Researchers at the Nanoscience Center at the University of Jyväskylä, Finland, have made a new opening in nanomaterial research. Opening’s essence resides in the exclusive use of metallic elements in flat, atomically thin nanostructures.
The best known flat nanomaterial is graphene. Graphene is stable because the non-metallic element carbon prefers covalent, directional bonds that effectively cause structural planarity. Metallic bonds are less directional, whereby metals often coalesce into compact clusters. However, recent experiments suggest that, by using pores in other nanostructures, even metals can be stabilized into atomically thin planes.
Inspired by these experimental indications, researchers at the Nanoscience Center, University of Jyväskylä, used computer simulations to predict systematically the properties of atomically thin structures made exclusively from metallic elements.
“We made a new opening in material research, which was basic research, but highly rewarding as such,” says postdoctoral researcher Janne Nevalaita. “One could say that we hit on an untouched estate, bulldozed it and created a foundation. Now others can build solid scientific structures based on that foundation,” he continues.
A spinout company of MIT, USA, has produced a new rechargeable lithium metal battery that can double the energy capacity of lithium-ion batteries and could make smartphones, drones and electric cars last twice as long.
The company behind the design, SolidEnergy Systems, developed the anode-free lithium metal battery by replacing a common battery anode material, graphite, for very thin, high-energy lithium-metal foil, which can hold more ions to increase energy capacity.
Hu, co-inventor and CEO of SolidEnergy commented, ‘With two-times the energy density, we can make a battery half the size, but that still last the same amount of time, as a lithium ion battery. Or we can make a battery the same size as a lithium ion battery, but now it will last twice as long.’
Hu developed a solid and liquid hybrid electrolyte solution. He coated the lithium metal foil with a thin solid electrolyte that doesn’t require heat. He also created a quasi-ionic liquid electrolyte, which proved inflammable, and has additional chemical modifications to the separator and cell design to stop it from negatively reacting with the lithium metal.
The final result was a battery with energy-capacity perks of lithium metal batteries, but with the safety and longevity features of lithium ion batteries able to operate at room temperature. ‘Combining the solid coating and new high-efficiency ionic liquid materials was the basis for SolidEnergy on the technology side,’ adds Hu.
The chemical modifications to the electrolyte allow the lithium metal batteries to be rechargeable and safer to use. The SolidEnergy has now moved into bigger space and Hu is hoping to ramp up production for their November launch.
Heating iron can alter its structure and is one of the methods for making various types of steel with different properties. That process is similar to the formation of frost flowers: one iron crystal structure transforms into another at a nucleus point, and the process expands further from that point. This type of nucleation in materials has the largest impact on their final properties, but is still the least understood in the field of metallurgy. For example, we still know little about how and where exactly this nucleation starts. Researchers at TU Delft have now shed new light on this subject in their publication ‘Preferential Nucleation during Polymorphic Transformations’ in Scientific Reports(Nature) of Wednesday 3 August.
The researchers demonstrated this nucleation process live by heating an iron sample to 1,000 degrees in a specially produced furnace at the European Synchrotron Radiation Facility in Grenoble, and monitoring the transformation process using X-rays. In this way, they were able to identify the places and their properties that were the most likely starting points for the nucleation process of the transition from ferrite to austenite.
Researchers from UNIGE have developed a new type of chemical sensor capable of detecting the presence of metals in the environment
An international team, led by researchers from the University of Geneva (UNIGE), Switzerland, has designed a family of molecules capable of binding to metal ions present in its environment and providing an easily detectable light signal during binding. This new type of sensor forms a 3D structure whose molecules are chiral, that is to say structurally identical but not superimposable, like an image and its reflection in a mirror, or like the left and right hands. These molecules consist of a ring and two luminescent arms that emit a particular type of light in a process called Circular Polarized Luminescence (CPL), and selectively detect ions, such as sodium. This research can be read about in Chemical Science.
“The luminescent arms of our molecules function like light bulbs that light up or turn off depending on the presence of a positively charged ion, a metal cation,” explains Jérôme Lacour, Dean of the Faculty of Science at UNIGE and Ordinary Professor in the Department of Organic Chemistry. These molecules can be compared to small locks: when they are ready to operate and detect the presence of metals, they emit a particular type of light (circularly polarized). When a metal ion is inserted, it acts on them like a key, the lock geometry changes and the light disappears.
