Starfish-shaped Co3O4/ZnFe2O4 Hollow Nanocomposite: Synthesis, Supercapacity, and Magnetic Properties.

A novel starfish-shaped porous Co3O4/ZnFe2O4 hollow nanocomposite was fabricated for the first time by a facile and stepwise hydrothermal approach, utilizing metal-organic frameworks as precursors and sacrificial templates. The morphology evolution in the synthetic process upon reaction time and amount of raw materials were investigated in detail. The as-synthesized starfish-shaped porous Co3O4/ZnFe2O4 composites were studied as an electrode material for supercapacitors showing good capacitive performances. Their specific capacitance can reach as high as 326 F g(-1) at 1 A g(-1). The rational combination of components with different potential windows in a composite material enables a wide overall potential range resulting in the highest energy density of 82.5 Wh kg(-1), significantly larger than that of the single components. Magnetic measurements show that the system presents a large coercivity and high squareness (at 1.8 K, Hc = 884 Oe and Mr/Ms = 0.52) with respect to the individual components, which may be attributed to the unique morphology of Co3O4/ZnFe2O4, as well as surface and interface exchange coupling effects. Materials with this novel design and fabrication may show promise for potential applications in electrochemical energy storage and magnetic devices.