Abstract: The invention relates to an electrode, to the method for manufacturing same and to a device for storing and delivering electric power including same. The electrode of the invention includes a mounting, made of a conductor or semiconductor material, the mounting including, on at least one of the surfaces thereof, at least one nanostructure made of a semiconductor material, characterized by also including a protective layer made of a material selected among a dielectric material having an intrinsic capacity of 1.5 10?6 to 10 10?6 F/cm2 and a metal, the layer having a thickness that is less than the height of said nanostructure, and covering the at least one nanostructure. The invention is useful in the field of electrochemical storage and, in particular, in the field of ultracapacitors.