The Graphene-Info newsletter (August 31, 2021)

Scientists studying two different configurations of bilayer graphene have detected electronic and optical interlayer resonances. In these resonant states, electrons bounce back and forth between the two atomic planes in the 2-D interface at the same frequency. By characterizing these states, they found that twisting one of the graphene layers by 30 degrees relative to the other, instead of stacking the layers directly on top of each other, shifts the resonance to a lower energy. From this result they deduced that the distance between the two layers increased significantly in the twisted configuration, compared to the stacked one. When this distance changes, so do the interlayer interactions, influencing how electrons move in the bilayer system. An understanding of this electron motion could inform the design of future quantum technologies for more powerful computing and more secure communication.

“Today’s computer chips are based on our knowledge of how electrons move in semiconductors, specifically silicon,” said first and co-corresponding author Zhongwei Dai, a postdoc in the Interface Science and Catalysis Group at the Center for Functional Nanomaterials (CFN) at the U.S. Department of Energy (DOE)’s Brookhaven National Laboratory. “But the physical properties of silicon are reaching a physical limit in terms of how small transistors can be made and how many can fit on a chip. If we can understand how electrons move at the small scale of a few nanometers in the reduced dimensions of 2-D materials, we may be able to unlock another way to utilize electrons for quantum information science.”

Researchers from Chalmers University of Technology, Sweden, Accurion GmbH, Germany and Institute of Organic Synthesis and Photoreactivity (ISOF) at the National Research Council of Italy have presented a novel concept for fabricating high-performance electrode materials for sodium batteries. It is based on a novel type of graphene to store one of the world's most common and cheap metal ions – sodium. The results of their study show that the capacity can match today’s lithium-ion batteries.

Sodium, unlike lithium, is an abundant low-cost metal, and a main ingredient in seawater. This makes sodium-ion batteries an interesting and sustainable alternative for reducing our need for critical raw materials. However, one major challenge is increasing the capacity. At the current level of performance, sodium-ion batteries cannot compete with lithium-ion cells. One limiting factor is the graphite, which is used as the anode in today’s lithium-ion batteries.

A team of researchers, led by Director Rod Ruoff at the Center for Multidimensional Carbon Materials (CMCM) within the Institute for Basic Science (IBS) and including graduate students at the Ulsan National Institute of Science and Technology (UNIST), has achieved growth and characterization of large area, single-crystal graphene totally free from wrinkles, folds, or adlayers. It was said to be 'the most perfect graphene that has been grown and characterized, to date'.

Director Ruoff notes: “This pioneering breakthrough was due to many contributing factors, including human ingenuity and the ability of the CMCM researchers to reproducibly make large-area single-crystal Cu-Ni(111) foils, on which the graphene was grown by chemical vapor deposition (CVD) using a mixture of ethylene with hydrogen in a stream of argon gas.” Student Meihui Wang, Dr. Ming Huang, and Dr. Da Luo along with Ruoff undertook a series of experiments of growing single-crystal and single-layer graphene on such ‘home-made’ Cu-Ni(111) foils under different temperatures.

Australia-based Graphene Manufacturing Group (GMG) announced that it is set to raise $900,000 CDN (around $715,000 USD) in a private placement. The follows the company's $10 million CDN public offering announced earlier this month, and represents the significant orders for the company's shares in the earlier offering.

In June 2021 GMG published the latest updates on its coin cell graphene aluminum-ion battery . GMG went public in April 2021 and trades at the TSX Venture Exchange in Canada (ticker: GMG).