Researchers at the University of California in San Diego, led by Assistant Professor Zheng Chen, have published an article in the Green Chemistry journal which says that they have developed a way to recycle used cathodes from spent lithium-ion batteries and restore them to perform as well as they did when new.

The process takes degraded particles from the cathodes of used lithium-ion battery. These are pressurized in a hot alkaline solution that contains lithium salt. The particles then go through a short heat-treating process in which temperatures reach more than 760°C.

After cooling, the regenerated particles can be used to make new cathodes.

Professor Chen expected that the cathodes with regenerated particles would give a performance which was reduced by 10 to 20% but found that the new cathodes have been able to maintain the same charging time, storage capacity and battery lifetime as the originals did.

In the laboratory,  the particles have been picked out manually from the spent batteries and the entire cycle has taken about 10 hours to complete. The researchers are now working on a way to simplify and accelerate the process so it can be economical on an industrial scale.