Impact of selenization time on the microstructure and electrochemical performance of CoSe/NiSe/Ni3Se2@NF composite materials

Transition metal compounds have garnered significant attention due to their high specific surface area, tunable composition, and synergistic effects. These materials exhibit excellent electrochemical performance, making them some of the most promising candidates for pseudocapacitive applications. Herein, cobalt selenide (CoSe), nickel selenide (NiSe), and trinickel diselenide (Ni 3 Se 2 ) nanosheets were grown on nickel foam using a simple two-step hydrothermal method. The three-dimensional network structure of the CoSe/NiSe/Ni 3 Se 2 @NF composite material provides a larger specific surface area and more electrochemically active sites. This architecture facilitates rapid electron transfer, enhances electrochemical performance, and results in a high specific capacitance of 2300.65 F· g −1 at a current density of 1 A· g −1 . The asymmetric supercapacitor device, assembled with CoSe/NiSe/Ni 3 Se 2 @NF as the positive electrode and activated carbon as the negative electrode, demonstrates an energy density of 63.16 Wh·kg −1 at a power density of 805.73 W·kg −1 . These outstanding electrochemical properties suggest that CoSe/NiSe/Ni 3 Se 2 @NF composite materials hold great potential as an energy storage material.