3-D Devices and Effects Batteries Computers and the Internet Electric and Hybrid Vehicles Electronics Laboratories and Scientific Equipment Lithium (Metal) Palacios, Tomas Physics San Francisco (Calif) Singapore Uncategorized Urban, Jeff your-feed-science Zheng, Liu

The Superpowers of Super-Thin Materials

In recent years, internet-connected devices have colonized a range of new frontiers — wrists, refrigerators, doorbells, cars. But to some researchers, the spread of the “internet of things” has not gone nearly far enough.

“What if we were able to embed electronics in absolutely everything,” Tomás Palacios, an electrical engineer at the Massachusetts Institute of Technology, said recently. “What if we did energy harvesting from solar cells inside highways, and had strain sensors embedded in tunnels and bridges to monitor the concrete? What if we could look outside and get the weather forecast in the window? Or bring electronics to my jacket to monitor my health?”

In January of 2019, Dr. Palacios and his colleagues published a paper in Nature describing an invention that would bring that future a little closer: an antenna that can absorb the ever-thickening ambient soup of Wi-Fi, Bluetooth and cellular signals and efficiently turn it into usable electrical energy.

The key to the technology is a promising new material called molybdenum disulfide, or MoS₂, that can be deposited in a layer just three atoms thick. In the world of engineering, things can’t get much thinner.

And thin is useful. For instance, a layer of MoS₂ could wrap around a desk and turn it into a laptop charger, without any power cords.

As researchers like Dr. Palacios see it, two-dimensional materials will be the linchpin of the internet of everything. They will be “painted” on bridges and form the sensors to watch for strain and cracks. They will cover windows with transparent layers that become visible only when information is displayed. And if his team’s radio wave-absorber succeeds, it will power those ever-present electronics. Increasingly, the future looks flat.

“There’s been absolutely explosive interest,” said Jeff Urban, a 2-D materials researcher at the Molecular Foundry at Lawrence Berkeley National Laboratory, in California. “There’s no other way to characterize it.”

Credit…Tony Luong for The New York Times
Credit…Tony Luong for The New York Times
Credit…Tony Luong for The New York Times
Credit…Tony Luong for The New York Times

The craze for 2-D chemistry began in 2004, when two researchers at the University of Liverpool used cellophane tape to peel one-atom-thick layers of carbon from chunks of graphite, forming graphene. Graphene is identical to graphite and diamond in composition, but the thinness gives it very different properties: It is flexible, transparent, extremely strong and an exceptional electrical and thermal conductor.

Researchers quickly set out to make all kinds of new and improved gadgets from it. Recently several companies released headphones with diaphragms — the vibrating membranes that produce sound in audio devices — made of graphene. Some paint manufacturers are adding graphene to their formulas to make longer-lasting coatings. Last October Huawei introduced the Mate 20 X, a large, powerful cellphone that uses graphene to help cool the processor. Samsung used graphene to develop a faster-charging battery, which may appear in phones in the near future.

Dr. Urban is working with 2-D materials to improve fuel cells, which have drawn interest as a clean propulsion system for green vehicles. Most fuel cells generate electricity from hydrogen, but even under high pressure hydrogen gas takes up several times more space than a comparable amount of gasoline, making it impractical to use in automobiles.

Instead, Dr. Urban is embedding hydrogen atoms in solids, which are much denser than gases. In March, he and his colleagues announced a new storage medium: tiny magnesium crystals wrapped in narrow strips called graphene nanoribbons. Hydrogen stored in this manner, they found, could provide nearly as much energy as the same volume of gasoline, while weighing much less.

Dr. Urban compared the process to baking chocolate chip cookies, where magnesium is the chocolate chip — the key part — because it holds the hydrogen. “We want a chocolate chip cookie with as many chocolate chips as possible,” he said, and graphene nanoribbon makes excellent cookie dough. The nanoribbon also helps hydrogen enter and exit the magnesium crystals quickly while boxing out oxygen, which competes with hydrogen for space in the crystals.

Dr. Urban peers into the super-thin realm at the Advanced Light Source, a domed laboratory with an expansive view of San Francisco and the neighboring bay. There, electrons are accelerated to near the speed of light, generating powerful X-rays that can be used to finely probe the atomic structure of materials.

