A facile preparation and electrochemical properties of nickel based compound–graphene sheet composites for supercapacitors

Composites of a nickel based compound incorporated with graphene sheets (NiBC–GS) are prepared by a simple flocculation, using hydrazine hydrate as flocculant and reductant, from a homogeneous intermixture of nickel dichloride and graphene oxide dispersed in N,N-dimethylformamide. Morphology, microstructure and thermal stability of the obtained products were characterized by field-emission scanning electron microscopy, X-ray diffraction and thermal gravimetric analysis. Furthermore, the electrochemical properties of NiBC–GS, as electrode materials for supercapacitors, were studied by cyclic voltammetry and galvanostatic charge/discharge in 2 mol L−1 KOH solution. It was determined that for NiBC–GS annealed at 250 °C, a high specific capacitance of 2394 F g−1 was achieved at a current density of 1 A g−1, with 78% of the value (i.e., 1864 F g−1) retained after 5000 times of repeated galvanostatic charge/discharge cycling. The high specific capacitance and available charge/discharge stability indicate the synthesized NiBC–GS250 composite is a good candidate as a novel electrode material for supercapacitors.

Graphical abstractComposites of a nickel based compound incorporated with graphene sheets (NiBC–GS) are prepared by simple flocculation from a homogeneous intermixture of nickel dichloride and graphene oxide dispersed in dimethylformamide using hydrazine hydrate, as flocculant. A high specific capacitance of 2394 F g−1 is achieved at a current density of 1 A g−1 for NiBC–GS annealed at 250 ̊C, with 78% of the value, i.e., 1864 F g−1, retained after 5000 times of repeated galvanostatic charge/discharge cycling.Figure optionsDownload full-size imageDownload as PowerPoint slide