With the increasing popularity of electric vehicles and portable devices, the management of used batteries has emerged as a significant global issue. Therefore, developing enhanced recycling technologies has become a pressing necessity, as the metals contained in batteries present a major threat of contaminating soil and water.
Traditional battery recycling involves shredding discarded batteries and extracting valuable metals such as lithium, nickel, and cobalt through various chemical methods. However, this technique relies on high-concentration chemicals, leading to the production of wastewater, and necessitates substantial energy use due to the requirement for high-temperature furnaces, which significantly contribute to carbon dioxide emissions.
To tackle these problems, direct recycling technology, which retrieves and reinstates the original materials without modifying them chemically, has garnered increasing attention. Nevertheless, direct recycling has its own limitations, as it requires high-temperature and high-pressure conditions and involves complicated processes, rendering it both labor-intensive and expensive.
Now, a research team led by Dr. Jung-Je Woo at the Gwangju Clean Energy Research Center, part of the Korea Institute of Energy Research (KIER), has developed a cost-effective and eco-friendly technology that effectively recycles cathode materials from spent lithium-ion batteries.
The research group has created an innovative method for directly recycling used cathode materials from lithium-ion batteries by employing a straightforward process that overcomes the shortcomings of traditional recycling techniques. This cutting-edge approach rejuvenates the spent cathode to its original condition by immersing it in a specialized restoration solution at ambient temperature and pressure, efficiently replenishing lithium ions. Central to this advancement is the strategic application of galvanic corrosion using the restoration solution.
Galvanic corrosion takes place when two different materials are in contact in an electrolyte environment, causing the selective corrosion of one metal to safeguard the other. By harnessing this sacrificial mechanism, the research group has creatively repurposed this phenomenon for use in battery recycling.
In the restoration solution, bromine triggers spontaneous corrosion when it comes into contact with the aluminum from the used battery. This process results in the release of electrons from the corroded aluminum, which are then transferred to the used cathode material. To preserve charge neutrality, lithium ions from the restoration solution are inserted into the cathode material.
This process of recovering lithium ions restores the cathode material to its initial state. Furthermore, in contrast to traditional methods that necessitate the disassembly of the used battery, the restoration reaction occurs directly within the cell, significantly improving the efficiency of the recycling process. The research group verified through electrochemical performance testing that the rejuvenated cathode achieved a capacity comparable 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,” emphasized Dr. Jung-Je Woo, the senior researcher. “The direct recycling of discarded electric vehicle batteries holds great potential for significantly reducing carbon emissions and establishing a circular resource economy.”
Journal reference:
- Jinju Song, Hayong Song, Jeonghwan Song, Geumui Noh, Hyungsub Kim, Jiyoung Ma, Jung-Je Woo. Reviving Spent NCM Cathodes via Spontaneous Galvanic Corrosion in Ambient Atmospheric Condition. Advanced Energy Materials, 2024; DOI: 10.1002/aenm.202402106
