Batteryless Device Detects Covid Droplets In the Air Around You

Researchers have developed a unique batteryless and wireless device that can detect within no time coronavirus in the air, if your surroundings contain Covid-19 particles or droplets the moment they enter the vicinity.

The device, which requires no batteries, employs a magnetostrictive clad plate composed of iron, cobalt and nickel, generating power via alternative magnetisation caused by vibration.

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Sodium Batteries May Power New Electric Cars

Half a century ago, the battery of the future was built out of sodium. The reason has to do with why the seas are salty. Sodium is a light element that ionizes easily, giving up one of its electrons. In a battery, those ions shuttle back and forth between two oppositely charged plates, generating a current. This looked like a promising way to power a house or a car. But then another element crashed the party: lithium, sodium’s upstairs neighbor on the periodic table. In 1991, Sony commercialized the first rechargeable lithium-ion battery, which was small and portable enough to power its handheld video cameras. Lithium was lighter and easier to work with than sodium, and so a battery industry grew up around it. Companies and research labs raced to pack more energy into less space. Sodium faded into the background.

So it was surprising this summer when China’s CATL, one of the world’s largest battery makers, announced sodium would play a role in the electrified future. CATL, like its competitors, is a lithium company through and through. But starting in 2023, it will begin placing sodium cells alongside lithium ones inside the battery packs that power electric cars. Why? Well, for one thing, a CATL executive pointed out that sodium is cheaper than lithium, and performs better in cold weather. But it was also hedging against an issue that was difficult to imagine in 1991. By the end of this decade, the world will be running short on the raw materials for batteries—not just lithium, but also metals like nickel and cobalt. Now that electrification is actually happening on a big scale, it’s time to think about diversifying. A CATL spokesperson said it started thinking about sodium 10 years ago.

CATL’s announcement “really injected new energy into the people who work on sodium,” says Shirley Meng, a battery scientist at the University of California, San Diego who works extensively with both elements. As a young professor, Meng started working with sodium in part because she was looking for a suitably weird niche to stand out in—but also because she believed it had potential. “The biggest barrier to success for sodium was that lithium was so successful,” she says.

Lithium is not exceptionally rare. But deposits are concentrated in places that are hard to mine. So companies like CATL compete to secure a slice of the supply from a limited number of mines, mostly located in Australia and the Andes. Meanwhile, reserves in North America are tied up in environmental disputes, raising concerns in the US about the security of the supply chains. Competition is even fiercer for nickel—which Elon Musk has called the “biggest concern” for the future of EV batteries, due to price and supply constraints—and for cobalt, 70 percent of which is dug up in the Democratic Republic of the Congo.

As more mines open, there will probably be enough lithium to power all the world’s vehicles, Meng says. But that doesn’t account for all of the things poised for electrification that aren’t cars: chiefly, the batteries that will manage the load within microgrids and keep our lights on at night when the rooftop solar panels are in the dark. Those are the kinds of applications Meng had in mind when she got into sodium research. “I was thinking everybody would have a refrigerator for electrons in your home in the same way you have a refrigerator for food,” she says. “I think that really is the vision for grid storage.


The Rise of the Hydrogen Electric Car

The race is on for car manufacturers to bring out their own range on electric vehicles (EV). But what if the new kid on the block ends up taking over? Honda, Hyundai, and Toyota are among the major firms now testing out hydrogen fuel cell electric vehicles (FCEVs) in their production lines to see which proves the most successful.

FCEVs have been criticized for being less efficient as only around 55 percent of the hydrogen energy created through electrolysis is usable, compared to between 70 and 80 percent in battery-electric cars. However, there are several advantages to fuel cells, including low recharge times – just a matter of minutes, and long-range. But several practical obstacles stand in the way of hydrogen FCEVs, such as the lack of charging infrastructure in contrast to the ever-expanding EV infrastructure. For example, at the beginning of 2021 there were only 12 hydrogen fuelling stations in the U.K., not surprising as only two brands of FCEV were on the market – the Toyota Mirai and the Hyundai Nexo.

In addition, hydrogen is currently much more expensive than electric fuel, costing around £60 for a 300-mile tank. Moreover, much of the hydrogen on the market comes from the excess carbon produced from fossil fuels by using carbon capture and storage (CCS) technologies. Yet, the disadvantages of battery EVs should not be overlooked. After years of investment, it is unlikely that we will see major advances in battery technology any time soon. Not to forget that lithium-ion batteries are heavy, making them near-impossible to use in freight and aviation. The metals used in existing battery production, such as cobalt and nickel, are also problematic due to ethical mining concerns as well a high costs adding to the overall price of price of EVs.

How To Recycle Greenhouse Gases into Fuel and Hydrogen

Scientists have taken a major step toward a circular carbon economy by developing a long-lasting, economical catalyst that recycles greenhouse gases into ingredients that can be used in fuel, hydrogen gas, and other chemicals. The results could be revolutionary in the effort to reverse global warming, according to the researchers. The study was published in Science.

Newly developed catalyst that recycles greenhouse gases into ingredients that can be used in fuel, hydrogen gas and other chemicals

We set out to develop an effective catalyst that can convert large amounts of the greenhouse gases carbon dioxide and methane without failure,” said Cafer T. Yavuz, paper author and associate professor of chemical and biomolecular engineering and of chemistry at KAIST (Korea).

The catalyst, made from inexpensive and abundant nickel, magnesium, and molybdenum, initiates and speeds up the rate of reaction that converts carbon dioxide and methane into hydrogen gas. It can work efficiently for more than a month.

