Fe3O4-embedded rGO composites as anode for rechargeable FeOx-air batteries

A simple formation of iron oxide (Fe3O4)-embedded reduced graphene oxide (rGO) composite was demonstrated using the chemical precipitation method proposed in this study. The rGO consisted of exfoliated nanosheets serves as a good framework for penetration and adsorption of the Fe precursor, allowing homogeneous formation of Fe3O4 crystals within the rGO nanosheet structure. The Fe3O4/rGO composite electrode, containing 60 wt.% Fe3O4, demonstrated promising electrochemical behavior at different scan rates. In a three-electrode charge discharge measurement, a prolonged cyclic performance with good capacity retention for 100 cycles was obtained. In the battery performance evaluation for alkaline aqueous rechargeable Fe-air batteries, a maximum and stable discharge capacity of approximately 420 mA h g(-1) was achieved. This simple fabrication method of Fe3O4/rGO composites is very promising not only for large-scale active materials fabrication for Fe-air batteries with enhanced performance, but also serves as a good platform for the development of complex-oxide-rGO hybrids in high performance energy storage materials.