what's next; from humble materials, a burst of power for batteries - lithium iron phosphate battery

Annie Eisenberg
2002 of battery development may have been driven from unexpected sources.
A research team at the Massachusetts Institute of Technology found that a small amount of metal was added-
Making compounds into cheap materials can greatly improve their conductivity.
Rechargeable battery by soued-
One day up material may prove useful in mixed gas
Electric vehicles, power tools and other applications that require a lot of relatively cheap power.
At present, most rechargeable batteries in portable electronic devices use lithium cobalt oxide as a positive electrode.
But cobalt is a relatively expensive metal, so researchers have been looking for a cheaper alternative for years. Now, Yet-
Jiang Ming, professor of materials science and engineeringI. T.
, His research team members there said they have found a way to convert a very cheap base material lithium iron phosphate into every point that is as conductive as Cobalt
Based on a fraction of the cost of cobalt.
Details of the experiment were reported in the October issue of the journal Nature Materials.
Researchers have long been interested in the potential use of the battery because it is cheap, non-toxic and stable.
However, its low conductivity hinders business development.
In a series of experiments, advertisingI. T.
The group inserted a small amount of metal impurities or additives into lithium iron phosphate, which significantly improved its conductivity.
Some other groups are trying to improve their conductivity by wrapping iron phosphate particles in carbon. But Dr.
Jiang believes that it is good to improve the retention of this material.
'I don't believe in the traditional view in the battery field that this material can't be naturally conductive,' he said. Instead, Dr.
Jiang borrowed a page from the solid.
For a long time, national physicists have added different elements to their materials to make them more conductive. Dr.
Jiang's experiment took about a year.
He said that most of the time spent trying to distribute element additives, metal ions like nb evenly in the lattice of parent compounds, and the necessary position to place it in the crystal that affects the conductivity.
Along the way, the group synthesized experimental samples of more than 50 materials.
In an accompanying article on natural materials, Michael sakeli, a researcher at the Argonne National Laboratory in Illinois, specializes in lithium battery materials, he wrote, A significant increase in the electronic conductivity of the lithium iron phosphate body has an exciting impact on the future use of the material in the next generation of lithiumion batteries.
"By inducing the intrinsic conductivity to these eight orders of magnitude, the group has greatly changed the electrical properties of the material," he said in an interview . ".
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The material used for the experiment is made of carbon-
Contains substances and retained carbon residues.
This increases the likelihood that carbon leads to an increase in conductivity.
"But the author discussed this possibility carefully in the paper," he said, ruling out the possibility on the grounds that samples that did not add any doping contained a similar amount of carbon and were high in content
The resolution electron microscope does not show any surface carbon.
The dark black of the doping sample is also an external indication of the material's conductivity enhancement. Dr. advertising
Jiang joined forces to set up a battery technology company that has moved from M. I. T.
And is committed to commercialize it.
He said the raw materials entering the compound were about a quarter of the cost of lithium cobalt oxide. George E.
Blomgren, a battery technology consultant at Lakewood, Ohio, said the material's potential to generate very high power makes it particularly interesting.
"Jiang showed far more power than the nickel metal hydrogen batteries currently used in hybrid electric vehicles," said Dr. Blomgren said.
For example, in most hybrid electric vehicles, high battery power density is required to speed up quickly and power up for later use when someone is stepping on the brakes. Ralph J.
Brodd, battery industry consultant for Nev Henderson. , said that Dr.
Jiang's materials not only provide advantages in terms of cost and power, but also in terms of stability.
"It is less likely to break down, releasing oxygen in the cells and creating safety issues," he said . ".
However, this new material is unlikely to find many uses in laptops and related applications where a lot of energy must be provided in a small space, M. said
Stanley whiteham, professor of materials and inorganic chemistry, director of the Materials Research Institute at the State University of New York at Binghamton.
He said that the energy stored in his material per unit volume is worse than the current lithium battery, although this material may find use in large batteries with very important costs.
"Jeff Dane, professor of physics and chemistry at Halifax Dalhousie University in Nova Scotia, specializes in new materials for advanced batteries, and he agrees with materials like Dr.
Jiang may have a home for a large battery, and its developers have to worry about the cost of cathode materials and their stability relative to other battery components.
"For example, in the case of abuse such as car accidents, it may have a place where the battery is crushed," he said . ". Dr.
At the same time, Dahn did not abandon the alternative route of coating lithium iron phosphate particles with carbon to improve their conductivity.
"As long as these substances are effectively mixed with carbon, it may still work," he said . ".
Ultimately, in terms of battery technology, lithium iron phosphate will have a huge impact on all of us.
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A version of this article was printed on page G00005 of the National edition on October 3, 2002, with the title: What is next;
From humble materials, the energy of the battery bursts.