This conversion is called ‘dry reforming’, where harmful gases, such as carbon dioxide, are processed to produce more useful chemicals that could be refined for use in fuel, plastics, or even pharmaceuticals. It is an effective process, but it previously required rare and expensive metals such as platinum and rhodium to induce a brief and inefficient chemical reaction.

Other researchers had previously proposed nickel as a more economical solution, but carbon byproducts would build up and the surface nanoparticles would bind together on the cheaper metal, fundamentally changing the composition and geometry of the catalyst and rendering it useless.

The difficulty arises from the lack of control on scores of active sites over the bulky catalysts surfaces because any refinement procedures attempted also change the nature of the catalyst itself,” Yavuz said.

The researchers produced nickel-molybdenum nanoparticles under a reductive environment in the presence of a single crystalline magnesium oxide. As the ingredients were heated under reactive gas, the nanoparticles moved on the pristine crystal surface seeking anchoring points. The resulting activated catalyst sealed its own high-energy active sites and permanently fixed the location of the nanoparticles — meaning that the nickel-based catalyst will not have a carbon build up, nor will the surface particles bind to one another.

It took us almost a year to understand the underlying mechanism,” said first author Youngdong Song, a graduate student in the Department of Chemical and Biomolecular Engineering at KAIST. “Once we studied all the chemical events in detail, we were shocked.”

The researchers dubbed the catalyst Nanocatalysts on Single Crystal Edges (NOSCE). The magnesium-oxide nanopowder comes from a finely structured form of magnesium oxide, where the molecules bind continuously to the edge. There are no breaks or defects in the surface, allowing for uniform and predictable reactions.

Our study solves a number of challenges the catalyst community faces,” Yavuz said. “We believe the NOSCE mechanism will improve other inefficient catalytic reactions and provide even further savings of greenhouse gas emissions.


How To Collect And Harvest More Solar Energy

In an article published in the SPIE Journal of Nanophotonics (JNP), researchers from a collaboration of three labs in Mexico demonstrate aninnovative nanodevice for harvesting solar energy. The paper,Thermoelectric efficiency optimization of nanoantennas for solar energy harvesting,reports that evolutive dipole nanoantennas (EDNs) generate a thermoelectric voltage three times larger than the classic dipole nanoantenna (CDN).

Capturing visible and infrared radiation using nanodevices is anessential aspect of collecting solar energy: solar cells and solar panels are common devices that utilize nanoantennas, which link electromagnetic radiation to specific optical fields. The EDNcan be useful in many areas where high thermoelectric efficiency is needed from energy harvesting to applications across the aerospace industry.

“The paper reports on a novel design and demonstration of a nanoantenna for efficient thermoelectric energy harvesting,” says Professor Ibrahim Abdulhalim, JNP Associate Editor, SPIE Fellow and a professor in the Electrooptics and Photonics Engineering Department at Ben-Gurion Universityof the Negev. “They demonstrated thermoelectric voltage three times larger than a classical antenna. This type of antenna can be useful in many fields from harvesting of energy from waste heat, in sensing and solar thermal energy harvesting.”

The nanoantennas are bimetallic, using nickel and platinum, and were fabricated using e-beam lithography. The nanoantenna design wasoptimized using simulations to determine the distance between the elements. In comparing their thermoelectric voltage to the classic dipole nanoantenna, the EDNs were 1.3 times more efficient. The characterization was done using a solar simulator analyzing the I-V curves. The results indicate that EDN arrays would be good candidates for the harvesting of waste heat energy.


Cost-Effective Method for Hydrogen Fuel Production

Nanoparticles composed of nickel and iron have been found to be more effective and efficient than other, more costly materials when used as catalysts in the production of hydrogen fuel through water electrolysis. The discovery was made by University of Arkansas researchers Jingyi Chen, associate professor of physical chemistry, and Lauren Greenlee, assistant professor of chemical engineering, as well as colleagues from Brookhaven National Lab and Argonne National Lab. The researchers demonstrated that using nanocatalysts composed of nickel and iron increases the efficiency of water electrolysis, the process of breaking water atoms apart to produce hydrogen and oxygen and combining them with electrons to create hydrogen gas.

Chen and her colleagues discovered that when nanoparticles composed of an iron and nickel shell around a nickel core are applied to the process, they interact with the hydrogen and oxygen atoms to weaken the bonds, increasing the efficiency of the reaction by allowing the generation of oxygen more easily. Nickel and iron are also less expensive than other catalysts, which are made from scarce materials.

This marks a step toward making water electrolysis a more practical and affordable method for producing hydrogen fuel. Current methods of water electrolysis are too energy-intensive to be effective.

Chen, Greenlee and their colleagues recently published their results in the journal Nanoscale.


Metallic Wood

Researchers at the School of Engineering and Applied Science, the University of Illinois at Urbana–Champaign, and the University of Cambridge have built a sheet of nickel with nanoscale pores that make it as strong as titanium, but four to five times lighter. The empty space of the pores, and the self-assembly process in which they’re made, make the porous metal akin to a natural material, such as wood. And just as the porosity of wood grain serves the biological function of transporting energy, the empty space in the researchers’ “metallic wood” could be infused with other materials. Infusing the scaffolding with anode and cathode materials would enable this metallic wood to serve double duty: a plane wing or prosthetic leg that’s also a battery. The study was led by James Pikul, assistant professor in the Department of Mechanical Engineering and Applied Mechanics at Penn Engineering.

Metallic wood foil on a plastic backing

The reason we call it metallic wood is not just its density, which is about that of wood, but its cellular nature,” Pikul says. “Cellular materials are porous; if you look at wood grain, that’s what you’re seeing—parts that are thick and dense and made to hold the structure, and parts that are porous and made to support biological functions, like transport to and from cells.

The study has been published in Nature Scientific Reports,