The Li-O 2 battery (LOB) is a promising energy storage system due to its exceptionally high theoretical energy density (∼ 3500 Whkg -1 ). However, the LOBs technology is still facing important challenges and limitations that have to be sorted out. Among them, there are the high charging potential that leads to low discharge/charge cycle efficiency, the reduced capacity at high discharge rates and the poor cathode and electrolyte stability. The main discharge product of the LOB is Li 2 O 2 whose insulating character deeply affects various aspect of the battery. The dominant reversible reaction that takes place at the cathode of a non-aqueous Li-O 2 cell is