USC Breakthrough May Mean Stronger, Faster Batteries

Fast-charging, high-capacity lithium ion batteries could be available in two or three years, if a breakthrough made by USC engineers turns out to be commercially viable. An engineering team at the Viterbi School of Engineering has successfully replaced the graphite terminals usually used in lithium batteries with porous silicon nanoparticles, offering the possibility of recharging appliances from smart phones to electric cars in as little as ten minutes. If they can be manufactured efficiently, these new batteries could hold three times the charge of batteries with standard graphite terminals -- meaning three times the range for electric cars.

"It's an exciting research. It opens the door for the design of the next generation lithium-ion batteries," said the USC Viterbi School of Engineering's professor Chongwu Zhou, who led the team that developed the battery with Yunhao Lu of Zhejiang University in China and USC graduate students Mingyuan Ge, Jipeng Rong, Xin Fang, and Anyi Zhang.

According to USC's press material, silicon has long been eyed as a potential component for battery anodes, which are the terminals through which current flows into the battery. But silicon in anodes has a habit of contracting and enlarging during battery use, which breaks the anode in short order. Zhou's team previously had success with using silicon nanowires as anode material etched with tiny pores that allowed the wires to expand and contract. Not only did the anodes not break, but the nanowire configuration allowed much faster recharging of the battery.

But nanowires are expensive to manufacture. Zhou's breakthrough this time around was in replacing the nanowires with similarly etched nanoparticles, which are much easier and cheaper to manufacture -- in fact, they're already commercially available in un-etched form.

Right now, the batteries with Zhou's nanoparticle anodes will last through about 200 recharge cycles, as opposed to 500 for typical graphite anodes. But as the nanowire version lasted for 2,000 recharge cycles, Zhou's team expects that they can adjust their design to increase battery life substantially.

Which would be nice. Much faster charging and greater capacity might be just what the electric car industry needs to finally replace gas-guzzlers once and for all.