In situ encapsulation of Co3O4 polyhedra in graphene sheets for high-capacitance supercapacitors

The graphene encapsulated Co₃O₄ polyhedra (rGO/Co₃O₄) exhibited large capacitance, high energy density, and excellent cycling stability, due to the 3D double conductive network from graphene sheets and porous channels of Co₃O₄ polyhedra/N-doped carbon hybrid.