Enhanced electrochemical performances of FeOx–graphene nanocomposites as anode materials for alkaline nickel–iron batteries

Abstract

A new type of graphene-based FeO_x nanocomposites have been synthesized by high temperature solid-state reaction using FeC₂O₄·2H₂O. The synthesis conditions are optimized by thermogravimetric analysis of the precursor. When evaluated as anode material for the alkaline nickel–iron battery, the FeO_x–graphene nanocomposites deliver a high specific capacity of 552.1 mA h g⁻¹ at a current density of 200 mA g⁻¹ and retain 91% of the initial capacity after 100 cycles. Furthermore, the hybridized FeO_x–graphene materials undergo only 26% capacity decay when the discharge current density is changed from 200 mA g⁻¹ to 1000 mA g⁻¹. The enhanced cycling and high discharge rate performance derives from the high specific surface area of iron oxide nanoparticles and particular electric conductivity of graphene. This study suggests a safe, inexpensive and powerful rechargeable iron electrode, enabling the promising prospect of large-scale energy storage based on the aqueous iron-based rechargeable battery.