We have successfully assembled graphene nanosheets into spherical shells using polystyrene spheres as templates. Compared with stacked planar graphene, the as-prepared graphene spherical shells have more free space in between the spheres, which results in a larger accessible surface area for adsorption of electrolyte ions in supercapacitors. Electrochemical tests show that the graphene hollow spheres exhibit a high specific capacitance of 273 F g−1 and excellent electrochemical stability.
