One‐Pot Synthesis of CuS Nanoflower‐Decorated Active Carbon Layer for High‐Performance Asymmetric Supercapacitors

Abstract Copper sulfide‐active carbon (CuS‐AC) with a three‐dimensional (3D) porous structure is fabricated based on AC‐supported CuS nanosheets by using a solvothermal method and used in a high‐performance asymmetric supercapacitor devices to enhance the specific capacitance, cycling stability, and energy density. The CuS nanosheets form an array on the AC layer, and the two kinds of materials are ideally combined, leading to increased conductivity and enlarged electroactive surface area of the electrode materials. Moreover, the 3D CuS‐AC porous structure exhibited excellent electrochemical energy storage properties with large specific capacitance (247 F g⁻¹ at a current density of 0.5 A g⁻¹), high energy density (24.88 Wh kg⁻¹ at the power density of 800 W kg⁻¹), and good long‐term cycling stability (92% capacitance retention after 5000 cycles). This superior electrochemical performance can be ascribed to the high pseudocapacitance of CuS and large surface area from AC. The experimental results indicate that the hierarchical nanostructure design of CuS grown on AC exhibits considerable potential for supercapacitor applications.