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@CoSg 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.