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Organic salt-derived nitrogen-rich,hierarchical porous carbon for ultrafast supercapacitors

发文时间:2018-11-05

Organic salt-derived nitrogen-rich,hierarchical porous carbon for ultrafast supercapacitors

Longfeng Hu, Li Ma, Qizhen Zhu, Lanyong Yu, Qi Wu, Chen Hu, Ning Qiao and Bin Xu*

 

Nitrogen-rich, hierarchical porous carbons with high surface area were simply prepared by direct pyrolysis of a nitrogen-containing organic salt, i.e. ethylenediaminetetraacetic acid calcium disodium salt (EDTANa2Ca), as electrode materials for supercapacitors. Besides micropores originating from the elimination of some **all molecular substances, the template effects of nano-CaO and nano-Na2CO3 particles (the intermediate products derived from EDTANa2Ca) created some meso/macropores, resulting in a developed hierarchical porous structure. As the pyrolysis temperature increases from 600 °C to 850 °C, the nitrogen content decreases from 10.8 at% to 1.48 at%, whereas both the BET surface area and the pore volume increase dramatically. The BET surface area and pore volume of the carbon prepared at 850 °C reach as high as 2015 m2 g−1 and 1.74 cm3 g−1, respectively, and the meso/macropores account for about 70% of the total pore volume. The developed hierarchical porous structure enables the carbon to exhibit excellent rate capability. It can endure an ultrafast scan rate of 5000 mV s−1 and an ultrahigh charge/discharge current up to 200 A g−1 with a capacitance of 115 F g−1 in 6 mol L−1 KOH.