Aluminum-air batteries have one of the highest theoretical energy densities of any storage chemistry, around 8,100 Wh per kilogram, but they have not become a commercial product. A review in Frontiers in Batteries and Electrochemistry explains why. The aluminum anode corrodes in alkaline electrolytes, solid aluminum hydroxide builds up and blocks the reaction, and the air cathode needs better catalysts to keep oxygen reduction efficient. Researchers are testing MOF-derived catalysts and protective coatings, but the article stresses that no single fix works on its own. Full-cell testing is the missing step. Most studies focus on one electrode, while real problems show up when anode byproducts poison the cathode or cathode inefficiency drains the electrolyte. If those integration issues are solved, aluminum-air could offer low-cost, long-duration storage for renewable energy. For now it remains a promising chemistry that needs to prove itself in complete prototypes, not just half-cell tests.
