Electrochemical Performance and Interface Analysis of Al-MgO Composite Anodes for Al-air Batteries

Al-0.5 wt.% MgO, Al-1 wt.% MgO, Al-1.5 wt.% MgO and pure Al anodes were prepared to investigate the effect of MgO particles addition on the electrochemical performance of aluminum anode for Al-air batteries in alkaline electrolyte. The electrochemical performance of these battery devices, including anodic polarization, corrosion characteristics, hydrogen evolution rate, AC impedance, and discharge behavior was examined and analyzed comparatively in 4 M KOH solution. The results show that Al-0.5 wt.% MgO, Al-1 wt.% MgO composite anodes exhibit a negative shift in the open-circuit potential compared with pure Al anode. Appropriate amount of MgO addition obviously improves the electrochemical activity, corrosion resistance and anode utilization of pure Al anode. These behaviors should be related to the interface characteristic of MgO particles with Al matrix which helps to destroy the integrity and compactness of the oxide layer on anode surface. The influence of MgO addition on the corrosion resistance of composite Al anode is well explained by the energy band and state density calculation based on density functional theory.