There’s a fundamental reaction in batteries that we call intercalation. Lithium ions in an electrolyte, intercalate themselves into solid electrodes, when we discharge these batteries. However, when we recharge them the process reverses. The material in the electrodes affects the efficiency of this process. Researchers at Massachusetts Institute of Technology (MIT) developed a model for predicting lithium intercalation rates, using different electrode materials.
Fundamental Influence of Lithium Intercalation Rates
The speed with which intercalation happens, has a fundamental influence on lithium-ion battery performance. It influences the amount of power the battery produces, and how quickly it recharges. However, when the MIT team began their research, much of intercalation remained a mystery.
They did not fully understand the exact mechanism of this reaction, or the factors that control its rate, the press release concedes. We blogged earlier how MIT discovered that electrons accompany lithium-ions on their journey, in a process they named ‘coupled ion-electron transfer’.
This discovery will no doubt guide scientists in their search for more powerful and faster-charging lithium-ion batteries. However, that was not all the MIT scientists learned, when predicting lithium ion intercalation rates in their laboratory. There was more to come!
A Fresh Way of Predicting Lithium-ion Flow
The researchers gained a better understanding of ion flow in lithium-ion batteries. However, the measurements that they obtained, did not always match the electrode charge and discharge rates predicted by the century-old Butler-Volmer equation.
And so the MIT researchers developed a new technique to measure lithium ion intercalation rates. They applied repeated short bursts of voltage to electrodes instead, using more than 50 electrolyte / electrode combinations.
These measurements were more internally consistent, although lower than Butler-Volmer predictions. This interesting side show from the primary research, should help battery scientists predict lithium intercalation rates more accurately in future.
More Information
How Ions And Electrons Work Together
Facts of Intercalation You May Not Know
Preview Image: Atoms Intercalated in Graphite
