Lithium-sulphur battery breakthrough claimed

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Researchers at the US Department of Energy's Oak Ridge National Laboratory (ORNL) have come up with a promising design for a lithium-sulphur battery that is considerably cheaper and more energy dense than the standard lithium-ion batteries used in today's electronics.

"Our approach is a complete change from the current battery concept of two electrodes joined by a liquid electrolyte, which has been used over the last 150 to 200 years," said project leader Chengdu Liang. While scientists have been excited about the potential of lithium-sulphur batteries for decades, long lasting, large scale versions for commercial applications have proven elusive. The ORNL team overcame these barriers by first synthesising a new class of sulphur-rich materials that conduct ions as well as the lithium metal oxides conventionally used in the battery's cathode. The researchers then combined the new sulphur-rich cathode and a lithium anode with a solid electrolyte material to create an energy dense, all-solid battery. The new ionically-conductive cathode enabled the ORNL battery to maintain a capacity of 1200mAh/g after 300 charge-discharge cycles at 60°C. For comparison, a traditional lithium-ion battery cathode has an average capacity between 140 and 170mAh/g. The team's all-solid design is also said to increase battery safety by eliminating flammable liquid electrolytes that can react with lithium metal. "This game changing shift from liquid to solid electrolytes eliminates the problem of sulphur dissolution and enables us to deliver on the promise of lithium-sulphur batteries," said Liang. "Our battery design has real potential to reduce cost, increase energy density and improve safety compared with existing lithium-ion technologies."