Researchers at Aalto University in Finland have discovered that Li-ion battery electrodes containing cobalt (LiCoO₂) can be reused as is after being newly saturated with lithium. In comparison to traditional recycling, which typically extracts metals from crushed batteries by melting or dissolving them, the new process saves valuable raw materials, and likely also energy. The research is published in the journal ChemSusChem.

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.

—Professor Tanja Kallio, corresponding author

In traditional battery recycling methods, some of batteries’ 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.

The results showed that after re‐lithiation, the structure of original LiCoO₂ is restored, the capacity of an aged LiCoO₂ reverts close to the capacity of a fresh LiCoO₂, and the material can thus be recovered.

Re‐lithiated Mg‐Ti doped LiCoO₂ provides rate capability properties only slightly declined from the rate capability of a fresh material and shows promising cyclability in half‐cells.

Kallio believes that with further development the method would also work on an industrial scale.

The researchers next aim to see if the same method could also be used with the nickel-based batteries of electric cars.

Resources

• Lahtinen, K., Rautama, E., Jiang, H., Räsänen, S. and Kallio, T. (2021), “The reuse of LiCoO₂ electrodes collected from spent Li‐ion batteries after the electrochemical re‐lithiation of the electrode.” ChemSusChem doi: 10.1002/cssc.202100629