A MASSACHUSETTS energy firm has developed an iron-based battery that can store electricity for four days using a novel method called “reverse rusting”.
Form Energy’s iron-air batteries can output electricity by using oxygen to convert iron metal into air, and then reverse this reaction by expelling the oxygen when they need to charge.
The technology, first developed by NASA in the 1960s, has proven popular as a form of renewable energy storage in the US.
Form has already established projects in several states, and secured US$405m from its recent funding round, taking its total investment to US$1.2bn.
A spokesperson for the company said: “For the electric grid long-duration energy storage (LDES) batteries have huge potential. For multi-day periods, it is helpful to have a battery that is capable of dispatching a lot of energy but dispatching it slowly.”