Nitrogen-doped porous carbons through KOH activation with superior performance in supercapacitors
2014
Zhou, Min | Pu, Fan | Wang, Zhao | Guan, Shiyou
A series of nitrogen-doped porous carbons are prepared through KOH activation of a nonporous nitrogen-enriched carbon which is synthesized by pyrolysis of the polymerized ethylenediamine and carbon tetrachloride. The porosity and nitrogen content of the nitrogen-doped porous carbons depend strongly on the weight ratio of KOH/carbon. As the weight ratio of KOH/carbon increases from 0.5 to 2, the specific surface area increases from 521 to 1913m²g⁻¹, while the nitrogen content decreases from 10.8 to 1.1wt.%. The nitrogen-doped porous carbon prepared with a moderate KOH/carbon weight ratio of 1, which possesses a balanced specific surface area (1463m²g⁻¹) and nitrogen content (3.3wt.%), exhibits the largest specific capacitance of 363Fg⁻¹ at a current density of 0.1Ag⁻¹ in 1M H2SO4 aqueous electrolyte, attributed to the co-contribution of double-layer capacitance and pseudocapacitance. Moreover, it shows excellent rate capability (182Fg⁻¹ remained at 20Ag⁻¹) and good cycling stability (97% capacitance retention over 5000 cycles), making it a promising electrode material for supercapacitors.
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