Because this advance, described online this week in Nature Materials, applies so far to negative electrodes, the percentage increase in capacity over today's batteries will depend on the capacity of the positive electrode as well. (See "Battery Breakthrough" for a description of one possible positive electrode candidate cited by the researchers.) The first applications of the technology will likely be extremely small batteries, Simon says. These could be useful for remote sensors or medical implants. Further applications will require increasing the size of the electrodes that the researchers can make, and also optimizing the active material they use. The materials used in reported experiments are not energy efficient -- about 20-25 percent of the energy used to charge them cannot be recovered while discharging them. This energy loss is not a big problem with cell-phone batteries, says Gerbrand Ceder, materials science and engineering professor at MIT. "Over the lifetime you probably spend a few pennies in charging the cell phone," he says. But for larger energy applications, such as electric vehicles, this lack of efficiency could be costly, especially with high electricity prices. For this reason, the researchers are incorporating different high-capacity active materials into their nanostructured electrodes that do not have this energy efficiency problem. In turning to nanotechnology to improve batteries, the French researchers are not unique. At least two companies, A123 Systems, in Watertown, MA, and Altair Nano, in Reno, NV, have made batteries that include electrodes with nanostructured active materials; and numerous research groups around the world are developing such electrodes. Simon describes his group's process as being simpler and cheaper than many other methods for making nanostructures. It is also versatile, capable of being used with a variety of active materials, he says. It could also be important for another key trend in battery research: the move away from flat layers of electrode materials to positive and negative electrodes that interpenetrate -- a three-dimensional architecture that can improve the mobility of ions and electrodes, thereby increasing battery power. The French group is also now working on a three-dimensional battery, says Simon, that will combine their negative electrodes with a high-performance positive electrode. |
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Lithium-Ion Motorcycles
07/19/2007
Massachusetts Institute of Technology
Comments
06/23/2006
Posts:1
06/23/2006
Posts:1
06/23/2006
Posts:1
The Nanosafe does not use copper nanotubes, instead using "nanotitanate", which Altair says provides holes of just the right size for the ions transferring back and forth in the charge/ discharlge cycles.
Altair claims the graphite terminals in conventional lithium-ion batteries are a poor match and so the ions distort, fatigue and heat the graphite until the plates fail.
The nanotitanate is, if I understand correctly, extremely porous on a nanoscale as in the plates described in the story above, but are more of a matrix of titanium, not nanotubes.
I have seen graphs of the usable charge available after 1,000, 2,000, 3,000 charge cycles, etc., and there is a 15% drop in capacity after about 1,000 charges... thereafter, the capacity stabilizes and does not appear to deteriorate further even after more than 30,000 cycles. This is quite exciting, since it suggests the batteries may last 60 years or more under typical use in a car... that it would, in fact, outlast the vehicle.
Altair claims that in safety tests, they have driven nails through fully-charged batteries, crushed them, and baked them in ovens. The only result is that the battery shorts out and is useless, rather than exploding or immolating as li-ions are known to do.
The Altair batteries are said to generate no heat even under aggressive charging and discharging. If this is true, these batteries would be far safer than any other source of power such as gasoline, ethanol, diesel, or hydrogen. After seeing how two pilots died recently in an aircraft accident not far from where I live, I could not help but hope that these batteries might make air travel far safer.
The battery is already being used in the Phoenix Motorcars electric cars and trucks, and is said to give them a range of up to 250 miles per charge, less than 3 cents per mile for electricity, and can be recharged in less than 10 minutes using special chargers that will be located in stores such as Costco and Starbucks.
Here in the Los Angeles area, there are some free government recharging stations to encourage electric car use. They were installed prior to the introduction of the Phoenix, but I believe they are compatible.
There has apparently been some limited independent verification of the Altair claims, but I look forward to seeing Underwriter's Laboratories, Consumer Reports or a similar entity's assesment of this battery.
The batteries apparently cost about the same as standard li-ion batteries, which are rather expensive, but Altair is working diligently to reduce manufacturing expenses. Since this is a very new technology, I am quite optimistic that they will succed. Yes, I am on the buyer's waiting list for the Phoenix Motorcar... I think they're that good.
billdale
01/13/2007
Posts:15
06/26/2006
Posts:1
You can order batteries with 10 time the capacity that recharge to full in 5 mins from A123 Sytems based on this technology....
06/28/2006
Posts:1
Higher capacity doesn't equate to greater risk of an accident, just risk of a more serious accident. It's not necessarily like a balloon getting more and more air.
New production methods and chemistry can make new batteries safer than current even with more energy.
It's a bigger bang, but not more prone to bang.
asdar
08/23/2006
Posts:69