2D material in three dimensions

The carbon material graphene has no well-defined thickness; it merely consists of one single layer of atoms. It is therefore often referred to as a "two-dimensional material." Trying to make a three-dimensional structure out of it may sound contradictory at first, but it is an important goal: if the properties of the graphene layer are to be exploited best, then as much active surface area as possible must be integrated within a limited volume.