Poly(vinylidene fluoride) as a porogen to prepare nitrogen-enriched porous carbon electrode materials from pyrolysis of melamine resin

Abstract

Nitrogen-enriched carbons with hierarchical pore structures were prepared by the direct pyrolysis of melamine resin and poly(vinylidene fluoride) (PVDF) in an inert atmosphere. Our preparation method produced carbons that feature high micropore surface areas of up to 966m2g−1, with the peak micropore width around 0.5–0.6nm, and 3–4nm mesopore channels without the need for a template or activation post-carbonization. The carbons were characterized using N2 and CO2 sorption analyses, X-ray photoelectron spectroscopy and elemental analysis. The concentrations of nitrogen at the carbon surface were in the range 3.1–4.5at.%. The electrochemical performance of carbon electrodes was evaluated using cyclic voltammetry, galvanostatic charge-discharge techniques and impedance spectroscopy in 1M H2SO4 and 1M TEABF4/acetonitrile. Electrochemical tests in aqueous electrolyte showed excellent rate performance with capacitive behaviour up to 500mVs−1 and a specific capacitance of 125Fg−1 at the current density of 0.05Ag−1 in a two-electrode cell. In both aqueous and organic electrolytes, good cycling performance are obtain with 96% and 77% of the initial capacitance after 10,000 and 5000 cycles, respectively.