Influence of MgO on the Electrochemical Performance of Nickel Electrode in Alkaline Aqueous Electrolyte

beta-nickel hydroxide (beta-Ni(OH)(2)) was prepared using precipitation method. Magnesium oxide (MgO) was synthesized by solution combustion method using magnesium nitrate as oxidizer and urea as a fuel. The effects of MgO additive on the structure and electrochemical performance of beta-Ni(OH)(2) electrode are examined. The structure and property of the MgO added beta-Ni(OH)(2) were characterized by X-ray diffraction (XRD), thermal gravimetric-differential thermal analysis (TG-DTA), Scanning electron microscopy (SEM), and Energy Dispersive X-ray (EDX) analysis. The results of the TG-DTA studies indicate that the MgO added beta-Ni(OH)(2) contains adsorbed water molecules and anions. Partial substitution of MgO for graphite to beta-nickel hydroxide is found to exhibit improvement in the electrochemical activity. Anodic peak potential (Epa) and cathodic peak potential (Epc) values are found to decrease remarkably after the incorporation of MgO into the beta-Ni(OH)(2) electrode. Further, addition of MgO is found to enhance the reversibility of the electrode reaction. Compared with beta-Ni(OH)(2) electrode, MgO substituted beta-Ni(OH)(2) electrode is found to exhibit higher proton diffusion coefficient. These findings suggest that the MgO substituted beta-Ni(OH)(2) electrode possess improved electrochemical properties such as enhanced reversibility of electrode reaction and higher proton diffusion coefficient and thus can be recognized as a promising candidate for the battery electrode applications.