Posts belonging to Category electronics

How To Store 10 Times More Energy In A Li-ion Battery

Scientists have been trying for years to make a practical lithium-ion battery anode out of silicon, which could store 10 times more energy per charge than today’s commercial anodes and make high-performance batteries a lot smaller and lighter. But two major problems have stood in the way: Silicon particles swell, crack and shatter during battery charging, and they react with the battery electrolyte to form a coating that saps their performance. Now, a team from Stanford University and the Department of Energy’s SLAC National Accelerator Laboratory has come up with a possible solution: Wrap each and every silicon anode particle in a custom-fit cage made of graphene, a pure form of carbon that is the thinnest and strongest material known and a great conductor of electricity.

In a report published Jan. 25 in Nature Energy, they describe a simple, three-step method for building microscopic graphene cages of just the right size: roomy enough to let the silicon particle expand as the battery charges, yet tight enough to hold all the pieces together when the particle falls apart, so it can continue to function at high capacity. The strong, flexible cages also block destructive chemical reactions with the electrolyte.

graphene_cageThis time-lapse movie from an electron microscope shows the new battery material in action: a silicon particle expanding and cracking inside a graphene cage while being charged. The cage holds the pieces of the particle together and preserves its electrical conductivity and performance

In testing, the graphene cages actually enhanced the electrical conductivity of the particles and provided high charge capacity, chemical stability and efficiency,” said Yi Cui, an associate professor at SLAC and Stanford who led the research. “The method can be applied to other electrode materials, too, making energy-dense, low-cost battery materials a realistic possibility.

This new method allows us to use much larger silicon particles that are one to three microns, or millionths of a meter, in diameter, which are cheap and widely available,” Cui adds. “In fact, the particles we used are very similar to the waste created by milling silicon ingots to make semiconductor chips; they’re like bits of sawdust of all shapes and sizes. Particles this big have never performed well in battery anodes before, so this is a very exciting new achievement, and we think it offers a practical solution.


Super Smart Band-Aids

This is what a band-aid in the future might look like. It’s a stretchable hydrogel that in many ways mimics
the properties of human tissue.

smart band-aid

Hydrogel is a polymer network infiltrated with water. Even though it is only 5 to 10 percent polymer, this network is extremely important“, says Xuanhe Zhao, Professor of Mechanical engineering at the Massachusetts Institute of Technology (MIT).

Important because the polymer makes up a microscopic scaffold that endows it with special properties uncommon to synthetic hydrogels. It is highly stretchable and can adhere easily to surfaces. Most importantly, it is specifically designed to be compatible with the human body – both inside and out. That compatibility could potentially give rise to a new class of biomedical devices.

We further embed electronic devices such as sensors, such as different drug delivery devices into this matrix to achieve what we call the smart applications“, comments Zhao.  Applications that could turn an ordinary band-aid into a tool to actively monitor and heal wounds autonomously. Zhao uses burns as an example… “Once the sensor senses an abnormal increase in temperature for example It will send out a command. Then the controlled drug delivery system can deliver a specific drug to that specific location“, he adds. The researchers are now fine tuning the properties and functionality of their hydrogels. They hope that soon healing everything from a scratch to an ulcer will be as simpleas putting on a band-aid.


How Cellulose Nanogenerators Power Bio-Implants

Implantable electronics that can deliver drugs, monitor vital signs and perform other health-related roles are on the horizon. But finding a way to power them remains a challenge. Now scientists have built a flexible nanogenerator out of cellulose, an abundant natural material, that could potentially harvest energy from the body — its heartbeats, blood flow and other almost imperceptible but constant movements.

implants to monitor vital signsImplantable electronics to monitor vital signs and perform other functions could one day be powered with tiny generators that harvest the body’s energy.

Efforts to convert the energy of motion — from footsteps, ocean waves, wind and other movement sources — are well underway. Many of these developing technologies are designed with the goal of powering everyday gadgets and even buildings. As such, they don’t need to bend and are often made with stiff materials. But to power biomedical devices inside the body, a flexible generator could provide more versatility. So Md. Mehebub Alam and Dipankar Mandal at Jadavpur University in India set out to design one.

