Homogeneous nanocube (Fe, Ni) S2 electrode material from Fe–Ni PBA for high-performance hybrid supercapacitors

Prussian blue analogs (PBAs) are multifunctional precursors for the synthesis of a series of transition metal nanomaterials. In this study, high-performance supercapacitor hybrid electrode materials [(Fe, Ni) S2] are obtained by a facile hydrothermal sulfidation method, where the Fe–Ni PBA is introduced as the precursor. The nanocube structure which is similar to the Fe–Ni PBA precursor is remained and delivers the structure with a large number of cracks, resulting in a larger specific surface area and good conductivity. The (Fe, Ni) S2 electrode material possesses a high specific capacitance of 1249.1 F g−1 at the current density of 1 A g−1, good rate capability (915.31 F g−1 at 20 A g−1), and the excellent cyclic stability (retention rate of 91.6%) after 5000 cycles. The two-electrode system condition test shows that the energy density of ASD reached 39.97 Wh kg−1 when the power density is 0.85 kW kg−1 including the material is a potential supercapacitor electrode material.