Controlled Synthesis of Flower-like Hierarchical NiCo-Layered Double Hydroxide Integrated with Metal-Organic Framework-Derived Co@C for Supercapacitors

Layered double hydroxides (LDHs) have come to the foregroundrecently,considering their unique layered structure and short ion channelswhen they act as electrode materials for supercapacitors (SCs). However,due to their poor rate and cycle performance, they are not highlysought after in the market. Therefore, a flower-like hierarchicalNiCo-LDH@C nanostructure with flake NiCo-LDH anchored on the carbonskeleton has emerged here, which is constructed by calcination andhydrothermal reaction and applying flake ZIF-67 as a precursor. Inthis structure, NiCo-LDH grows outward with abundant and homogeneouslydistributed Co nanoparticles on Co@C as nucleation sites, forminga hierarchical structure that is combined tightly with the carbonskeleton. The flower-like hierarchical nanostructures formed by thecomposite of metal-organic frameworks (MOFs) and LDHs havesuccessfully enhanced the cycle and rate performance of LDH materialson the strength of strong structural stability, large specific surfacearea, and unique cooperative effect. The NiCo-LDH@C electrode displayssuperb electrochemical performance, with a specific capacitance of2210.6 F g(-1) at 1 A g(-1) and 88.8%capacitance retention at 10 A g(-1). Furthermore,the asymmetric supercapacitor (ASC) constructed with NiCo-LDH@C//RGOreveals a remarkable energy density of 45.02 W h kg(-1) with a power density of 799.96 W kg(-1). This projectaims to propose a novel avenue to exploit NiCo-LDH electrode materialsand provide theory and methodological guidance for deriving complexstructures from MOF derivatives.

Automated summary

A flower-like hierarchical NiCo-LDH@C nanostructure has been successfully constructed, with flake NiCo-LDH anchored on the carbon skeleton. This structure, formed by the composite of MOFs and LDHs, exhibits enhanced cycle and rate performance, contributing to its strong structural stability, large specific surface area, and unique cooperative effect.