The researchers turned to cellulose, the most abundant biopolymer on earth, and mixed it in a simple process with a kind of silicone called polydimethylsiloxane — the stuff of breast implants — and carbon nanotubes. Repeated pressing on the resulting nanogenerator lit up about two dozen LEDs instantly. It also charged capacitors that powered a portable LCD, a calculator and a wrist watch. And because cellulose is non-toxic, the researchers say the device could potentially be implanted in the body and harvest its internal stretches, vibrations and other movements.

The findings appear in the journal ACS Applied Materials & Interfaces.


Revolution In The Nanotechnology Industry

After six years of painstaking effort, a group of University of Wisconsin-Madison (UW-Madison) materials scientists believe their breakthrough in growing tiny sheets of zinc oxide could have huge implications for the future of nanomaterial manufacturing—and in turn, on a host of electronic and biomedical devices.
The group, led by Xudong Wang, an associate professor of science and engineering at UW-Madison, and postdoctoral researcher Fei Wang, has developed a novel technique for synthesizing two-dimensional nanosheets from compounds that do not naturally form the atomic-layer-thick materials. Essentially the microscopic equivalent of a single sheet of paper, a 2D nanosheet is a material that is constrained to up to only a few atomic layers in one direction. Nanomaterials—materials that are constrained in at least one dimension to a maximum of a handful of atomic layers—have unique physical properties that alter their electronic and chemical properties in relation to their compositionally identical but conventional, and larger, material counterparts.


What’s nice with a 2D nanomaterial is that because it’s a sheet, it’s much easier for us to manipulate compared to other types of nanomaterials,” says Xudong Wang. Xudong Wang first had the idea for using a surfactant to grow nanosheets during a lecture he was giving in a course on nanotechnology in 2009. “The course includes a lecture about self-assembly of monolayers,” adds Xudong Wang. “Under the correct conditions, a surfactant will self-assemble to form a monolayer. This is a well-known process that I teach in class. So while teaching this I wondered why we wouldn’t be able to reverse this method and use the surfactant monolayer first to grow the crystalline face.

It is the first time such a technique has been successful, and the researchers described their findings in the journal Nature Communications.


Bionic Human

A new  program from the Defense Advanced Research Project Agency (DARPA) aims to develop an implantable neural interface able to provide unprecedented signal resolution and data-transfer bandwidth between the human brain and the digital world. The interface would serve as a translator, converting between the electrochemical language used by neurons in the brain and the ones and zeros that constitute the language of information technology. The goal is to achieve this communications link in a biocompatible device no larger than one cubic centimeter in size, roughly the volume of two nickels stacked back to back.

The program, Neural Engineering System Design (NESD), stands to dramatically enhance research capabilities in neurotechnology and provide a foundation for new therapies.

artificial intelligence

Today’s best brain-computer interface systems are like two supercomputers trying to talk to each other using an old 300-baud modem,” said Phillip Alvelda, the NESD program manager. “Imagine what will become possible when we upgrade our tools to really open the channel between the human brain and modern electronics.”

To familiarize potential participants with the technical objectives of NESD, DARPA will host a Proposers Day meeting that runs Tuesday and Wednesday, February 2-3, 2016, in Arlington, Va. The Special Notice announcing the Proposers Day meeting is available at
More details about the Industry Group that will support NESD is available at
A Broad Agency Announcement describing the specific capabilities sought is available at:


Bubble-Pen To Build Nanocomputer, Sensor, Solar Panel…

Researchers in the Cockrell School of Engineering at The University of Texas at Austin have solved a problem in micro- and nanofabrication — how to quickly, gently and precisely handle tiny particles — that will allow researchers to more easily build tiny machines, biomedical sensors, optical computers, solar panels and other devices. They have developed a device and technique, called bubble-pen lithography, that can efficiently handle nanoparticles — the tiny pieces of gold, silicon and other materials used in nanomanufacturing. The new method relies on microbubbles to inscribe, or write, nanoparticles onto a surface.

A research team led by Texas Engineering assistant professor Yuebing Zheng has invented a way to handle these small particles and lock them into position without damaging them. Using microbubbles to gently transport the particles, the bubble-pen lithography technique can quickly arrange particles in various shapes, sizes, compositions and distances between nanostructures.

bubble-pen litho

The ability to control a single nanoparticle and fix it to a substrate without damaging it could open up great opportunities for the creation of new materials and devices,” Zheng said. “The capability of arranging the particles will help to advance a class of new materials, known as metamaterials, with properties and functions that do not exist in current natural materials.

