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The article is... light on details. Even with the wikipedia article [0] I'm having a hard time seeing how the pieces fit together. What's the interface between

The article is... light on details. Even with the wikipedia article [0] I'm having a hard time seeing how the pieces fit together. What's the interface between the air and the electrolyte, and the interface between the electrodes and the grid? It can't quite just be some wires connected to a bunch of FeO powder in a pool, right? Also, it seems like in the charging process, they crack water to get back the H2 they consumed while discharging, and just throw off the oxygen. Because the discharge process involves using the Fe to crack water into H2 and O and immediately running the H2 through a fuel cell to get H2O again. I guess that's easier than just storing H2 and running it back and forth through a fuel cell? Am I just tired or is this wiki article written kind of badly? Anyway, it sounds like the company in the OP is based on figuring out implementation details rather than brand new technology, which is kind of encouraging, as these things go. [0] https://en.wikipedia.org/wiki/Metal%E2%80%93air_electrochemical_cell#Iron https://en.wikipedia.org/wiki/Metal%E2%80%93air_electrochemi...

abdullahkhalids 2y ago
In a hydrogen fuel cell, you have stored hydrogen. Whenever you want electricity, you combine it with oxygen to produce water. You can also drive the fuel cell in reverse, using an external source of electricity to convert water into hydrogen (which is stored)+oxygen. In the iron-air cell, they are adding another layer of the process on top of the above, to avoid storing hydrogen. To store power in the cell, you use electricity to break down water into hydrogen+oxygen. The hydrogen is then immediately reacted with FeO/rust to create Iron+water. These two are easy to store. To get power from the cell, you allow the iron to combine with water, i.e iron+water=Rust+Hydrogen. The hydrogen is then immediately used in the fuel cell to produce electricity.
- taskforcegemini 2y ago
  not a day goes by where hn doesn't try to convince that rust is the future. jokes aside, thank you for this explanation.
- abdullahkhalids 2y ago
  Next day, comment, mostly to myself as an alternate way of writing the above. In a hydrogen fuel cell: Storage: electricity + water -> hydrogen + oxygen. Hydrogen is stored. Consume: hydrogen + oxygen -> water + electricity In the iron-air cell: Storage: (electricity + water) + rust -> oxygen + (hydrogen + rust) -> oxygen + water + iron. The iron is stored. Consume: (iron + water) + oxygen -> rust + (hydrogen + oxygen) -> rust + water + electricity Not as readable as I thought writing it.
pjc50 2y ago
It's just a press release. We're a long way from seeing any kind of details. There isn't even a picture of a lab setup. "Form Energy" seem a bit closer to actually building things. https://www.energy-storage.news/startup-form-energys-100-hour-iron-air-battery-tech-attracts-another-us-utilitys-attention/ https://www.energy-storage.news/startup-form-energys-100-hou...

abdullahkhalids 2y ago

In a hydrogen fuel cell, you have stored hydrogen. Whenever you want electricity, you combine it with oxygen to produce water. You can also drive the fuel cell in reverse, using an external source of electricity to convert water into hydrogen (which is stored)+oxygen. In the iron-air cell, they are adding another layer of the process on top of the above, to avoid storing hydrogen. To store power in the cell, you use electricity to break down water into hydrogen+oxygen. The hydrogen is then immediately reacted with FeO/rust to create Iron+water. These two are easy to store. To get power from the cell, you allow the iron to combine with water, i.e iron+water=Rust+Hydrogen. The hydrogen is then immediately used in the fuel cell to produce electricity.

taskforcegemini 2y ago
not a day goes by where hn doesn't try to convince that rust is the future. jokes aside, thank you for this explanation.
abdullahkhalids 2y ago
Next day, comment, mostly to myself as an alternate way of writing the above. In a hydrogen fuel cell: Storage: electricity + water -> hydrogen + oxygen. Hydrogen is stored. Consume: hydrogen + oxygen -> water + electricity In the iron-air cell: Storage: (electricity + water) + rust -> oxygen + (hydrogen + rust) -> oxygen + water + iron. The iron is stored. Consume: (iron + water) + oxygen -> rust + (hydrogen + oxygen) -> rust + water + electricity Not as readable as I thought writing it.

pjc50 2y ago

It's just a press release. We're a long way from seeing any kind of details. There isn't even a picture of a lab setup. "Form Energy" seem a bit closer to actually building things. https://www.energy-storage.news/startup-form-energys-100-hour-iron-air-battery-tech-attracts-another-us-utilitys-attention/ https://www.energy-storage.news/startup-form-energys-100-hou...