At the A.L.S., Dr. Urban and his colleagues learned exactly how graphene wrapped around and bonded tightly to magnesium. Those bonds, they believe, are what make the composite material stable over long periods — an important trait for real-world use.

Credit…Anastasiia Sapon for The New York Times
Credit…Anastasiia Sapon for The New York Times
Credit…Anastasiia Sapon for The New York Times
Credit…Anastasiia Sapon for The New York Times

Elsewhere, researchers are taking super-thin layers of materials and stacking them into three-dimensional blocks that have properties distinct from both 2-D and conventional 3-D materials.

Kwabena Bediako, a chemist at the University of California, Berkeley, published a study last year in Nature that described how he and his colleagues had embedded lithium ions between many layers of two-dimensional materials, including graphene.

“We start out with a piece of bread, slap on some mayo, bring it down on cheese, bring it down on some ham,” he said. “You can do that as many times as you want and create a sandwich.”

By varying the different layers in the three-dimensional stack, the researchers were able to fine-tune how the materials stored lithium, which could lead to the development of new, high-capacity batteries for electronic devices.

Xining Zang, a postdoctoral candidate in materials science at M.I.T., recently discovered a surprisingly easy way to build stacks of 2-D materials using gelatin, the ingredient that gives Jell-O and marshmallows their structure. She and several colleagues combined gelatin, metal ions and water. The gelatin assembled itself into layers (as it does when it forms Jell-O), thereby arranging the metal ions into layers, too. Some of the carbon in the gelatin then reacted with the metal to produce two-dimensional sheets of metal carbides; these worked as catalysts to help split water into oxygen and hydrogen, a process that could be employed to generate electricity in fuel cells.

“I hesitate to say the technique was crude, because it was really elegant when you think about it,” said Nate Hohman, a staff scientist formerly at the Molecular Foundry and an author on the paper. “It’s right at this interface between high-tech and low-tech.”

One place where two-dimensional materials are blossoming is in Singapore, in the lab of Liu Zheng, at Nanyang Technological University. Singapore is known as the Garden City, and the tiny country has zealously filled its land with greenery — including at the university, which has placed gardens in spare nooks all around its modern buildings.

Dr. Zheng sees his research as a different kind of cultivation. “I’m a gardener,” he said. “There is a 2-D garden, with all kinds of flowers. They’re all beautiful.”

Last year Dr. Zheng and his colleagues drastically expanded this garden by creating dozens of new 2-D materials from a class of compounds called transition metal chalcogenides, or T.M.C.s. The key discovery was in using ordinary table salt to lower the temperatures at which the metals are typically melted; this allowed the metals to be vaporized and deposited in thin films.

Credit…Amos Zeeberg
Credit…Amos Zeeberg
Credit…Amos Zeeberg
Credit…Amos Zeeberg

“One day a student told me, ‘I can make all of the T.M.C.s with salt,’” Dr. Zheng said. “I was really surprised. This was my dream for many years.”

One set of shelves in Dr. Zheng’s busy lab is stacked with clear, airtight containers; these hold silicon wafers, on which the 2-D materials are deposited. The films often form a visible triangle or hexagon, according to the geometric structures of the crystals in each material.

After the films are deposited, Dr. Zheng’s team moves to a nearby lab to study the resulting structures in detail. The room is dominated by a transmission electron microscope that stands a dozen feet tall and weighs a ton and a half — a giant device for viewing individual atoms.

Many T.M.C.s, including the MoS₂ used by Dr. Palacios to absorb radio waves, show potential for various industrial uses. The two-dimensional platinum selenide made in the Singapore lab could make for cheaper fuel cells, which typically use the precious metal platinum to separate a hydrogen atom’s proton from its electron. Switching to two-dimensional platinum selenide could reduce the amount of platinum used by 99 percent, Dr. Zheng said. Nanyang Technological University is in talks with manufacturers about commercializing the technology. The future isn’t yet two-dimensional, but it’s getting closer.

“I see really great commercial potential of this material,” Dr. Zheng said. “We can make a huge impact in the market.”

