Will Silicon be used to increase the capacity of Lithium Batteries?

Will Silicon be used to increase the capacity of Lithium Batteries?

Researchers at Georgia Tech have devised an anode for Lithium batteries incorporating embedded silicon nanoparticles. Electrical measurements in some experimental batteries have shown that these new hybrid carbon-silicon anodes have five times the capacity of a battery with a normal anode.

The new tech, should it see its way into mainstream manufacturing could have significant impact on everything from the new breed of Hybrid Vehicle to portable devices.

Details of the new self-assembly approach were published online in the journal Nature Materials on March 14.

“Development of a novel approach to producing hierarchical anode or cathode particles with controlled properties opens the door to many new directions for lithium-ion battery technology,” said Gleb Yushin, an assistant professor in the School of Materials Science and Engineering at the Georgia Institute of Technology. “This is a significant step toward commercial production of silicon-based anode materials for lithium-ion batteries.”

Currently Lithium-ion (Li-ion) batteries work by transferring lithium ions between two electrodes, a cathode and an anode through a liquid electrolyte. The more efficiently the lithium ions can enter the two electrodes during charge and discharge cycles, the larger the battery’s capacity can be.

Existing Li-ion batteries contain anodes made from Graphite, (a form of carbon). New Silicon anodes are able to (theoretically at least) offer as much as a ten-fold capacity improvement over the current Graphite type, but the new Silicon-based anodes have as yet not been stable enough to be used on a practical level.

The new nanocomposite material solves that degradation problem, (expansion and contraction as the lithium ions enter and leave the silicon creates cracks that quickly cause the anode to fail), potentially allowing battery designers to tap the capacity advantages of silicon. This all  means that the new design can achieve a  higher power output from a given battery size, or allow a smaller battery to produce a required amount of power.

Thus far researchers have only put the new composite anode through more than a hundred charge-discharge cycles, but Prof. Yushin believes the material would remain stable for thousands of cycles because no degradation mechanisms have yet to become apparent.

“If this technology can offer a lower cost on a capacity basis, or lighter weight compared to current techniques, this will help advance the market for lithium batteries,” he said. “If we are able to produce less expensive batteries that last for a long time, this could also facilitate the adoption of many ‘green’ technologies, such as electric vehicles or solar cells.”

This entry was posted on 24/03/2010 at 07:12 pm and is filed under Tech News. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response or trackback from your own site.

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