Engineering news
Researchers at Aalto University in Finland discovered that cobalt-containing electrodes in lithium batteries can be reused ‘as is’ after being newly saturated with lithium. Compared to conventional recycling, which typically extracts metals from crushed batteries by melting or dissolving them, the new process saves valuable raw materials – and likely also energy.
“In our earlier study of how lithium cobalt oxide batteries age, we noticed that one of the main causes of battery deterioration is the depletion of lithium in the electrode material. The structures can nevertheless remain relatively stable, so we wanted to see if they can be reused,” said Professor Tanja Kallio.
Many raw materials used in batteries, such as cobalt, may soon be in short supply. The European Commission is preparing a new battery decree, which would require the recycling of 95% of the cobalt in batteries.
Rechargeable lithium-ion batteries have two electrodes, between which electrically charged particles move. Lithium cobalt oxide is used in one electrode and – in most cases – the other is made of carbon and copper.
In conventional battery recycling methods, some raw materials are lost and lithium cobalt oxide turns into other cobalt compounds, which require a lengthy chemical refinement process to turn them back into electrode material.
The new method sidesteps this ‘painstaking’ process by replenishing the spent lithium in the electrode through an electrolysis process commonly used in industry.
“The cobalt compound can be directly reused,” a research announcement said. “The results show that the performance of electrodes newly saturated with lithium is almost as good as that of those made of new material.”
Professor Kallio said the method would work on an industrial scale after further development. “By reusing the structures of batteries we can avoid a lot of the labour that is common in recycling and potentially save energy at the same time. We believe that the method could help companies that are developing industrial recycling.”
The researchers’ next aim to see if the same method could be used with nickel-based batteries of electric cars.
The work was published in ChemSusChem.
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