A blank suitable for use as a body of a supercapacitor comprises a first porous semiconductor volume and a second porous semiconductor volume, the second porous semiconductor volume laterally surrounded by the first porous semiconductor volume and separated from it by a trench that is suitable for receiving an electrolyte, whereby the first and second porous semiconductor volume comprise channels opening to the trench. A supercapacitor comprises a body formed by using the blank according to any one of the preceding claims, so that the first porous semiconductor volume acts as one electrode and the second porous semiconductor volume acts as another electrode, with an electrolyte in the trench.