Fires on or in aircraft are anathema, leaving a pilot and passengers with few options. Even a laptop starting to smoke in the cabin will cause an emergency descent and a diversion to the nearest airport. As designers incorporate larger lithium batteries into new aircraft (and they are essential to motor-driven planes), the need to keep things from self-igniting becomes imperative. Researchers at Stanford University and the Department of Energy’s SLAC National Accelerator Laboratory, working with funding from the Joint Center for Energy Storage Research (JCESR) discovered, “That adding two chemicals to the electrolyte of a lithium metal battery prevents the formation of dendrites – ‘fingers’ of lithium that pierce the barrier between the battery’s halves, causing it to short out, overheat and sometimes burst into flame.” Preventing these shorts will lead to the next-generation batteries being able to take advantage of lithium-sulfur and lithium-air technologies with up to 10 times the energy per weight of batteries now used in …
Aluminum Yolks and Titanium Shells
A new “yolk-and-shell” nanoparticle could boost the capacity and power of lithium-ion batteries. MIT’s press release gives a graphic overview of what damages electrodes and shortens battery life. “One big problem faced by electrodes in rechargeable batteries, as they go through repeated cycles of charging and discharging, is that they must expand and shrink during each cycle — sometimes doubling in volume, and then shrinking back. This can lead to repeated shedding and reformation of its “skin” layer that consumes lithium irreversibly, degrading the battery’s performance over time.” Dr. Yi Cui and teams at Stanford’s National Accelerator Laboratory (Formerly the Stanford Linear Accelerator Center), and the Environmental Molecular Sciences Laboratory (EMSL) at Pacific Northwest National Laboratory all published papers on a similar joint accomplishment three years ago, as reported in this blog. Dr. Cui had studied several alternative ways to reduce the effects of expansion and contraction on electrodes. According to an MIT news release, “Now a team of researchers at MIT, led …
MSCs Could be AOK
Of late, your editor has noticed several press releases concerning scientific findings that don’t read in a scientific way. You know that objective kind of writing: the use of words and phrases such as “tend to,” “suggesting,” or “of potential interest,” and the ever-popular, “further study is required.” An announcement from the Center for Integrated Nanostructure Physics at the Institute for Basic Science (IBS) and Department of Energy Science at Sungkyunkwan University in South Korea tells a hopeful story of a new discovery mimicking nature and “displaying electrical properties about five orders of magnitude higher than similar lithium batteries, and even claiming, “stunning test results.” These sound more like PR than simple declarative statements. Before running to your broker to see if an IPO is imminent, let’s determine what those “similar lithium batteries” are and what electrical properties are being compared. The abstract for the team’s paper in the May 6 edition of Advanced Energy Materials is more circumspect. “Inspired by natural …
High-capacity, Soft Batteries From Trees
This is not pulp fiction, but pulp fact, trees being converted into squishy new nerf-like batteries. Researchers at Sweden’s KTH Royal Institute of Technology and Stanford University have made elastic, high-capacity batteries from wood pulp. The foam-like battery material can withstand shock and stress, according to the schools. Max Hamedi, a researcher at KTH and Harvard University, says, “It is possible to make incredible materials from trees and cellulose.” The wood-based aerogel material can be used for three-dimensional structures, important for overcoming certain restrictions imposed by two-dimensional approaches. Hamedi explains, “There are limits to how thin a battery can be, but that becomes less relevant in 3D. We are no longer restricted to two dimensions. We can build in three dimensions, enabling us to fit more electronics in a smaller space.” Moving past former obstacle of using three-dimensional, porous materials in crafting electrodes, researchers managed to make this a non-problem. Hamedi adds, “In fact, this type of structure and material …
Designer Carbon: High Surface Area and Porosity
Stanford researchers, working with scientists at Korea’s Ulsan National Institute of Science and Technology (UNIST) and China’s National Laboratory of Microstructures (Nanjing), School of Electronic Science and Engineering, at Nanjing University, have squeezed carbon as flat (if not flatter than) as graphene and poked lots of well-sized holes in it to make designer battery and supercapacitor components. Professor Zhenan Bao led the efforts at Stanford. The combined teams’ paper, “Ultrahigh Surface Area Three-Dimensional Porous Graphitic Carbon from Conjugated Polymeric Molecular Framework,” appeared as a cover article in the May 18 edition of the journal ACS Central Science. The paper explains, “High surface area porous carbon materials are of great technological importance due to their diverse functionalities and excellent physical/chemical robustness. Their high electronic conductivity, large surface area, and good chemical and electrochemical stability are of particular interest for electrochemical energy storage devices, such as electrochemical capacitors (or supercapacitors) and batteries.” High surface area gives more space for electrolyte to interact with …
