This is a Iron fuel cell technically. Iron is trivalent so you can store three electrons per Iron atom , aluminum is also trivalent. Lithium is only bivalent so Iron or aluminum stores 1/3 more electricity per atom that is significant. These won’t pollute the air they take oxygen from the air and turn Fe metal into FeO3 commonly called rust which is nontoxic human routinely eat feric oxide in vitamin pills as a source of dietary Iron. Charging this battery would release life oxygen back to the surrounding air which is already 19% O2 zero pollution unless you consider medical grade pure oxygen as pollution.
They claim one megawatt of power in an acre and they have the time as 100 hours of.discharge so this would mean 100 megawatt hours of storage per acre and they claim three times as much for the high density version 300 mwh per acre is nothing to bawk at. That’s enough for 10,000 homes using an average of 30kWh over a 24 HR period European homes use 10kWh per day or less Americans avg 30 kWh.
The key metric for them is if they can get to $20 kWh for storage capacity they can buy low cost power at night and sell it during the day for ten times or more of the night prices. That alone would make the owners a fortune being a peaker dispatchable source.
I accept the principle. But an ICE combusts with only oxygen from the atmosphere, too, theoretically. There’s theory and actual performance. It’s hard to believe that the other components of Earth’s atmosphere, or impurities in the iron are not going to be involved.
Also, for all of the BS surrounding carbon compounds in emissions, I can’t help but think that the real problem is the consumption of oxygen. This doesn’t help that, at all.