Influence of cerium on microstructures and electrochemical properties of Al-Mg-Sn-Hg anode materials for seawater battery

Aluminum is an innovative anode material for seawater battery. But large polarization and low electrochemical activity restrict its application. In this research, Al-Mg-Sn-Hg-Ce anode materials were prepared and the microstructures were investigated by scanning electron microscopy (SEM). The electrochemical properties of Al-Mg-Sn-Hg-Ce anode materials were measured by potentiodynamic polarization and potential-time discharge in a 4.5 wt.%NaOH solution at 353 K. The results indicated that the increasing content of cerium addition refined the grain structure of Al-Mg-Sn-Hg alloy and promoted the uniform distribution of Sn and Hg elements in Al matrix. The morphology of second phases changed from disperse granular to intergranulate strip with the increasing content of cerium addition in Al-Mg-Sn-Hg alloy. During the half-cell tests at a 650 mA/cm3 current density, the discharge activity of Al-Mg-Sn-Hg-Ce alloy was improved with the increasing content of cerium addition. The average discharge potential of Al-Mg-Sn-Hg-0.3 wt.%Ce alloy was −1.721 V (vs. SCE), which was more negative than −1.406 V (vs. SCE) in AZ91D. The best corrosion resistance occurred in Al-Mg-Sn-Hg-0.05 wt.%Ce alloy with the corrosion current density, 18.84± 2.21 mA/cm2. The corrosion behaviours of Al-Mg-Sn-Hg-Ce alloys were also analyzed.

Graphical AbstractPolarization curves of Al-Mg-Sn-Hg-Ce alloys in a 4.5 wt.% NaOH solution at 353 KFigure optionsDownload as PowerPoint slide