September 22, 2026, 8:31 am | Read time: 5 minutes
Lithium-ion batteries are considered difficult to recycle. Today, they are found in smartphones, laptops, and electric cars. After many charging cycles, however, they lose performance and eventually end up in recycling. Researchers have now developed a method that could significantly change this process. Instead of completely dismantling old batteries and recovering the raw materials, they aim to directly reuse important components. This could not only save costs but also significantly reduce the energy required for recycling.
What’s Behind the New Battery Restoration
The research comes from a team at Cornell University in the U.S. The scientists call their approach “Direct Electrode-to-Electrode Regeneration,” or DEER for short. Translated, this means “direct regeneration from electrode to electrode.”
Electrodes are among the most important components inside a battery. Simply put, electrical charges move between them during charging and discharging. The researchers aim to preserve and refurbish these components instead of destroying them as before.
The research is also driven by concerns about the long-term availability of critical raw materials. “When lithium-ion batteries hit the market, no one thought that these minerals in the Earth’s crust are limited and cannot be extracted indefinitely,” says Vibha Kalra, project leader and professor of chemical engineering at Cornell.
Recycling today is an act of “brutal force,” says Kalra. Used lithium-ion batteries are shredded or melted down. Companies then recover raw materials like lithium, nickel, or cobalt. These materials must be reprocessed to make new batteries. The DEER approach takes a different path. It aims to keep existing components usable for as long as possible.
Why Batteries Lose Performance
Many lithium-ion batteries do not become unusable because their materials are completely worn out. Instead, deposits form inside the battery over time.
The Cornell team led by Kalra refers to this as a “Solid Electrolyte Interphase,” or SEI. It is a thin layer that forms on the electrodes during use. A small amount is normal and even necessary. Over time, however, the layer becomes thicker and hinders chemical processes. The result: The capacity decreases, and the battery doesn’t last as long.
To remove these deposits, the researchers take the electrodes out of old batteries and place them in a special chemical solution. This contains the compound 1,3-Dimethyl-2-Imidazolidinone, or DMI. The solution is intended to remove the obstructive deposits without damaging the electrodes themselves.
A Second Life for Old Batteries
According to the research team, batteries that had only reached 70 to 80 percent of their original capacity could be restored to up to 95 percent after treatment.
The regenerated batteries not only performed better in terms of capacity in the tests but also aged more slowly. While untreated batteries lost an average of 0.072 percent of their capacity per charge cycle, this figure was 0.042 percent for cells treated with DEER. The researchers observed this effect over about 800 charge cycles.
Interestingly, a battery that had already been regenerated could be treated a second time. It then reached around 90 percent of its original capacity again. This means the process could extend the usable life of batteries more than once under certain conditions.
What Does “Black Mass” Have to Do with Recycling?
A key difference from current methods lies in the handling of the batteries. In traditional recycling, batteries are often ground into a dark powder. This mixture is called “Black Mass.” It contains lithium, nickel, cobalt, copper, and other valuable raw materials. They can be recovered later. However, the original components of the battery are lost in the process.
This is exactly what the Cornell research team wants to avoid. Their approach treats the battery less as a source of raw materials and more as a product whose individual components can be repaired.
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Researchers See Savings Potential
An accompanying analysis concludes that processing costs could be reduced by 56 percent compared to conventional recycling methods. Water consumption and emissions could also decrease.
The researchers also see economic potential. According to the research team’s calculations, DEER-treated battery cells could cost around $15.25 per kilogram. Conventional recycling methods based on high temperatures or chemical processes cost about $26.31 per kilogram.
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However, this calculation does not yet take into account that the DMI solution used could be reprocessed. According to the scientists, this chemical alone accounts for about 63 percent of the process costs. If it can be reused multiple times, it could further improve the economic viability of the approach.
Not Every Battery Can Be Saved
However, the method is not suitable for every battery, explains the tech magazine “Techspot.” It can be particularly helpful when performance has declined due to deposits on the electrodes. If, on the other hand, critical components inside are already permanently damaged or lost, traditional recycling remains necessary.
Moreover, DEER does not solve all practical challenges. The batteries still need to be opened so that the electrodes can be treated separately. Introducing the cleaning solution into a closed battery proved significantly less effective in the experiments. Therefore, for industrial use, a complex disassembly of the battery would still be required.
Whether the technology will prove itself outside the lab remains to be seen. The researchers now want to test larger battery systems and determine which types of batteries the method is actually suitable for.