Electrochemical performances of ZnO with different morphology as anodic materials for Ni/Zn secondary batteries

The hollow fusiform ZnO and the hexagonal taper-like ZnO have been prepared by hydrothermal method. The synthetic materials have been characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). As anodic materials for Ni/Zn cells, electrochemical performances of the hollow fusiform ZnO and the hexagonal taper-like ZnO have been investigated by cyclic voltammetry (CV) and galvanostatic charge–discharge measurement. Compared to the conventional ZnO, the hollow fusiform ZnO and the hexagonal taper-like ZnO have shown better cycle stability than the conventional ZnO. Furthermore, the initial discharge capacity of hollow fusiform ZnO is 476 mAh g−1, and the discharge capacity is almost unchangeable with the capacity retention ratio of 99.5% over 50 cycles. Comparatively, the hexagonal taper-like ZnO delivers an initial discharge capacity of 470 mAh g−1 and with the capacity retention ratio of 94.7% over 50 cycles. They are much higher than that of the conventional ZnO. The better electrochemical performance is attributed to higher electrochemical activity, which is ascribed to the novel initial morphology and size of as-prepared ZnO active material. And the formation of zinc dendrite is suppressed much essentially, the reason could be attributable to initial morphology of the active materials. And the zinc dendrite is suppressed effectively, which results in improvement of cycle stability of Ni/Zn secondary cells.