Conversion of low molecular weight hydrogel to nitrogen-doped carbon materials and its application as supercapacitor

Abstract

Nitrogen-doping in carbon materials is a common strategy to enhance electrochemical capacitance. Most studies focused on the application of N-doped materials. However, the evolution of nitrogen in the materials and the effect of nitrogen content of materials on capacitance is rarely discussed. In this study, we use low molecular weight hydrogel as a precursor, doped with different amount of urea to change nitrogen content. We discovered that the nitrogen-doping may change the morphology of the materials after pyrolysis. We further analyzed the electrochemical properties of the N-doped porous carbon materials. The electrochemical capacitance may increase due to nitrogen-doping, but with high nitrogen content, the capacitance decreased conversely. The increase of electrochemical capacitance may relate to the content of quaternary nitrogen.