Stanford University assistant professor Yi Cui and his research team are about to revolutionize lithium ion battery technology. Cui was able to overcome an existing design limitation and construct a battery capable of producing ten times more electricity than an equivalent sized lithium ion battery using current technology. Just imagine being able to use a battery-powered notebook for 20 hours instead of the 2-3 hours of service that existing lithium ion batteries provide now.
All due to silicon nanowires
The storage capacity of a typical lithium ion battery is limited by the amount of lithium that can be held in the battery’s anode, which is typically made from carbon. In the process of trying to improve the lithium ion battery researchers found that an anode made from silicon is able to hold significantly more lithium than a carbon anode. Sounds great, but using silicon instead of carbon has a downside. As the battery is charging—silicon anode is absorbing lithium—the silicon physically swells up to four times its original size. Then as the battery discharges, the silicon anode shrinks back to its normal size. The swelling and shrinking of the silicon material lead to the rapid deterioration of the silicon anode, reducing the storage capacity of the battery.
Professor Cui and his team resolved this problem by using silicon nanowires as noted in this ScienceDaily article. Silicon nanowires—having a diameter of one thousandth of the thickness of sheet of paper—are bonded to a stainless steel substrate and made into a usable battery. The silicon still swells and shrinks, but the nanowires remain stable creating a system that is able to hold ten times the lithium resulting in ten times the charge capacity.
The potential uses for this technology are vast. Any device that uses lithium ion batteries stands to benefit from a tenfold increase in battery life. Professor Cui mentions:
It’s not a small improvement. It’s a revolutionary development … Given the mature infrastructure behind silicon, this new technology can be pushed to real life quickly.
It appears that this technology will also spread to electric cars and solar-powered systems as these batteries are an efficient method to store electricity and power devices.