Photosynthesis copycat may improve solar cells

The diagram shows light hitting the semiconductor (purple) layered over the mirror-like photonic structure. The polaritons—mixtures of light, electrons and “holes”—then travel to the detector (truncated disc), where they generate current.
Image credit: Xinjing Huang and Bin Liu, Optoelectronic Components and Materials Group

A relatively new kind of semiconductor, layered atop a mirror-like structure, can mimic the way that leaves move energy from the sun over relatively long distances before using it to fuel chemical reactions. The approach may one day improve the efficiency of solar cells.

“Energy transport is one of the crucial steps for solar energy harvesting and conversion in solar cells,” said Bin Liu, a postdoctoral researcher in electrical and computer engineering and first author of the study in the journal Optica.

“We created a structure that can support hybrid light-matter mixture states, enabling efficient and exceptionally long-range energy transport.”

One of the ways that solar cells lose energy is in leakage currents generated in the absence of light. This occurs in the part of the solar cell that takes the negatively charged electrons and the positively charged “holes,” generated by the absorption of light, and separates them at a junction between different semiconductors to create an electrical current.

Remote-controllable cyborg cockroach

Cyborg cockroach
An insect developed in this study, equipped with a tiny wireless control module that is powered by a rechargeable battery attached to a solar cell.
Credit: RIKEN

An international team led by researchers at the RIKEN Cluster for Pioneering Research (CPR) has engineered a system for creating remote controlled cyborg cockroaches, equipped with a tiny wireless control module that is powered by a rechargeable battery attached to a solar cell. Despite the mechanical devices, ultrathin electronics and flexible materials allow the insects to move freely. These achievements, reported in the scientific journal npj Flexible Electronics on September 5, will help make the use of cyborg insects a practical reality.

Researchers have been trying to design cyborg insects—part insect, part machine—to help inspect hazardous areas or monitor the environment. However, for the use of cyborg insects to be practical, handlers must be able to control them remotely for long periods of time. This requires wireless control of their leg segments, powered by a tiny rechargeable battery. Keeping the battery adequately charged is fundamental—nobody wants a suddenly out-of-control team of cyborg cockroaches roaming around. While it’s possible to build docking stations for recharging the battery, the need to return and recharge could disrupt time-sensitive missions. Therefore, the best solution is to include an on-board solar cell that can continuously ensure that the battery stays charged.

All of this is easier said than done. To successfully integrate these devices into a cockroach that has limited surface area required the research team to develop a special backpack, ultrathin organic solar cell modules, and an adhesion system that keeps the machinery attached for long periods of time while also allowing natural movements.

Engineers Study Bird Flight

Photo credit: Karin Hiselius on Unsplash

People have been fascinated by bird flight for centuries, but exactly how birds can be so agile in the air remains mysterious. A new study, published the week of Sept. 5 in Proceedings of the National Academy of Sciences, uses modeling and aerodynamics to describe how gulls can change the shape of their wings to control their response to gusts or other disturbances. The lessons could one day apply to uncrewed aerial vehicles or other flying machines.

“Birds easily perform challenging maneuvers and they’re adaptable, so what exactly about their flight is most useful to implement in future aircraft?” said Christina Harvey, assistant professor in the Department of Mechanical and Aerospace Engineering at the University of California, Davis, and lead author on the paper.

Harvey began studying gulls as a master’s student in zoology at the University of British Columbia, after earning her bachelor’s degree in mechanical engineering.

“Gulls are very common and easy to find, and they’re really impressive gliders,” she said.

Harvey continued her work on gulls as a doctoral student at the University of Michigan. She recently joined the faculty at UC Davis after completing her Ph.D. in aerospace engineering.

Walking and slithering aren’t as different as you think

Abrahamic texts treat slithering as a special indignity visited on the wicked serpent, but evolution may draw a more continuous line through the motion of swimming microbes, wriggling worms, skittering spiders and walking horses.

A new study found that all of these kinds of motion are well represented by a single mathematical model.

“This didn’t come out of nowhere—this is from our real robot data,” said Dan Zhao, first author of the study in the Proceedings of the National Academy of Sciences and a recent Ph.D. graduate in mechanical engineering at the University of Michigan.

“Even when the robot looks like it’s sliding, like its feet are slipping, its velocity is still proportional to how quickly it’s moving its body.”

Unlike the dynamic motion of gliding birds and sharks and galloping horses—where speed is driven, at least in part, by momentum—every bit of speed for ants, centipedes, snakes and swimming microbes is driven by changing the shape of the body. This is known as kinematic motion.

