Template free and facile microwave-assisted synthesis method to prepare mesoporous copper sulfide nanosheets for high-performance hybrid supercapacitor

Development of high energy density supercapacitor has stimulated a great deal of research over the past decade. The electrochemical performance of a hybrid supercapacitor is strongly affected by the structural morphology and the surface area of its electrode material. Herein, we report mesoporous nanosheet structures composed of copper sulfide which are synthesized by an instant and simple microwave-assisted method. The electrode material based on CuS nanosheets consist of mesoporous structures (pore diameter < 25 nm) and a large surface area (∼169m²g⁻¹). This high surface area nanosheets structure provides more active sites for electrochemical reactions and short ion/electron diffusion path for excellent super-capacitive performance. The mesoporous CuS nanosheets electrode exhibits a high specific capacitance of 2535 Fg⁻¹ at a current density of 1 Ag⁻¹ in an aqueous electrolyte (2MKOH) with excellent rate capability. The fabricated device for practical application possesses an excellent energy density of 63.2 Whkg⁻¹ at a high power density of 400W kg⁻¹, the good specific capacitance of 177 Fg⁻¹ at 0.5A g⁻¹ and high cycling stability at 10 Ag⁻¹ (88% retention after 10000 cycles). This work not only demonstrates the promising potential of the mesoporous CuS electrodes for application in the high-performance hybrid asymmetric capacitor but also shows a path to synthesize different transition metal sulfide architecture by using microwave radiation method.