Metal–organic framework templated fabrication of Cu7S4@Ni(OH)2 core–shell nanoarrays for high-performance supercapacitors

Abstract

Well-controlled core–shell nanostructured arrays are highly attractive and rational combination of hybrid electrochemical active materials as promising candidate electrodes for supercapacitors still remains a great challenge. In this work, ultrathin Ni(OH)₂ nanosheets as the “shell” were anchored on Cu₇S₄ nanorods as the “core” to form core–shell hybrid nanoarrays on copper foam (CF), which were firstly fabricated by a facile metal–organic framework templated synthetic strategy with a three-step procedure of in situ interface growth, sulfurization and hydrothermal synthesis. The core–shell Cu₇S₄@Ni(OH)₂/CF hybrid nanoarrays as binder-free electrodes show a high specific capacitance of 1072.5 F g⁻¹ (482.6 C g⁻¹) at a current density of 1 A g⁻¹, superior rate capacity of 86.4% at 10 A g⁻¹ and an outstanding cycling stability of 94.5% capacitance retention after 10 000 cycles. What's more, the assembled asymmetric supercapacitor device based on Cu₇S₄@Ni(OH)₂/CF as a positive electrode and activated carbon (AC) as a negative electrode shows a high energy density of 52.5 W h kg⁻¹ at a power density of 750 W kg⁻¹ with decent cycling stability. This strategy can be extended to form other unique copper sulfide-based core–shell nanoarray architectures with enhanced electrochemical activity for high-performance energy storage devices.