Simple growth of mesoporous zinc cobaltite urchin-like microstructures towards high-performance electrochemical capacitors

Abstract

Novel urchin-like ZnCo2O4 microstructures have been successfully prepared through a facile two-step synthetic strategy involving a solvothermal process in a combined solution of water and ethanol, and subsequent annealing treatment of the precursor in air. These urchin-like ZnCo2O4 microspheres are composed of many porous nanorods with diameter ranging from 80 to 200 nm, achieving a specific surface area of 28 m2 g−1. The shapes of resultant ZnCo2O4 samples can be effectively controlled by changing the volume ratios of water to ethanol. The unique urchin-like ZnCo2O4 microsphere electrode delivers a high specific capacitance of 677 F g−1 at 1 A g−1 as well as a remarkable cycling stability with 107.3% capacitance retention after 5000-cycle charge-discharge process at 5 A g−1 in KOH electrolyte (2 M). The enhanced supercapacitor behavior is probably attributed to its mesoporous structure providing large reaction surface area and fast transfer for ions/electrons. It exhibits a great potential as an advanced electrode material in the field of high-performance electrochemical capacitors.