New graphene material could enable the fabrication of high-performance electrodes for sodium batteries

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.

Twisted bi-layer graphene displays unique quantum behavior

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 develop flexible and self-adaptive airflow sensor enabled by a graphene and CNTs membrane

Researchers at the Ningbo Institute of Materials Technology and Engineering (NIMTE) of the Chinese Academy of Sciences (CAS), led by Prof. Chen Tao, have developed a flexible and self-adaptive airflow sensor enabled by a graphene and CNTs membrane, which is mediated by the reversible microspring effect.

Airflow sensors based on the mechanical deformation mechanism have been drawing increasing attention thanks to their excellent flexibility and sensitivity. However, fabricating highly sensitive and self-adaptive airflow sensors via facile and controllable methods remains a challenge. Recently, inspired by the bats' wing membrane which shows unique airflow sensing capacity, the researchers at NIMTE prepared graphene/single-walled nanotubes (SWNTs)-Ecoflex membrane (GSEM), which can be arbitrarily transferred and subsequently adapt to diverse flat/bend and smooth/rough surface. Relying on the reversible microspring effect, the researchers developed a highly sensitive and self-adaptive GSEM-based airflow sensor.

Graphene assists researchers to develop a prototype for an artificial neuron

A team of researchers from CNRS and the Ecole Normale Supérieure in France developed a prototype of an artificial neuron. Their system uses ions to carry information, and relies on a thin layer of water transporting ions within long graphene incisions.

The human brain manages to consume relatively small amounts of energy, even while performing complex tasks. This high efficiency comes from neurons, which have a membrane with tiny pores called ion channels. These channels can open and close according to the stimuli received from neighboring neurons. The result is an electric current going from neuron to neuron, allowing these cells to communicate with each other.

Boron nitride assists in protecting graphene in order to achieve next-gen electronics

Researchers from AMO, Oxford Instruments, Cambridge University, RWTH Aachen University and the University of Wuppertal have demonstrated a new method to use plasma enhanced atomic layer deposition (PEALD) on graphene without introducing defects into the graphene itself.

Currently, the most advanced technique for depositing dielectrics on graphene is atomic layer deposition (ALD), which allows to precisely control the uniformity, the composition and the thickness of the film. The process typically used on graphene and other 2D materials is thermal water-based ALD, as it does not damage the graphene sheet. However, the lack of nucleation sites on graphene limits the quality of the dielectric film, and requires the deposition of a seed layer prior to ALD to achieve good results. Another approach is plasma enhanced atomic layer deposition (PEALD), which, when applied to growth on graphene, can introduce surface damage. This is what to team addressed in this recent work.