To investigate whether this deterring effect has any influence in Zn-O2 full cell performance, charge-discharge experiments are conducted at a constant current density of 5 mA/cm² using a split-cell setup having Zn as an anode, 20 weight % Pt/C coated porous carbon paper as a cathode and 6 M KOH as the electrolyte. One set of the experiment is conducted with a continuous supply of pure O2 in the cell via the cathodic inlet at a constant flow rate while the other set is performed with a mixture of N2 and O2 gases (80% N2, 20% O2) named as 'air', the schematic is shown in Fig. (inset shows oxygen transfer from cathode to anode). The chargedischarge plots are shown in Fig. , indicating a nearly five-fold increase in the cyclability in the air environment compared to that in the O2 environment. The drastic voltage drop after cycling impedes further charging and is identified due to the insulating ZnO formation, as shown in our previous studies. The observed higher overpotential during discharge for the cell running in air- environment (Fig. ) is due to the sluggish ORR because of the O2 mass transfer limitation in the cathodic process, as proven in the later part. However, there is a pronounced influence on the cyclability of the cell, where it reaches up to ~60 hours in the case of air while the cell failure occurs in~12 hours in O2 supplied one. To test the role of N2, the experiments are also conducted in an Ar diluted O2 mixture where cyclability enhancement and overpotential losses are observed (SI Appendix, Fig. ). This indicates that the presence of O2 influences both, cathodic and anodic processes where its role in anodic process is not unraveled so far.