Direct Recovery Technology Restores Cathodes in Used Lithium-Ion Batteries

According to the latest issue of Advanced Energy Materials, a research team from the Gwangju Center for Clean Energy at the Korea Institute of Energy Research has developed an economical and eco-friendly technology to directly recover and restore cathode materials from used lithium-ion batteries.

Cathode materials store and release lithium ions during charging and discharging cycles, playing a critical role in energy generation.

Traditional battery recycling methods involve crushing used batteries and chemically extracting valuable metals like lithium, nickel, and cobalt. However, this process is energy-intensive and generates wastewater and carbon dioxide. While direct recovery methods aim to reclaim and restore original materials without altering their chemical properties, they typically require high temperatures and pressures and involve complex procedures.

The research team has now developed a direct recovery technology that overcomes these limitations. Their innovative approach restores cathode materials in used lithium-ion batteries through a simple process that operates at room temperature and ambient pressure. By immersing spent cathode materials into a regeneration solution, lithium ions are effectively replenished, restoring the material to its original state.

The key to this new method lies in using a regeneration solution to trigger galvanic corrosion. When two different materials come into contact in an electrolyte environment, galvanic corrosion occurs, causing one metal to corrode selectively to protect the other. The researchers ingeniously applied this "sacrificial" mechanism to battery restoration.

In the process, bromine in the regeneration solution reacts with aluminum in the spent battery, triggering spontaneous corrosion. As the aluminum corrodes, it releases electrons, which then transfer to the used cathode material. To maintain charge neutrality, lithium ions from the solution migrate into the cathode material. This lithium-ion replenishment effectively restores the cathode material to its original state.

Unlike conventional recycling methods that require battery disassembly, this regeneration reaction takes place directly within the battery, significantly improving the efficiency of the recovery process.

Electrochemical performance tests confirmed that the restored cathode materials exhibit capacities comparable to those of new materials.