Georgia Tech researchers find aluminum-foil anodes effective for solid-state batteries

A group of researchers from the Georgia Institute of Technology have developed aluminum foil-based anode for all-solid state batteries with higher energy density and greater stability. The team's new battery system, detailed in Nature Communications, could enable electric vehicles to run longer on a single charge, would be cheaper to manufacture and safer to use, they claim. 

The project began as a collaboration between the Georgia Tech team and leading aluminum manufacturer Novelis as part of the Novelis Innovation Hub at Georgia Tech.

Led by Matthew McDowell, associate professor in the George W. Woodruff School of Mechanical Engineering and the School of Materials Science and Engineering, commented, "We are always looking for batteries with higher energy density, which would enable electric vehicles to drive for longer distances on a charge. It's interesting that we can use aluminum as a battery material, because it's cost-effective, highly recyclable, and easy to work with."

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Although aluminum is considered as a viable battery material for conventional lithium-ion batteries, solid-state batteries enable the integration of new high-performance active materials, as shown in this research. While lithium-ion batteries contain a flammable liquid that can lead to fires, solid-state batteries contain a solid material that's not flammable and, therefore, likely safer.

Although the research team knew that aluminum would have energy, cost, and manufacturing benefits when used as a material in the battery's anode, pure aluminum foils were failing rapidly when tested in batteries.

Instead of using pure aluminum in the foils, the researchers added small amounts of other materials to the aluminum to create foils with particular 'microstructures' or arrangements of different materials. They tested over 100 different materials to understand how they would behave in batteries, they claimed. 

"We needed to incorporate a material that would address aluminum's fundamental issues as a battery anode," said Yuhgene Liu, a Ph.D. student in McDowell's lab and first author on the paper. "Our new aluminum foil anode demonstrated markedly improved performance and stability when implemented in solid-state batteries, as opposed to conventional lithium-ion batteries."

The team has observed that the aluminum anode could store more lithium than conventional anode materials, and therefore more energy. In the end, they had created high energy density batteries that could potentially outperform lithium-ion batteries.

"One of the benefits of our aluminum anode that we're excited about is that it enables performance improvements, but it also can be very cost-effective," McDowell said. "On top of that, when using a foil directly as a battery component, we actually remove a lot of the manufacturing steps that would normally be required to produce a battery material."

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"The initial success of these aluminum foil anodes presents a new direction for discovering other potential battery materials," Liu said. "This hopefully opens pathways for reimagining a more energy-optimized and cost-effective battery cell architecture."

The team is currently working to scale up the size of the batteries to understand how size influences the aluminum's behavior. The group is also actively exploring other materials and microstructures with the goal of creating very cheap foils for battery systems.

"This is a story about a material that was known about for a long time, but was largely abandoned early on in battery development," McDowell said. "But with new knowledge, combined with a new technology of solid-state battery, we've figured out how we can rejuvenate the idea and achieve really promising performance."