A new report overcomes hurdles related to the electrochemistry underlying the lithium-oxygen battery, making it a little more likely this high-powered battery could be broadly adopted in years ahead. Lithium oxygen (Li-O2) batteries are of great interest due to their high-energy densities, which can exceed that of Li-ion batteries by at least one order of magnitude. Composed of a lithium anode, a carbon cathode and an organic electrolyte containing lithium ions, they typically create lithium peroxide (Li2O2) during use. However, Li2O2 is highly reactive and leads to the decomposition of the organic electrolyte solution and corrosion of the carbon cathode, obstacles which have impeded the technology's commercial adoption. In contrast, lithium oxide (Li2O) is much less reactive. According to the authors, the formation of the more reactive peroxide is favored under ambient conditions - those typical of battery use cases - and as a result, cells based on it are far more common than those based on less reactive Li2O. Here, Chun Xia and colleagues demonstrate a way to overcome the thermodynamic and kinetic barriers associated with the lithium-oxygen battery, by increasing the operating temperature of the battery to 150 °Celsius, and by using different materials (an inorganic electrolyte and a nickel-oxide based cathode). The resulting cell operates with a coulombic efficiency (the ratio of discharge to charge capacity) of nearly 100%. In a related Perspective Shuting Feng et al. underscore the need for high-density energy storage, like that offered by Li-O2 batteries, to help bridge the gap between renewable energy and our rising energy demand. "Xia et al.'s work catalyzes fundamental and applied research to advance the realization of rechargeable lithium-oxygen batteries using molten-salt electrolytes," write Shuting Feng et al. in a related Perspective.
###
Journal
Science