Monday, November 21, 2011

How to improve lithium-ion batteries?

Scientists are conducting various different researches aimed at creating new cellphone batteries that could stay charged for a very long time and which could be recharged in very short time. The concept of a cellphone battery that would last for a week or so and could be recharged in just 15 minutes or so certainly sounds appealing and science is already making huge steps in turning this concept into a reality.

The scientists at the Northwestern University were able to create an electrode for lithium-ion batteries that gives the batteries an ability to hold a charge up to 10 times greater than current technology. Not only that, these new batteries can charge 10 times faster than current batteries.

The researchers first needed to stabilize the silicon in order to maintain maximum charge capacity and they have achieved this by sandwiching the clusters of silicon between the graphene sheets. Such process enabled a greater number of lithium atoms in the electrode while the flexibility of graphene sheets was used to accommodate the volume changes of silicon during use.

The team leader Harold H. Kung said that they now "have much higher energy density because of the silicon, and the sandwiching reduces the capacity loss caused by the silicon expanding and contracting. Even if the silicon clusters break up, the silicon won't be lost."

Up to now, the energy capacity of cellphone battery was limited with the number of lithium ions that can be packed into the anode or cathode (currently used technology is able to accommodate only one lithium atom for every six carbon atoms), and the speed of a battery's charge rate is hindered by the shape of the graphene sheets (graphene sheets used in current technologies are very long which means that a lithium ion must travel all the way to the outer edges of graphene sheet).

The scientists hope that in years to come this technology could pave the way for much smaller and more efficient electric car batteries. This technology could make its way in the marketplace in the next three to five years