Researchers at the University of Waterloo in Canada have created a cathode capable of sustaining a reversible electrochemical reaction at high current rates, a discovery which they claim is a crucial step forward in the creation of lithium-sulphur rechargeable batteries and paves the way for better electric cars.

At present, lithium-sulphur batteries are what most people believe to be the best hope for batteries for electric cars. They are touted as the next generation of rechargeable batteries because they have an energy density which is far greater than the standard lithium-ion batteries. This means that using lithium-sulphur batteries will mean batteries can be made smaller with a higher capacity, as well as being cheap and made from less toxic parts. Lithium-sulphur batteries are also said to be less volatile than their lithium-ion counterparts.

However, there are currently drawbacks to lithium-sulphur batteries that scientists are working hard to overcome. The first is that current lithium-sulphur batteries support far fewer recharge cycles than lithium-ion batteries, thus their lifespan may be shorter. There is also the problem of getting the cathode-end reaction to store and release efficiently during the charge-recharge cycles – and this is where the University of Canada’s research should help.

The new research uses mesporous carbon to create tiny carbon rods which house tiny pores of consistent depth and diameter. Liquid sulphur is then poured onto the rods and this sulphur is drawn into the rods. This means that there is close contact between the electrically active sulphur and the carbon cathodes, thus giving a larger surface area to work with and therefore ensuring a smoother flow of electrons.

This approach is very different to the ‘traditional’ design which uses carbon-sulphur materials which are unable to bring the two substances close enough to give a smooth flow of electrons.

Popularity: 3% [?]