Electric VehiclesAs sustainable technologies continue to expand into the marketplace, the demand for better batteries rises. Many researchers in the field are looking toward all-solid-state batteries as a promising venture, citing safety and energy density properties. Now, one company is looking to take that work from the lab to the marketplace.

Electric car maker Fisker has recently filed patents for solid state lithium-ion batteries, stating that mass scale production could begin as soon as 2023. The patent covers novel materials and manufacturing processes that the company plans to use to develop automotive-ready batteries.

Unlike other types of rechargeable batteries that use liquid electrodes and electrolytes, solid state batteries utilize both solid electrodes and solid electrolytes. While liquid electrolytes are efficient in conducting ions, there are certain safety hazards attached (i.e. fires if the battery overheats or is short-circuited). In addition to better safety, solid electrodes could also impact battery cost and energy density, opening up new possibilities for large scale storage applications.

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SemiconductorScientists have figured out how to make tiny individual films—each just a few atoms high—and stack them for use in new kinds of electronics.

Over the past half-century, scientists have shaved silicon films down to just a wisp of atoms in pursuit of smaller, faster electronics. For the next set of breakthroughs, though, they’ll need new ways to build even tinier and more powerful devices.

In a study that appears in Nature, researchers describe an innovative method to make stacks of thin, uniform layers of semiconductors just a few atoms thick which could expand capabilities for devices like solar cells and cell phones.

Stacking thin layers of materials offers a range of possibilities for making electronic devices with unique properties. But manufacturing them is a delicate process, with little room for error, researchers say.

“The scale of the problem we’re looking at is, imagine trying to lay down a flat sheet of plastic wrap the size of Chicago without getting any air bubbles in it,” says Jiwoong Park, a professor of chemistry at the University of Chicago and at the Institute for Molecular Engineering and the James Franck Institute. “When the material itself is just atoms thick, every little stray atom is a problem.”

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SemiconductorEngineers have created a high-frequency electronic chip potentially capable of transmitting tens of gigabits of data per second, much faster than the fastest internet available today.

Omeed Momeni, an assistant professor of electrical and computer engineering at University of California, Davis, and doctoral student Hossein Jalili designed the chip using a phased array antenna system. Phased array systems funnel the energy from multiple sources into a single beam that can be narrowly steered and directed to a specific location.

“Phased arrays are pretty difficult to create, especially at higher frequencies,” Momeni says. “We are the first to achieve this much bandwidth at this frequency.”

The chip prototyped by Momeni and Jalili successfully operates at 370 GHz with 52 GHz of bandwidth. For comparison, FM radio waves broadcast between 87.5 and 108 MHz; 4G and LTE cellular networks generally function between 800 MHz and 2.6 GHz with up to 20 MHz of bandwidth.

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Battery fires led to the recall of nearly 2 million Samsung Galaxy Note 7 smartphones. In order to address this safety concern, researchers at Stanford University have identified 21 solid electrolytes for solid state batteries that could power the next-generation of electronics.

“Electrolytes shuttle lithium ions back and forth between the battery’s positive and negative electrodes,” says lead author of the study Austin Sendek, a doctoral candidate at Stanford University, who worked with ECS member Yi Cui on this research. “Liquid electrolytes are cheap and conduct ions really well, but they can catch fire if the battery overheats or is short-circuited by puncturing.”

As demands from the electronics industry grow and consumers become more suspicious of lithium-ion technology, researchers have started focusing efforts on creating an all-solid-state battery.

“The main advantage of solid electrolytes is stability,” Sendek says. “Solids are far less likely to blow up or vaporize than organic solvents. They’re also much more rigid and would make the battery structurally stronger.”

Join Additional Primary Divisions!

Attention prospective and current ECS members! Did you know? As of this year, you can belong to more than one primary division!

Divisions

Each ECS division corresponds to a topical interest area. ECS has seven electrochemistry divisions and six solid state science and technology divisions:

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Discussing the importance of cyber security

Cyber Security via IStockWhile cyberwar may sound like the plot of the latest sci-fi blockbuster, the realities of the phenomena are much more palpable. Few understand that better than Yaw Obeng, ECS member and senior scientist at the U.S. Department of Commerce’s National Institute of Standards and Technology.

In light of the 2014 hack on Sony Pictures, the suspected Russian hacking of U.S. Democratic National Committee emails, and the data breach of the U.S. government, in which the personal information of 21.5 million government employees was leaked, the scientists at NIST – specifically researchers like Obeng – have been shifting their attention to cyber security.

