The influence of urea on composition, microstructure and electrochemical properties of nitrogen-enriched carbon based on polyvinylpyrrolidone/melamine formaldehyde resin

Abstract

Purpose

The purpose of this paper is to develop porous nitrogen-enriched carbon (NC-U) with high nitrogen concentration and high specific capacitance (Cpe) as the electrode material for supercapacitors.

Design/methodology/approach

NC-U was obtained by carbonization of polyvinylpyrrolidone/melamine formaldehyde resin (PVP/MF) with different contents of urea. In comparison, NC-K was also prepared by the KOH activation method. A series of asymmetric supercapacitors with NC as a negative electrode was assembled. The composition, microstructure and electrochemical properties of NC and their supercapacitors were studied.

Findings

The results show that NC-U shows irregular particles with a porous honeycomb structure. High Cpe was obtained for urea-treated NC-U because of the improvement of nitrogen, conductivity and specific surface area (S _BET ). NC-U50 with 13.15 per cent at nitrogen has the highest Cpe of 148.53 F/g because of the highest concentration of N-6 and N-5. NC-K with higher S _BET has lower Cpe than NC-U50 because of its lower nitrogen concentration. When the specific power of the supercapacitor with NC-U50 as a negative electrode is 1,565.56 W/kg, its specific energy is still 4.35 Wh/kg. There is only 5.9 per cent decay in Cpe over 1,000 cycles.

Research limitations/implications

NC-U is a suitable electrode material for supercapacitors, which can be used in the field of electric vehicles to solve the problems of energy shortage and environmental pollutions.

Originality/value

Porous NC-U based on PVP/MF/urea composites with high nitrogen concentration and Cpe is novel, and it owns good electrochemical properties.

Citation

Li, Q., Du, J., Zhang, X., Qin, C., Jin, Z. and Bai, X. (2015), "The influence of urea on composition, microstructure and electrochemical properties of nitrogen-enriched carbon based on polyvinylpyrrolidone/melamine formaldehyde resin", Pigment & Resin Technology, Vol. 44 No. 5, pp. 257-265. https://doi.org/10.1108/PRT-02-2015-0017