Self-supported FeCo2O4/CoO@CNTs film as cathode material to construct high energy density supercapacitor

A simple hydrothermal method was used to synthesize FeCo₂O₄/CoO@CNTs composite material as the cathode material of asymmetric supercapacitor. Based on the advantages of single/bimetal oxide and the synergistic effect after compounding, the hierarchical structure material can improve the energy density. The electrode material has a capacitance of 965 F g⁻¹ at 1 A/g. The specific capacitance of an asymmetric supercapacitor assembled with FeCo₂O₄/CoO@CNTs as the positive electrode, carbon nanotubes (CNTs) as the negative electrode and KOH as the electrolyte is 142.5 F g⁻¹ at 1 A/g. The capacity retention rate is 93.7 % after 10,000 cycles, and the device delivered efficient energy of 44.5 Wh kg⁻¹ at 750 W kg⁻¹. It demonstrates the application prospects of the prepared composite materials in energy storage.