Study on the preparation and electrochemical behaviors of histidine-based N-doped hierarchical porous carbon as a supercapacitor material

Abstract

Hierarchical porous carbon materials can be obtained by etching carbonaceous materials with potassium hydroxide at high temperature. In this work, we chose the environment-friendly biomolecular galactose as the source to prepare carbon materials, histidine as the nitrogen source to improve the surface properties, and potassium hydroxide as the pore-forming agent. A series of carbon precursors were obtained via simultaneous calcination of histidine and galactose with different weight ratios under the nitrogen atmosphere. The porous carbon materials with meso/micro pores were further prepared using KOH as the activation agent. The optimal carbon material G8H1 featured with a large pore volume (1.05 cm3·g−1) and a high proportion of mesopores (Vnonmicro/Vmicro=1.62), large specific surface area (2040.2 m2·g−1), high content oxygen (12.6 at%) and nitrogen (2.32 at%), and good wettability. At three electrode system, G8H1 electrode material showed excellent specific capacitance performance 312 F·g−1 in the 6 M KOH electrolyte when the current density was 0.5 A·g−1. While symmetric supercapacitors were further assembled using 1 M Na2SO4, a capacitance of 85.4 F·g−1 at 0.05 A·g−1 was achieved with a maximal energy density of 38.43 kW·kg−1. Overall, the hierarchical porous carbon materials derived from biomolecules galactose and histidine showed excellent specific capacitance performance, which played a positive role in expanding the raw materials of synthetic carbon materials.