Rational Construction of ZnCo-ZIF-Derived ZnS@CoS@NiV-LDH/NF Binder-Free Electrodes Via Core–Shell Design for Supercapacitor Applications with Enhanced Rate Capability

The improvement of metal–organic framework materials through rational structural design and construction and the construction of core–shell nanostructures to obtain affluent active sites and high redox activity have always been research hotspots in green energy field. In this work, high-quality supported binder-free ZnS@CoS@NiV-LDH/NF was in situ grown on Ni foam by using bimetal ZnCo ZIFs as a template. The designed ZnS@CoS@NiV-LDH/NF electrode material reveals excellent battery-type redox kinetics with the highest specific capacitance of 2918.4 F g–1 (1459.2 C g–1) at 1 A g–1. In addition, ZnS@CoS@NiV-LDH/NF exhibits excellent lifetime maintaining up to 87.5% under 20 A g–1 for 10,000 cycles. Meanwhile, battery–supercapacitor hybrid devices fabricated with the ZnS@CoS@NiV-LDH/NF composite and activated carbon as positive and negative electrodes achieved a remarkable energy density of 71.02 W h kg–1 at a power density of 750 W kg–1. The excellent electrochemical performance of ZnS@CoS@NiV-LDH/NF can be attributed to the synergistic effect of the composite electrode material and its core–shell structure. The ZnS@CoS@NiV-LDH/NF is extremely promising as a functional material for green energy storage.