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Category: materials – Page 39

Lithium-sulfur battery advancements promise faster charging and longer life

In the first study, a team led by Professor Jong-sung Yu at the DGIST Department of Energy Science and Engineering developed a nitrogen-doped porous carbon material to enhance the charging speed of lithium-sulfur batteries. This material, synthesized using a magnesium-assisted thermal reduction method, acts as a sulfur host in the battery cathode. The resulting battery exhibited remarkable performance, achieving a high capacity of 705 mAh g⁻¹ even when fully charged in just 12 minutes.

The carbon structure, formed by the reaction of magnesium with nitrogen in ZIF-8 at high temperatures, enabled higher sulfur loading and improved electrolyte contact. This advancement resulted in a 1.6-fold increase in capacity compared to conventional batteries under rapid charging conditions. Furthermore, the nitrogen doping effectively suppressed lithium polysulfide migration, allowing the battery to retain 82 percent of its capacity after 1,000 charge-discharge cycles.

Collaboration with Argonne National Laboratory revealed that lithium sulfide formed in a specific orientation within the carbon material’s layered structures. This finding confirmed the benefits of nitrogen doping and the porous carbon structure in boosting sulfur loading and accelerating reaction speed.

Twisting light: Novel metasurface offers compact solution for circularly polarized light

Left and right circularly polarized light, where the electromagnetic waves spiral in a clockwise and counterclockwise manner as they travel, plays a crucial role in a wide range of applications, from enhancing medical imaging techniques to enabling advanced communication technologies. However, generating circularly polarized light often requires complex and bulky optical set-ups, which hinders its use in systems with space constraints.

To address this challenge, a team of researchers from Singapore led by Associate Professor Wu Lin of Singapore University of Technology and Design (SUTD) has put forth a new type of metasurface—an ultra-thin material with properties not found in nature—that may be able to replace traditional complex and bulky optical set-ups.

They have published their research in the Physical Review Letters paper “Enabling all-to-circular polarization up-conversion by nonlinear chiral metasurfaces with rotational symmetry.”

Peeling back the layers: Exploring capping effects on nickelate superconductivity

So-called “infinite-layer” nickelate materials, characterized by their unique crystal and electronic structures, exhibit significant potential as high-temperature superconductors. Studying these materials remains challenging for researchers; they have only been synthesized as thin films and then “capped” with a protective layer that could alter properties of the nickelate layered system.

To address this challenge, a team led by researchers at the National Synchrotron Light Source II (NSLS-II)—a U.S. Department of Energy (DOE) Office of Science user facility at DOE’s Brookhaven National Laboratory—used complementary X-ray techniques at two different beamlines to gain new insights into these materials. Their results were published in Physical Review Letters.

Metastable marvel: X-rays illuminate an exotic material transformation

A dry material makes a great fire starter, and a soft material lends itself to a sweater. Batteries require materials that can store lots of energy, and microchips need components that can turn the flow of electricity on and off.

Each material’s properties are a result of what’s happening internally. The structure of a material’s atomic scaffolding can take many forms and is often a complex combination of competing patterns. This atomic and electronic landscape determines how a material will interact with the rest of the world, including other materials, electric and magnetic fields, and light.

Scientists at the U.S. Department of Energy’s (DOE) Argonne National Laboratory, as part of a multi-institutional team of universities and national laboratories, are investigating a material with a highly unusual structure—one that changes dramatically when exposed to an ultrafast pulse of light from a laser.

Is the moon a chunk ejected from Earth? Study sheds light on moon formation, origin of water on Earth

A research team from the University of Göttingen and the Max Planck Institute for Solar System Research (MPS) has discovered another piece in the puzzle of the formation of the moon and water on Earth. The prevailing theory had been that the moon was the result of a collision between early Earth and the protoplanet Theia. New measurements indicate that the moon formed from material ejected from the Earth’s mantle with little contribution from Theia.

In addition, the findings support the idea that water could have reached Earth early in its development and may not have been added by late impacts. The results are published in the Proceedings of the National Academy of Sciences.

The researchers analyzed from 14 samples from the and carried out 191 measurements on minerals from Earth. Isotopes are varieties of the same element that differ only in the weight of their nucleus. The team used an improved version of laser fluorination, a method in which oxygen is released from rock using a laser.

Researchers propose new physical model for predicting hardness of materials

Physically Intuitive Anisotropic Model of Hardness https://arxiv.org/abs/2412.

Skoltech researchers have presented a new simple physical model for predicting the hardness of materials based on information about the shear modulus and equations of the state of crystal structures. The model is useful for a wide range of practical applications—all parameters in it can be determined through basic calculations or measured experimentally.

The results of the study are presented in the Physical Review Materials journal.

Hardness is an important property of materials that determines their ability to resist deformations and other damage (dents, scratches) due to external forces. It is typically determined by pressing the indenter into the test sample, and the indenter must be made of a harder material, usually diamond.

Hubble reveals surprising spiral shape of galaxy hosting young jet

The night sky has always played a crucial role in navigation, from early ocean crossings to modern GPS. Besides stars, the United States Navy uses quasars as beacons. Quasars are distant galaxies with supermassive black holes, surrounded by brilliantly hot disks of swirling gas that can blast off jets of material.

Following up on the groundbreaking 2020 discovery of newborn jets in a number of quasars, aspiring naval officer Olivia Achenbach of the United States Naval Academy has used NASA’s Hubble Space Telescope to reveal surprising properties of one of them, quasar J0742+2704.

“The biggest surprise was seeing the distinct spiral shape in the Hubble Space Telescope images. At first I was worried I had made an error,” said Achenbach, who made the discovery during the course of a four-week internship.