We’ve written a great deal about ways of making so-called “bio-fuels,” those ethanol, methanol and even diesel substitutes that avoid the high toxicity and environmental harm of fossil fuels. Often though, these substitutes require the diversion of foodstocks or the use of exotic catalysts and high energy inputs to trigger the appropriate mechanisms. Scientists as Stanford University may have found a way to use copper, though, to make ethanol without corn or other plants. They’ve “created a copper-based catalyst that produces large quantities of ethanol from carbon monoxide gas at room temperature.” Matthew W. Kanan, Assistant Professor at Stanford, has been working toward this kind of biofuel production for many years. His University profile contains the following: “The ability to convert H2O, CO2 and N2 into fuels using renewable energy inputs could in principle provide a viable alternative to the current dominance of fossil fuels. This prospect faces great technical challenges, the foremost of which is the lack of efficient …
Dr. Cui’s Pomegranate-inspired Battery Bears Fruit
Dr. Yi Cui seems to get inspiration from food. A few years ago, his research team came up with a “yolk-shell structure” that helped contain the high amount of lithium that silicon anodes were able to absorb. That battery design promised much, and an embellishment of that design seems to hold even greater promise. His newest effort, working at Stanford University with the Department of Energy’s SLAC National Accelerator Laboratory, features an electrode “designed like a pomegranate – with silicon nanoparticles clustered like seed in a tough carbon rind.” This approach, according to its inventors, overcomes several remaining obstacles to the use of silicon in a new generation of lithium-ion batteries. Yi said the battery’s efficiency and longevity are promising. “Experiments showed our pomegranate-inspired anode operates at 97 percent capacity even after 1,000 cycles of charging and discharging, which puts it well within the desired range for commercial operation.” Cui’s team has been working on preventing anode breakup for the …
Airliners Get Better Mileage than Cars, and Trains do Even Better
Airliners beat cars in fuel economy, especially on longer trips. That would not be news to attendees at recent Electric Aircraft Symposia, where speakers like Ilan Kroo, Stanford University professor and aircraft designer, have brought that message home. One of Kroo’s slides, shown below in a 2009 lecture (It’s nearly an hour, but worth a look and listen), lists a “narrow-body” airliner (in this case a Boeing 737-800) as able to fly one passenger coast-to-coast on 29 gallons of fuel, at about 81 passenger miles per gallon. A person carpooling his or her four-passenger Prius and driving responsibly could beat that (although not in the five hours required for the jet to make the total flight), but most trips are solo affairs, especially during commutes. Not anywhere near Green Flight Challenge efficiencies (403.5 ppmg for the winning Pipistrel G-4), such economies are improving with more modern versions of fuel efficient airliners. Cars are also gaining in fuel economy, prompted by government …
Unique, From A (for Aerodynamics) to Zee
Ilan Kroo, according to his biography page, is a Professor of Aeronautics and Astronautics at Stanford University, an advanced cross-country hang glider pilot, and designer of the Swift flying wing hang glider, unmanned aerial vehicles, a flying Pterosaur replica, America’s Cup sailboats, and high-speed research aircraft. Currently on a leave of absence from Stanford, he has started Zee Aero, “a bay area start-up company focusing on bringing new technologies to civil aircraft.” Zee Aero, on its first of five sparse web pages, proclaims, “We’re creating an entirely new aircraft,” a heady claim considering the lack of supporting descriptions or illustrations. But other sources have been made available, including Zee’s patent applications, which show a slim tricycle-gear fuselage surmounted by variously drawn structures holding eight upward-facing propellers and two propellers in the tail, apparently to push the whole assembly along. KGO television sent a news crew to Zee’s Mountain View headquarters, and broadcast nice views of the secure building in which …
Batteries That Heal Themselves
Alert reader Colin Rush provided this breaking development in battery science. Regular readers will remember Dr. Yi Cui’s name. He’s a Stanford University scientist who has worked with paper batteries, much more powerful electrodes, and means of helping batteries stay together under the continuous strain of expanding and contracting during charging and discharging. He explained that at the third annual Electric Aircraft Symposium at the Hiller Aviation Museum, and has since adopted several tactics to overcome that problem. One commercial outgrowth of his work, Amprius, is working on commercial production that benefits from his insights. Since that internal flexing eventually leads to cracking of electrodes, Dr. Cui’s latest announcement brings some hope that such things can not only be overcome, but literally healed. Just as our bodies have internal resources to fight diseases and repair muscle and bone, batteries can be made to be self-healing. Dr. Cui has been a proponent of using silicon as a major component in electrodes, …
Breaking Up Isn’t So Hard to Do
