Sun Kanjun,Li Jindan,Peng Hui,Feng Enke,Ma Guofu,Lei Ziqiang
Nitrogen-doped porous activated carbons (N-PHACs) have been successfully synthesized using pomegranate husk as carbon precursor via ZnCl 2 -activation carbonization and subsequent urea-assisted hydrothermal nitrogen-doping method. The obtained N-PHACs possesses abundant mesoporous structure, high specific surface area (up to 1754.8 m 2 g −1 ), pore volume (1.05 cm 3 g −1 ), and nitrogen-doping content (4.51 wt%). Besides, the N-PHACs-based material showed a high specific capacitance of 254 F g −1 at a current density of 0.5 A g −1 and excellent rate performance (73% capacitance retention ratio even at 20 A g −1 ) in 2 M KOH aqueous electrolyte, which is attributed to the contribution of double-layer capacitance and pseudocapacitance. The assembled N-PHACs-based symmetric capacitor with a wide operating voltage range of 0–1.8 V exhibits a maximum energy density of 15.3 Wh kg −1 at a power density of 225 W kg −1 and superior cycle stability (only 6% loss after 5000 cycles) in 0.5 M Na 2 SO 4 aqueous electrolyte. These exciting results suggest that the novel N-doping porous carbon material prepared by a green and low-cost design strategy has a potential application as high-performance electrode materials for supercapacitors.
Guofu Ma,Dongyang Guo,Kanjun Sun,Hui Peng,Qian Yang,Xiaozhong Zhou,Xiaolong Zhao,Ziqiang Lei
Cotton-based porous activated carbons (CACs) are prepared through a simple chemical activation method using cotton fiber as carbon source and ZnCl2 as activating agent. Powder X-ray diffraction, scanning electron microscopy, and N2 adsorption–desorption tests demonstrate that the carbons activated with different amounts of ZnCl2 have a large number of mesopores, notably, a maximum specific surface area of 2548.6 m2 g−1 and ultrahigh pore volume of 1.54 cm3 g−1 for CAC2 sample are obtained when the cotton/ZnCl2 mass ratio is 1 : 2. As an electrode material for supercapacitors, the CAC2 possesses a high specific capacitance of 239 F g−1 at 0.5 A g−1 and good rate capability (82% capacitance retention even at 8 A g−1) in 2 mol L−1 KOH aqueous electrolyte. Moreover, the as-assembled CAC2//CAC2 symmetric supercapacitor exhibits a high energy density of 13.75 Wh kg−1 at a power density of 225 W kg−1 operated at the voltage range of 0 to 1.8 V in 0.5 mol L−1 Na2SO4 aqueous electrolyte and an excellent cyclability retaining about 93% initial capacitance after 5000 cycles.
危险品化学品经营许可证（带存储）