Hydrogen halide-promoted construction of 3D graphene aerogels

Three-dimensional (3D) graphene aerogels were fabricated from graphene oxide using HBr, HCl and HI as promoters. The structures and properties of the aerogels were characterized by scanning electron microscopy, X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy and thermal gravimetric analysis. It was found that 3D graphene aerogels can be made in the presence of HI. Their formation is promoted by the synergistic effects of the acidic H⁺ and the reductive I^-. The electrical conductivity and thermal stability of the aerogels were significantly improved compared with those of graphene oxide. When the aerogels were used as supercapacitor electrodes, excellent specific capacitance and rate capability were achieved.