Carbon sulphur battery doubles energy density, cuts costs

The researchers have achieved this by developing a composite of sulphur and nanostructured carbon for use as a battery cathode. "Using sulphur, instead of the materials currently used in lithium-ion batteries, could substantially reduce production costs, as sulphur is a fraction of the cost of other materials," says Dr Can Zhang of the Department of Engineering. "Additionally, carbon-sulphur electrodes achieve double the energy density per unit of weight." The carbon-sulphur electrodes are produced by growing a 'forest' of high quality carbon nanotubes (CNTs) on a layer of metal foam. The CNT forest provides excellent electrical conductivity and acts as a 3d scaffold into which the sulphur is injected in order to form the cathode. Although they offer higher density and lower cost, lithium-sulphur batteries have suffered from short cycle life, typically less than 80 charge-discharge cycles. According to the researchers, the CNT-sulphur composite enhances the cycle performance of lithium-sulphur batteries, retaining 80% capacity after over 250 full charge-discharge cycles. The team now intends to develop a roll to roll machine to produce the cathode material continuously.