Facile One-Step Microwave-Assisted Method to Synthesize Nickel Selenide Nanosheets for High-Performance Hybrid Supercapacitor

Nanosheets structures can be employed as the most promising electrode material to enhance electrochemical performance for supercapacitors. Nickel Selenide (Ni_0.85Se) nanosheets are synthesized using a rapid microwave synthesis method in a single step. The Ni_0.85Se nanosheets possess a high surface area (125 m²g⁻¹) with a hexagonal crystalline structure. It shows magnificent electrochemical properties, such as splendid specific capacitance (2530 Fg^-1 at 0.5 Ag⁻¹). An asymmetric hybrid supercapacitor is fabricated with nickel selenide nanosheets as a positive electrode and activated carbon as a negative electrode. The assembled hybrid supercapacitor displays a high energy density of 63.5 WhKg⁻¹ at a power density of 404 WKg⁻¹, and after 8000 cycles, only 5% capacitance is lost along with the better voltage window at 0–1.6 V.