World's largest iron-air battery

Really interesting developments are happening in battery technologies. One alternative to the lithium-ion battery that we’re all familiar with from our phones, laptops, and EVs is iron-air technology. This is the specialty of Form Energy, who just agreed to a deal with Google for a giant energy-storage facility in Minnesota. Lithium-ion is great, and a key technology that continues to come down in cost as it continues to be deployed all over the place. But it doesn’t have the long-term ability that iron-air does:

While lithium-ion batteries are effective for 4-hour shifts, they cannot handle the multi-day storage. Form Energy said its iron-air batteries can store renewables-sourced electricity for 100 hours at system costs competitive with conventional power plants.

The technology itself is fascinating: the energy is actually stored in rust, which can then be de-rusted:

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.

The technology is less energy-dense than its lithium-ion counterparts, making it a better fit for large grid-scale applications. Form Energy said an individual battery module is about the size of a side-by-side washer/dryer set and contains a stack of approximately 50 one meter-tall cells. The cells include iron and air electrodes, the parts of the battery that enable the electrochemical reactions to store and discharge electricity. Each of these cells are filled with water-based, non-flammable electrolyte, like the electrolyte used in AA batteries.

This is the kind of thing that research and government support dollars should be going to (as opposed to, say, continuing to prop up the dirty, ugly coal industry).