Hemispherical flower-like N-doped porous carbon/NiCo2O4 hybrid electrode for supercapacitors

Abstract

The N-doped porous carbon/NiCo2O4 (NPC/NiCo2O4) substance is designed and synthesized via hydrothermal treatment, polymerization, carbonization, activation, and chemical bath deposition. The as-prepared NPC/NiCo2O4 holds hemispherical flower-like structure that consists of two things: a porous bowl-shaped NPC at the inside, and sheet NiCo2O4 at the whole outside, in which NPC works as a scaffold for NiCo2O4 to restrain NiCo2O4 nanosheets from aggregation in the synthesis process and NiCo2O4 acts as a capacitive coating layer, and causing a synergic effect. The composite electrode has a specific capacitance of 948.30 F g−1 at a current density of 1 A g−1, enhanced rate capability (727.43 F g−1 at 16 A g−1) and good conductivity. Additionally, NPC/NiCo2O4 reaches a desirable cycling stability (87.4% capacitance retention after 2000 cycles even at a high current density of 10 A g−1), suggesting a hopeful electrode material for the electrochemical supercapacitors.