The team, which includes Cockrell School associate professor Deji Akinwande and professor Andrew Dunn, describe their patented device and technique in a paper published in Nano Letters.


Brain Injury: How To Monitor Temperature, Pressure

 A new class of small, thin electronic sensors can monitor temperature and pressure within the skullcrucial health parameters after a brain injury or surgery – then melt away when they are no longer needed, eliminating the need for additional surgery to remove the monitors and reducing the risk of infection and hemorrhage.

Nanoparticles Destroy Antibiotic-Resistant “Superbugs”

In the ever-escalating evolutionary battle with drug-resistant bacteria, humans may soon have a leg up thanks to adaptive, light-activated nanotherapy developed by researchers at the University of Colorado Boulder (CU-Boulder). Antibiotic-resistant bacteria such as Salmonella, E. Coli and Staphylococcus infect some 2 million people and kill at least 23,000 people in the United States each year. Efforts to thwart these so-called “psuperbugs” have consistently fallen short due to the bacteria’s ability to rapidly adapt and develop immunity to common antibiotics such as penicillin.  New research from CU-Boulder, however, suggests that the solution to this big global problem might be to think small—very small.

In findings published today in the journal Nature Materials, researchers at the Department of Chemical and Biological Engineering and the BioFrontiers Institute describe new light-activated therapeutic nanoparticles known as “quantum dots.” The dots, which are about 20,000 times smaller than a human hair and resemble the tiny semiconductors used in consumer electronics, successfully killed 92 percent of drug-resistant bacterial cells in a lab-grown culture.

salmonella bacteria

By shrinking these semiconductors down to the nanoscale, we’re able to create highly specific interactions within the cellular environment that only target the infection,” said Prashant Nagpal, an assistant professor in the Department of Chemical and Biological Engineering at CU-Boulder and a senior author of the study.


Efficient Triboelectric Generator Embedded In A Shoe

A two-stage power management and storage system could dramatically improve the efficiency of triboelectric generators that harvest energy from irregular human motion such as walking, running or finger tapping. The system uses a small capacitor to capture alternating current generated by the biomechanical activity. When the first capacitor fills, a power management circuit then feeds the electricity into a battery or larger capacitor. This second storage device supplies DC current at voltages appropriate for powering wearable and mobile devices such as watches, heart monitors, calculators, thermometers – and even wireless remote entry devices for vehicles. By matching the impedance of the storage device to that of the triboelectric generators, the new system can boost energy efficiency from just one percent to as much as 60 percent.

Triboelectric shoes

llustration shows how a triboelectric generator embedded in a shoe would produce electricity as a person walked

With a high-output triboelectric generator and this power management circuit, we can power a range of applications from human motion,” said Simiao Niu, a graduate research assistant in the School of Materials Science and Engineering at the Georgia Institute of Technology. “The first stage of our system is matched to the triboelectric nanogenerator, and the second stage is matched to the application that it will be powering.

The research has been reported in the journal Nature Communications.


Virtual Hug

Skin care giant Nivea has allowed a mother and son to have a ‘virtual hug’ from two different countries thanks to its ‘Second Skin Project’ involving nanotechnology. However, all is not as it seems.

second skin

A video was created with Leo Burnett Madrid to highlight the importance of the human touch and initially discloses how nanotechnology helped the company recreate the effect from thousands of miles apart. A mother and son who were based in Uruguay and Spain were selected for the experiment, with Beiersdorf-owned Nivea using a ground-breaking fabric that is said to simulate human skin. According to the video, the material is woven with a number of sensors and can retain electrical impulses. As a result of this, when one person touches it, the other can feel the touch from thousands of miles away.

However, at the end of the video the project is ousted as not being real, and is instead a shrewd marketing campaign for the importance of the human touch, and, in effect, its skin cream. Watch the video, and get your tissues at the ready, to see it unfold.


