 h) were prepared by HNO3 oxidation of ACA.
• MACA-6 h showed the best rate capability and the highest specific capacitance.
• An optimal condition was required for the highest supercapacitive performance.

Carbon aerogel was prepared by a sol–gel polymerization of resorcinol–formaldehyde (RF) method, and it was activated with CO2 to obtain activated carbon aerogel (ACA). A series of modified activated carbon aerogels (MACA-X, X = 3, 6, 9, and 12 h) were then prepared by HNO3 oxidation of ACA with a variation of oxidation time (X) in order to investigate the effect of surface oxygen group on their electrochemical performance as supercapacitor electrode material. Electrochemical properties of ACA and MACA-X were measured by cyclic voltammetry, galvanostatic charge/discharge, and EIS (electrochemical impedance spectroscopy) measurements. Among the samples, MACA-6 h showed the best rate capability and the highest specific capacitance. Thus, an optimal HNO3 oxidation condition was required for the highest supercapacitive electrochemical performance of modified activated carbon aerogel.

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