Synthesis and electrochemical properties of NiCo₂O₄ microsphere

The mesoporous NiCo₂O₄ microsphere was synthesized via a facile hydrothermal method followed by thermal annealing treatment. The surface morphology, valence of the elements and electrochemical performance of the samples were characterized by FESEM, TEM, XPS and the electrochemical workstation. The results show that the as-prepared NiCo₂O₄ microsphere presents 3D structure constructed with rich porous nanoneedles, and deliveres a high specific surface area. The NiCo₂O₄ microsphere electrode reveals amazing pseudocapacitive properties with high specific capacitance (1 554 F · g^-1 at 1 A · g^-1) and a favorable rate capability (87.5% from 1 to 20 A · g^-1) due to the 3D structure. Moreover, the specific capacitance remains 90.4% of its initial value after 2 000 cycles at 5 A · g^-1. The good electrochemical performances indicate that NiCo₂O₄ microsphere could be a promising material for supercapacitor electrode.