A puzzle has baffled the battery industry for decades: certain materials used in the lithium-ion batteries that power our laptops, phones and cars store much more energy than theoretically expected.
Thanks to a research collaboration spanning three countries, this puzzle has been solved and researchers see opportunities to develop new technologies from batteries to quantum devices.
Researchers at the Institute for Quantum Computing (IQC), the Massachusetts Institute of Technology and the University of Texas at Austin, as well as Qingdao University and Shandong University in China, harnessed a technique normally used in physics to investigate batteries and discover their inner workings.
“The challenge is probing what's going on inside of a battery non-destructively while it is operating,” said Guo-Xing Miao, associate professor at IQC and in the University of Waterloo Department of Electrical and Computer Engineering.
When you charge a battery by plugging it in or discharge a battery by using it, you may also change the magnetism within the battery. The researchers took advantage of this fact and used an in situ magnetometry technique to probe the internal magnetism of a battery in real time.
In a work published in Nature Materials in August 2020 , they found that the extra capacity of transition-metal oxides often used as electrodes in lithium-ion batteries mostly resides in nanoparticles that physically collect around the surface of these materials after regular use of the battery. These clouds of nanoparticles hold the extra charge that has puzzled researchers for decades when only chemical reactions had been taken into consideration.
Extra storage capacity in transition metal oxide lithium-ion batteries revealed by in situ magnetometry was published in Nature Materials August 17, 2020. Operando Magnetometry Probing the Charge Storage Mechanism of CoO Lithium Ion Batteries was published in Advanced Materials February 12, 2021.
This project is supported in part by the Canada First Research Excellence Fund (CFREF) through the Transforming Quantum Technologies (TQT) program.