Preparing for the next generation of batteries

In the ongoing quest to build a better battery, researchers used the Canadian Light Source (CLS) at the University of Saskatchewan to identify the potential of using polymer composites as electrode matrices to increase the capacity of rechargeable lithium-ion (Li-ion) batteries.

“The composition of the adhesive and conductive framework for batteries hasn’t changed in years,” said Dr. Christian Kuss, assistant professor in the Department of Chemistry at the University of Manitoba and one of three researchers on the project. “But, we’re reaching the limit of how much capacity Li-Ion batteries have so this work is essentially preparing for the next generation of batteries.”

Over many cycles of charging and discharging, battery materials begin to break down, he explained. “The goal is to find new matrix materials that allow the electrode to stay intact over longer periods of time and thereby increase capacity.”

The new matrix material Kuss and his colleagues studied was based on a mixture of two polymers – one adhesive and the other conductive. The adhesive polymer is cellulose based, he said, while the conductive one “is easily synthesized and fairly cheap.” Cost is an important consideration “because you ultimately want a battery that is comparable in terms of pricing to what’s already available.”

At the CLS, the researchers used the Spectromicroscopy beamline to study the chemical structure of the polymer mixture. “With this technique, we could see the mixture and see how the polymers were distributed at a microscale.”

They were able to get connectivity using the polymer mixture matrix, “and charge and discharge the battery within less than one hour, which was pretty neat,” he said. “That shows that these mixtures are certainly feasible as a matrix for Li-ion batteries.”

Kuss said they did observe “some degradation that we don’t quite understand so that’s ongoing research. We’re now taking the battery apart to see how the matrix changed.” There are a number of possible causes for the degradation, both chemical and mechanical, “but that’s why we do research.”

A paper about the research will be published in the December issue of the Journal of Power Sources Advances, suggesting this preliminary work paves the way for the development of a promising new type of electrode matrix that can remain active over more cycles and are commercially feasible.