Recent developments in materials for aluminum–air batteries: A review

The aluminum–air battery is an attractive candidate as a metal–air battery because of its high theoretical electrochemical equivalent value, 2.98Ahg−1, which is higher than those of other active metals, such as magnesium (2.20Ahg−1) and zinc (0.82Ahg−1). This paper provides an overview of recently developed materials for aluminum–air batteries to be used in various elements, including the anode, air cathode and electrolyte. Aluminum can be alloyed with other active metal elements such as Tin (Sn), Indium (In), Gallium (Ga) and Zinc (Zn). Its binary and tertiary alloys demonstrate improved battery performance. Bifunctional air cathodes fabricated using oxygen reduction reaction (ORR) catalysts, CoO/N-CNT with oxygen evolution reaction (OER) catalysts, Ni–Fe-layered double hydroxide/CNT and MnO2/N-CNT yield excellent results. With regard to electrolytes, several types have been considered: aqueous, non-aqueous, aprotic solvent and solid-state electrolytes. The addition of corrosion inhibitors to an aqueous electrolyte helps to enhance battery performance, whereas non-aqueous and aprotic solvent electrolytes can be used to prevent hydrogen evolution. Polymer electrolytes can overcome the battery leakage problem. As a conclusion, the future research trends related to this type of battery have also been indicated.