Scientists Deliver a Longer-Lasting Lithium-Oxygen Battery (technologyreview.com)

Packing more energy into batteries is the key to delivering electric cars with longer range, smartphones that can last days -- and cheaper electronic products all around. Lithium-oxygen batteries represent one of the more promising paths toward that end. From a report: They could boost energy density by an order of magnitude above conventional lithium-ion batteries -- in theory, at least. In a paper published this week in Science journal, researchers at the University of Waterloo identified ways of addressing some of the major hurdles to converting that potential into commercial reality.

A critical problem has been that as a lithium-oxygen battery discharges, oxygen is converted into superoxide and then lithium peroxide, reactive compounds that corrode the battery's components over time. That, in turn, limits its recharging ability -- and any real-world utility. To get around the problem, researchers switched from a carbon cathode to one made of nickel oxide and supported by a stainless steel mesh. They also used molten salt for the electrolyte -- the part of the battery that allows positively charged ions to move between the electrodes -- and raised the battery's operating temperature to 150C. Those steps made it possible to achieve about three times the number of charging cycles as earlier lithium-oxygen efforts. The researchers also managed to increase the energy per unit of mass by more than 50 percent.