Iron-Air Battery

Iron-air batteries are a rechargeable battery technology built around the reversible rusting of iron, storing and releasing electricity through the oxidation and reduction of iron and iron oxide in a water-based electrolyte exposed to air. Because iron and air are cheap and abundant, the chemistry targets long-duration grid storage that can discharge for many hours at a much lower cost per kilowatt-hour than lithium-ion batteries, rather than short bursts of high power. The theoretical specific energy of the iron-air couple is about 1,431 watt-hours per kilogram including the oxygen drawn from the air, though practical grid systems trade energy density for low cost and long cycle life. Developers have aimed the technology at utilities that need to store solar and wind power for use during periods when renewable generation runs low.