▎ 摘　　要

NOVELTY - Preparation of graphene by electrochemical exfoliation, involves: providing a first electrode E1 and a second electrode E2, where at least the first electrode E1 comprises a carbon starting material having a layered structure; bringing at least the first electrode E1 in contact with a liquid electrolyte, where the liquid electrolyte comprises an ammonium cation, and an inorganic sulfur-containing anion; applying an electric potential between the first electrode E1 and the second electrode E2 so as to exfoliate graphene from the carbon starting material. USE - The process is useful for the preparation of graphene used in preparing a layered assembly which is part of an electronic device, an optoelectronic device, a composite material, or an energy-storage (claimed). ADVANTAGE - The process provides an efficient electrochemical exfoliation process for preparing graphene at high yield and with a high content of single-layer graphene, while simultaneously keeping defect density of the prepared graphene as low as possible. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for: (1) a graphene, obtainable by the electrochemical exfoliation process; (2) a process for preparing a graphene dispersion, which involves: preparing a graphene by the electrochemical exfoliation process; and dispersing the graphene in a liquid dispersant medium; (3) a graphene dispersion, obtainable by the latter process; and (4) a process for preparing a layered assembly, which involves: preparing the graphene or the graphene dispersion; and applying the graphene or the graphene dispersion on a substrate so as to form a graphene film.