Credit…Anastasiia Sapon for The New York Times
Company Reports Electric and Hybrid Vehicles Factories and Manufacturing Musk, Elon Tesla Motors Inc Uncategorized

Tesla Reports Record Output as Elon Musk Achieves Goal

Tesla said on Friday that it had produced over 100,000 vehicles and delivered even more in the fourth quarter of 2019, meeting a goal it had laid out to investors and ending the year on stronger footing than at the start.

In a statement, the electric-vehicle maker said it had delivered 112,000 cars in the final three months of last year and produced a record 104,891, showing healthy demand as it continues to focus on global growth.

“When you deliver more cars than you produce, you get into your bank more cash than you spent,” said Pierre Ferragu, an analyst with New Street Research. He said that would enable Tesla to continue its expansion, including its manufacturing presence in China, where cars are beginning to roll off a Shanghai assembly line.

Mr. Ferragu estimated that Tesla had delivered 60,000 vehicles in North America and 52,000 internationally in the fourth quarter. The company did not provide a breakdown.

Friday’s figures put Tesla’s total deliveries for 2019 at 367,500, which the company said was 50 percent more than in 2018. It had forecast deliveries of 360,000 to 400,000 for the year, and analysts say the company could deliver as many as half a million vehicles in 2020.

The news caps a volatile year for Tesla, which turned a corner in the second half of 2019 after the strain of a $1.1 billion loss in the first half. After falling as low as $177 in June, the company’s stock price started to soar in late October, when Tesla reported a third-quarter profit. The stock hit a record closing price Friday, $443.01, up 3 percent for the day even as the overall market declined.

The share price last week surpassed a milestone of $420. In 2018, Tesla’s chief executive, Elon Musk, said he had “funding secured” to take the company private at that price. The deal turned out to be less solid than Mr. Musk had made it seem, attracting the scrutiny of federal regulators and resulting in his stepping down as chairman.

Expectations for the year ahead are mixed. Some analysts predict Tesla’s stock will rise above $500 because of increasing interest in electric vehicles and the company’s strong recent performance. Others say the company is greatly overvalued.

By most accounts, however, Tesla underwent a difficult yet successful evolution in the last year as it ramped up production and sales of its less-expensive Model 3, shifting away from its larger and lower-volume Model X and Model S.

“Those transitions are usually never seamless, never easy,” said Jed Dorsheimer, an analyst with Canaccord Genuity. “They’re bumpy, and they can be ugly. But the company executed pretty well.” He expects Tesla’s stock to reach $515 as demand for electric vehicles accelerates.

The Model 3 accounted for more than 80 percent of the cars produced and delivered by Tesla in the fourth quarter, according to the figures released Friday.

Tesla this week announced the first deliveries of the nearly 1,000 cars it has produced so far at its Shanghai factory, less than a year after breaking ground. Until now, Tesla output had been limited to its assembly line in Fremont, Calif. The company said it had demonstrated an ability to produce more than 3,000 vehicles per week at the Shanghai plant.

Such news has heartened optimistic analysts like Mr. Ferragu and Mr. Dorsheimer, but others are more skeptical about the year ahead for Tesla.

While the company has been a leading maker of electric vehicles, it faces growing competition from established carmakers and start-ups alike, said Craig Irwin, an analyst with Roth Capital Partners.

“Yeah, they’re the innovator,” he said. “Yeah, they’re aggressively out there first on the technology, and they’ve done a superb job. But others will be in that market, too. It’s not just going to be exclusively for Tesla.”

To Mr. Irwin, the company’s stock is “egregiously” overvalued because many investors still treat Tesla as a company defined by aggressive growth even though it has matured into something different.

“Now it needs to be treated like an automotive company,” he said.

Tesla had also benefited in recent years from a federal tax credit on electric vehicles that effectively lowered the cost of its vehicles by as much as $7,500. But the credit began phasing out after Tesla sold 200,000 qualifying cars and was fully eliminated at the end of last year.

That may be an advantage for Tesla rivals that are able to offer the credit. But analysts do not expect the loss of the tax credit to have a major long-term effect on sales for Tesla, a well-known brand at a time when demand for electric vehicles is rising.

In addition to its global expansion, Tesla plans to begin deliveries of its all-electric, midsize sport utility vehicle, the Model Y, in the fall. Thanks to a significant overlap in components with the Model 3, the company should be able to save on production costs for the Model Y, analysts said, though some question whether the new S.U.V. will eat into demand for the Model 3.