A great deal of the research on lithium batteries goes into figuring out how to keep them together for the greatest number of charge-discharge cycles. Unfortunately, the active compounds in these batteries that give the greatest energy storage capacity or power output, also tend to be those compounds that come unglued under stress. Taking high-resolution 3D movies with X-ray tomography (somewhat like the CAT scans used on human subjects), researchers at the Swiss Light Source, a mecca for seeing the unseeable, have witnessed the expansion and contraction of the internal structure of lithium-ion batteries, while the batteries are operating. Stanford University’s Dr. Cui has explained that the expansion and contraction of batteries leads to their eventual failure, but until now, there has been no real-time observation of these internal reactions. Martin Ebner, a Ph.D. candidate at the Laboratory for Nanoelectronics in the Department of Information Technology and Electrical Engineering (D-ITET) at ETH (Eidgenössische Technische Hochschule) and Professor Vanessa Wood, head of the …
Lithium Gets a Good Wrap
Shadi Dayeh, professor in the Department of Electrical and Computer Engineering at the UC San Diego Jacobs School of Engineering, has been designing new electrode architectures that could solve one of lithium batteries’ biggest problems. When lithium diffuses across the surface of a lithium-ion battery electrode, it causes the electrode to expand and contract depending on its charging or discharging. This eventually leads to cracking and ultimate disintegration of the anode or cathode – weakening and finally disabling the battery. Dayeh, working with colleagues at the University and Sandia and Los Alamos National Laboratories, came up with nanowires that, “Block diffusion of lithium (Li) across their silicon surface and promote layer-by-layer axial lithiation of the nanowire’s germanium core.” Seeing possibilities beyond his current research, Dayeh says the work could lead to, “An effective way to tailor volume expansion of lithium ion battery electrodes which could potentially minimize their cracking, improve their durability, and perhaps influence how one could think about …
Stanford scientists develop high-efficiency zinc-air battery
Battery researchers, including those at Stanford University, have been focusing for years on improving lithium batteries of multiple chemistries. While IBM tries to create the 500-mile battery based on lithium-air reactions, and ReVolt in Portland works on perfecting a long-lasting zinc-air cell, Stanford researcher Hongjie Dai and his team claim to have “developed an advanced zinc-air battery with higher catalytic activity and durability than similar batteries made with costly platinum and iridium catalysts.” The resulting battery, detailed in the May 7 online edition of the journal Nature Communications, could be the forerunner of something with greater endurance and lower cost than current efforts. Mark Schwartz, writing for Stanford, quotes Dai, a professor of chemistry at the University and lead author of the study: “There have been increasing demands for high-performance, inexpensive and safe batteries for portable electronics, electric vehicles and other energy storage applications. Metal-air batteries offer a possible low-cost solution.” Lithium-ion batteries, despite their limited energy density (energy stored per …
A Milestone on the Road to Dr. Cui’s 10X Battery
Seeing the Amprius web site, one would never know that some “dramatic improvements” promised in the terse announcement might mean so much in terms of true breakthroughs. Neatly centered, Amprius’ total web site is a few lines of discrete text. Amprius is a leading Lithium-Ion battery developer Amprius’s silicon technology was originally developed at Stanford University and enables dramatic improvements in the energy density and specific energy of Lithium-Ion batteries. Amprius is backed by some of the world’s leading investors, including Trident Capital, VantagePoint Venture Partners, IPV Capital, Kleiner Perkins Caufield & Byers, and Dr. Eric Schmidt. Amprius, Inc., 225 Humboldt Ct. Sunnyvale, CA 94089 But the battery manufacturer has two first-generation product offerings with volumetric energy densities of 580 Watt-hours and 600 Watt-hours per liter. Most lithium batteries fall into a range from 250-500 Wh/l., putting the new cells at the upper limit of such batteries. Both Amprius batteries are now in production and available to original equipment manufacturers, …
Peel-and-Stick Solar Cells Make Debut
The U. S. Department of Energy’s National Renewable Energy Laboratory (NREL) and Stanford University have teamed up to create what may be the thinnest of thin solar cells – a peel-and-stick decal. One micron thick, the decal-like peel-and-stick, or water-assisted transfer printing (WTP), technologies were developed by Stanford researchers and have been used for nanowire based electronics. Meeting at a conference where both made presentations, Stanford’s Xiaolin Zheng talked about her peel-and-stick technology, and NREL principal scientist Qi Wang spoke on his team’s research in thin-film amorphous solar cells. Zheng realized that the NREL had the type of solar cells needed for her peel-and-stick project, according to the NREL announcement. The NREL press release explains, “The university and NREL showed that thin-film solar cells less than one-micron thick can be removed from a silicon substrate used for fabrication by dipping them in water at room temperature. Then, after exposure to heat of about 90°C for a few seconds, they can …