Supercapacitance of core-shell hierarchical porous nitrogen-doped carbon in non-aqueous electrolyte

Abstract

Abstract Uniform nitrogen-doped carbon sphere with a 250 nm diameter macro hollow core and 75 nm thick shell structure containing 8 nm mesopores is synthesized from a silica hard template. The synthesized nitrogen doped hollow core mesoporous shell carbon (Fe-N-HCMS) presents excellent supercapacitor performance with a capacitance of 352 F g−1 (0.5 A g−1) in 0.5 M H2SO4 and a capacitance of 189.4 F g−1 (0.5 A g−1) in 1 M TEABF4/ACN. The capacitance retention of Fe-N-HCMS carbon is as high as 92% after tests of 8000 repeating cycles. The improved high-rate performance of Fe-N-HCMS carbon is ascribed to the high surface area (1788 m2 g−1), large pore volume (3.98 cm3 g−1), well-defined mesopores, leading to lower transport resistance and a thin diffusion layer. The enhanced durability of Fe-N-HCMS carbon also results from improved mechanical strength and better electrical conductivity with a higher graphitic content.