Big nano-news for batteries

Tomorrow’s lithium batteries – including those that will power electric cars – may hold more energy, longer, thanks to researchers at the University of California at Riverside.

Lithium batteries, now the standard power source for most consumer electronics, typically contain 10 to 30 times more graphite – used for the battery’s negative electrode – than lithium. Engineers have long sought to replace graphite in batteries with silicon, which is lightweight, abundant, environmentally benign, and able to store more electric charge per unit of weight than any other known material. But when silicon combines with lithium, it can triple in volume, degrading a battery’s performance and even blowing its seams.

Now, a team of developers at the UC Riverside’s Bourns College of Engineering may have learned how to make it work. They found a way to make silicon nanofibers, 100 times thinner than a human hair, to replace the graphite, creating a sort of silicon sponge or webwork that exposes more of the electrode to the lithium electrolyte and doesn’t balloon. The resulting battery could hold more energy and endure many more charging cycles than a cell containing graphite.

The development could “significantly boost the range capabilities of electric vehicles,” says Zach Favors, a member of the research group.

The next challenge: finding a way to scale the process from making a few grams of the fibers in a lab to making commercial quantities quickly in a factory.