The shape of catalysts has been regarded as a crucial physical factor to determine its catalytic activity in various applications. However, very little is known about the catalyst shape-dependent activities for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in the cathode of Li–O2 battery. Hence, we synthesized Pt3Co nanocube (NC) for the comparison with Pt3Co nanoparticle (NP) by regulating the ratio of reducer (hexadecanediol; HDD) amount. Consequently, we could report on very high capacity (10,000mAh gcarbon −1), superb rate capability (3500mAh gcarbon −1 at 2000mA gcarbon −1) and high reversibility of Lithium–O2 batteries using Pt3Co NC catalysts. Particularly, the Pt3Co NCs catalyst exhibited a low OER potential of 3.1V, providing the highest round trip efficiency of ~86.5% at a current density of 200mA gcarbon −1, which is much superior to NPs catalyst.