The expanded understanding of kinematic motion could change the way roboticists think about programming many-limbed robots, opening new possibilities for walking planetary rovers, for instance.

How new motion-sensing technology may help standardize back-pain care

William S. Marras Professor Neurological Surgery, Orthopedics, Physical Medicine and Rehabilitation
 Credit/Source: Ohio State University

Digital health systems can tell clinicians when someone’s heart-disease risk calls for a drug to lower cholesterol or whether insulin shots are warranted for a person with type 2 diabetes.

But for millions of low-back pain sufferers, care decisions rely heavily on subjective measures of patient discomfort – often leading to expensive tests and treatments (back pain is the third-highest U.S. health care expenditure, after diabetes and heart disease) that don’t necessarily offer a permanent solution.

Ohio State University engineering and medical researchers are developing a digital health system approach designed to enhance back-pain clinical decision-making. After completing a series of studies testing precise, objective measurements they’ve perfected in the lab, the team aims to apply the data-driven practices to the assessment and repair of back problems brought on by dysfunction in the spine.

In a recent study published in Clinical Biomechanics, researchers combined self-reported pain and disability measures with data from a wearable motion-sensing system to evaluate low-back function in lumbar fusion surgery patients. While post-operative pain relief and lower disability were self-reported within six weeks, the objective metrics didn’t detect actual functional improvement in the spine for at least six months after surgery.

Faster Fish Tracking Through the Cloud

Researchers at Pacific Northwest National Laboratory developed a receiver that can transmit near-real-time information on fish tracking to inform decisions about dam operations that support fish passage. 
 Credit: Composite photo by Cortland Johnson | Pacific Northwest National Laboratory

The fastest way to track a fish is to use the cloud, figuratively speaking. A new acoustic receiver developed by researchers at Pacific Northwest National Laboratory (PNNL) and published in the journal IEEE Internet of Things, sends near-real-time fish tracking data to the digital cloud, providing timely information to dam operators and decision-makers about when, where, and how many fish are expected to pass through dams. Instead of relying on seasonal estimates of fish migration from previous years, these data from tagged fish support more informed decisions about dam operations that affect fish passage.

“This receiver provides up-to-the-hour data to dam operators to assist in making informed day-to-day decisions in support of fish passage, like adjusting water flow when it’s clear that a large group of juvenile fish are approaching the dam,” said Jayson Martinez, a PNNL mechanical engineer who co-developed the receiver.

Hydropower dams are an important source of dependable renewable energy, generating about six percent of total electricity in the United States. Helping fish navigate them safely is a key part of reducing dams’ environmental impact. The new receiver is a critical piece of the puzzle in the ongoing endeavor to improve fish passage.

Study paves way for widespread architectural use of end-of-life tires

'Earthship' built from recycled tires at Ironbank, SA. 
Credit: Earthship Ironbank

A new study by The University of South Australia published in the journal Engineering Structures has tested and verified the structural integrity of walls constructed from tires packed with earth, with the results potentially providing new opportunities for the reuse of end-of-life tires in the construction industry.

Tire waste represents a major sustainability challenge globally, with Australia alone generating an average of 55 million (450,000 tons) end-of-life tires each year.

While earth-packed tire walls have been used in niche construction scenarios for decades, there has previously been no strong empirical data available to support their use, a fact that has limited their wider uptake by architects and engineers.

Supported by Tire Stewardship Australia, a UniSA team consisting of Yachong Xu, Martin Freney, Reza Hassanli, Yan Zhuge, Mizanur Rahman and Rajibul Karim, has rigorously assessed the structural integrity of a test tire wall to examine how the structure performed under various stressors.

According to Dr. Martin Freney, the wall proved to be as structurally sound as conventional walls used in residential applications.

“The wall we tested was the first of its kind to be scientifically tested in this fashion, and all the data indicates tire walls can be extremely strong and safe structures,” Dr. Freney says.

A new neuromorphic chip for AI on the edge, at a small fraction of the energy and size of today’s compute platforms

 The NeuRRAM chip is an innovative neuromorphic chip
Credit: David Baillot/University of California San Diego

An international team of researchers has designed and built a chip that runs computations directly in memory and can run a wide variety of AI applications–all at a fraction of the energy consumed by computing platforms for general-purpose AI computing.

