One-step synthesis of 2D–2D Co(OH)₂–MoSe₂ hybrid nanosheets as an efficient electrode material for high-performance asymmetric supercapacitor

2D transition metal based nanomaterials are of great importance in electrochemical applications due to their high surface area and rich available electrochemical sites. However, 2D nanosheets arrays face an aggregation problem with low electrical conductivity which can deteriorate their overall electrochemical outcome. It is the need of the hour to develop an efficient 2D hybrid nanomaterials for supercapacitor applications. This study illustrates that unique 2D-2D Co(OH)₂–MoSe₂ hybrid nanosheets display high electrochemical performance. The Co(OH)₂–MoSe₂ hybrid nanosheets are synthesized by a simple one-step hydrothermal method. The Co(OH)₂–MoSe₂ hybrid nanosheets have shown a high specific capacitance of 541.55 F g⁻¹ at a current density of 1 A g⁻¹ in a three-electrode system, and these retain a minimum specific capacitance of 397 F g⁻¹ at a maximum current density of 10 A g⁻¹. The Co(OH)₂–MoSe₂ hybrid nanosheets maintain a capacitance retention of 91.4% after 3000 cycles. Furthermore, asymmetric supercapacitor device is fabricated by using Co(OH)₂–MoSe₂ hybrid nanosheets as a positive electrode and activated carbon (AC) as a negative electrode. The Co(OH)₂–MoSe₂//AC ASC device displays a high energy density of 30.12 Wh kg⁻¹ at a power density value of 985.74 W kg⁻¹. It maintains an energy density of 18.28 Wh kg⁻¹ at a maximum power density of 12.209 kW kg⁻¹. The as-fabricated Co(OH)₂–MoSe₂//AC ASC device maintains a capacitance retention of 86.2% after 3000-cycles. The obtained electrochemical results demonstrate that Co(OH)₂–MoSe₂ hybrid nanosheets can be used as a promising cathode electrode material for high-performance asymmetric supercapacitor.