Heterogeneous nucleation and growth of interlaced CuO nanosheets on porous nickel foams as binder-free electrode material

Abstract

The monoclinic CuO has a natural tendency to grow into sheet-like structures from alkaline solutions without the need for any specialized reaction conditions or structural directing agents. We demonstrate this growth habit of CuO by heterogeneously nucleating it onto Ni foam substrate from just the ammonical solutions of Cu salts. The growth kinetics were found to be fast and, dense, interlaced thin films with an average sheet width of 20 nm can be grown by simply controlling the degree of supersaturation of the solution. Strongly adhered films with thicknesses up-to 5 μm were deposited from three different Cu salt solutions. Due to faster growth kinetics, growth time has little effect on both the film and nanosheet thickness. Detailed structural and compositional characterizations of the CuO nanosheets were made using FESEM, HRTEM, SAED, XRD and, XPS. The utility of the grown CuO nanosheets is demonstrated as a ready to use electrode for electrochemical supercapacitors. Specific capacitance in excess of 498 F/g was calculated from the Galvanostatic charge–discharge measurements collected at a current density of 0.5 A/g.

Keywords

• Crystal growth
• Super saturation
• Nanosheets
• Thick films
• Aqueous chemical growth