(July 16,
2012) Rice
University, Lockheed Martin researchers extract multiple anodes from a single
wafer for lithium-ion batteries
Researchers at Rice University and Lockheed Martin reported
this month that they’ve found a way to make multiple high-performance anodes
from a single silicon wafer. The process uses simple silicon to replace
graphite as an element in rechargeable lithium-ion batteries, laying the
groundwork for longer-lasting, more powerful batteries for such applications as
commercial electronics and electric vehicles.
The work led by Sibani Lisa
Biswal, an assistant professor of chemical and biomolecular engineering at
Rice, and lead author Madhuri Thakur, a Rice research scientist, details the
process by which Swiss cheese-like silicon “sponges” that store more than four
times their weight in lithium can be electrochemically lifted off of wafers.
The research was reported online
this month in the American Chemical Society journal Chemistry of Materials.
Silicon – one of the most common
elements on Earth – is a candidate to replace graphite as the anode in
batteries. In a previous advance by Biswal and her team, porous silicon was
found to soak up 10 times more lithium than graphite.
Because silicon expands as it
absorbs lithium ions, the sponge-like configuration gives it room to grow
internally without degrading the battery’s performance, the researchers
reported. The promise that silicon sponges, with pores a micron wide and 12
microns deep, held for batteries was revealed in 2010 at Rice’s Buckyball
Discovery Conference by Thakur, Biswal, their Rice colleague Michael Wong, a
professor of chemical and biomolecular engineering and of chemistry, and Steven
Sinsabaugh, a Lockheed Martin Fellow. But even then Thakur saw room for
improvement as the solid silicon substrate served no purpose in absorbing
lithium.