Facile preparation of CoNi2S4@NiSe nano arrays on compressed nickel foam for high performance flexible supercapacitors

Abstract

CoNi₂S₄@NiSe nano arrays with hierarchical structure are in situ prepared on compressed nickel foam for a high performance flexible supercapacitor by a three-step solution-based method which involves a one-step solvothermal process and a two-step hydrothermal process. During the preparation process, the nickel foam serves not only as a support but also as the nickel source for NiSe nanorods, which is beneficial for improving the electronic conductivity and reducing the contact resistant of the active materials/current collector. The CoNi₂S₄@NiSe nano arrays with ample active sites and porous structure contribute to increasing the electrochemical performance. The flexible supercapacitor based on CoNi₂S₄@NiSe nano arrays was prepared, which exhibits a high areal capacitance of 312.95 mF cm⁻² at a scan rate of 5 mV s⁻¹ and good cycling stability with 97.59% capacitance retention after 1000 cycles. Meanwhile, it also exhibits excellent electrochemical stability which can maintain great capacitive performance even in the bending state. Therefore, the CoNi₂S₄@NiSe nano arrays with hierarchical structure on the compressed nickel foam could be a promising electrode material for high performance flexible supercapacitors.