▎ 摘　　要

NOVELTY - The preparation method of controllable graphene layers involves: (1) taking expanded graphite as a cathode and an anode, applying bidirectional alternating pulse voltage between cathode and anode, and carrying out electrolysis using acidic electrolyte to obtain an agglomerated graphene oxide mixed solution; (2) adding industrial vitamin C, and reducing the group on the surface of graphene; and (3) separating the solid product in the previous step and cleaning to obtain graphene product. USE - The method is useful for preparing controllable graphene layers. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for controllable graphene layers, where the number of graphene layers is controlled at 1-10 layers.