The standard battery for gadgets is lithium-ion, which stores a lot of energy for its weight. But lithium is a rare Earth element with most of the deposits located in
Chile, Argentina, China and Australia. This is one reason the batteries in the average
laptop are so expensive.
Lowering the cost of batteries is one reason researchers have been exploring other materials. A team at the Tokyo University of
Science, led by Shinichi Komaba, have been looking at sodium-based batteries,
using sodium ions as the cathode (positive side) and carbon from ordinary sugar
as the anode (negative side).
To get the carbon from the sugar (sucrose), the scientists burned it in
the absence of oxygen at a temperature of 1,800 to 2,700 degrees — hot enough to
melt cast iron at the upper end. That produces a hard black carbon powder of
high quality. In this form, the sodium-sucrose battery stored 20 percent more energy
than one made with conventional carbon.
It will be some time before such a battery is
commercialized, but if it's successful, it will mean that batteries can be made of
materials that have essentially no supply problem. While lithium is recycled,
it is only on a limited scale. Sodium, by contrast, is everywhere (including in
table salt), as is sucrose.
One of the issues with sodium-based batteries is that they
don't survive as many charge cycles as lithium-ion batteries do. Improving that
will be the next step. Komaba told Diginfo.tv that it will likely be about five
years before we see the first sodium batteries on the shelves.
Credit: Corbis Images