A team of Rice University and Lockheed Martin scientists has discovered a way to use simple silicon to radically increase the capacity of lithium-ion batteries.
Sibani Lisa Biswal, an assistant professor of chemical and biomolecular engineering, revealed how she, colleague Michael Wong, a professor of chemical and biomolecular engineering and of chemistry, and Steven Sinsabaugh, a Lockheed Martin Fellow, are enhancing the inherent ability of silicon to absorb lithium ions.
They believe they've figured out how to prevent silicon from cracking after a couple of cycles of absorbing and releasing lithium atoms.
Silicon has the highest theoretical capacity of any material for storing lithium, but there's a serious drawback to its use. "It can sop up a lot of lithium, about 10 times more than carbon, which seems fantastic," Wong said. "But after a couple of cycles of swelling and shrinking, it's going to crack."
Other labs have tried to solve the problem with carpets of silicon nanowires that absorb lithium like a mop soaks up water, but the Rice team took a different tack.
Their approach might increase lithium battery storage capacity by an order of magnitude.
With Mahduri Thakur, a post-doctoral researcher in Rice's Chemical and Biomolecular Engineering Department, and Mark Isaacson of Lockheed Martin, Biswal, Wong and Sinsabaugh found that putting micron-sized pores into the surface of a silicon wafer gives the material sufficient room to expand. While common lithium-ion batteries hold about 300 milliamp hours per gram of carbon-based anode material, they determined the treated silicon could theoretically store more than 10 times that amount.
We'd all benefit from a large increase in battery capacity. Of course laptop computers and cell phones would work much longer between charges. But also, an order of magnitude increase in battery capacity would make electric cars feasible for most uses. Oil price worries would gradually fade away. We'd breathe cleaner air and cars would last longer with less need for maintenance.
|Share |||Randall Parker, 2010 October 13 11:04 PM Energy Batteries|