Granules of graphene oxide may be produced from a dispersion of nanoscale graphene oxide sheets by a spray drying method. Such granules have a three-dimensional corrugated morphology. The complexity of the corrugations, and the size distribution of the granules can be varied through selection of the spray-drying equipment used, and variation of the composition of the dispersion and the spray-drying parameters. Structural modifiers may be included in the graphene oxide dispersion to control the ultimate morphology of the granules. The granules of graphene oxide may be thermally reduced at a moderate temperature of 220° C. to increase the granules' electrical conductivity. The reduced granules may be used to fabricate electrodes for supercapacitors. The power and energy density of such an electrode material is comparable to those of conventional/commercial activated carbon-based electrodes.