Metal–organic framework derived petal-like Co3O4@CoNi2S4 hybrid on carbon cloth with enhanced performance for supercapacitors

Abstract

Although ternary cobalt nickel sulfide is a promising electrode material for supercapacitors, its wide application is limited by its relatively poor electrochemical stability, low rate capacity and inefficient nanostructure. Here, we demonstrate that the electrochemical activity of cobalt nickel sulfide can be significantly improved by synergy from a Co-MOF-derived Co₃O₄ skeleton. We design and fabricate petal-like Co₃O₄@CoNi₂S₄ nanowall arrays combined with carbon cloth as an excellent self-standing electrode for asymmetric supercapacitors. The Co₃O₄@CoNi₂S₄ electrode exhibits a high specific capacitance of 244.4 mA h g⁻¹ at a current density of 1 A g⁻¹ and an excellent rate capability of 81.3% at 16 A g⁻¹. Furthermore, the assembled Co₃O₄@CoNi₂S₄//AC asymmetric supercapacitor (ASC) shows a high energy density of 55.6 W h kg⁻¹ at a power density of 884.4 W kg⁻¹, and the capacitance retention of Co₃O₄@CoNi₂S₄ is up to 86% after 10 000 cycles. It is believed that the presented work opens up a new strategy to fabricate high-performance supercapacitor electrodes.