Heteroatoms-Doped Hierarchical Porous Carbon Materials Based on Biomass-Metal Ternary Complex for Supercapacitor

Abstract

Engineering large active surface area, fast ion transfer, and wide work voltage are indispensable for using porous carbon as an electrode material for high energy density and high rate capability supercapacitors. Here, a method is proposed to fabricate N/O/P/S heteroatom co-doped hierarchical porous carbon materials via zinc carbonate hydroxide ([ZnCO3]2∙[Zn(OH)2]3) assisted activation of the biomass-based ternary complex. By adjusting the pH of the ternary complex and the mass ratio of [ZnCO3]2∙[Zn(OH)2]3, it is demonstrated that TCPC-7-0.5 with high specific surface area (1360 m2 g−1), appropriate micropore surface area (672 m2 g−1), and micropore volume (0.3 cm3 g−1) possesses excellent electrochemical performance. The unique pore structure accelerates the transport of electrolyte ions and provides more effective active sites for their adsorption. As a result, as an electrode material for supercapacitors, it maintains excellent frequency response at a larger scan rate of 1 V s−1. The working voltage range of the assembled symmetrical supercapacitor TCPC-7-0.5//TCPC-7-0.5 in 6 M KOH electrolyte can be effectively expanded to 1.2 V. Most importantly, it can simultaneously achieve an energy density of 7.01 W h kg−1 at a high-power density of 15 kW kg−1.