Preparation and Supercapacitors Performances of Nickel-Cobalt Layered Double Hydroxides Microspheres with Flower-Like Patterns

Using SiO 2 @ AlOOH as hard template and adding nickel-cobalt precursor and alkali source in ethanol and water( V( CH 3 CH 2 OH) ∶ V( H 2 O) = 9 ∶ 1). Nickel-cobalt layered double hydroxides microspheres( NiCo-LDHM) with flower-like patterns structure were successfully synthesized by hydrothermal synthesis method. The scanning electron microscope( SEM),transmission electron microscope( TEM) and electrochemical workstation were employed for the characterizations of the composite. The results indicated that the microspheres fabricated with nanosheets with the thickness of about 10 nm as in situ formed building units present a porous structure,and have an average size of about 2. 5 μm. Its maximum specific capacitance was found to be 1 108. 8 F / g at current density of 1 A / g,which is obviously higher than that of common nickel-cobalt layered double hydroxides( 710. 5 A / g). The specific capacitance can remain at 700. 5 F / g when the current density increases to 7 A / g. After galvanostatic charge-discharge 1 500 cycles,the specific capacitance can keep at more than 94. 5%,indicating that the composite shows excellent supercapacitor performances.