To run the grid reliably and affordably, we need new cost-effective technologies capable of storing electricity for multiple days. Form Energy reinvented and optimized the iron-air battery for the electric grid. The active components of our iron-air battery system are some of the safest, cheapest, and most abundant materials on the planet — low-cost iron, water, and air.
The iron-air battery is composed of cells filled with thousands of iron pellets that are exposed to air and create rust. The oxygen is then removed, reverting the rust to iron. Controlling this process allows the battery to be charged and discharged.
Source: Form Energy