Bulk scale growth of CVD graphene on Ni nanowire foams for a highly dense and elastic 3D conducting electrode

A new and simple method to prepare three-dimensional (3D) graphene foams is developed. It uses 3D Ni nanowire foams as a catalyst for chemical vapor deposition (CVD). Ni nanowires were synthesized on a large scale by the reduction of Ni ions under an applied magnetic field, and then assembled into a 3D film by filtrating a bulk Ni nanowire solution or by pressing Ni nanowire powder. An additional CVD process was conducted to develop graphene on the 3D Ni nanowire foam at 670 °C, which is considerably lower than the conventional growth temperatures of around 1000 °C. The resulting 3D graphene exhibited higher electrical conductivity (17.5 S/cm) as well as a higher specific surface area (145 m2/g) due to its highly dense and interconnected structure, with pores on the order of several microns. The 3D graphene foam also exhibited excellent electrical and mechanical properties under repeated mechanical deformations (stretching, bending and folding), demonstrating their potential for use in such applications as the electrodes in wearable devices and electrochemical catalysts.