Researchers in Korea have developed a cost-effective and eco-friendly technology for recycling cathode materials from spent lithium-ion batteries through a simple process within an existing cell without the need for disassembly, writes Nick Flaherty.

By 2040, the number of decommissioned EVs is expected to exceed 40 million, leading to a sharp increase in waste batteries. Developing recycling technologies has thus become an urgent priority, as the metals pose a significant risk of soil and water contamination.

In conventional recycling, the typical method involves crushing and processing spent batteries to create a ‘black mass’, and then extracting metals such as lithium, nickel and cobalt through chemical processes. However, this requires highly concentrated chemicals, which generate wastewater, and substantial energy consumption for high-temperature furnaces.

Instead, direct recycling technology recovers and restores original materials without chemical alteration. However, this can also require high-temperature and high-pressure conditions, and it involves complex procedures, making it both time-consuming and costly.

The research team, led by Dr. Jung-Je Woo at the Gwangju Clean Energy Research Centre at the Korea Institute of Energy Research (KIER), developed a process that restores the spent cathode to its original state by immersing it in a restoration solution under ambient temperature and pressure, effectively replenishing lithium-ions.

The key is galvanic corrosion, which occurs when two dissimilar materials come into contact in an electrolyte environment, leading to the selective corrosion of one metal to protect the other.

The bromine in the restoration solution initiates spontaneous corrosion upon contact with the aluminium in the spent battery. Electrons are released from the corroded aluminium and transferred to the spent cathode material. To maintain charge neutrality, lithium-ions in the restoration solution are inserted into the cathode material, which restores the latter to its original state.

Unlike conventional methods, which require disassembly of the spent battery, the restoration reaction occurs directly within the cell, significantly enhancing the efficiency of the recycling process.

Electrochemical performance testing confirmed that the restored cathode achieved a capacity equivalent to that of new materials.

“This research introduces a novel approach to restoring spent cathode materials without the need for high-temperature heat treatment or harmful chemicals,” said Dr. Jung-Je Woo.