If there were a pantheon of technological hipness, right now three front-runners for induction would be 3D printing, aerogel and graphene. They all rank high on the disruptive technology scale, have enormous amounts of good press, and excite the imagination with their potential. Lawrence Livermore National Laboratory researchers have gone beyond combining chocolate and peanut butter by blending the three higher-tech ingredients into a rather amazing battery material with excellent electrical and mechanical properties. We have discussed the idea of structural batteries in this blog, and this new melding of technologies holds much promise. Aerogel, as defined in the Laboratory’s announcement, “is a synthetic porous, ultralight material derived from a gel, in which the liquid component of the gel has been replaced with a gas. It is often referred to as ‘liquid smoke.’” Lawrence Livermore researchers have used a 3D printing technique known as direct ink writing to craft an engineered architecture microlattice with well-defined pores – which are essential …
Caging Hydrogen in Self-assembling Origami Structures
Let’s say that you’re really good at folding pieces of paper into miniature birds such as cranes, or life-size elephants, something origami artist Sipho Mabona did recently, starting with a 50-foot by 50-foot piece of paper (he had help from up to 40 others). The paper elephant, including a metal subframe to support it, weighs over 500 pounds. How about using origami to trap hydrogen in a novel approach to storing energy for fuel cells? Only, instead of paper, you might use sheets of graphene cleverly folded into cages no more than a few nanometers across – the opposite of the elephant in the art gallery. Researchers at the University of Maryland’s Department of Mechanical Engineering and Maryland NanoCenter, have done just that, but so far just as a simulation of the molecular dynamics involved. They have demonstrated that such cages can be opened and closed “in response to an electrical charge using a technique they call hydrogenation-assisted graphene origami …
Solar Cells a Few Atoms Thick
Researchers at the Vienna University of Technology have come up with a way to create one-atom thick, flexible, semi-transparent solar cells. Instead of the graphene often touted as a means toward such an end, however, the scientists have turned to atom-thick layers of tungsten diselenide for their wonder material. Experiments show that ultrathin layers of tungsten and selenium may have properties that would make them applicable even to electric aircraft use – if they can capture a significant amount of energy – or at least as much as thin-film silicon cells can. Graphene has been a popular favorite since its Russian “discoverers” were awarded the Nobel Prize in physics in 2010. One of the strongest materials, graphene can manage stresses and strains better than most and has “great opto-electronic properties.” Its atomic-scale thinness allows it to transform optical signals into electronic pulses extremely quickly. Despite these outstanding characteristics, “The electronic states are not very practical for creating photovoltaics,” according to …
Graphene Works and Plays Well With Other Materials
Graphene is a highly promising material, one atom thick, strong enough to support an elephant standing on a pencil (only theoretically so far, with no actual demonstration having taken place), and electrically conductive. All these properties bode well for its use in batteries, solar cells, and even energy-storing structural members. One concern, however, has been in how graphene would interact with other materials in a practical setting. After all, so far most experiments with graphene have taken place at the atomic level, not a feasible working arrangement for the ham-handed and those without scanning electron microscopes in their garage workshops. Dr. Marc Gluba and Professor Dr. Norbert Nickel of the Helmholz Zentrum Berlin have, doubtless with some pretty intense tools available at their Institute for Silicon Photovoltaics, managed to coat a graphene film with a thin silicon film. According to the Institute, “They grew graphene on a thin copper sheet, next transferred it to a glass substrate, and finally coated …
Thinner than Kleenex®, as Powerful as the Sun
David L. Chandler of the Massachusetts Institute of Technology (MIT) News Office reports that an MIT research team headed by Jeffrey Grossman has found a way to make sheets that push “towards the ultimate power conversion from a material” for solar power. His team has managed to fabricate molecule-thick photovoltaic sheets which could pack hundreds of times more power per weight than conventional solar cells. Senior author of a new paper on the team’s study in Nano Letters, Grossman found that despite the interest in two-dimensional materials such as graphene – only an atom thick – few have studied their potential for solar applications. Grossman says, “They’re not only OK, but it’s amazing how well they do.” Stacking sheets of graphene and materials such as molybdenum disulfide would make solar cells with one to two percent efficiency in converting sunlight to electricity. That seems disappointingly low compared to the 15 to 20 percent efficiency of commercially available silicon solar cells. …
Making Graphene and Carbon Fibers Even Lighter and Stronger
