A high-energy-density lithium-oxygen battery based on a reversible four-electron conversion to lithium oxide

An elevated lithium battery Batteries based on lithium metal and oxygen could offer energy densities an order of magnitude larger than that of lithium ion cells. But, under normal operation conditions, the lithium oxidizes to form peroxide or superoxide. Xia et al. show that, at increased temperatures, the formation of lithium oxide is favored, through a process in which four electrons are transferred for each oxygen molecule (see the Perspective by Feng et al. ). Reversible cycling is achieved through the use of a thermally stable inorganic electrolyte and a bifunctional catalyst for both oxygen reduction and evolution reactions. Science , this issue p. 777 ; see also p. 758