N-doped mesoporous carbon by a hard-template strategy associated with chemical activation and its enhanced supercapacitance performance

Abstract

Well-controlled mesoporosity is of importance for porous carbons as electrochemical electrode materials. However, the ordered mesoporous carbons prepared from the template approaches face the fact of relative low specific surface area in comparison to activated carbons. Herein, we employed a hard-template route associated with the chemical activation to prepare N-doped mesoporous carbon by co-casting of carbon and nitrogen precursors into the pore channels of mesoporous silica. The obtained activated N-doped mesoporous carbon (ANMC) material preserved the morphology and mesoporous structure of template, and meanwhile a secondary mesoporosity was introduced by the KOH activation. It was demonstrated that the dominant porosity in ANMC sample was from mesopore, and it possessed a high mesopore surface area (2505.6m2g−1) and mesopore volume (1.74cm3g−1). The N dopant was determined to be pyridinic-N, pyrrolic-N, quaternary-N and pyridine-N-oxide, which did not only contribute the pseudocapaticance but also facilitated the electron transfer in the carbon skeleton. The developed mesoporosity and N doping made this material exhibit superior electrochemical performance that was much higher than those of ordered mesoporous carbon, N-doped ordered mesoporous carbon and activated N-doped carbon samples. Also, the specific capacitance 336.9Fg−1 (0.5Ag−1) and the rate capability were higher than those of other reported mesoporous carbons. In addition, the assembled symmetrical supercapaictor simultaneously showed the high energy density and power density, as well as presented the superb cycling ability (∼98.5% capacitance retaining after 5000 runs).