They have one of the highest energy densities of all batteries, but they are not widely used because of problems with high anode cost and byproduct removal when using traditional electrolytes.
[4] In March 2013, Phinergy[5] released a video demonstration of an electric car using aluminium–air cells driven 330 km using a special cathode and potassium hydroxide.
[6] On May 27, 2013, the Israeli channel 10 evening news broadcast showed a car with Phinergy battery in the back, claiming 2,000 kilometres (1,200 mi) range before replacement of the aluminium anodes is necessary.
[8] Aluminium (Al) has been widely used as an anode material in metal-air batteries due to its high energy density, recyclability, and abundance.
Corrosion reactions produce hydrogen and form aluminium hydroxides, while the formation of an oxide film upon exposure to air or water further limits functionality.
[10] In this study, aluminium anodes with finer grain sizes were created using a method called Equal Channel Angular Pressing (ECAP).
The results showed that refining the grain size improved the anode’s electrochemical activity, reduced corrosion, and increased polarization and charge-transfer resistance.
[11] In addition to refining the microstructure and developing better processing methods, alloying Al with elements like Ga, Zn, and Sn helps mitigate corrosion and hydrogen evolution.
Zinc, in particular, is widely recognized as a beneficial alloying element in Al-air battery anodes because it helps reduce the self-corrosion rate and increases the nominal cell voltage.
The In ions repeatedly create defects within the Type 2 film through a cycle of breakdown and re-passivation, effectively weakening the protective barrier and enhancing the battery's discharge efficiency.
Copper-deposited Al alloys have also shown promise as an anode material, forming protective layers that decrease hydrogen evolution and enhance discharge performance.
From this analysis, Al/air EVs are the most promising candidates compared to ICEs in terms of travel range, purchase price, fuel cost, and life-cycle cost.Technical problems remain to be solved to make Al–air batteries suitable for electric vehicles.
Modern air cathodes consist of a reactive layer of carbon with a nickel-grid current collector, a catalyst (e.g., cobalt), and a porous hydrophobic polytetrafluoroethylene film that prevents electrolyte leakage.
[15] Aluminium–air batteries may become an effective solution for marine applications due to their high energy density, low cost, and the abundance of aluminium, with no emissions at the point of use in boats and ships.
Research and development is taking place on alternative, safer, and higher performance electrolytes such as organic solvents and ionic liquids.