The NeuRRAM neuromorphic chip brings AI a step closer to running on a broad range of edge devices, disconnected from the cloud, where they can perform sophisticated cognitive tasks anywhere and anytime without relying on a network connection to a centralized server. Applications abound in every corner of the world and every facet of our lives, and range from smart watches, to VR headsets, smart earbuds, smart sensors in factories and rovers for space exploration.

The NeuRRAM chip is not only twice as energy efficient as the state-of-the-art “compute-in-memory” chips, an innovative class of hybrid chips that runs computations in memory, it also delivers results that are just as accurate as conventional digital chips. Conventional AI platforms are a lot bulkier and typically are constrained to using large data servers operating in the cloud.

In addition, the NeuRRAM chip is highly versatile and supports many different neural network models and architectures. As a result, the chip can be used for many different applications, including image recognition and reconstruction as well as voice recognition.

A gold inflatable Martian House designed to withstand life on Mars has landed in Bristol

The exterior of the Martian House
Credit: Luke O’Donovan

A two-story house designed for future life on Mars has landed on M Shed Square in Bristol, UK as part of an ongoing public art project, Building a Martian House.

The brainchild of local artists and Watershed Pervasive Media Studio residents Ella Good and Nicki Kent, the project has been designed over several years and brought together space scientists, world renowned architects, engineers, designers, school children and the public, to explore how considering future life on Mars, a planet with low power, zero emissions and zero waste, can inspire us to think creatively about how we can live more sustainably on earth and reassess our relationship with consumerism.

A team led by Hugh Broughton Architects, world experts in creating buildings for extreme environments including the Halley VI British Antarctic Research Station, working in partnership with design studio Pearce+, developed the design of the house.

The design team worked alongside space science and engineering experts Professor Lucy Berthoud, Dr Robert Myhill and Professor James Norman from the University of Bristol. A cohort of construction companies led by Southern Construction Framework generously donated their time and expertise to bring the project to life and funding has been provided by the Edward Marshall Trust.

MIT team reports giant response of semiconductors to light

MIT graduate student Jiahao Dong with the nanoindentation machine used in recent MIT work on the response of semiconductors to light.
Credits: Elizabeth Thomson/Materials Research Laboratory

In an example of the adage “everything old is new again,” MIT engineers report a new discovery in semiconductors, well-known materials that have been the focus of intense study for over 100 years thanks to their many applications in electronic devices.

The team found that these important materials not only become much stiffer in response to light, but the effect is reversible when the light is turned off. The engineers also explain what is happening at the atomic scale, and show how the effect can be tuned by making the materials in a certain way — introducing specific defects — and using different colors and intensities of light.

“We’re excited about these results because we’ve uncovered a new scientific direction in an otherwise very well-trod field. In addition, we found that the phenomenon may be present in many other compounds,” says Rafael Jaramillo, the Thomas Lord Associate Professor of Materials Science and Engineering at MIT and leader of the team.

Says Ju Li, another MIT professor involved in the work, "to see defects having such big effects on elastic response is very surprising, which opens the door to a variety of applications. Computation could help us screen many more such materials." Li is the Battelle Energy Alliance Professor in Nuclear Science and Engineering (NSE) with a joint appointment in the Department of Materials Science and Engineering (DMSE). Both Jaramillo and Li are also affiliated with the Materials Research Laboratory.

Two Monumental Milestones Achieved in CT Imaging

Conventional chest CT image (left side) of the human airways compared to the new and improved PCD-CT system (right side). The image produced with the PCD-CT system shows better delineation of the bronchial walls. Preliminary studies showed that the PCD-CT system allowed radiologists to see smaller airways than with standard CT systems.
Image credit: Cynthia McCollough, Mayo Clinic, Rochester, Minnesota.

Two biomedical imaging technologies developed with support from the National Institute of Biomedical Imaging and Bioengineering (NIBIB) have been cleared for clinical use by the Food and Drug Administration (FDA). Both technologies offer advances in computed tomography (CT).

In one of these developments, project lead Cynthia McCollough, Ph.D., director of Mayo Clinic’s CT Clinical Innovation Center and her team helped develop the first photon-counting detector (PCD)-CT system, which is superior to current CT technology. CT imaging has been an immense clinical asset for diagnosing many diseases and injuries. However, since its introduction into the clinic in 1971, the way that the CT detector converts x-rays to electrical signals has remained essentially the same. Photon-counting detectors operate using a fundamentally different mechanism than any prior CT detector ever has.

