Scientists worldwide are seeking ways to improve the power density, durability and overall performance of lithium-ion (Li-ion) batteries. Researchers in Japan now report an advance in Li-ion battery technology that yields a significantly higher-performing battery. The difference is a cathode positive electrode of lithium cobalt oxide in which the compound's individual grains are aligned in a specific orientation.
Researchers from North Carolina State Univ. have, for the first time, integrated a material called bismuth ferrite (BFO) as a single crystal onto a silicon chip, opening the door to a new generation of multifunctional, smart devices. Integrating the BFO into the silicon substrate as a single crystal makes the BFO more efficient by limiting the amount of electric charge that “leaks” out of the BFO into the substrate.
Organic solar cells have long been touted as lightweight, low-cost alternatives to rigid solar panels made of silicon. Dramatic improvements in the efficiency of organic photovoltaics have been made in recent years, yet the fundamental question of how these devices convert sunlight into electricity is still hotly debated. Now a Stanford Univ. research team is weighing in on the controversy.
Cooling systems generally rely on water pumped through pipes to remove unwanted heat. Now, researchers at Massachusetts Institute of Technology and in Australia have found a way of enhancing heat transfer in such systems by using magnetic fields, a method that could prevent hotspots that can lead to system failures. The system could also be applied to cooling everything from electronic devices to advanced fusion reactors, they say.
Researchers at Lawrence Berkeley National Laboratory have demonstrated in the laboratory a lithium-sulfur battery that has more than twice the specific energy of lithium-ion batteries, and that lasts for more than 1,500 cycles of charge-discharge with minimal decay of the battery’s capacity. This is the longest cycle life reported so far for any lithium-sulfur battery.
Ferroelectric materials are known for their ability to spontaneously switch polarization when an electric field is applied. An Oak Ridge National Laboratory-led team took advantage of this property to draw areas of switched polarization called domains on the surface of a ferroelectric material. To the researchers’ surprise, the domains began forming complex and unpredictable patterns that the researchers say should not be possible.
Batteries that power electric cars have problems. They take a long time to charge. The charge doesn’t hold long enough to drive long distances. They don’t allow drivers to quickly accelerate. They are big and bulky. By creating nanoparticles with controlled shape, engineers in California believe smaller, more powerful and energy-efficient batteries for vehicles can be built.
Northwestern Univ. and Argonne National Laboratory scientists have recently overcome problems with growing graphene on chemically inert substrates, demonstrating the first growth of graphene on a single-crystal silver substrate. Their method could advance graphene-based optical devices and enable the interfacing of graphene with other two-dimensional materials.
An interdisciplinary team of researchers has set its sights on improving the materials that make solar energy conversion/photocatalysis possible. Together, they have developed a new form of high-performance solar photocatalyst based on the combination of the titanium dioxide and other “metallic” oxides that greatly enhance the visible light absorption and promote more efficient utilization of the solar spectrum for energy applications.
A team of scientists have demonstrated new application of graphene using positive feedback. Using graphene’s electrical conduction, Columbia Univ. engineers have created a nano-mechanical system that can create FM signals. It is, in effect, the world's smallest FM radio transmitter.
From the production of tougher, more durable smartphones and other electronic devices, to a wider variety of longer lasting biomedical implants, bulk metallic glasses are poised to be mainstay materials for the 21st Century. Featuring a non-crystalline amorphous structure, bulk metallic glasses can be as strong or stronger than steel, as malleable as plastics, conduct electricity and resist corrosion.
Researchers have made the first battery electrode that heals itself, opening a new and potentially commercially viable path for making the next generation of lithium-ion batteries for electric cars, cell phones and other devices. The secret is a stretchy polymer that coats the electrode, binds it together and spontaneously heals tiny cracks that develop during battery operation.
Sometimes big change comes from small beginnings. That’s especially true in the research of Anatoly Frenkel, a prof. of physics at Yeshiva Univ., who is working to reinvent the way we use and produce energy by unlocking the potential of some of the world’s tiniest structures: nanoparticles.
