Self-Assembling Material Could Be the Key to Recyclable EV Batteries

A new self-assembling battery material developed by researchers at the Massachusetts Institute of Technology (MIT) may provide a more sustainable way to dismantle solid-state electric vehicle batteries. The team’s findings, published in Nature Chemistry, demonstrate how this organic material can be used as an electrolyte that spontaneously disintegrates in response to a benign liquid, allowing the battery to fall apart for easier recycling.

Self-assembly for easier recycling

This approach is intended to address one of the more difficult challenges in lithium-ion battery recycling: the removal of the electrolyte layer that binds electrodes together. By developing a component designed to be dismantled, the researchers aim to enable more efficient material separation without relying on high heat or caustic chemicals.

“So far in the battery industry, we’ve focused on high-performing materials and designs, and only later tried to figure out how to recycle batteries made with complex structures and hard-to-recycle materials,” said first author Yukio Cho, who was a PhD student at MIT at the time of the research and is now a a postdoc at Stanford University. “Our approach is to start with easily recyclable materials and figure out how to make them battery-compatible. Designing batteries for recyclability from the beginning is a new approach.”

The researchers used a class of molecules known as aramid amphiphiles (AAs), which mimic the structure of Kevlar, providing mechanical strength, and also self-assemble in water. They then modified these molecules to contain polyethylene glycol (PEG) segments that enable lithium-ion transport. When exposed to water, the resulting molecules self-assemble into mechanically stable nanoribbons with ion-conducting PEG surfaces.

“The material is composed of two parts,” Cho explained. “The first part is this flexible chain that gives us a nest, or host, for lithium ions to jump around. The second part is this strong organic material component that is used in the Kevlar, which is a bulletproof material. Those make the whole structure stable.”

Once assembled, these nanoribbons form a gel-like material that can be pressed into a flexible, solid-state electrolyte. During operation, this material supports the flow of lithium ions between the battery’s electrodes. When placed in organic solvents, however, the nanoribbon structure rapidly disassembles, allowing the battery to be taken apart with minimal effort.

Validating the new approach

The MIT team constructed a functional solid-state battery using lithium iron phosphate as the cathode and lithium titanium oxide as the anode – two materials already used in commercial batteries. They found that the PEG-based nanoribbons could successfully transport lithium ions across the electrolyte.

However, tests revealed that the rate of ion movement into the electrodes was slower than ideal, due to polarization. This effect limited the battery’s performance during periods of rapid charging or discharging.

“The lithium ions moved along the nanofiber all right, but getting the lithium ion from the nanofibers to the metal oxide seems to be the most sluggish point of the process,” Cho said. 

However, as a proof-of-concept, the researchers are pleased with the performance that their battery was able to achieve.

“We don’t want to say we solved all the problems with this material,” Cho said. “Our battery performance was not fantastic because we used only this material as the entire electrolyte for the paper, but what we’re picturing is using this material as one layer in the battery electrolyte. It doesn’t have to be the entire electrolyte to kick off the recycling process.”

A recycle-first mindset

The work represents an early example of a “recycle-first” strategy in battery design, in contrast to current industry practices that prioritize performance and address recyclability only later. The team’s battery disassembled within minutes when immersed in organic solvents, allowing each component to be recovered.

“People are starting to realize how important this is,” Cho said. “If we can start to recycle lithium-ion batteries from battery waste at scale, it’ll have the same effect as opening lithium mines in the U.S. Also, each battery requires a certain amount of lithium, so extrapolating out the growth of electric vehicles, we need to reuse this material to avoid massive lithium price spikes.”

Encouraged by these early findings, the team are now exploring different ways to integrate similar types of materials into existing battery designs, as well as in new battery chemistries.

“It’s very challenging to convince existing vendors to do something very differently,” Cho says. “But with new battery materials that may come out in five or 10 years, it could be easier to integrate this into new designs in the beginning.”

Reference: Cho Y, Fincher CD, Lamour G, et al. Reversible self-assembly of small molecules for recyclable solid-state battery electrolytes. Nat Chem. 2025. doi: 10.1038/s41557-025-01917-6

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