Lithium-sulfur batteries have the potential to store up to five times the energy per gram that Lithium-ion batteries do, and at a lower cost. The science of using sulfur in batteries is sound, but putting the theory into practice has proven to be difficult. There are concerns about durability and safety. The particular properties of Lithium-sulfur cells can cause short circuits which lead to overheating and fires.
Various groups are working on solving these problems and making Lithium-sulfur batteries a reality. OXIS Energy aims to be the first to market, with production starting this year. However, there are many interested companies, including big players in the auto industry.