Stanford Univ. researchers have developed an inexpensive device that uses light to split water into oxygen and clean-burning hydrogen. The goal is to supplement solar cells with hydrogen-powered fuel cells that can generate electricity when the sun isn't shining or demand is high.
Scientists in Japan have recently shown that structural control of small magnetic vortex structures called skyrmions could lead to a compact, low-power alternative to conventional magnetic data storage. Skyrmions occur rarely in certain magnetic compounds, but after it was discovered that they can exist near room temperature and can be manipulated with little current, research interest has grown.
Researchers have created tiny holograms using a metasurface capable of the ultra-efficient control of light, representing a potential new technology for advanced sensors, high-resolution displays and information processing. The metasurface, thousands of V-shaped nanoantennas formed into an ultra-thin gold foil, could make possible optical switches small enough to be integrated into computer chips for information processing.
When you squeeze atoms, you don’t get atom juice. You get magnets. According to a new theory by Rice Univ. scientists, imperfections in certain 2-D materials create the conditions by which nanoscale magnetic fields arise. Calculations by the laboratory of Rice theoretical physicist Boris Yakobson show these imperfections, called grain boundaries, in 2-D semiconducting materials known as dichalcogenides can be magnetic.
The phonon, like the photon or electron, is a physical particle that travels like waves, representing mechanical vibration. Phonons transmit everyday sound and heat. Recent progress in phononics by a research scientist at Georgia Institute of Technology has led to the development of new ideas and devices that are using phononic properties to control sound and heat, even to the point of freeing bustling city blocks from the noise of traffic.
Superfluidity refers to a state in which matter behaves like a liquid with zero viscosity. With a few exceptions, superfluidity has generally been regarded as a macroscopic phenomenon, resulting from “bulky” collections of particles rather than individual atoms. Scientists in Switzerland have now provided the first experimental evidence of superfluidity at the nanoscale, shedding light on the fundamental basis of the phenomenon.
Semiconductors, the foundation of modern electronics used in flatscreen televisions and fighter jets, could become even more versatile as researchers make headway on a novel, inexpensive way to turn them into thin films. Their report on a new liquid that can quickly dissolve nine types of key semiconductors appears in the Journal of the American Chemical Society.
Using the x-ray beams at the European Synchrotron Research Facility a research team has showed that the electrons absorbed and released by cerium dioxide nanoparticles during chemical reactions behave in a completely different way than previously thought. They show that the electrons are not bound to individual atoms but, like a cloud, distribute themselves over the whole nanoparticle, like an electron “sponge".
Despite their almost incomprehensibly small size, single-walled carbon nanotubes come in a plethora of different “species,” each with its own structure and unique combination of electronic and optical properties. Characterizing the structure and properties of an individual carbon nanotube has involved a lot of guesswork, until now.
Commercially available as instrumentation designed for macro-size sampling, Raman spectroscopy drew interest for providing information similar but complementary to infrared (FTIR) spectroscopy for chemical identification. In addition to chemical fingerprinting, the technique could provide molecular backbone information, materials morphology, sensitivity to symmetric bonds and the ability to analyze inorganic samples and components.
A computational method to quantify the adsorption of gas by porous zeolites should help labs know what to expect before they embark upon slow, costly experiments, according to researchers at Rice Univ. The new method created by engineers in Rice’s Multiscale Materials Modeling Lab accurately calculated the ability of two zeolites, small cage-like molecules with enormous surface area, to trap and store gas molecules.
When an earthquake and tsunami struck Japan’s Fukushima nuclear power plant in 2011, crews sprayed cooling seawater on the reactors, but to no avail. One possible reason: Droplets can’t land on surfaces that hot and instantly begin to evaporate, forming a thin layer of vapor and then bouncing along it. Now, MIT researchers have come up with a way to cool hot surfaces more effectively by keeping droplets from bouncing.