Influence of small amount of Mg incorporated into hexagonal ZnO crystal on cell performance in membrane free Zinc–Nickel redox battery

Abstract

This study focused on improving the cell efficiency of Zinc–Nickel redox battery. The cycle life of zinc anodic material in KOH alkaline electrolyte was enhanced by small amount of Mg insertion into ZnO framework through a typical hydrothermal method. The as-prepared ZnO and MgxZn1−xO (x=0.001, 0.0025, and 0.005) anodic materials before and after charging/discharging test were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectrometer (EDX) to investigate the effect of inserted Mg ions on the zinc dendrite growth. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were utilized to examine the electrochemical performances of Mg-inserted ZnO as anodic material. The Mg-inserted ZnO–Ni membrane free redox batteries possess higher discharge voltage, higher cycle stability, lower corrosion current, and smaller charge-transfer resistance in comparison with bare ZnO. In addition, the redox cell efficiency was 85% in the ZnO anodic material inserted Mg of 0.0025mol even after 100 cycles.