MIT Researchers Develop New Model to Accelerate Battery Charging and Extend Lifespan
September 2025 – Massachusetts Institute of Technology (MIT)
A research team at MIT has unveiled a new theoretical model that could guide the design of faster-charging, longer-lasting lithium-ion batteries.
At the core of all lithium-ion batteries is lithium intercalation — the process in which lithium ions move from the electrolyte and insert themselves into the solid electrode during discharge, then exit during charging. The speed and efficiency of this reaction largely determine a battery’s power and charging rate, but until now, the underlying mechanism has been poorly understood.
In a paper published in Science, MIT researchers demonstrated that lithium intercalation is not solely controlled by ion diffusion, as long believed under the century-old Butler-Volmer model. Instead, they discovered that the process is governed by coupled ion-electron transfer (CIET), in which a lithium ion and an electron move together into the electrode.
This new framework explains why past experimental measurements of reaction rates often varied by factors of up to one billion and were inconsistent with Butler-Volmer predictions.
Using advanced electrochemical techniques, the MIT team measured intercalation rates across more than 50 combinations of electrodes and electrolytes. Materials tested included lithium nickel manganese cobalt oxide (NMC) — widely used in electric vehicle batteries — and lithium cobalt oxide (LCO), common in portable electronics. The results confirmed that CIET provides a much more accurate prediction of intercalation behavior.
By adjusting the composition of electrolytes, researchers found they could tune reaction rates, lowering the energy barrier for lithium insertion and improving charging efficiency. This insight could enable new electrode designs and tailored electrolytes that extend battery life, reduce degradation, and accelerate charging.
“What we hope is enabled by this work is to get the reactions to be faster and more controlled, which can speed up charging and discharging,” said Professor Martin Bazant, Chevron Professor of Chemical Engineering at MIT.
“Tuning intercalation kinetics by changing electrolytes offers great opportunities to enhance power and energy,” added Professor Yang Shao-Horn, J.R. East Professor of Engineering.
The research team included MIT graduate students and alumni now leading faculty roles at Rice University, Princeton University, and the University of Utah, highlighting the growing collaborative push toward next-generation battery science.
