Metal–organic framework derived hierarchical zinc nickel selenide/nickel hydroxide microflower supported on nickel foam with enhanced electrochemical properties for supercapacitor

As a kind of electrode materials, zeolite imidazole frameworks have attracted extensive interest for supercapacitor in virtue of its high porosity, large specific surface area and structural diversity. Herein, a novel composite Zn–Ni–Se/Ni(OH)2 hierarchical microflower composed of looser and corrugated nanosheets has been successfully fabricated with coprecipitation and an uncomplicated two-step hydrothermal method utilizing zeolite imidazole frameworks-8 as precursor. The resultant Zn–Ni–Se/Ni(OH)2-based electrode exhibits markedly improved electrochemical properties with a specific capacitance of 1632.8 F g−1 at 2 A g−1 and superior cycling stability (85.4% of the initial retention after 2000 cycles at 6 A g−1), which are superior to those of Zn–Ni–Se and Ni(OH)2 electrodes. The enhanced performance of Zn–Ni–Se/Ni(OH)2 composite is attributed to the synergistic contributions from Zn–Ni–Se and Ni(OH)2 materials together with the superior properties of specific hierarchical microflower structure. This work provides a meaningful guidance for designing and preparing other composites with distinctive morphologies for pseudocapacitor application.