Rational design of FeCo-Se@NiMn-LDH/NF heterostructure electrode materials for enhanced supercapacitor performance

Layered double hydroxides (LDHs) are promising candidates for high-performance electrode materials in aqueous energy storage systems due to their high electrochemical activity. However, the practical application of LDHs is constrained by their relatively low specific capacitance and poor rate capability. Herein, we rationally design and fabricate a novel FeCo-Se@NiMn-LDH heterostructure supported on nickel foam via a three-step way involving electrodeposition followed by hydrothermal treatment. The hierarchical heterostructure ensures uniform growth of active materials and promotes the formation of interconnected porous architectures. This unique configuration significantly enhances charge storage kinetics by accelerating ion diffusion and electron transport. Moreover, the conductive nickel foam substrate improves structural integrity and mitigates electrode degradation. As a result, the FeCo-Se@NiMn-LDH/NF electrode exhibits an ultrahigh specific capacitance of 1867.6F g^-1 and excellent cycle stability. The supercapacitor of FeCo-Se@NiMn-LDH/NF//AC obtains a remarkable energy density of 58.42 Wh kg^-1 (800 W kg^-1). This work provides an effective and feasible approach for engineering high-performance heterostructured electrodes, paving the way for advanced supercapacitor applications.