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A Greater Range for Electric Cars? New Battery Material Tested

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A new study may help batteries, including those for cars like the Tesla models seen here, gain more mileage. | Photo: sasa.mutic/Flickr/Creative Commons License

An extremely thin "paper" made of silicon may offer a way to store a lot more electrical power in common batteries, according to a new study by University of California, Riverside, engineers.

The extremely thin material is made up of nanofibers of a silicon compound, each of which is less than a hundredth the width of a typical human hair. Used in the electrodes of lithium ion batteries, according to the UC Riverside researchers, the material may allow those batteries to store several times more electrical charge per weight as common graphite-based electrodes.

If the discovery pans out, that could mean longer periods of use between charges for consumer electronics, say the scientists -- and greater range for electric cars.

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Scanning electron microscope images of silicon nanofibers used in battery electrodes | Photo: UC Riversid
 

Silicon materials used in battery electrodes have a much greater "charge density" than conventionally used graphite: as much as ten times greater. But graphite has an advantage over most silicon-based electrodes. Silicon materials in high-tech electrodes can swell to three times their former size when the battery is charged. That can lead to mechanical failure, drastically shortening the usable lifespan of the batteries.

In the study, the scientists found that their paper-thin electrodes spun out of nanofiber did not expand nearly as radically under charge as other silicon electrodes, raising the possibility that this silicon-based "paper" could be used in batteries usable through hundreds of charge cycles.

The "paper" electrodes would also beat graphite in two other ways: unlike graphite, they'd need neither conductive metal components (graphite electrodes usually incorporate copper sheets) or the binders used to keep the powdery graphite from coming apart in use.

The team -- electrical and computer engineering professor Mihri Ozkan and mechanical engineering professor Cengiz S. Ozkan of UC Riverside's Bourn School of Engineering and their grad students Zach Favors, Hamed Hosseini Bay, Zafer Mutlu, Kazi Ahmed, Robert Ionescu, and Rachel Ye -- published their findings this month in a paper in the journal Nature Scientific Reports.

The team suggests that their findings may be of immense use in energy storage and alternative transportation. "Eliminating the need for metal current collectors and inactive polymer binders while switching to an energy dense material such as silicon will significantly boost the range capabilities of electric vehicles," graduate student Zach Favors said in a UCR press release.

For ongoing environmental coverage in March 2017 and afterward, please visit our show Earth Focus, or browse Redefine for historic material.
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