Because of their superior power and energy densities, supercapacitors have garnered considerable amounts of attention in energy storage technologies. Co₃O₄ is considered as a regularly used electrode material for supercapacitors because of its high theoretical capacitance and outstanding electrochemical activity. However, owing to the Co₃O₄ electrode materials’ rapid capacity decay and low intrinsic conductivity, it is challenging to achieve high theoretical capacitance. As a result, doping Co₃O₄ with metal components can enhance its electrical and surface characteristics while also raising its conductivity. Through a straightforward hydrothermal reaction and subsequent thermal decomposition, a series of Fe doping into Co₃O₄ has been successfully realized in this paper. This generates a nanosheet floral cluster structure and exposes more active sites, and the two metal elements work in concert to improve the capacitance performance. The electrochemical performance of the Co-0.2Fe-450 electrode material appears satisfactory when the doping amount of Fe is 0.2 mmol and its thermal decomposition temperature is 450 °C. The specific capacitance at 1 A g⁻¹ is 680 F g⁻¹. The capacitance retention rate at 10 A g⁻¹ current density after 5000 charge–discharge cycles is 84.67%. Notably, the assembled asymmetric supercapacitor retains 105.5% of its capacitance after 5000 cycles and has a power density of 803.13 W kg⁻¹ and an energy density of 17.78 W h kg⁻¹. Fe-doped Co₃O₄ has a strong future in energy storage, as evidenced by its exceptional electrochemical characteristics.