Electrochemical Performances of Ni-Coated ZnO as an Anode Material for Lithium-Ion Batteries

Ni-coated ZnO was prepared by electroless nickel plating as an anode material for lithium-ion batteries. The microstructure of the Ni-coated ZnO was characterized by means of X-ray diffraction, transmission electron microscopy, and energy dispersive X-ray spectroscopy. The electrochemical properties of the anodes were measured by galvanostatic charge-discharge tests and electrochemical impedance spectroscopy. The results show that the Ni-coated ZnO delivered a higher reversible discharge capacity than the raw ZnO , exhibited good cyclability, and the initial coulombic efficiency of the ZnO was significantly improved after coating (from 49.5% to 75%). The presence of the nickel membrane plays three important roles in the improvement of initial coulombic efficiency and the cycling performance of ZnO. First, nickel as a conductor can improve the high rate properties of ZnO. Second, nickel acts as a buffer to alleviate the stress during cycling. Third, nickel also has the catalytic activity to facilitate decomposition.