Cornell's electrochemical bath brings spent EV batteries back to 95% and could rewrite recycling

A new battery-recycling breakthrough from Cornell University could help address one of the messiest challenges in the electric vehicle industry: what happens after a battery reaches the end of its useful life.

Researchers say spent EV batteries may be revived through a chemical treatment rather than being broken down or processed in high-temperature furnaces, restoring up to 95% of their capacity while reducing recycling manufacturing costs by 56%.

What's happening?

At Cornell, scientists developed a battery-repair technique known as Direct Electrode-to-Electrode Regeneration, or DEER, designed to recover battery components in their original form, Interesting Engineering reported.

The process addresses a major source of decline in lithium-ion batteries. Over time, cells develop a dense layer called the solid electrolyte interphase, which impedes the flow of energy, even though much of the battery material remains.

In the Cornell process, the battery is opened, and its electrodes are taken out without being destroyed. Those intact components are then placed in a solvent called 1,3-dimethyl-2-imidazolidinone, which removes the buildup while leaving the underlying structure in place, unlike conventional recycling methods that turn batteries into "black mass" and use harsh acids to extract minerals.

Published June 9 in Energy and Environmental Science, the research showed that the method can currently be used on batteries that still retain about 70-80% of their state of health, which is generally when EV packs are considered ready for retirement.

Why does it matter?

As EV use and battery storage expand, handling retired batteries is becoming a bigger issue. Existing recycling options are often expensive, pollution and energy-intensive, and they rely on supply networks that are vulnerable to delays and other disruptions.

Battery costs remain a major factor in EV prices. If used battery materials can be restored more cheaply and closer to where they are used, that could eventually help lower costs for automakers, battery suppliers, and drivers alike.

The U.S. has limited access to domestic supplies of important battery minerals, and its refining and recycling capacity remains underdeveloped. A process that keeps battery components intact could support a stronger domestic supply chain while also lowering waste, reducing water consumption, and cutting air pollution.

That kind of local capacity could prove especially important as cities, utilities, and companies expand battery storage systems that help keep power flowing during blackouts, storms, and other disruptions.

What's being done?

Rather than sending battery materials through destructive recycling steps and overseas rebuilding, Cornell's method aims to recover usable parts directly. That could make U.S.-based battery recycling faster and easier to carry out.

Researchers now plan to apply DEER to larger battery systems and modify it to handle additional forms of degradation, including permanent lithium loss. Doing so could allow more batteries to be restored instead of discarded.

Better battery recovery could mean lower costs and less waste as EV adoption grows. It could also strengthen the systems behind electric vehicles, home batteries, and grid storage without requiring an entirely new stream of mined materials.

"We repair them, as is, without shredding or powdering them, and then put them back into a new battery," said Vibha Kalra, the Fred H. Rhodes Professor of Chemical Engineering in the Cornell Duffield College of Engineering. 

"The dissolution is basically what helps the battery recover its capacity. It shows 95 percent recovery. So we are shortening the circularity loop immensely."

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