Electrochemical synthesis of binder-free interconnected nanosheets of Mn-doped Co₃O₄ on Ni foam for high-performance electrochemical energy storage application

In this study, various nanostructures of Mn-doped Co₃O₄ were synthesized on Ni foam using binder-free electrochemical technology for electrochemical energy storage applications. Using the cyclic voltammetry method with different scan rates, diverse nanostructures, i.e., irregularly oriented nanooctahedra, interconnected standing nanosheets, and nanopetals of Mn-doped Co₃O₄, were obtained. The standing interconnected nanosheets on the Ni foam exhibited remarkable supercapacitive performance due to the void space between the sheets and mesoporous structure, which provided additional active sites for faradic transitions. The nanosheets exhibited excellent electrochemical performance with a maximum specific capacitance of 1005F g⁻¹ and a cyclic stability of 88% during 5000 charge–discharge cycles. Moreover, an asymmetric supercapacitor was assembled comprising activated carbon on Ni foam and interconnected nanosheets of Mn-doped Co₃O₄ on Ni foam as negative and positive electrodes, respectively. This assembled device exhibited an improved potential of 1.6 V, a maximum specific energy of 20.6 Wh kg⁻¹, and a maximum specific power of 16 kW kg⁻¹ with 80.6% capacity retention after 2000 charge–discharge cycles, which is superior for SC devices.