▎ 摘　　要

NOVELTY - Manufacture of expanded graphite involves (a) mixing graphite with sulfuric acid/phosphoric acid to form a mixture (M1), (b) adding potassium manganese oxide to the mixture (M1) to form a mixture (M2), (c) adding at least one iron(III) salt to the mixture (M2) under conditions to form a solid graphite-intercalated compound, (d) separating the solid graphite-intercalated compound from the mixture (M2) and (e) heating the solid graphite-intercalated compound under conditions. USE - Manufacture of expanded graphite used for forming exfoliated graphene oxide for forming graphene-based nanomaterials such as energy storage materials for portable electronic devices and electric vehicles, sensing materials and energy conversion materials (all claimed) such as electrocatalyst in water splitting applications. ADVANTAGE - The method enables energy efficient, environmentally-friendly and stable manufacture of expanded graphite without the use of any binding material. The expanded graphite foil is electrochemically exfoliated into graphene oxide in aqueous electrolyte, without the use of additional organic compounds and with reduced chemical wastes. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for manufacture of exfoliated graphene oxide, which involves (f) compressing the expanded graphite to form a flexible graphite foil, (g) immersing the flexible graphite foil in a solution comprising at least one alkali metal hydroxide and optionally at least one oxidizing agent, and applying a first voltage, (h) removing at least a portion of the flexible graphite foil from the solution, and (i) re-immersing the flexible graphite foil in the solution and applying a second voltage under conditions to electrochemically exfoliate the flexible graphite foil.