By combining multiple nanomaterials into a single structure, scientists can create hybrid materials that incorporate the best properties of each component and outperform any single substance. A controlled method for making triple-layered hollow nanostructures has now been developed at KAUST. The hybrid structures consist of a conductive organic core sandwiched between layers of electrocatalytically active metals: their potential uses range from better battery electrodes to renewable fuel production.
Although several methods exist to create two-layer materials, making three-layered structures has proven much more difficult, says Peng Wang from the Water Desalination and Reuse Center who co-led the current research with Professor Yu Han, member of the Advanced Membranes and Porous Materials Center at KAUST. The researchers developed a new, dual-template approach, explains Sifei Zhuo, a postdoctoral member of Wang’s team.
The researchers grew their hybrid nanomaterial directly on carbon paper—a mat of electrically conductive carbon fibers. They first produced a bristling forest of nickel cobalt hydroxyl carbonate (NiCoHC) nanowires onto the surface of each carbon fiber (image 1). Each tiny inorganic bristle was coated with an organic layer called hydrogen substituted graphdiyne (HsGDY) (image 2).
Henry Bessemer (1813-1893) was a prolific inventor and talented businessman. His most significant contribution to engineering was a new low-cost process for making steel. Before Bessemer’s process, cast and wrought iron were the predominant construction materials, as although steel was superior, it was too expensive.
Through his invention, Bessemer kicked off the proliferation of steel across the globe from Sheffield, UK.
Bessemer discovered that by blowing cold compressed air into molten pig iron, carbon and other impurities burned off. Central to the process is a large vat, now known as a Bessemer converter. Previously, steel was made by re-processing wrought iron. Bessemer took out a patent on the invention in 1856.
The facts
- Bessemer made his first fortune through the development of a copper powder, which could be added to paint to give it a gold-coloured sheen. He kept the manufacturing process for the powder a closely guarded secret, giving his own business a monopoly.
- One of his earlier inventions was an anti-forgery stamp developed for the Royal Mail.
- Bessemer invented a new type of spinning projectile for cannons, but the iron barrels were not strong enough to fire them. Searching for a stronger material to make the barrels was the impetus behind the discovery of his process.
- It took many years to perfect the Bessemer process. One stumbling block was that only iron that did not contain phosphorous could be used. It was Sidney Gilchrist Thomas who solved this problem around 1878, by developing a new refractory lining.
- Bessemer had more than 100 patents at the time of his death in 1898.
- A former steelmaking town in Jacksonville, Alabama, is named after Bessemer. With iron ore, coal and limestone all mined nearby, it was a prime site for making steel in the early 20th century.
The quote
‘I had an immense advantage over many others dealing with the problem inasmuch as I had no fixed ideas derived from long-established practice to control and bias my mind, and did not suffer from the general belief that whatever is, is right.’
A new case study from the Northwestern University, led by Professor Eric Masanet, has found a way to help the airline industry save money by saving the environment all at the same time. The solution – 3D printing. According to a new case study from the Northwestern University, 3D-printing c…
The perovskite NaOsO3 has a complicated but interesting temperature-dependent metal-insulator transition (MIT). A team led by Drs. Raimundas Sereika and Yang Ding from the Center for High Pressure Science and Technology Advanced Research (HPSTAR) showed that the insulating ground state in NaOsO3 can be preserved up to at least 35 GPa with a sluggish MIT reduction from 410 K to a near room temperature and possible transformation to a polar phase. The work has been published in npj Quantum Materials.
NaOsO3 perovskite undergoes a metal-insulator transition concomitant with the onset of an antiferromagnetic long-range ordering at a Neel temperature of about 410 K, which is accompanied by a magnetic ordering without any lattice distortion.
The team carried out a combined experimental and computational study to understand the effect of external pressure on perovskite NaOsO3. They found hidden hysteretic resistance properties with a transient metallic state near 200 K. Also three electronic character anomalies (at 1.7, 9.0, and 25.5 GPa), and a structural transition to the singular polar phase (at ~ 18 GPa) were discovered.
