Nanostructured porous wires of iron cobaltite: novel positive electrode for high-performance hybrid energy storage devices

Abstract

The demand for more efficient energy storage systems stimulates research efforts to seek and develop new energy materials with promising properties. In this regard, binary metal oxides have attracted great attention due to their better electrochemical performance as compared to their single oxide analogues. Herein, nanostructured porous wires of FeCo₂O₄ were grown on nickel foam via a facile hydrothermal route and employed as binder/additive-free electrodes to investigate the electrochemical behavior of FeCo₂O₄ as electrode materials for supercapacitors. The FeCo₂O₄ sample exhibits a high specific capacitance of 407 F g⁻¹ at a scan rate of 10 mV s⁻¹ in the initial cycling. After cycling for 2000 cycles, electro-activation of the material results in subsequent increase in capacitance up to 610 F g⁻¹, showing promising characteristics of this material for energy storage. The performance of the prepared FeCo₂O₄ sample is found to be much better than that of the corresponding single oxides. Furthermore, porous nanostructured FeCo₂O₄//AC asymmetric supercapacitors were assembled and could achieve a high energy density of 23 W h kg⁻¹ and a maximum power density of 3780 W kg⁻¹.