Why are iron-air batteries making headlines in 2025?

The answer

In 2025, Form Energy began manufacturing iron-air batteries at scale - a technology that stores electricity by reversibly rusting iron. When the battery discharges, iron plates are exposed to air, forming iron oxide (rust) and releasing electrons. When charging, electricity reverses the process, converting rust back to iron. The key breakthrough: these batteries can store energy for up to 100 hours, compared to 4–6 hours for lithium-ion batteries. Made from abundant, cheap iron instead of scarce lithium or cobalt, they're designed for grid-scale storage to smooth out the intermittent nature of solar and wind power - solving one of renewable energy's biggest challenges.