Influence of Ag doped CuO nanosheet arrays on electrochemical behaviors for supercapacitors

The electrode of array of CuO nanosheet is prepared via a template-free growth method, and it is doped by Ag via the silver mirror reaction. The morphology of Ag-doped CuO nanosheet is examined by scanning electron microscopy. The phase structure of the Ag-doped CuO nanosheet is analyzed by X-ray diffraction spectroscopy. The supercapacitance behavior of Ag-doped CuO nanosheet is investigated by cyclic voltammetry, galvanostatic charge/discharge test and electrochemical impedance spectroscopy. The results show that the thickness of a single nanosheet is up to around 150 nm. The specific capacitance of the Ag-doped CuO nanosheet electrode is 689 F g−1 at 1 A g−1 and 299 F g−1 at 10 A g−1, respectively, much higher than that of the unmodified CuO nanosheet arrays (418 F g−1 at 1 A g−1 and 127 F g−1 at 10 A g−1). The improved capacitance is explained in terms of the presence of dispersed Ag particle coated the CuO nanosheet arrays having good electrical conductivity.