Published in News

Battery designers call Mr Sandman

by on14 July 2014

Bring me a dream

Battery designers have discovered that they can overcome some of the problems of lithium-ion battery by using sand. A boffin at the University of California, Zachary Favors, a graduate student at UC Riverside who was working on developing better lithium-ion batteries, noticed that the beach sand he was relaxing on after surfing in San Clemente, California was primarily made up of quartz, or silicon dioxide.

Researching where in the US sand could be found with a high percentage of quartz, he ended up at the Cedar Creek Reservoir in Texas. He took some of the sand back to the Bourns College of Engineering at UC Riverside where he worked with engineering professors Cengiz and Mihri Ozkan. Favors started milling the sand down to the nanometer scale before putting it through a series of purification steps. He then ground salt and magnesium into the purified quartz and heated the resulting powder. Salt acts as a heat absorber while the magnesium removed oxygen from the quartz, resulted in pure silicon. 

The nano-silicon formed in a very porous, 3D silicon sponge which is one of the keys to improving the performance of battery anodes as it provides a large surface area and allows lithium ions to travel through them more quickly. The team has developed a coin-sized lithium-ion battery using the new anode that they claim significantly outperforms conventional lithium-ion batteries. 

Apparently the improved performance of the nano-silicon electrode could be expected to equate to a threefold increase in battery life. Electric car batteries could last three times longer, cutting down on expensive replacement costs. The researchers are now looking to produce the nano-silicon in larger quantities and move from coin-size batteries to pouch-size batteries like those used in mobile phones.

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