The preparation and electrochemical performances of the composite materials of CeO2 and ZnO as anode material for Ni–Zn secondary batteries

The composite materials of CeO2 and ZnO (CeO2/ZnO) were prepared by one step hydrothermal method. The X-ray diffraction (XRD) patterns reveal that CeO2 does not enter the lattice of ZnO and no new phase is generated. The energy dispersive spectrometer (EDS) spectra of CeO2/ZnO demonstrates that the elemental composition on the surface of CeO2/ZnO is Ce, Zn, O. The scanning electron microscopy (SEM) images of CeO2/ZnO and pure ZnO show that the grain sizes of CeO2/ZnO significantly increased after compositing and part of CeO2 coating on the surface of ZnO. Tafel plot, cyclic voltammetry (CV), electrochemical impedance spectroscope (EIS) and galvanostatic charge–discharge measurements were utilized to examine the electrochemical performances of CeO2/ZnO. Compared with pure ZnO and ZnO physical mixed with CeO2 (ZMC), the CeO2/ZnO have a more positive corrosion potential in the zinc electrodes which indicates the CeO2/ZnO has a good anticorrosion ability. A lower charge platform and a flatter discharge platform of CeO2/ZnO indicate that the CeO2/ZnO have a better charge/discharge performance as anodic material for Ni/Zn cells. Most important of all, the CeO2/ZnO anodes show much more stable cycle stability. At the 50th cycle, the discharge capacity of pure ZnO anode reduces to 358.4 mAh g−1 at 1 C with the capacity retention ratio of 68%, while the capacity retention ratio of CeO2/ZnO anodes are 96.7%, 99.1% and 95.2%, respectively.