One-step electrodeposition of CuSe/CoSe2 heterostructure composite for high-performance asymmetric supercapacitor electrodes

In recent years, hybrid supercapacitors have attracted considerable attention owing to their remarkable energy density and power density. However, the performance of these devices is critically dependent on the rational design and optimization of electrode materials. Transition metal selenides are a type of phase change material with unique properties, structures, and electrical properties. In this manuscript, a heterogeneous material-CuSe/CoSe₂ (CCSe) was grown on the surface of Ni foam (NF) via one-step electrodeposition. Leveraging its intrinsic electric field, the CCSe electrode significantly enhances electron transfer kinetics while providing an enlarged effective electrode surface area, thereby achieving superior electrochemical performance. When a current density (D_c) is 1 A g⁻¹, the specific capacity (C_s) of the CCSe is up to 1464 C g⁻¹. Also, the CCSe electrode exhibits excellent cycling stability, retaining 82.2% of its initial C_s after 5000 cycles. Additionally, the assembled hybrid supercapacitors (SCs) constructed with the CCSe as the positive electrode and active carbon (AC) as the negative electrode also show good application potential. A high energy density (E_d) of 49.73 Wh kg⁻¹ can be obtained at a power density (P_d) of 800.0 W kg⁻¹.