Figure 1: The synthesis and structure of graphene sponges.

(a) Illustration of the solvothermal conversion of ethanol-dispersed GO platelets into a graphene sponge. (b) Photographs of rectangular (left) and cylindrical (right) graphene sponges. (c) An optical image of the cup and cone structure that is observed when the graphene sponge is elongated to fracture. Scale bar, 1 cm. (d) A radial cross-sectional SEM image of a graphene sponge (scale bar, 20 μm) and a magnified SEM image (inset, scale bar, 5 μm) showing an interwall connection.