One-step microwave synthesis of self-supported CoSe2@NiSe2 nanoflowers on 3D nickel foam for high performance supercapacitors

The work reports the fabrication of CoSe 2 @NiSe 2 nanoflowers on nickel foam substrates via one-step microwave method, in which the Ni foam serves as a skeleton and a nickel source. The as-prepared CoSe 2 @NiSe 2 nanoflowers display high capacitance value of 1434 F g −1 at the current density of 1 A g −1 and excellent cycling performance of 87.5% retention after 20,000 cycles at 10 A g −1 . In addition, the supercapacitor device using CoSe 2 @NiSe 2 nanoflowers as the positive electrode and activated carbon (AC) as the negative electrode not only can exhibit wide voltage window of 1.6 V, but also deliver a maximum high energy density of 20.4 Wh Kg −1 at power density of 798 W Kg −1 and 86.6% of capacity retention after 20,000 cycles.