New catalyst provides boost to lithium-air batteries

A researcher at the University of Texas at Dallas has made a discovery that could open the door to cellphone and car batteries that last five times longer than current ones. Kyeongjae Cho, professor of materials science and engineering in the Erik Jonsson School of Engineering and Computer Science, has discovered new catalyst materials that can help expand the capacity of lithium-air batteries. The research is published in Nature Energy.

"There's huge promise in lithium-air batteries. However, despite the aggressive research being done by groups all over the world, those promises are not being delivered in real life," Cho said. "So this is very exciting progress. Yongping Zheng [a UT Dallas graduate student] and our collaboration team have demonstrated that this problem can be solved. Hopefully, this discovery will revitalize research in this area and create momentum for further development."

Lithium-air (or lithium-oxygen) batteries ‘breathe’ oxygen from the air to power the chemical reactions that release electricity, rather than store an oxidizer internally, as in conventional lithium-ion batteries. Because of this, lithium-air batteries boast a theoretical energy density comparable to gasoline – as much as 10 times that of current lithium-ion batteries – giving them tremendous potential for storing renewable energy, particularly in applications such as mobile devices and electric cars.

For example, at one-fifth the cost and weight of commercially-available lithium-ion batteries, a lithium-air battery would allow an electric car to drive 400 miles on a single charge and a mobile phone to last a week without recharging. However, practical attempts to realize this theoretical energy density have so far have not yielded great results, Cho said, despite efforts from major corporations and universities. Until now, these attempts have resulted in low efficiency and poor rate performance, instability and unwanted chemical reactions.

In their new study, Cho and Zheng focused on the electrolyte catalysts inside lithium-air batteries. When exposed to oxygen, these catalysts promote the chemical reactions that generate electricity. They found that soluble catalysts possess significant advantages over conventional solid catalysts, generally exhibiting much higher efficiencies. However, they also discovered that only certain organic materials make effective soluble catalysts.

Based on this finding, Cho and Zheng then collaborated with researchers at Seoul National University in South Korea to create a new catalyst material for lithium-air batteries. Known as dimethylphenazine, this material produces a battery with higher stability and increased voltage efficiency. "The catalyst should enable the lithium-air battery to become a more practical energy storage solution," Zheng said.

According to Cho, his catalyst research should open the door to additional advances in battery technology. But he also said it could take five to 10 years before this research translates into new batteries that can be used in consumer devices and electric vehicles.

He has, however, been providing research updates to car manufacturers and telecommunications companies, and said there has been interest in his studies. "Automobile and mobile device batteries are facing serious challenges because they need higher capacity," he explained. "This is a major step. Hopefully it will revitalize the interest in lithium-air battery research, creating momentum that can make this practical, rather than just an academic research study."

This story is adapted from material from the University of Texas at Dallas, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.