Nanostructured electrodes and active materials could shrink batteries for portable electronics and electric vehicles.
Researchers in France have created lithium-ion battery electrodes with several times the energy capacity, by weight and volume, of conventional electrodes. The new electrodes could help shrink the size of cell-phone and laptop batteries, or else increase the length of time a device could run on a charge. What's more, the nanotech methods used to make these electrodes could provide a simple and inexpensive way to structure new materials for next-generation batteries for plug-in hybrid and all-electric vehicles.
A forest of copper rods about 100 nanometers in diameter create much more surface area for high-capacity battery electrodes.
The key advance is the development of an inexpensive and simple way to organize tiny particles into a desired nanostructure, says Patrice Simon, a chemistry professor at the Université Paul Sabatier, who participated in the work along with other researchers at the university and Université Picardie Jules Verne.
In a conventional battery electrode, ions and electrons will move quickly into and out of the active material -- allowing fast charging and discharging -- only if the material is deposited in a very thin film. Thin films, however, limit the amount of active material that can be incorporated into a battery. For high-capacity batteries, engineers typically increase the thickness of the active material, trading off fast charging and high-power bursts for more energy storage.
This new nanostructure allows for both high power and high storage capacity. Active materials are applied in a very thin film to copper nanorods anchored to sheets of copper foil. This thin film allows for fast movement of ions and electrons -- providing the power. At the same time, the high surface area of the forest of nanorods makes it possible to pack much more active material into an electrode than thin films typically allow, thus increasing energy capacity. The rods provide 50 square centimeters of surface area for every square centimeter of electrode.
In addition, the high ion and electron mobility of the thin layer makes it possible to use a new active material and a new chemical reaction for lithium-ion batteries. This new chemistry is attractive because it can accommodate far more lithium ions, and their electron counterparts, than the chemistry used now, thereby potentially storing more energy.
The new electrodes, which would be used as the negative electrodes in lithium-ion batteries, also showed the ability to retain their high capacity after being charged and discharged many times, suggesting that the electrodes may have a long useable lifetime, Simon says, although more extensive tests are needed to confirm this supposition.
Chinese startup develops new, low-cost ways to improve the properties of lithium-iron phosphate, a leading electrode material.
Better batteries are making electric motorcycles possible, providing a cleaner alternative to pollution-spewing gas-powered bikes.
A123 Systems has built a powerful, lightweight lithium-ion battery pack that could lower the price of hybrid vehicles.
Guest (Johan)
About four years late ?
You can order batteries with 10 time the capacity that recharge to full in 5 mins from A123 Sytems based on this technology....
The technology for the existing A123 battery came from MIT.
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.
Vulvox has begun experiments on lithium ion batteries with unprecedented energy storage capacity; 42 kwh/kg. They also take advantage of less expensive processes of manufacturing silicon nanowires. Our breakthrough batteries will store as much energy per unit weight as fuel cells and will be used in the growing fleet of plug in hybrid vehicles. Our R&D program has been underway for several years. Vulvox is developing a comparable battery that will cost much less to manufacture, and we've been in the race to develop a super lithium ion battery for some time now. Our research was based on the same theoretical foundations as the research at Stanford. Our patent pending carbon nanotube adhesive material has shown properties such as ultra high porosity; necessary to manufacture ultracapacitors and it might be useful as electrode material for lithium ion batteries also.
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Guest (WorryWart)
Bang & Burn
When you put a lot of joules into a small or light package, you increase the risk of fire or worse. Each advance in battery tech seems to increase this threat.
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Guest (Sim)
Agree, but if you calculate the number of Joule in nanostructured electrodes, with the thermal conductivity of copper, heat dissipation is not high.
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Guest (nanogeek)
Actually this development looks very similar to what was done by Altair Nano (altairnano.com) and Toshiba. Both were mentioned previously here on New Scientist.
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billdale
15 Comments
Re: Altair Nanosafe battery
I am more familiar with the chemistry of the Nanosafe than the A123 and other batteries mentioned, but the distinctions I see between them are:
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.
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Guest (battery guy)
Higher Capacity Lithium
Increasing surface area will not increase capacity, only current delivering capability. The real challenge is how to manage the heat.
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