Nitrogen-doped porous carbon simply prepared by pyrolyzing a nitrogen-containing organic salt for supercapacitors

•Carbons were simply prepared by pyrolysis of nitrogen-containing organic salt.•The carbons have developed porosity and rich nitrogen element.•The carbon exhibits high capacitance in aqueous supercapacitors.•It also shows excellent rate capability and cycle durability.

Nitrogen-doped porous carbons are very simply prepared by direct pyrolysis of a nitrogen-containing organic salt, the tetrasodium salt of ethylenediamine tetraacetic acid for example, at 600–900 °C in an inert atmosphere without activation. The porosity and surface chemistry of the carbon depend strongly on the pyrolysis temperature. The surface area and pore volume increase with the pyrolysis temperature, and vary from 408 to 1171 m2 g−1 and 0.209 to 0.709 cm3 g−1, respectively. While the nitrogen content decreases from 8.59 at% for pyrolysis at 600 °C to 1.02 at% at 900 °C. The unique microstructure and nitrogen functionalities enable the carbon to exhibit a capacitance of 245 F g−1 in a 6 mol L−1 KOH aqueous electrolytes, which is attributed to the contributions of double layer capacitance and pseudo-capacitance, with an excellent rate capability (188 F g−1 remained at 20 A g−1) and cycle durability.

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