We have been using lithium-ion batteries for decades. Now we know more about how they work

In science, there is an surprisingly long list of things that we have not yet understood, but that we still use because they work. This was the case unexpectedly for lithium -ion batteries – a power source for electric vehicles and various portable electrons – where scientists knew what the mechanism was, but did not know exactly how it worked.

Fortunately, MIT scientists found the answer. For a scientific document published on October 2, researchers describe a model that illustrates how the transfer of coupled ion-electron (CIET), an electron in which an electrode goes to the electrode with an ion, in this case an ion lithium, may explain the source of life of a lithium-ion battery. The idea could “guide the design of more powerful and faster lithium-ion batteries”, according to the researchers.

A cascade of molecules

A typical lithium-ion battery works via a chemical mechanism called intercalation. Essentially, during the battery discharge, the lithium ions dissolved in an electrolyte solution are inside a solid electrode. When the ions “desecque” and return to electrolyte, the battery loads.

The intercalation rate governs everything, from the net power of a battery at its load speed – the reason why researchers have found imperative to better understand the underlying mechanisms, the article said.

Previously, scientists thought that the lithium intercalation in a battery electrode was driven by a model describing the speed with which lithium ions could diffuse between electrolyte and electrode. However, the real experiences had not quite equaled what this model had predicted, suggesting to researchers that there can be another option.

A travel pair

For the new study, the researchers have prepared more than 50 combinations of electrolytes and electrodes to straighten things once and for all. Like previous experiences, they found important inconsistencies between real data and the model. Instead, the team offered several alternatives that could explain what they saw.

Finally, they decided on a model based on the hypothesis that a lithium ion could only enter an electrode if it moves with an electron from an electrolyte solution – the transfer of coupled ion ions. This electrochemical pairing facilitates the intercalation, the researchers explained the researchers and the mathematics behind CIET adapt well to the data.

“The electrochemical step is not the insertion of lithium, what you might think is essential, but it is in fact the transfer of electrons to reduce the solid equipment that hosts lithium,” MIT News Martin Bazant, study co-author and mathematician at MIT. “Lithium is interspersed at the same time as the electron is transferred, and they facilitate.”

Not only that, but the researchers also accidentally discovered that the reduction in the composition of electrolytes has influenced intercalation rates. The follow-up surveys could reveal more effective means of creating stronger and faster batteries, they explained.

“What we hope is allowed by this work is to ensure that the reactions are faster and more controlled, which can speed up the load and the discharge,” said Bazant.