Aluminum (Al) is an attractive candidate anode material for
metal–air batteries because it has a high theoretical electrochemi-
cal equivalent value, 2.98 A h g1, which is the second highest after
that of lithium (3.86 A h g1) and higher than those of other active
metals, such as magnesium (2.20 A h g1) and zinc (0.82 A h g1)
[16–18]. Aluminum is also an inexpensive metal, as it is the second
most abundant metallic element after silicon, and is characterized
by its environmental friendliness, non-toxicity and high recyclability
[19]. The theoretical specific energy of an Al–air battery with
an alkaline electrolyte can be as high as 200 W h kg1, and with a
neutral salt solution, it is between 300 W h kg1 and 500 W h kg1
[18]. In this paper, we will provide an overview of recent material
developments for various elements of aluminum–air batteries,
including the anode, air cathode and electrolyte. Each component
and material has its own strengths and challenges.