Aging lithium-ion batteries may not be as finished as they seem. Researchers at Cornell University have developed a regeneration process that can bring worn cells back to nearly their original performance, with early tests reaching 95% of the initial capacity.
The approach is called Direct Electrode-to-Electrode Regeneration, or DEER. Instead of dismantling a battery and sending it through a full recycling chain, the process uses an electrochemical solution to dissolve a thick buildup called the solid electrolyte interphase, or SEI.
Why battery capacity drops
SEI is not entirely a bad thing. The layer is necessary for battery operation, but it keeps growing after hundreds of charge and discharge cycles, which raises resistance and reduces capacity.
| Item | What It Does | Result |
|---|---|---|
| SEI layer | Protects and enables battery operation | Thickens over time and lowers performance |
| DEER process | Dissolves the buildup without destroying the cell | Restores much of the lost capacity |
That buildup is one of the main reasons batteries are retired even when their physical structure is still intact. DEER has drawn attention because it targets the part of the cell that most often drives performance loss rather than replacing the entire battery.
What the early tests showed
In the initial trials, treated batteries recovered to 95% of their original capacity. The treatment also left behind a thin protective layer that helps slow future degradation.
Further regeneration cycles showed the method may extend useful life even more. After additional rounds of treatment, the batteries still held about 90% capacity, suggesting the process could add several more life cycles.
Cost and environmental impact
The industrial appeal is equally notable. Analysis linked to the process suggests DEER could cut the cost of making recycled cells by 56% compared with conventional methods.
The environmental upside is also significant. The process is said to reduce hazardous air pollutants and water use, both of which are major burdens in traditional battery recycling.
| Measure | DEER Reported Impact |
|---|---|
| Recovered capacity | 95% in early testing |
| Capacity after additional cycles | About 90% |
| Estimated recycled cell cost reduction | 56% |
Traditional battery recycling usually requires full disassembly and energy-intensive processing to recover valuable materials. If DEER can scale beyond the lab, battery recovery could become faster, cheaper, and more efficient.
The researchers are now working to expand the technology beyond SEI-related damage. Their next focus includes other forms of wear, such as lithium loss, with potential relevance for electric vehicles and large-scale energy storage systems.