Surface modification of soft-templated ordered mesoporous carbon for electrochemical supercapacitors

• Ordered mesoporous carbon was surface-modified by wet oxidation.
• Systematic investigation of EDLC performances, based on comparisons with oxidized microporous carbons.
• Oxygen functionalization combined with ordered mesostructure improves the EDLC performance.

The increasing demand for energy has triggered numerous research efforts for the development of electricity storage devices consisting of templated nanoporous carbons. In this study, ordered mesoporous carbon with a modest specific surface area (520 m2/g) was prepared by a soft-templating method and surface-modified by a wet oxidation using nitric acid and ammonium peroxodisulfate. More oxygen-containing functional groups were introduced on the surface by oxidation using ammonium peroxodisulfate rather than nitric acid. Our study systematically investigates the effect of surface modification on electrochemical performance, based on comparisons with oxidized commercial activated microporous carbons. Oxygen functionalization leads to an increased capacitance for the ordered mesoporous carbon and a decreased capacitance for the activated microporous carbon at higher power densities. The ordered mesoporous carbon oxidized by nitric acid demonstrates excellent electrochemical performance with gravimetric capacitance of 290 F/g and volumetric capacitance of 300 F/cm3 at 0.1 A/g and retains over 70% of the capacitance at high current density of 5 A/g even though its surface area remained moderate (430 m2/g). The device demonstrates remarkable performance with an energy density of 17.4 Wh/kg, power density of 5.2 kW/kg, and excellent cycle life.

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