The technology promises to store four to five times as much energy as today’s best lithium-ion batteries but they are aren’t practical because they don’t last very long. Lithium-ion batteries can last 1,000 charge cycles, but lithium- sulphur batteries tend to fail before they’re charged 100 times.
Jeffrey Pyun, a chemist at the University of Arizona thinks electrodes made from sulphur polymers, like other plastic products, should be inexpensive to manufacture on a large scale. Then last year, Pyun’s group reported a way to transform this sulphur into an inexpensive cathode material. By heating the sulphur to 185 ºC and then adding an organic compound, 1,3-diisopropenylbenzene, the researchers form a copolymer containing strings of sulphur atoms tangled up with the diisopropenylbenzene.
To become a commercial product, a battery made with the sulphur polymer will need to have a steady storage capacity throughout its lifetime and be able to last the 1,000 cycles of today’s batteries. To get there, Pyun is experimenting with other kinds of sulphur copolymers that may have better properties.
He is not there yet but he thinks he is pretty close.