Dead batteries cough up lithium after a bath in CO₂ and water, boffins say

Still or sparkling? Either way, the problem of scale remains

Lithium-ion batteries are everywhere, and recycling them cleanly and safely at scale is still hard. Now, a Chinese research team claims to have discovered a way to recycle Li-ion batteries using carbon dioxide and water. Just don't expect it to revolutionize the market overnight.

The team, from the Chinese Academy of Sciences and Beijing Institute of Technology, recently published their findings in Nature Communications. According to their research, the process not only avoids conventional leaching chemicals and extreme heat to extract lithium from old batteries, but it also uses carbon dioxide in what the authors call a sequestration step, and turns other battery transition metals into new catalysts - with CO₂-rich water doing most of the chemical work.

According to the researchers, more than 95 percent of the lithium in spent batteries can be recovered after mechanochemically treating the cathodes and then leaching them with CO₂-rich water, where carbonic acid formation enables selective separation of lithium as water-soluble lithium bicarbonate.

"Conducted under ambient conditions without additional grinding aids or leaching agents, this method minimizes environmental impact," the boffins explained. Other "methods often require substantial reagent inputs, produce hazardous emissions and secondary pollution, and generate leaching residues." 

Those residues, the team explained, then typically have to be processed using acid leaching to be converted into salt solutions before reuse, which further reduces their value. 

The "three-in-one" strategy developed by the team also eliminates those additional processing needs, with transition metals in the cathode, like cobalt, nickel, and the like, "simultaneously transformed into high-performance oxygen evolution reaction (OER) catalysts," the researchers explained. OER catalysts are a key component in converting electrical energy into stored chemical energy in water-splitting systems, and are used in electrolyzers and related energy-conversion technologies, giving the non-lithium components of lithium-ion batteries a continued role in the energy supply chain.

Finally, the team claims that their method incorporates some of the carbon dioxide used in the process into bicarbonate and carbonate intermediates, which they describe as a form of CO₂ sequestration.

A distant solution to an immediate problem

Lithium batteries take many forms and can be found in everything from disposable single-use electronics to electric vehicles. As the default form of energy storage used in most electronics, lithium and its rechargeable variant lithium-ion, is being produced in greater quantities each year, with no signs of the battery market slowing down. 

It's debatable how many lithium batteries are actually recycled, with an often-cited but contested figure suggesting the number could be as low as just five percent. Regardless of the actual figure, a cleaner and more sustainable method of recycling lithium batteries is necessary and it's not clear whether the Chinese CO₂ method will scale or be commercially viable any time soon.

Case in point, the Chinese team isn't even the first to have figured this particular method out. 

Ames National Laboratory in Iowa, USA, published its own findings in 2024 on an ambient-temperature method for recycling lithium-ion batteries that relies on water and carbon dioxide rather than harsh chemicals or high heat. Dubbed the Battery Recycling and Water Splitting (BRAWS) method, the approach shares the use of CO₂ and water with the Chinese team's work, but focuses on a different part of the battery and emphasizes different outputs.

One key difference we noted is that BRAWS concentrates on extracting lithium from the anode rather than the cathode, recovers lithium in the form of lithium carbonate rather than lithium bicarbonate, and is explicitly designed to produce green hydrogen as a byproduct through water splitting, alongside lithium recovery.

Needless to say, it's 2026 and BRAWS is nowhere in sight as a commercial alternative to more hazardous methods of lithium extraction despite the immediate need for widespread use of such a technology. In other words, don't expect the Chinese method to immediately change the lithium-ion recycling game either.

We contacted both Ames and the Chinese research team to learn more about how their methods differ and whether we could expect either to scale in the near future, but didn't hear back. ®