Despite having the capability of achieving high energy densities, Li–O2 batteries still suffer from many inherent disadvantages such as electrolyte stability, sluggish kinetics of the oxygen reduction/evolution reactions in the aprotic environment and electrodes stability. Our research demonstrates by combining electrochemical and analytical techniques that the performances of Li–O2 batteries based on LiTFSI-Tetraglyme electrolyte and Au-coated carbon electrodes are manly hindered by the instability of the lithium metal anode in the oxygen-saturated environment. Although the Au-coated carbon electrodes are able to minimize side reactions arising from electrolyte decomposition, oxygen crossover on the lithium metal results in the formation of decomposition products (LiOH, Li2CO3) that are clearly detrimental for the battery performance. Finally it is demonstrated that the Au-coated carbon electrodes in combination with the LiTFSI-Tetraglyme electrolyte can sustain extended cycling (100 cycles) when a more stable source of Li-ion, namely lithium iron phosphate (LFP), is used.