Aluminium is a well-known construction and manufacturing
material due to its lightness and toughness, and is extensively used
in automotive, aerospace or infrastructure industries. There is a
great variety of commercial alloys classified as function of the
mayor alloying. Most of these alloys are focused in enhancing the
mechanical properties of the resulting metal, and so, alloying elements
like Fe, Mg, Zn or Si are commonly present. The use of
commercial alloys as anodes in Al-air batteries could make a revolution
in low-cost energy storage. The main problem is the
spontaneous formation of an oxide film in the Al surface when in
contact with air or aqueous media. The latter results in a protective
layer covering the electrode that shifts the corrosion potential in
the positive direction and the reactivity of the aluminium is slowed
down notoriously [5,7e10]. This change causes a significant
reduction in the available energy and makes Al, in principle, unattractive
as an energy storage material. Nevertheless, many
research groups have focused on developing an Al-air cell because
of his high theoretical cell voltage of 2.4 V, and specific capacity of
2978 mAh g1, comparable to that of lithium 3840 mAh g1, and
much higher than the ones for Na or Zn, 1165 and 830 mAh g1
respectively.