Flake graphite has a layered structure constituting carbon atoms in a hexagonal lattice. Each planer layer constitutes carbon atoms with sp2 configuration, each carbon atom is bonded to three other carbon atoms via covalent bonds, leaving one free electron each. These planer sheets, one sheet is called graphene, are weakly bonded via Van der Waals force giving the flaky nature to the material. Given these molecular characteristic, flake graphite is a material with a unique set of properties, making it the preferred and mostly non-repalceable choice in various industries, products and applications. Though it is a non-metal, it has unique properties of both metals and non-metals.
Given the above two properties, flake graphite is the only known material occurring in a free-flowing powder which is also a good conductor, making it the material of choice in various applications, including energy storage.