All-Electron Battery – Stanford Strikes Again
With recent news of a solid-state battery coming for the labs of Yi Cui, a second solid-state solution seems to follow from another Stanford Laboratory. The All-Electron Battery, funded at least partly by an ARPA-E grant that underwrote the program from 2010 to 2012, has fostered a startup, QuantumScape. Starting from the stated need for a battery “with twice the energy storage of today’s state-of-the-art Li-Ion battery at 30% of the cost,” ARPA-E worked with the premise that Stanford was “developing an all-electron battery that would create a completely new class of energy storage devices for EVs. Stanford’s all-electron battery stores energy by moving electrons rather than ions. Electrons are lighter and faster than the ion charge carriers in conventional Li-Ion batteries. Stanford’s all-electron battery also uses an advanced structural design that separates critical battery functions, which increases both the life of the battery and the amount of energy it can store. The battery could be charged 1000s of times …
H2 – Many Benefits, Many Challenges
The benefits of hydrogen are fairly obvious. It would almost necessarily be a domestically produced material with few environmental shortcomings if made by clean processes. The challenges to be overcome are many and varied, though – with the biggest obstacle to wide-spread use being in the distribution of the fuel. The U. S. Department of Energy, on its Fuel Economy.gov web site, concedes, “The current infrastructure for producing, delivering, and dispensing hydrogen to consumers cannot yet support the widespread adoption of FCVs (fuel cell vehicles).” As different strategies are tested and adopted, this is likely to change, as are the costs for fuel cells and their longevity. Auto makers, working to bring FCVs to market, have dropped prices from the million dollar estimate for a Honda Clarity at its introduction to a few lucky individuals in 2008 to the projected $50,000-$100,000 price range at which its successor, the FCV, might be introduced today. The same type of controversy surrounds this …
Audi Drives Hockenheim with “Bobby”
“Bobby” is Audi’s computerized “driver” for their RS 7, which they demonstrated before thousands of spectators in the grandstands at the 4.574 kilometer (2.842 mile) Hockenheim race track in Baden-Wurttemberg, Germany on October 19. The video, despite the somewhat sometimes annoying narration, gives a good impression of the run, showing the acceleration, braking and cornering through all 17 turns from both inside and outside the car. The inside views belie the speed the car attains, looking a bit unearthly by the precise, smooth lines the car takes, the envy of any “real” race car driver. Green Car Congress reports, “The Audi RS 7 piloted driving concept car drove a clean racing line at the Hockenheimring—full throttle on the straights, full braking before the corners, precise turn-in and perfectly metered acceleration when exiting the corners. Forces of over 1.3 g occur during braking, and lateral acceleration in the corners can reach 1.1 g. Tests on the track in Hockenheim suggested an …
Cheap Hydrogen, Anyone?
Researchers in Glasgow and at Stanford University have devised ways to decouple oxygen and hydrogen from water without resort to expensive extraction or storage techniques. Both breakthroughs involve low-cost materials, low-energy requirements, and the production of clean hydrogen through what should be renewable energy resources. The latter overcomes one major objection to hydrogen production. As Professor Lee Cronin of the University of Glasgow’s School of Chemistry explains, “Around 95% of the world’s hydrogen supply is currently obtained from fossil fuels, a finite resource which we know harms the environment and speeds climate change. Some of this hydrogen is used to make ammonia fertilizer and as such, fossil hydrogen helps feed more than half of the world’s population. “The potential for reliable hydrogen production from renewable sources is huge. The sun, for example, provides more energy in a single hour of sunlight than the entire world’s population uses in a year. If we can tap and store even a fraction of …
EAS VIII: Sebastian Thrun Updates Us
Sebastian Thrun is best known for his leadership in the “Google Cars” program, fielding self-driving Priuses in the San Francisco Bay area and having the cars demonstrate a spotless accident record (except for those caused by other drivers running into them.) He shared the current status of that project with attendees at the eighth annual CAFE Foundation Electric Aircraft Symposium in late April. He’s also been responsible for Google Glass, those controversial mega-spectacles that have furnished stand-up comics with new realms of material, although the last laugh may be on scoffers as these ingenious devices point the way toward wearable computers. Thrun’s also created a new type of open university – one that takes advantage of the online experience. “Udacity was born out of a Stanford University experiment in which Sebastian Thrun and Peter Norvig offered their ‘Introduction to Artificial Intelligence’ course online to anyone, for free. Over 160,000 students in more than 190 countries enrolled and not much later, …