Toyota and UC San Diego researchers dissolve a battery binder in water to free electrode materials

A recycler taking apart a spent lithium-ion cell has to get rid of the binder before the electrode coating will leave its foil. Most cells use fluorine-containing binders ^[6]. Those leave residues that take high temperatures or corrosive chemicals to remove ^[9]. In the UC San Diego and Toyota work, researchers took finished cells apart and soaked the electrodes in water ^[3][12]. The binder dissolved, and the coatings came off their metal foils with no residue, according to Interesting Engineering's account of the study, which was published in Nature Communications ^[12][15].

The report calls the result a potential way to cut manufacturing waste, energy use and recycling costs ^[17]. The work itself is lab cells and a soak. The account does not include cost figures or a production-scale trial. The recycled cells only matched cells made from conventionally recovered material ^[13], so the recycling gain is the heat or chemical step that no longer has to happen ^[5].

Recycling gets the headline. The person who would have to approve the switch works for a cell maker, and that person looks at the production line first. Fluorine-containing binders need toxic solvents, then large ovens to dry the electrodes, then more processing to recover and purify the solvent ^[7]. "Those extra steps significantly increase the cost and energy use," said Jiao Lin, the study's first author and a postdoctoral researcher at UC San Diego, who listed environmental impact alongside them ^[8]. The new binder is mixed in water ^[4].

I'd expect a cell maker to judge it on line costs and cycle life first. Two questions settle where a given operator stands. The first is chemistry: the binder was tested with lithium iron phosphate and nickel-rich cathodes, and with graphite and silicon anodes ^[11]. The second is whether the same company takes its own cells back through direct recycling, the route the team used to regenerate recovered material ^[13].

- Tested chemistry, you run the recycling loop. The solvent savings and the soak both land with you. This is the case for a pilot. - Tested chemistry, someone else recycles your cells. Judge the binder on solvent, oven and recovery costs alone. The soak is the recycler's gain. - Untested chemistry, you run the loop. Wait for the versions the team says it is optimizing for other chemistries ^[14]. - Untested chemistry, someone else recycles. Nothing in this result changes your line yet.