credit: rsc.org
The Lithium-air battery technology is a promising solution to make the range of electric vehicles comparable to gasoline-powered vehicles. It has the potential to store ten times more energy than the best lithium-ion battery available in the market nowadays. However, no stable battery configuration had been designed until now.
In order to operate, the components of the lithium-air battery must be stable. During discharge, lithium atoms at the lithium metal electrode, called an anode, lose electrons and form the mobile lithium ions. These ions move through a conductive electrolyte solution towards the cathode where they combine with oxygen from air to form lithium oxide. The applied voltage reverses the reaction when the battery is charged.
Early versions of the battery failed after several charge and discharge cycles. The carbon used to make the cathode and the electrolyte solution undergo unwanted side reactions.
In the new version of the battery, Peter Bruce, chemist at the University of St. Andrews in the UK, opted to swap the previous offenders. He replaced carbon with inert gold particles for the cathode. The electrolyte solution, which was usually made from polycarbonates or polyethers, was replaced with dimethylsulfoxide (DMSO) that is less likely to react at the cathode.
The new combination worked as reported online in the Science. The new battery was stable for 100 charge and discharge cycles with only five percent loss of power.
Linda Nazar, chemist at the University of Waterloo in Canada, says the results are very promising. However, she cautions that the new battery is not yet ready for commercialization. For one thing, gold is too expensive and too heavy to serve as the only cathode material in a practical cell. For another thing, DMSO has the potential to react over time with the lithium metal in the anode.
Considerable work still needs to be done to improve the new battery design, but scientists are optimistic that lithium-air battery will soon be a real world technology.
[via sciencemag]
