Composite g‐C₃N₄/NiCo₂O₄ with Excellent Electrochemical Impedance as an Electrode for Supercapacitors

Abstract

For the development of supercapacitors, electrode materials with the advantages of simple synthesis and high specific capacitance are one of the very important factors. Herein, we synthesized g‐C 3 N 4 and NiCo 2 O 4 by thermal polymerization method and hydrothermal method, respectively, and finally synthesized NiCo 2 O 4 /g‐C 3 N 4 nanomaterials by mixing, grinding, and calcining g‐C 3 N 4 and NiCo 2 O 4 . NiCo 2 O 4 /g‐C 3 N 4 nanomaterials are characterized by X‐ray diffraction and X‐ray photoelectron spectroscopy. The microscopic morphology, lattice structure, and element distribution of NiCo 2 O 4 /g‐C 3 N 4 nanomaterials were characterized by scanning electron microscopy (SEM), transmission electron microscopy, high resoultion transmission electron microscopy, and mapping methods. The electrochemical performance and cycle stability of NiCo 2 O 4 /g‐C 3 N 4 were tested in a 6 M KOH aqueous solution as electrolyte under a three‐electrode system. Due to the physical mixing structure of g‐C 3 N 4 and NiCo 2 O 4 nanomaterials, the electrochemical energy storage performance of NiCo 2 O 4 /g‐C 3 N 4 supercapacitor electrodes is better than that of NiCo 2 O 4 supercapacitor electrodes. At a current density of 1 A/g, the capacitances of NiCo 2 O 4 and NiCo 2 O 4 /g‐C 3 N 4 are 98.86 and 1,127.71 F/g, respectively. At a current density of 10 A/g, the capacitance of NiCo 2 O 4 /g‐C 3 N 4 supercapacitor electrode maintains 70.5% after 3,000 cycles. NiCo 2 O 4 /g‐C 3 N 4 electrode has excellent electrochemical performance, which may be due to the formation of physical mixing between NiCo 2 O 4 and g‐C 3 N 4 , which has broad application prospects. This research is of great importance for the development of materials in high‐performance energy storage devices, catalysis, sensors, and other applications.