Designing nanographitic domains in N-doped porous carbon foam for high performance supercapacitors

Abstract

Porous carbon with high surface area and low cost has emerged as promising alternative electrode for supercapacitor. However, the poor electrical conductivity arising from the rich existence of sp3 carbon remains a big challenge. Here, a novel strategy is reported for the nanographitic domains (sp2 carbon) distributed in porous carbon via transition metal acetate (M(CH3COO)2 M = Fe, Co, Ni) assistance and in situ N-doping during the activation process. The resultant different N-doped porous carbon foams (denoted as NCF (Fe), NCF (Co), NCF (Ni)) exhibit a localized graphitic structure and hierarchically porous framework with micropore integrating into macroporous scaffold. Whereas, the NCF (Fe) shows ultra-high BET surface areas of up to 2630 m2 g−1, a large pore volume of up to 1.1 cm3 g−1, notable nitrogen content of 5.34 wt %, optimal pore size and superior hydrophilicity. When adopted as supercapacitor electrode, the NCF (Fe) presents a reversible capacity of 273.7 F g−1 in 6 M KOH aqueous electrolyte. Even at a high current of 10 A g−1, a capacity of 200.5 F g−1 can also be achieved, which makes it a potential capacitive material for high-rate supercapacitor. Considering other advantages of the method such as cheap precursor, facile process et al., NCF (Fe) can be rendered to be a promising candidate for commercial supercapacitors.