Electrochemical Properties of Al-based Solid Solutions Alloyed by Element Mg, Ga, Zn and Mn under the Guide of First Principles

Molecular simulation method was firstly used for analyzing the energy of aluminum alloy systems alloyed by Mg, Ga, Zn and Mn. Based on the analyses, Al-Mg, Al-Ga, Al-Zn, Al-Mn alloys were metallurgically prepared. The structures, electrochemical activities and utilization ratios were characterized by X-ray diffraction patterns (XRD), anodic polarization measurement and galvanostatic discharge. The calculated energies of the aluminum alloy systems increase in the following order: Al< Al-Mn < Al-Mg < Al-Zn < Al-Ga. The absolute values of the open circuit potentials of the alloys measured in alkaline solution rank in the following orders: phi(Al-Ga alloy) > phi(Al-Zn alloy) > phi(Al-Mg alloy) > phi(Al-Mn alloy) and the order is consistent with the calculated energies. The results indicate that molecular simulation based on the first-principles is a useful method in the alloying design and thermodynamic performance prediction. Alloy additives Zn and Ga effectively change the open circuit potential of metal aluminum to a more negative potential. In addition, alloy additive Zn increases the charge transfer resistance of AlAl3+, which decreases the discharge current density. Alloy additive Mg diminishes the grain size of the alloy and notably enhances the discharge current density. Alloy additive Mn improves the utilization ratio remarkably when discharging in alkaline solution.