Fe2O3 nanocluster-decorated graphene as O-2 electrode for high energy Li-O-2 batteries

Fe2O3 nanocluster-decorated graphene (Fe2O3/graphene) hybrids with controlled contents of Fe2O3 were prepared by a facile electrochemical process. These Fe2O3/graphene hybrids were tested as O-2 electrodes for Li-O-2 batteries, which exhibited enhanced discharge capacities as compared to that of a pure graphene based O-2 electrode, e.g. the Fe2O3/graphene electrode with 29.0 wt% of Fe2O3 delivered a discharge capacity of 8290 mA h g(-1) and a round-trip efficiency of 65.9% as compared to 5100 mA h g(-1) and 57.5% for a pure graphene electrode. The excellent electrochemical properties of Fe2O3/graphene as an O-2 electrode is ascribed to the combination of the fast kinetics of electron transport provided by the graphene sheets and the high electrocatalytic activity for O-2 reduction provided by the Fe2O3.