We’ve known for a while that battery performance depends on the speed, with which charge-carrying ions travel through electrolyte. Classic science holds that this speed is a function of the rate of the reaction, and the potential difference driving it. But now we’ve learned how ions and electrons work together to influence this reaction in lithium-ion batteries.
How Ions And Electrons Combine Forces
Scientists at Department of Chemical Engineering at Massachusetts Institute of Technology (MIT) confirmed this remarkable discovery on October 2, 2025. This important finding challenges the assumption that lithium-ions migrate independently between electrodes during discharging and recharging.
Well to be perfectly honest, this is still partly true, although something else determines the speed which this happens. The MIT scientists learned how ions and electrons work together when they looked closer:
- The speed with which the ions traveled was inconsistent. In some instances it was lightning fast. At other times it was frustratingly slow.
- The MIT scientists revisited this phenomenon. They discovered that lithium ions do not travel alone. They actually have companions!
MIT Identifies an Ion-Electron “Buddy System’
The Massachusetts Institute of Technology team took a fresh look at the intercalation process. This is a phenomenon whereby ions slip between electrode layers as they arrive at the end of their journey.
What the MIT team learned was quite remarkable, and set to make major changes to battery science. Ions do not travel alone on their journey. They take a ‘buddy electron’ along with them for the ride. This turns our understanding of how lithium-ion batteries work on its head …
Further investigation revealed that lithium ions only complete their journey when an electron travels with them. The reason for this could be that the electron lowers electrode resistance, increasing the probability of a reaction.
Tech Explorist sums this up with this quote by an MIT professor: “The electrochemical step is not lithium insertion, which you might think is the main thing. It’s actually electron transfer, which reduces the solid material that is hosting the lithium.”
More Information
Very Simple Guide to Electrons
Who Developed The Lithium-Ion Battery?
