Effect of surfactant on the morphology and capacitive performance of porous NiCo2O4

A promising nickel cobaltite oxide (NiCo2O4) composite electrode material was successfully synthesized by a sol-gel method and followed by a simple sintering process. The microstructure and surface morphology of NiCo2O4 modified by hexadecyltrimethylammonium bromide (CTAB) and polyvinyl alcohol were physically characterized by powder X-ray diffraction and scanning electron microscopy. Meanwhile, electrochemical performance was widely investigated in 2 M KOH aqueous electrolyte using cyclic voltammetry, galvanostatic charge-discharge test, and electrochemical impedance spectroscopy. The results show that evident porous microstructure was successfully fabricated by CTAB. The NiCo2O4 controlled by CTAB exhibited highly specific capacitance of 1,440 F g−1 at a current density of 5 mA cm−2. Remarkably, it still displays desirable cycle retention of 94.1 % over 1,000 cycle numbers at a current density of 20 mA cm−2. The excellent electrochemical performance suggests its potential application in electrode material for electrochemical capacitors.