Graphene Supported Ni-based Nanocomposites as Electrode Materials with High Capacitance

• Ni based/graphene materials are prepared with a facile hydrothermal method.
• 15%Ni(OH)2/graphene shows the highest specific capacitance of 2077 Fg-1.
• 15%Ni/graphene by calcined 15%Ni(OH)2/graphene has a low capacitance of 633 Fg-1.
• The capacitance of 15%Ni(OH)2/graphene is 965 Fg-1 after 500 cycles at 50 mVs-1.

The Ni-based/graphene materials were synthesized by a simple hydrothermal method, using the graphene oxide as the support precursor. The textural and structural properties of the as-prepared Ni-based/graphene samples were fully characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, thermalgravimetric analysis and Fourier transform infrared spectroscopy, respectively. Electrochemical properties were examined by cyclic voltammetry, electrochemical impedance spectroscopy and cyclic charge-discharge tests. The results showed that the 15%-β-Ni(OH)2/graphene had the high specific capacity of 2077 F g−1 at 5 mV s−1 in the range of 0.0–0.7 V (vs. Ag/AgCl) and had a good cycle life with 965 F g−1 after 500 cycles at 50 mV s−1.

All the Ni-based graphene materials show a relatively high capacitance at the scan rate of 5 mV s−1. 15%Ni(OH)2/graphene shows the highest specific capacitance of 2077 F g−1 and 15%Ni/graphene by calcined 15%Ni(OH)2/graphene has a low capacitance of 633 F g−1. The cycle-life tests of β-Ni(OH)2 and Ni-based/graphene materials were conducted by 500 cycles between 0.0 and 0.7 V at a scan rate of 50 mV s−1. The capacitance of 15%Ni(OH)2/graphene is 965 F g−1 after 500 cycles.Figure optionsDownload as PowerPoint slide