Angewandte Chemie International Edition: Efficient and mild: recycling of used lithium-ion batteries

[OKIsItJustMe]

Angewandte Chemie International Edition
doi.org/10.1002/anie.202310435

Nr. 39/2023
September 5, 2023

Lithium Recovery
Efficient and mild: recycling of used lithium-ion batteries

© Wiley-VCH, re-use with credit to 'Angewandte Chemie' and a link to the original article.

Lithium-ion batteries (LIBs) provide our portable devices like tablets and mobiles—and increasingly also vehicles—with power. As the share of volatile renewable energy needing electricity storage increases, more and more LIBs are needed, lithium prices rise, resources dwindle, and the amount of depleted batteries that contain toxic substances increases. In the journal Angewandte Chemie, researchers introduce a novel approach for the recovery of lithium from used LIBs.

The recycling of LIBs is a difficult undertaking. The recovery of lithium of a quality high enough to be used again is complicated and expensive. Most recycling processes are targeted at extracting the lithium from cathodes (where most of the lithium in discharged batteries is located). However, it then precipitates out together with other metals contained in the cathode and must be painstakingly separated. Extraction from the anodes, which consist primarily of graphite, is significantly more efficient and can be carried out without discharging the battery beforehand. Because of their high reactivity, however, the risk of fires and explosions is high if the anodes are leached out with aqueous solutions, as is usual. These reactions release large amounts of energy and may produce hydrogen.

A team led by Yu-Guo Guo and Qinghai Meng at the Institute of Chemistry of the Chinese Academy of Sciences (ICCAS) and the University of Chinese Academy of Sciences (UCAS) has now developed an alternative method that avoids these problems. Instead of water, they use aprotic organic solutions to recover lithium from anodes. Aprotic substances cannot release any hydrogen ions, so no hydrogen gas can form.

The solutions consist of a polycyclic aromatic hydrocarbon (PAH) and an ether as the solvent. Certain PAHs can take up a positively charged lithium ion from the graphite anode together with one electron. Under mild conditions, this redox reaction is controlled and very efficient. With the PAH pyrene in tetraethylene glycol dimethyl ether, it was possible to dissolve the active lithium from the anodes almost completely.

…

[Think. Again.]

1. Sounds hopeful....

...but I still think that for vehicles, H2 is the way to go because it can be produced in virtually unlimited quantities, without the worry of price-fixing, monopolization, or national control of the mine ownership.

Let's save the lithium for use in batteries where H2 won't work.

[OKIsItJustMe]

2. Hydrogen offers some attractive advantages

A few advantages (assuming you’re using a pressure tank to store it) are:

• A tank can be filled faster than a storage battery can be charged. — Frankly, people are used to filling up an empty fuel tank in a few minutes.
• A storage tank of hydrogen is smaller, and weighs less than a comparable storage battery.
• In theory, it could eventually become less expensive to build a fuel cell powered car than a battery powered car, since they require fewer raw materials.

A few disadvantages:

• Storage batteries can be recharged essentially wherever there is suitable electric service. Hydrogen can (theoretically) be produced anywhere there is a reliable supply of electricity and water. Home generation of hydrogen is possible, but at this point, unlikely. Fresh water supplies are becoming somewhat constrained. For example, the “Desert Southwest” might not want to use water to generate hydrogen.
• While more expensive than comparable ICE vehicles, BEV’s are getting closer in price. FCEV’s are much less expensive than they were, but are currently still more explensive than BEV’s.
• Practical BEV’s are currently being manufactured in volume, practical FCEV’s are not. As you have observed, we have very little time to play around.
• While BEV’s may require a great deal of lithium, hydrogen electrolysis and fuel cells at this point, are reliant on precious and rare-earth metals.
• Assuming you are starting with electricity, from a clean grid, driving a BEV is significantly more efficient than a FCEV.
• At this time, fuel cell stacks are not durable/reliable enough for widespread use.

In the future, we may see more use of hydrogen FCEV’s. However, today, BEV’s are probably more practical, especially for smaller/lighter vehicles, driven relatively short distances. (Larger/heavier vehicles, driven longer distances make storage batteries less and less attractive.)

[Think. Again.]

3. Don't forget the advantages...

...of H2 combustion engines for heavier vehicles, construction and farm equipment, ships, trains, portable generators, etc.

And the fact that both H2 production and H2 distribution is not necessarily reliant on a grid.

[OKIsItJustMe]

4. Burning hydrogen is even less efficient than using a fuel cell

Burning hydrogen in a portable generator makes no sense to me at all. Better to get a small, portable fuel cell in my opinion.
https://duckduckgo.com/?q=portable+hydrogen+fuel+cell

Burning hydrogen makes the most sense when you are using it as a “drop-in” replacement for natural gas (say in large industrial processes.)

For combustion in large engines (in my opinion) it makes more sense to combine the hydrogen with CO₂ to make hydrocarbons.
https://duckduckgo.com/?q=electrofuels

[Think. Again.]

5. Throwing around the efficiency argument makes no sense...

...when the all the other pros and cons of each type of power generation are not factored into the entire equation.

Sometimes the best option is H2 combustion even with the efficiencies accounted for.

[OKIsItJustMe]

6. Efficiency cannot be simply ignored

In theory, you want to move to a renewable grid. That will be quite enough of a challenge at peak efficiency.

Hydrogen combustion makes sense when you have no better alternative (as I suggested) as a plug-in alternative for natural gas, or mixed with natural gas.

[Think. Again.]

7. As I said...

Sometimes the best option is H2 combustion even with the efficiencies accounted for.

[NNadir]

8. Many hundred of papers with this approximate title are published each year.

I run across them regularly.

The number that has made batteries sustainable is zero.