Lithium oxygen battery is considered as one of the most promising energy storage systems due to its high theoretical energy density. However, its development is severely hindered by the large overpotentials and poor cycling stability. Efforts have previously been taken on the development of various types of electrocatalysts to enhance the electrode reactions. However, issues pertaining to surface passivation and pore clogging of the cathode remain. Homogenous catalysis with soluble redox mediators thus comes to the attention. While effective in addressing the surface passivation issue, pore clogging problem remains unsolved due to the limited space in the cathode. Therefore, redox flow lithium oxygen battery was proposed by introducing a gas diffusion tank, which elegantly overcomes these hurdles. Lastly, the gap between present research work and practical applications, as well as future development of lithium oxygen battery is briefly discussed.