“This is the first major imaging advancement cleared by the FDA for CT in a decade,” stated Behrouz Shabestari, Ph.D., director of the division of Health Informatics Technologies. “The impact of this development will be far-reaching and provide clinicians with more detailed information for medical diagnoses.”

A CT scan is obtained when an x-ray beam rotates around a patient, allowing x-rays to pass through the patient. As the x-rays leave the patient a picture is taken by a detector and the information is transmitted to a computer for further processing. “Standard CT detectors use a two-step process, where x-rays are turned into light and then light is converted to an electrical signal,” explained Cynthia McCollough. “The photon-counting detector uses a one-step process where the x-ray is immediately transformed into an electrical signal.”

Synthetic genetic circuits that could help plants adapt to pressures from climate change

The activity of synthetic genetic circuits that process the presence or absence of specific signals in plant leaves was measured in high throughput by placing leaf punches in 96-well plates. When the correct combinations of inputs are delivered to leaves, they fluoresce green, and the fluorescence can be measured using a plate reader.
Image credit: Jennifer Brophy

Using synthetic genes, researchers at Stanford have been able to modify the root structures of plants. Their work could make crops more efficient at gathering nutrients and water, and more resilient to increasing pressures from climate change.

Increasingly, global food production is being threatened by the effects of climate change. As floods, droughts, and extreme heat waves become more common, crops need to be able to adapt faster than ever.

Researchers at Stanford University are working on ways to manipulate biological processes in plants to help them grow more efficiently and effectively in a variety of conditions. Jennifer Brophy, an assistant professor of bioengineering, and her colleagues have designed a series of synthetic genetic circuits that allow them to control the decisions made by different types of plant cells. In a paper published recently in Science, they used these tools to grow plants with modified root structures. Their work is the first step in designing crops that are better able to collect water and nutrients from the soil and provides a framework for designing, testing, and improving synthetic genetic circuits for other applications in plants.

“Our synthetic genetic circuits are going to allow us to build very specific root systems or very specific leaf structures to see what is optimal for the challenging environmental conditions that we know are coming,” Brophy said. “We’re making the engineering of plants much more precise.”

New research "UNCOVERS" hidden objects in high resolution

Target objects and the images of them created with UNCOVER NLOS technology.
Credit: Caltech

Imagine driving home after a long day at work. Suddenly, a car careens out of an obscured side street and turns right in front of you. Luckily, your autonomous car saw this vehicle long before it came within your line of sight and slowed to avoid a crash. This might seem like magic, but a novel technique developed at Caltech could bring it closer to a reality.

With the advent of autonomous vehicles, advanced spacecraft, and other technologies that rely on sensors for navigation, there is an ever-increasing need for advanced technologies that can scan for obstacles, pedestrians, or other objects. But what if something is hidden behind another object?

In a paper recently published in the journal Nature Photonics, Caltech researchers and their colleagues describe a new method that essentially transforms nearby surfaces into lenses that can be used to indirectly image previously obscured objects.

The technology, developed in the laboratory of Changhuei Yang, Thomas G. Myers Professor of Electrical Engineering, Bioengineering, and Medical Engineering; and Heritage Medical Research Institute investigator, is a form of non-line-of-sight (NLOS) sensing—or sensing that detects an object of interest outside of the viewer's line of sight. The new method, dubbed UNCOVER, does this by using nearby flat surfaces, such as walls, like a lens to clearly view the hidden object.

In control of chaos

Assembly line: A different chemical mixture is created in each of the droplets within the "Tubular flow reactor" – under exactly the same boundary conditions.
Image Credit: Empa

Crystals consisting of wildly mixed ingredients - so-called high-entropy materials - are currently attracting growing scientific interest. Their advantage is that they are particularly stable at extremely high temperatures and could be used, for example, for energy storage and chemical production processes. An Empa team is producing and researching these mysterious ceramic materials, which have only been known since 2015.

Nature strives for chaos. That's a nice, comforting phrase when yet another coffee cup has toppled over the computer keyboard and you imagine you could wish the sugary, milky brew back into the coffee cup - where it had been just seconds before. But wishing won't work. Because, as mentioned, nature strives for chaos.

Scientists have coined the term entropy for this effect - a measure of disorder. In most cases, if the disorder increases, processes run spontaneously and the way back to the previously prevailing order is blocked. See the spilled coffee cup. Even thermal power plants, which generate a huge cloud of steam above their cooling tower from a neat pile of wood or a heap of hard coal, operate driven by entropy. Disorder increases dramatically in many combustion processes - and humans take advantage of this, tapping a bit of energy in the form of electricity from the ongoing process for their own purposes.