New Efficiency Record with Dual-Junction Solar Cell

Scientists at the Energy Department’s National Renewable Energy Laboratory (NREL) and at the Swiss Center for Electronics and Microtechnology (CSEM) have jointly set a new world record for converting non-concentrated (1-sun) sunlight into electricity using a dual-junction III-V/Si solar cellThe newly certified record conversion efficiency of 29.8 percent was set using a top cell made of gallium indium phosphide developed by NREL, and a bottom cell made of crystalline silicon developed by CSEM using silicon heterojunction technology. The two cells were made separately and then stacked by NREL.

dual junctio solar cell

It’s a record within this mechanically stacked category,” said David Young, a senior researcher at NREL. “The performance of the dual-junction device exceeded the theoretical limit of 29.4 percent for crystalline silicon solar cells.”

Young is co-author of a paper, “Realization of GaInP/Si dual-junction solar cells with 29.8 percent one-sun efficiency,” which details the steps taken to break the previous record. His co-authors from NREL are Stephanie Essig, Myles Steiner, John Geisz, Scott Ward, Tom Moriarty, Vincenzo LaSalvia, and Pauls Stradins. The paper has been submitted for publication in the IEEE Journal of Photovoltaics.

Essig attracted interest from CSEM when she presented a paper, “Progress Towards a 30 percent Efficient GaInP/Si Tandem Solar Cell,” to the 5th International Conference on Silicon Photovoltaics, in Germany in March. “We believe that the silicon heterojunction technology is today the most efficient silicon technology for application in tandem solar cells” said Christophe Ballif, head of PV activities at CSEM.

CSEM partnered with the NREL scientists with the objective to demonstrate that 30 percent efficient tandem cells can be realized using silicon heterojunction bottom cells, thanks to the combination with high performance top cells such as those developed by NREL,” said Matthieu Despeisse, the manager of crystalline silicon activities at CSEM.

The record was published in “Solar cell efficiency tables.”


Nanotechnology Hero

Judith Driscoll, 49, is professor of materials science at the University of Cambridge and an expert on nanotechnology. She read materials science at Imperial College London, followed by a PhD in superconductivity at Cambridge and post-doctoral research at Stanford University, California and IBM Almaden Research Centre. Following  is her testimony.


Science is Passion

I’m always surprised more people don’t study materials science. It’s broad and creative and so important to our everyday lives. I loved physics, chemistry and maths at school and hit on materials science as a great way of continuing with them.”

“Studying for a PhD was tough. It’s completely different from a first degree. Intelligence isn’t enough. You have to be creative, have your own ideas, cope with setbacks and work largely unaided. But it is a great way of finding out whether a career in research is right for you.” “The research for which I’m most famous happened on sabbatical. After eight years mostly spent teaching, doing admin and raising money I really wanted to get back into the lab, so I went to Los Alamos National Laboratory in New Mexico to work on a new idea I had to combine superconductivity and nanotechnology.” “Nanotechnology is unbelievably small. A nanometre is one billionth of a metre, roughly the length a human hair grows in the time it takes to pick up a razor.” “Nanotechnology lets you create substances as small as one molecule thick, giving enormous surface area for speeding up chemical reactions. You can also miniaturise computer components, potentially storing a terabyte of data per square inch.” “And you can achieve quantum confinement, where particles are so small that electrons behave differently from normal, enabling new optical, electrical and magnetic properties to be realised.”

“My big breakthrough concerned the creation of “perfectdefects in very thin films of superconductors. My brainwave was to create nanoparticles within a thin film superconductor using a different material that I knew the superconductor wouldn’t react with.” “It worked right away, achieving very much higher currents in the superconductor and opening up a whole new world of applications in power transmission, conversion and storage, and in high-power magnets for important science experiments such as the Large Hadron Collider and fusion research.” Nanotechnology may be tiny but its potential is huge. It could give us much more efficient solar power, better storage of renewable energy, cancer-killing drugs delivered to just the right cells in the body, biotechnology to clean polluted environments, even molecular-scale robots called nanobots.

“My latest research involves making new kinds of composite thin films that mimic how the brain works.”

“Being a senior academic is rather like running a small business. Your “product” is your research output and you have to raise funding, manage the lab and the people, supervise the work and “market” your work to other academics.” “The wonderful thing about my job is the freedom. In my research nobody tells me what to do or when, and when my daughters were young I was able to work very flexibly”. “You need to be really passionate to succeed in science. If you’re not the type to give up your weekend to really understand something then you’re probably not cut out for it.”