While scientists at Columbia University have used chemical vapor deposition (CVD) to create large sheets of stronger-than-average graphene, a research team at Massachusetts Institute of Technology (MIT) has found ways to weave stronger carbon nanotubes. James Hone and Jeffrey Kysar, professors of mechanical engineering at Columbia University, learned that the enormous strength of graphene is usually achieved in only small patches. The “grain boundaries” for larger sheets were often far weaker than the theoretical strengths of which the material is capable. That strength is phenomenal. Hone explains, “It would take an elephant, balanced on a pencil, to break through a sheet of graphene the thickness of Saran Wrap.” Results of their study were published in the journal Science. The paper’s lead author, Gwan-Hyoung Lee, a postdoctoral fellow in the Hone lab, says, “Our findings clearly correct the mistaken consensus that grain boundaries of graphene are weak. This is great news because graphene offers such a plethora of opportunities both for …
GraphExeter Aims for Power with Transparency
It doesn’t sound much like dispassionate, objective scholarly reporting, but the University of Exeter in England headlines its report on a University-created breakthrough material, “Revolutionary new device joins world of smart electronics.” Layering graphene and the GraphExeter, a material obviously headed for product marketing, gives a “new flexible, transparent, photosensitive device” that can lead to solar-powered clothing able to charge the wearer’s cell phone, “intelligent” windows that can “harvest light and display images,” and just maybe (in this writer’s dreams) help power electric cars and airplanes. GraphExeter, Exeter claims, is the best known room temperature transparent conductor and with graphene – the thinnest conductive material – the pair make for great potential. Researchers developed GraphExeter by sandwiching molecules of ferric chloride in between two layers of graphene. According to the University, “Saverio Russo, Professor of Physics at the University of Exeter said: ‘This new flexible and transparent photosensitive device uses graphene and graphExeter to convert light into electrical signals …
What Do You Have on Your DVD Burner?
Richard Kaner and Maher El-Kady have “micro-scale graphene-based supercapacitors” on their front DVD burner, showing an energetic alternative to saving all those ‘80’s rockers to disc. Dr. Kaner is a member of the California NanoSystems Institute at the University of California at Los Angeles (UCLA) and professor of chemistry and biochemistry. He and graduate student El-Kady are using a “consumer grade” LightScribe DVD burner to make dozens of micro supercapacitors on what looks like a typical DVD. Dr. Kaner’s research lab hosts 17 undergraduate and graduate student researchers who’ve helped amass at least 390 papers in four main areas of research; conducting polymers, graphene, superhard materials and thermoelectric materials. Their recent investigation of supercapacitor fabrication seems to encompass almost all of these fields. An abstract for their recent article in Nature Communications hints at the possibilities this research may realize in the commercial world. “The rapid development of miniaturized electronic devices has increased the demand for compact on-chip energy storage. …
A Layer of Graphene, A Layer of Nanowires…
Combine nano-anything with graphene, and that seems to describe most of what’s driving physics and chemistry laboratories at our major universities. The blog reported last week on Princeton researchers who’ve created a thin, flexible solar cell that absorbs 96-percent of received light and draws energy from off-axis and varied wavelengths of light. MIT researchers, too, have created a thin, flexible solar cell, but one based on layers of flexible graphene sheets, each coated with a layer of nanowires. Besides flexibility, these sheets offer transparency, enabling their use on windows as well as other surfaces. David Chandler, reporting for MIT states that the new cells may prove to be far less expensive than today’s silicon equivalents, which require high-purity silicon that undergoes crystallization and extremely thin slicing. Alternatives use indium tin oxide (ITO), itself an expensive substitute for or adjunct to silicon. Nanostructured cells such as that from Princeton may allow lower-priced material, although one version uses a gold foil top layer. Silvija …
Thomas Alva Would Be Proud
The best batteries as now produced use expensive materials and processes to achieve high energy density. Could a century-old idea be resurrected to provide an inexpensive alternative to today’s costly electric storage devices? Science Daily reports on a recent attempt to improve on a proven technology. Stanford University’s Hongjie Dai, professor of chemistry and head of a research group, is working with the Edison battery, named for Thomas Alva Edison, and using the nickel-iron electrodes Edison favored, but with a modern twist to overcome one of its disadvantages. Stanford’s news bulletin quotes Dai. “The Edison battery is very durable, but it has a number of drawbacks. A typical battery can take hours to charge, and the rate of discharge is also very slow.” Powering electric vehicles in the early 1900s, Edison’s battery is used today in limited instances to store surplus electricity from solar panels and wind turbines where charging and discharge speeds are not a major consideration. Dai’s …