With the increasing popularity of electric vehicles, how to repurpose batteries that have reached the end of their lifespan has become a crucial issue. Cornell University researchers have developed the DEER system, which stands out as an electric vehicle battery regeneration technology. This new technique allows lithium-ion batteries to be reused without the need to completely disassemble them into their raw materials. This method, called Direct Electrode-to-Electrode Regeneration, or DEER, aims to directly renew the electrodes in worn-out batteries.

A Method That Restores Battery Capacity

Currently used lithium-ion batteries form a protective layer called SEI on the electrode surfaces throughout their lifespan. While this layer initially helps the battery function properly, it begins to thicken as charging and discharging cycles increase.

Researchers aim to eliminate this problem without completely replacing the electrodes using the DEER method. Electrodes removed from used batteries are cleaned with a special chemical solution called DMI.

This process cleans the thick SEI layer that has accumulated over time without damaging the electrode itself. Thus, the aging electrode becomes reusable and gains a second life by being installed in a new battery cell.

In laboratory tests, it was observed that cells refurbished with the DEER formula regained up to 95 percent of their brand-new capacity. In addition, it was found that the capacity loss of refurbished batteries occurred more slowly than that of untreated batteries.

Capacity loss in untreated batteries was 0.072% per cycle, while in cells regenerated with DEER, this rate was measured at 0.042%. This low degradation rate was successfully maintained for approximately 800 cycles.

Researchers managed to restore the capacity of a previously regenerated battery to 90% after a second process. Classic

lithium-ion battery recycling methods

mostly focus on breaking down the cells to separate valuable metals. In traditional recycling processes, cells are often broken down into a mixture from which valuable materials such as lithium, cobalt, nickel, manganese, copper, and aluminum are recovered. These classic processes can require high power and involve complex separation steps.

The DEER method, on the other hand, provides an alternative to this complex breaking down process by directly preserving and reprocessing the electrodes. This increases resource efficiency and extends the lifespan of valuable materials used in battery production.

Cost Advantage and Technical Limitations

The DEER approach has significant potential for extending electric car battery life because it attempts to directly preserve usable electrodes. Vehicle batteries are often removed from automotive use when they reach 70-80% of their original capacity.

However, the electrodes in batteries at this level may not be completely unusable. According to Cornell’s calculations, the cost of cells recycled with DEER can remain at around $15.25 per kilogram. There are also some significant limitations in the application of the method. DEER is particularly effective in cells where capacity loss is due to SEI accumulation.

When lithium loss, cracked particles, structural damage, or mechanical failures are involved, classic

waste battery reprocessing methods

will continue to be used. To move DEER from the laboratory phase to commercial use, the technical processes need to be improved.

Optimizing the processes for disassembling batteries, processing electrodes, and reusing DMI is essential. Time will tell whether this new technology can reduce costs in the electric vehicle sector. How effective do you think these types of battery refurbishment technologies can be in the widespread adoption of electric vehicles?

Cornell University is able to recover up to 100% of the capacity with DEER, an electric vehicle battery refurbishment technology.

Battery, Method, Capacity, Cells, Lithium