Scientists from the U.S. Department of Energy's Ames Laboratory discovered a first-of-its-kind copper and graphite combination that, they say, could have implications for improving the energy efficiency of lithium-ion batteries.
The discovery took place after they bombarded graphite in an ultra-high vacuum environment with ions to create surface defects. Copper was then deposited on the ion-bombarded graphite while holding it at elevated temperature, at 600-800 K. The synthetic route created multilayer copper islands that are completely covered by graphene layers.
"Copper is a highly conductive material but susceptible to oxidation. Being able to successfully embed it just underneath the surface of graphite protects the copper, and suggests a number of potential applications, including battery technology," Research Assistant Ann Lii-Rosales said in a press release.
It took the work of almost a dozen researchers to get to this finding, with Lii-Rosales leading the way and publishing their results in a paper titled "Formation of Multilayer Cu Islands Embedded beneath the Surface of Graphite: Characterization and Fundamental Insights," which was just published in the Journal of Physical Chemistry C.
In the same media statement, the scientists explained that this research is the continuation of a discovery from last year, when a team at the same lab encapsulated dysprosium, a magnetic rare-earth metal, underneath a single layer of graphene. Encouraged by their success, they began testing the possibilities of the method with other elements, including copper.
"We're pretty excited by this because we didn't expect it," said Pat Thiel, Distinguished Professor of Chemistry and Materials Science and Engineering at Iowa State University, who also works at the Ames Lab. "Copper doesn't seem to interact strongly or favorably with graphitic materials at all, so this was a big surprise. It really challenges us to understand the reasons and mechanisms involved."