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An electronic microscope image of the rod-like nanoparticles formed by the microwave production method. They perform extremely well in low discharge scenarios, but are being tweaked after disappointing performance in rapid discharge scenarios.  (Source: Arumugam Manthiram, University of Texas at Austin )
Could an affordable electronic car be in the future?

Lithium-ion batteries are in high demand, seeing strong growth in the consumer electronics, power tools, and automotive industry.  Lithium-ion batteries are prized for their outstanding energy-to-weight ratios, their lack of memory effect, and their slower charge loss rate than other battery technologies.

The technology is particularly critical to the budding electric car business.  With such companies as Dyson, GM, and Lightning Car Company using the batteries in their upcoming commercial releases the future of the electric car in the short term is riding on lithium-ion technology. 

Unfortunately, the costs of lithium-ion batteries are currently quite high.  An analyst estimated that the much-anticipated Chevy Volt's battery pack would cost nearly $10,000; about a fourth of the total projected cost.  The pressing demand from a variety of industries has fueled lithium-ion prices to rise even higher.

Fortunately relief is in sight, thanks to a processing breakthrough from University of Texas at Austin.  The researchers found a way to possibly transform the long and complicated baking process involved in one of the more common lithium-ion battery materials into a quick and easy process.

Originally, most lithium-ion batteries used lithium cobalt oxide.  Most of the computer industry still relies on this material; however, the automotive industry has turned to lithium iron phosphate, which is considered more attractive as iron is cheaper than cobalt.  It is also safer than the more fire-prone lithium cobalt oxide, and is capable of being crafted to release charge faster.  A downside is it stores slightly less charge.

Companies have invested big in developing and bringing lithium iron phosphate to the market.  A123 Systems, the Watertown, MA startup that is manufacturing the Chevy Volt's battery, has already commercially offered lithium iron phosphate batteries for power tools.  It has managed to raise $148M USD in investment capital to help fund its efforts.

With current technology, the biggest downside to the lithium iron phosphate is the manufacturing.  Currently, the process takes hours of baking at temperatures in excess of 700 °C.  The extra manpower and effort required due to this has meant that Lithium iron phosphate batteries, which should from a materials perspective be much cheaper than lithium cobalt oxide, are actually more expensive than their competitor.

Led by Professor Arumugam Manthiram, a U of T professor of materials engineering, the researchers at U of T examined how a microwave could be used to speed the cooking process.  The results were dramatic.

The team first mixed conventional materials -- lithium hydroxide, iron acetate, and phosphoric acid -- in a solvent.  They then popped the mixture in the microwave for about five minutes, which heated the mix to about 300 °C. 

The process yielded high performing rod shaped nanoparticles of lithium iron phosphate.  The best nanoparticles were found to be approximately 100 nm long and just 25 nm wide.  The small size allows the ion exchange to be performed more easily.  The finished particles were then covered with an electrically conductive polymer doped with sulfonic acid to improve performance.

The new particles performed extremely well in low-discharge scenarios.  The material achieved a capacity of 166 milliamp hours per gram, amazingly close to the 170 milliamp hours per gram theoretical capacity.  High discharge scenarios were not so friendly to the new material, but Professor Manthiram says that will be fixable.  He says new versions have already shown improvement in this metric.

It is unclear exactly how much will be saved using the new method.  With the short time higher production should be possible, and the lower temperatures will reduce energy demands, both effects that should help to lower the cost of production.  Some are skeptical, though; whether the material will save much at all.  Stanley Whittingham a professor of chemistry, materials science, and engineering at the State University of New York, at Binghamton warns that the savings may be offset by the polymer cost and the cost of the changes necessary to the production.

Professor Manthiram is also exploring other lithium ion materials and has developed two key improvements on other materials.  He is working with an Austin, TX based startup, ActaCell to commercialize his tech.  The startup has licensed some of his technology with the help of the $5.58M USD in startup funds in has raised, but declined to specify which technologies or whether the new lithium iron phosphate production technology had been licensed yet.



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RE: Electric is the future
By JustTom on 8/3/2008 1:25:29 PM , Rating: 2
Proven oil reserves is misleading. Proven reserve have been fairly static over the last decade despite all the oil pumped out of the ground.


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