Hydrothermal Synthesis and Electrochemical Li-storage Performances of NiCo2O4@C Nanocomposite

Rodlike NiCo2O4 precursor was prepored via one. step hydrothermal method and then a series of NiCo2O4 and NiCo2O4@C products was prepared by regulating the amount of glucose as well as the calcination conditions such as calcination temperature and atmosphere. The products were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy and charge/discharge testing, cyclic voltammetry and electrochemical impedance spectroscopy. The results show that proper amount of glucose(0.5 g) in conjunction with appropriate post. calcination conditions can produce NiCo2O4@C nanocomposite with good rate capability and cycling stability. At a current density of 100 mA/g, the material demonstrated the charge/discharge capacities of 634.1/767.2 mA . h/g, corresponding to a Coulombic efficiency of 82.7%, and maintained the discharge capacity of 650.1 mA . h/g after five cycles with a retention rate of 84.74%. Furthermore, at a higher current density of 300 mA/g, the material could still afford a high reversible capacity of 225. 9 mA . h/g.