Shape‐Controlled Synthesis of NiCo2O4 and Its Supercapacitive Performance

NiCo2O4 was obtained by a hydrothermal synthesis method through adjusting different types of surfactants, followed by calcining at 350 °C. X‐ray diffraction analyses demonstrate that addition of surfactant affects the crystallite size and the phase purity of NiCo2O4. Scanning electron microscopy images show that addition of sodium dodecyl sulfate has a great influence on the morphology of NiCo2O4. However, the morphology of NiCo2O4 prepared with addition of Triton X‐100 or cetyl trimethyl ammonium bromide slightly change. Cyclic voltammetry and chronopotentiometry of NiCo2O4 was studied by electrochemical workstation. Results show that addition of surfactants have a great influence on its capacitive performance. Compared with NiCo2O4 prepared without any surfactants, NiCo2O4 synthesized with addition of sodium dodecyl sulfate shows higher specific capacitance. However, NiCo2O4 obtained with addition of Triton X‐100 or cetyl trimethyl ammonium bromide exhibits lower specific capacitance. Meanwhile, NiCo2O4 synthesized with addition of sodium dodecyl sulfate shows better cycling stability than that synthesized without any surfactants, with addition of Triton X‐100 or cetyl trimethyl ammonium bromide. The morphology of NiCo2O4 was controlled by a hydrothermal method through changing surfactants and the effect of different surfactants on the capacitive properties of NiCo2O4 was studied. Compared with NiCo2O4 prepared without any surfactants, NiCo2O4 synthesized with addition of sodium dodecyl sulfate shows higher specific capacitance and good cycling stability. Whereas, NiCo2O4 prepared with addition of Triton X‐100 or cetyl trimethyl ammonium bromide exhibits lower specific capacitance and relatively poor cycling stability.