Hierarchical Fe3O4@FeS2 Nanocomposite as High-Specific-Capacitance Electrode Material for Supercapacitors

Iron-based materials are ideal faradaic electrodes for supercapacitors. However, boosting the specific capacitance and preparation with the simple method of iron-based materials remains a great challenge. Herein, hierarchical Fe3O4@FeS2 nanocomposites are constructed through an annealing strategy with monohydrate ferrous sulfate as the precursor. X-ray diffractometry, high-resolution transition electron, and X-ray photoelectron spectroscopy results reveal that the hierarchical Fe3O4@FeS2 nanocomposite is successively fabricated. The as-prepared materials exhibit a remarkable specific capacitance of 597.1 F g(-1) at a current density of 3 A g(-1) as electrode materials of supercapacitors. Inspiringly, specific capacitance is superior to most iron-based electrodes in previous reports. This may be ascribed to the junction at the interface of the different components and the efficient electron transfer of FeS2. This work is meaningful for the design and preparation of electrode materials with specific capacitance.