Structure-directed synthesis of bimetallic ZIF-67 LDH nanocomposites for high-performance supercapacitors†

Abstract

The energy storage ability of a device highly depends on the morphology of the materials used. A structure-directing agent (SDA) can be used to design materials with a specific surface morphology. Zeolite imidazole (ZIF-67) is a favorable electroactive material for energy storage devices. Here, we present a novel approach for synthesizing a ZIF-67 derived NiCo layer double hydroxide hollow surface sheet like morphology, in which potassium fluoroborate acts as a SDA. The hollow sheets possess the largest specific capacitance of 1171 F g⁻¹ at 1 A g⁻¹. The energy storage device composed of ZIF-67 derivatives and a carbon electrode presents a maximum energy density of 26 W h kg⁻¹ at a power density of 804 W kg⁻¹. The device shows good cyclic stability of 84% after 10 000 charge–discharge cycles. These outcomes reveal the promising potential of zeolite imidazole (ZIF-67)-based materials for use in next-generation energy storage devices.