“An electric car battery made from silicon that will turn into sand that would be recycled into silicon and then into power again.”
Prof. Yair Ein-Eli
Breakthrough research with silicon results in efficient, environmentally friendly battery with infinite shelf life Prof. Yair Ein-Eli from Technion’s Faculty of Materials Engineering has developed an important revolutionary approach to batteries based on silicon-air. There is plenty of silicon available: it is the eighth most abundant element in the universe and the second most plentiful in the earth’s crust. The reaction product silicon oxide can even be reduced back to sand. Thermodynamically, silicon is an attractive fuel for batteries. Furthermore, it is non-toxic and the reaction product silicon oxide can be disposed of safely or used, for example, in building materials. Such batteries may find immediate applications in MEMS (microelectromechanical systems), sensors, and medical appliances, as they can provide an autonomous and self-sustained energy source for silicon-based devices. This research was published in the leading professional journal Electrochemistry Communications in October 2009.
Together with research colleagues Rika Hagiwara from Kyoto University, Japan, and Digby D. Macdonald from Penn State University in the U.S., Ein-Eli provides an improvement on existing high-capacity metal-air batteries as a portable power source.
Ein-Eli explains that a prime objective is reducing the size of the power source while at the same time increasing its energy or power density. In recent years, a leap in metal-air battery technology has been accomplished with the introduction of a nonaqueous lithium-air cell. The silicon-air battery system can outperform existing metal-air battery technologies, the scientists claim. Their novel air battery can support relatively high current densities drawn from flat polished silicon wafer anodes.
According to Ein-Eli, the patent-pending technology does not yet result in a rechargeable battery - that’s still a few years away - but it can supply thousands of hours of power.
The novel battery is small enough for hearing aids, and is far more efficient than the costly lithium batteries that need frequent replacing.
Further development in the lab will enable a significant increase in power output, and Ein-Eli envisions a future for his battery in the electric car industry. “An electric car battery made from silicon that will turn into sand that would be recycled into silicon and then into power again…” he muses.