Synthesis of Mesoporous Co₃O₄/NiCo₂O₄ Nanorods and Their Electrochemical Study.

Mesoporous Co₃O₄/NiCo₂O₄ nanorods were obtained by a hydrothermal reaction with the assistance of Ni foam and subsequent annealing treatment. The characterization of this composition by X-ray diffraction, X-ray photoelectron spectroscopy, high-resolution transmission electron microscopy, energy dispersive spectra and Brunauer-Emmett-Teller analysis revealed that the nanorods consisted of Co₃O₄ and NiCo₂O₄ phase, exhibiting high porosity and rich crystal defects. The electrochemical data showed a specific capacitance of 1173 mF cm-2 and 606 mF cm-2 at 2 mV s-1 and 1 mA cm-2, respectively. Its cycling performance was 83.9% at 3 mA cm-2 after 4000 cycles. Furthermore, the asymmetric supercapacitor Co₃O₄/NiCo₂O₄//AC delivered an energy density of 11.7 W h kg-1 and power density of 760 W kg-1.