New method tracks physical processes inside liquid and solid parts of Li-ion batteries

What if you could charge your electric vehicle in the time it takes to fill up with gas? In a new article published in Jouleresearchers from McGill University and the Université du Québec à Montréal (UQAM) announced the development of a new method that allows researchers to observe the inside of Li-ion batteries and, for the first time, to follow the physical processes taking place in both the liquid and solid parts of the battery cells as they occur.

This advancement sheds new light on the factors that influence the speed at which Li-ion batteries can be charged or discharged and could lead to fast-charging capabilities in some of the most essential and widely used electronic devices and vehicles , from laptops and cell phones to electric bikes, scooters and cars.

The research team, led by chemistry professors Janine Mauzeroll of McGill and Steen B. Schougaard of UQAM, in collaboration with the European Synchrotron Radiation Facility (ESRF), used highly concentrated X-rays to examine the inside Li-ion battery cells and discovered that the This technique was able to map changes in lithium concentration, in real time, as the batteries charged or discharged.

“When a Li-ion battery charges or discharges, the lithium moves inside the cell in both a liquid electrolyte and a solid active material, and the rate at which this happens generally depends on “How quickly lithium can move from one side of the cell to the other through these two phases,” said Jeremy Dawkins, who worked on the project as a doctoral student in Schougaard’s labs. and Mauzeroll.

“This work is the first report of a method to map lithium both in solution and in the solid phase of a Li-ion battery during battery operation, allowing us to quantify the performance of a cell at molecular level.”

This is a development that could have far-reaching implications, stretching from the highly specialized battery research community to almost anyone who uses an electronic device or vehicle. “This work is exciting because it provides researchers with an important new tool for studying the performance of Li-ion batteries, and it opens many doors that were previously closed,” Dawkins said.

“We hope this will lead to accelerated battery research, for example achieving superior electrode architectures much earlier. This could translate into better performance of the batteries we use every day.”

According to the researchers, the project was a success in the face of COVID-19. Although the McGill and UQAM teams are based in Montreal, the European synchrotron radiation facility, where the measurements were made, is in Grenoble, France. In 2020, when the pandemic hit and governments began implementing travel restrictions, the project was thrown into uncertainty.

“The science faculties of McGill and UQAM have granted key travel exemptions to make these measures possible,” Mauzeroll said. “Our collaborators at the ESRF in France did everything they could to measure our samples during the peak years of the pandemic,” Dawkins added. “Thanks to our willpower and a little luck, our limited measurement time ended up being successful.”