Whizzes' lithium-iron-oxide battery 'octuples' capacity on the cheap

Illinois team says cell tech great for mobes and 'leccy cars

A band of boffins from Illinois have published a paper detailing a new battery design for mobile devices and electric vehicles that could increase capacity up to eight times while reducing costs.

One half of the team, based at Northwestern University, focused on making digital models, while their partners at Argonne National Laboratory performed the physical experiments. The two groups then wrote the paper, titled "Enabling the high capacity of lithium-rich anti-fluorite lithium iron oxide by simultaneous anionic and cationic redox", together, publishing it in the journal Nature Energy.

The design features an iron-oxide cathode in the place of the normal cobalt-oxide one. Iron is cheaper than cobalt, and would decrease the price of batteries should it be adopted commercially.

The other major development is the successful use of oxygen ions in the battery's reactions.

Zhenpeng Yao, PhD student at Northwestern's McCormick School of Engineering and one of the paper's lead authors, explained the issue with utilising the gas. "The problem previously was that often, if you tried to get oxygen to participate in the reaction, the compound would become unstable. Oxygen would be released from the battery, making the reaction irreversible."

Using digital models, Northwestern found a specific mix of lithium, iron and oxygen ions that will allow the use of oxygen without it escaping the cell.

Using oxygen to transfer electrons allows the use of four times the standard quantity of lithium in the battery, therefore increasing the amount of usable energy it produces.

"Four lithium ions for each metal would change everything" said Christopher Wolverton, professor of materials science and engineering at McCormick.

"That means that your phone could last eight times longer or your car could drive eight times farther. If battery-powered cars can compete with or exceed gasoline-powered cars in terms of range and cost, that will change the world.

"Not only does the battery have an interesting chemistry because we're getting electrons from both the metal and oxygen, but we're using iron. That has the potential to make a better battery that is also cheap."

The Register asked George Brocklehurst, research director for semiconductors and electronics at Gartner, for his take on the announcement.

"This seems a lot more embryonic than most battery advancements," he said. "Beyond a computer simulation there are no indications as to the practicalities of producing at volume, and implementing this technology in real world use-cases.

"In the article it mentions an 8x increase on capacity, but in the paper they are only talking about doubling (maybe tripling).

"As things move towards production and you start hitting it with the real conditions of a use case, we only tend to see a reduction in performance so 2x today might become 1.5x on a production part and maybe 1.2-1.3x in worst case conditions.

"If successful, I think it's easy to say it's more than five years away at a minimum, probably closer to 10."

The team has filed a provisional patent for the design, and now intends to test the capabilities of other compounds using the same method. ®




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