“Right now, everything that can be attached to the internet has been attached to the internet – right down to toothbrushes,” says Obeng, ECS Dielectric Science and Technology Division chair. “The question then becomes: How do we make sure that these devices are secure so they cannot be hijacked or compromised?”

(MORE: Read Obeng’s paper on this topic published in ECS Transactions.)

The answer to that question, however, may not be as simple as some would hope.

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As the landscape of energy harvesting evolves, so do the devices that store that energy. According to researchers from Toyohashi University, all-solid-state lithium rechargeable batteries are at the top of the list of promising future energy storage technologies due to their high energy density, safety, and extreme cycle stability.

ECS member Yoji Sakurai and a team from the university’s Department of Electrical and Electronic Information Engineering recently published a paper detailing their development to advance the all-solid-state batteries, which pushes past barriers related to electrochemical performance.

(MORE: Read Sakurai’s previously published paper in ECS Electrochemistry Letters.)

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JSS Editors’ Choice article discusses AlGaN/GaN HEMTs

When it comes to putting technology in space, size and mass are prime considerations. High-power gallium nitride-based high electron mobility transistors (HEMTs) are appealing in this regard because they have the potential to replace bulkier, less efficient transistors, and are also more tolerant of the harsh radiation environment of space. Compared to similar aluminum gallium arsenide/gallium arsenide HEMTs, the gallium nitride-based HEMTs are ten times more tolerant of radiation-induced displacement damage.

Until recently, scientists could only guess why this phenomena occurred: Was the gallium nitride material system itself so inherently disordered that adding more defects had scant effect? Or did the strong binding of gallium and nitrogen atoms to their lattice sites render the atoms more difficult to displace?

The answer, according to scientists at the Naval Research Laboratory, is none of the above.

Examining radiation response

In a recent open access article published in the ECS Journal of Solid State Science and Technology entitled, “On the Radiation Tolerance of AlGaN/GaN HEMTs,” the team of researchers from NRL state that by studying the effect of proton irradiation on gallium nitride-based HEMTs with a wide range of initial threading dislocation defectiveness, they found that the pre-irradiation material quality had no effect on radiation response.

Additionally, the team discovered that the order-of-magnitude difference in radiation tolerance between gallium arsenide- and gallium nitride-based HEMTs is much too large to be explained by differences in binding energy. Instead, they noticed that radiation-induced disorder causes the carrier mobility to decrease and the scattering rate to increase as expected, but the carrier concentration remains significantly less affected than it should be.

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From televisions screens we can roll up like newspapers to see-through batteries, researchers are moving electronics toward a more flexible, more transparent future.

The most recent development in this area comes from a group that has developed transparent, flexible supercapacitors made of carbon nanotube films. But this development goes far beyond wearable electronics, with potential applications in both energy storage and harvesting.

“Potential applications can be roughly divided into two categories: high-aesthetic-value products, such as activity bands and smart clothes, and inherently transparent end-uses, such as displays and windows,” co-author of the study Tanja Kallio, told Phys.org. “The latter include, for example, such future applications as smart windows for automobiles and aerospace vehicles, self-powered rolled-up displays, self-powered wearable optoelectronics, and electronic skin.”

With the thin films demonstrating 92 percent transparency and high efficiency compared to other carbon-based counterparts, the researchers believe that further improvements to the supercapacitors durability and energy density could make the product commercially viable.

Nanowire cooling

Flexible electrocaloric fabric of nanowire array can cool.
Image: Qing Wang/Penn State

The utilization of nanowires has opened a new branch of science for many researchers. While some have focused on applying this technology to energy systems, researchers from Penn State are using the nanowires to develop solid state personal cooling systems.

A new study from the university shows that nanowires could help develop a material for lightweight cooling systems, which could be incorporated into firefighting gear, athletic uniforms, and other wearables.

“Most electrocaloric ceramic materials contain lead,” says Qing Wang, professor of materials science and engineering at Penn State. “We try not to use lead. Conventional cooling systems use coolants that can be environmentally problematic as well. Our nanowire array can cool without these problems.”

This from Penn State:

Electrocaloric materials are nanostructured materials that show a reversible temperature change under an applied electric field. Previously available electrocaloric materials were single crystals, bulk ceramics, or ceramic thin films that could cool, but are limited because they are rigid, fragile, and have poor processability. Ferroelectric polymers also can cool, but the electric field needed to induce cooling is above the safety limit for humans.

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