CuS/CoS heterojunction with enhanced redox kinetics via electrodeposition for high-performance supercapacitors

For the purpose of further boosting the electrochemical properties of transition metal sulfide electrode materials, constructing heterojunction is an effective strategy. Under this circumstance, CuS/CoS heterojunction with unique hierarchical flower-like morphology is synthesized via a simple two-step Cyclic Voltammetry (CV) electrodeposition. The newly acquired flower-like structure significantly enlarges the contact area between the electrode material and electrolyte while also increasing the material's active sites. Additionally, a distinct synergistic interaction between CuS and CoS is demonstrated. More importantly, the build-in internal electric field among heterojunction can effectively separate the electrons and holes, so as to achieve improved conductivity, which is also undoubtedly beneficial to enhance the redox kinetics. The combination of these advantages ultimately yields outstanding capacitance characteristics, achieving 0.79 mWh cm⁻² (7.09 F cm⁻² at 2 mA cm⁻²) and remarkable cycle life (68.17 % retention over 8500 cycles). Notably, the corresponding assembled asymmetric supercapacitor (ASC) device can achieve up to an energy density of 1.04 mW h cm⁻² at a power density of 5.91 mW cm⁻² and 71.85 % capacity retention at 8500 cycles, surpassing most other relevant reports. All in all, the developed heterojunction presents significant potential as high-performance energy storage electrode material and provides a practical and effective pathway for advancing the field of energy storage.