An inorganic-organic protective anode interface towards high‐performance Al-air battery

Aqueous aluminium-air batteries (AABs) are promising candidates for next-generation energy storage devices owing to their high theoretical voltage and theoretical capacity of 2.98 Ah g−1 with additional advantages of aluminium (Al) being abundant, cost-effective, and recyclable. Despite striking advantages, practical application of Al-air batteries is hindered by undesirable self-corrosion and passivation of Al surface, as well as severe hydrogen evolution reaction (HER), thereby reducing anodic efficiency and battery capacity. To address these issues, herein, a dual protective coating comprising LDH-PVA-acetal as an inorganic-organic hybrid material has been developed. This coating forms a stable film over the Al substrate and synergistically suppresses self-corrosion and HER by blocking bulk water molecules from direct contact with the Al anode along with slow diffused release of hydroxide ions. The battery assembled utilizing LDH-PVA-acetal/Al as anode demonstrates an outstanding capacity of 2577 mAh g−1 and 2698 mAh g−1 with 86.4% and 90.5% anodic utilization @30 mA cm−2 and 50 mA cm−2. A waste beverage can coated with LDH-PVA-acetal showed practical applicability towards waste to wealth, thus, demonstrating potential application towards corrosion inhibition in alkaline media for other metals as well.