Metal-air battery is an environmental friendly energy storage system
with unique open structure. Magnesium (Mg) and its alloys have been
extensively attempted as anodes for air batteries due to high
theoretical energy density, low cost, and recyclability. However, the
study on Mg-air battery (MAB) is still at the laboratory level
currently, mainly owing to the low anodic efficiency caused by the poor
corrosion resistance. In order to reduce corrosion losses and achieve
optimal utilization efficiency of Mg anode, the design strategies are
reviewed from microstructure perspectives. Firstly, the corrosion
behaviors have been discussed, especially the negative difference effect
derived by hydrogen evolution. Special attention is given to the effect
of anode micro-structures on the MAB, which includes grain size, grain
orientation, second phases, crystal structure, twins, and dislocations.
For further improvement, the discharge performance, long period stacking
ordered phase and its enhancing effect are considered. Meanwhile, given
the current debates over Mg dendrites, the potential risk, the impact
on discharge, and the elimination strategies are discussed.
Microstructure control and single crystal would be promising ways for
MAB anode.
Keywords
Magnesium;Air battery;Anode;Microstructure;Anodic efficiency
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