A porous body with a framework having an integrally continuous, three-dimensional network structure, the framework comprising an outer shell and a core including one or both of a hollow or a conductive material, the outer shell including nickel and cobalt, the cobalt having a ratio in mass of 0.2 or more and 0.4 or less or 0.6 or more and 0.8 or less relative to the total mass of the nickel and the cobalt.