▎ 摘　　要

NOVELTY - The method involves providing a first electrode and a second electrode, at least the first electrode comprises a carbon starting material having a layered structure. At least the first electrode is brought in contact with a liquid electrolyte. The liquid electrolyte comprises a salt which is a salt of a sulfonic acid or a salt of a sulfuric acid monoester, and is an ionic liquid. An electric potential is applied between the electrodes so as to exfoliate graphene from the carbon starting material. USE - Method for preparing graphene by electrochemical exfoliation to obtain electrochemically exfoliated graphene (claimed) used to prepare graphene dispersion (claimed) for manufacturing a device (claimed). Uses include but are not limited to an electronic device, an optoelectronic device, an energy-storing device or an energy-transforming device, preferably selected from an electrochemical capacitor, an alternating current line filter, a lithium ion battery, or a device containing an electrocatalyst. ADVANTAGE - Graphene can be prepared with a process which is economically efficient and provides high quality graphene which is suitable for preparing electronic, optoelectronic or energy-storing or energy-transforming devices. Generation of oxygen gas improves separation of graphene layers from the layered carbon starting material which in turn improves efficiency of the exfoliation process. The electrochemically exfoliated graphene is not only obtainable by an economically efficient and easy-to-perform method but also enables the preparation of electrochemical capacitors having surprisingly low RC time constants.