N-doped layered porous carbon electrodes with high mass loadings for high-performance supercapacitors

We report a porous carbon material (NPCM) with a high N content as a high-performance supercapacitor electrode material which was prepared by a simple activation-doping process using Metaplexis Japonica shell as the carbon precursor, ammonium chloride as the nitrogen source and zinc chloride as the activation agent. Its high electrical conductivity, large ion-accessible surface area and fast ion transport ability make it possible to achieve a high mass loading of NPCM per area of the electrode and a high energy and high power density supercapacitor. An electrode with a low NPCM mass loading of 1 mg cm(-2) has a gravimetric specific capacitance of 457 F g(-1) and an areal specific capacitance of 47.8 mu F cm(-2). At a much high NPCM loading of 17.7 mg cm(-2) it has a high gravimetric capacitance of 161 F g(-1). Furthermore, an assembled NPCM//NPCM symmetric supercapacitor with an optimal NPCM loading of 12.3 mg cm-2 delivered a high specific energy of 12.5 Wh kg(-1) at an ultrahigh power of 80 kW kg(-1) in 1 mol L-1 Na2SO4. The achievement of such high-energy and high-power densities using NPCM will open exciting opportunities for carbon-based supercapacitors in many different applications.

Automated summary

A porous carbon material (NPCM) with high N content was prepared by a simple activation-doping process and used as a high-performance supercapacitor electrode material. The NPCM exhibited high electrical conductivity, large ion-accessible surface area, and fast ion transport ability, leading to high specific capacitance and capacitance density. Assembled symmetric supercapacitors using NPCM showed high specific energy and power densities, indicating promising applications in various fields.