“We’ve Got the Power”

Logan Rapp (left) and Darryn Fleming, Sandia National Laboratories mechanical engineers, stand with the control system for the supercritical carbon dioxide Brayton cycle test loop. Earlier this year, the engineers delivered electricity produced by this system to the grid for the first time.
Credit: Bret Latter / Sandia National Laboratories

For the first time, Sandia National Laboratories researchers delivered electricity produced by a new power-generating system to the Sandia-Kirtland Air Force Base electrical grid.

The system uses heated supercritical carbon dioxide instead of steam to generate electricity and is based on a closed-loop Brayton cycle. The Brayton cycle is named after 19th century engineer George Brayton, who developed this method of using hot, pressurized fluid to spin a turbine, much like a jet engine.

Supercritical carbon dioxide is a non-toxic, stable material that is under so much pressure it acts like both a liquid and a gas. This carbon dioxide, which stays within the system and is not released as a greenhouse gas, can get much hotter than steam — 1,290 degrees Fahrenheit or 700 Celsius. Partially because of this heat, the Brayton cycle has the potential to be much more efficient at turning heat from power plants — nuclear, natural gas or even concentrated solar — into energy than the traditional steam-based Rankine cycle. Because so much energy is lost turning steam back into water in the Rankine cycle, at most a third of the power in the steam can be converted into electricity. In comparison, the Brayton cycle has a theoretical conversion efficiency upwards of 50 percent.

“We’ve been striving to get here for a number of years, and to be able to demonstrate that we can connect our system through a commercial device to the grid is the first bridge to more efficient electricity generation,” said Rodney Keith, manager for the advanced concepts group working on the Brayton cycle technology. “Maybe it’s just a pontoon bridge, but it’s definitely a bridge. It may not sound super significant, but it was quite a path to get here. Now that we can get across the river, we can get a lot more going.”

Optical Fibers with Unusual Properties Created in Russia

Monocrystal.
Credit: Vladimir Petrov

Researchers of the Science Lab of Fiber Technology and Photonics at Ural Federal University have developed and produced infrared optical fibers with unique properties. The fibers are nontoxic and, as studies have shown, retain their outstanding properties when treated with ionizing beta radiation by doses up to 1 MGy. The team of scientists published an article describing the research, properties and areas of application of the obtained fibers in the scientific journal Optical Materials.

"This opens up the prospect of application of light guides made of the obtained fibers in conditions of intense ionizing radiation. That is, not only in the traditional field of optoelectronics, but also in laser surgery, endoscopic and diagnostic medicine, in determining the composition of hazardous waste from the nuclear industry, and in space," lists Liya Zhukova, Chief Scientist of the Laboratory, Professor of the Department of Physical Chemistry and Chemistry of Colloids at UrFU.

Because the fibers are capable of receiving and transmitting radiation from space objects, they can be embedded in infrared space telescopes, replacing massive mirrors and lenses. The lifespan of the fibers will be longer than the life cycle of the telescopes themselves, the developers claim.

Fibers are also highly productive in the non-hazardous for humans terahertz radiation region (between the region of mid- and far-infrared radiation, on the one hand, and microwave radiation, on the other hand). This means that fiber optic cables are suitable for creating equipment that could become a safe substitute for magnetic resonance imaging and x-rays - in medicine or in the process of pre-boarding scanning of passengers and their luggage. It would not require the use of cumbersome and expensive metal detectors, and passengers would not even feel that they are being screened.

UC gets NASA grant to improve drone navigation

UC will work with the Pennsylvania company VISIMO to develop better autonomous navigation for drones as part of a NASA grant.
Resized Image using AI by SFLORG
Credit: Andrew Higley/UC Marketing + Brand

NASA awarded a small business grant to the University of Cincinnati and a Pennsylvania company to develop better autonomous navigation for drones.

UC is among 41 public institutions and 257 small businesses across the United States that will share $50 million in Small Business Innovation Research grants.

“NASA is working on ambitious, groundbreaking missions that require innovative solutions from a variety of sources, especially our small businesses,” NASA Deputy Administrator Pam Melroy said.

