Hierarchical porous nitrogen-doped graphite from tissue paper as efficient electrode material for symmetric supercapacitor

Hierarchical porous nitrogen-doped graphite from tissue paper (N-ATG) is synthesized and used as symmetric supercapacitor electrode material. Electrochemical characterizations show that the N-ATG has an ultrahigh capacitance of 696 F g(-1) (473 F cm(-3)) at 0.5 A g(-1) and mass loading of 1 mg cm(-2), in 6 mol L-1 KOH solution. The capacitance retention rate is 49.6% at 80 A g(-1) from mass loading of 1 mg cm(-2) to 20 mg cm(-2). The energy densities of the N-ATG are 24.2 and 9.8 Wh kg(-1) (i.e. 16.5 and 6.7 Wh L-1) at power densities of 320 and 39831 W kg(-1) (i.e. 218 and 27085 W L-1), respectively, which rank the highest performances especially at high power densities among heteroatom-doped carbon electrodes. The N-ATG possesses ultrahigh specific surface area of 2327 m(2) g(-1), large average pore diameter of 10.3 nm, high contents of doped N (6.5 at.%), graphitized structure with 1-5 graphene layers and widened lattice distance, dense defects, and high packing density (0.68 g cm(-3)), which account for the excellent gravimetric and volumetric capacitances as well as the high rate capacity.

Automated summary

Hierarchical porous nitrogen-doped graphite from tissue paper (N-ATG) shows excellent performance as a symmetric supercapacitor electrode material, with ultra-high capacitance and energy densities suitable for high power density operations. Its key features include high specific surface area, large pore diameter, high nitrogen doping content, graphitized structure with widened lattice distance, dense defects and high packing density, which contribute to its outstanding performance.