UC College of Engineering and Applied Science aerospace engineering professor Kelly Cohen will work with the company VISIMO, based in Carnegie, Pennsylvania, to develop a testing environment that helps evaluate the safety and stability of artificial intelligence models used in autonomous drones. Using a 3D simulation, the project will test the complex sensor fusion and decision-making routines needed for real-time autonomous navigation.

According to the grant application, the simulations will help put the artificial intelligence to the test in situations that feature cascading failures in emergency situations such as a sudden storm that knocks out a drone’s sensor or cameras.

New Optical Switch Could Lead to Ultrafast All-Optical Signal Processing

An artist's illustration of an optical switch, splitting
 light pulses based on their energies.
Credit: Y. Wang, N. Thu, and S. Zhou

Engineers at Caltech have developed a switch—one of the most fundamental components of computing—using optical, rather than electronic, components. The development could aid efforts to achieve ultrafast all-optical signal processing and computing.

Optical devices have the capacity to transmit signals far faster than electrical devices by using pulses of light rather than electrical signals. That is why modern devices often employ optics to send data; for example, think of the fiberoptic cables that provide much faster internet speeds than conventional Ethernet cables.

The field of optics has the potential to revolutionize computing by doing more, at faster speeds, and with less power. However, one of the major limitations of optics-based systems at present is that, at a certain point, they still need to have electronics-based transistors to efficiently process the data.

Now, using the power of optical nonlinearity (more on that later), a team led by Alireza Marandi, assistant professor of electrical engineering and applied physics at Caltech, has created an all-optical switch. Such a switch could eventually enable data processing using photons. The research was published in the journal Nature Photonics on July 28.

Switches are among the simplest components of a computer. A signal comes into the switch and, depending on certain conditions, the switch either allows the signal to move forward or halts it. That on/off property is the foundation of logic gates and binary computation, and is what digital transistors were designed to accomplish. However, until this new work, achieving the same function with light has proved difficult. Unlike electrons in transistors, which can strongly affect each other's flow and thereby cause "switching," photons usually do not easily interact with each other.

New sensing platform deployed at controlled burn site, could help prevent forest fires

Argonne scientists conduct a controlled burn on the Konza prairie in Kansas using the Sage monitoring system. 
Resized Image using AI by SFLORG
Credit: Rajesh Sankaran/Argonne National Laboratory.

Smokey Bear has lots of great tips about preventing forest fires. But how do you stop one that’s started before it gets out of control? The answer may lie in pairing multichannel sensing with advanced computing technologies provided by a new platform called Sage.

Sage offers a one-of-a-kind combination. This combination involves both multiple types of sensors with computing ​“at the edge”, as well as embedded machine learning algorithms that enable scientists to process the enormous amounts of data generated in the field without having to transfer it all back to the laboratory. Computing ​“at the edge” means that data is processed where it is collected, in the field, while machine learning algorithms are computer programs that train themselves how to recognize patterns.

Sage is funded by the National Science Foundation and developed by the Northwestern-Argonne Institute for Science and Engineering (NAISE), a partnership between Northwestern University and the U.S. Department of Energy’s Argonne National Laboratory.

These Energy-Packed Batteries Work Well in Extreme Cold and Heat

Study first author Guorui Cai, a nanoengineering postdoctoral researcher at UC San Diego, prepares a battery pouch cell for testing at subfreezing temperature.
Credit: David Baillot/UC San Diego Jacobs School of Engineering

Engineers at the University of California San Diego have developed lithium-ion batteries that perform well at freezing cold and scorching hot temperatures, while packing a lot of energy. The researchers accomplished this feat by developing an electrolyte that is not only versatile and robust throughout a wide temperature range, but also compatible with a high energy anode and cathode.

The temperature-resilient batteries are described in a paper published the week of July 4 in Proceedings of the National Academy of Sciences (PNAS). (As of this posting the paper is not on PNAS)

Such batteries could allow electric vehicles in cold climates to travel farther on a single charge; they could also reduce the need for cooling systems to keep the vehicles’ battery packs from overheating in hot climates, said Zheng Chen, a professor of nanoengineering at the UC San Diego Jacobs School of Engineering and senior author of the study.

“You need high temperature operation in areas where the ambient temperature can reach triple digits and the roads get even hotter. In electric vehicles, the battery packs are typically under the floor, close to these hot roads,” explained Chen, who is also a faculty member of the UC San Diego Sustainable Power and Energy Center. “Also, batteries warm up just from having a current run through during operation. If the batteries cannot tolerate this warmup at high temperature, their performance will quickly degrade.”