Abstract: A current collector structure includes a metal foil substrate and a graphene conductive layer provided on at least one surface of the metal foil substrate. The graphene conductive layer includes a plurality of graphene sheets and a polymer binder used to bind the graphene sheets together and to adhere the graphene sheets onto the metal foil substrate. The conductive layer has a thickness of 0.1 ?m to 5 ?m and a resistance less than 1 ?-cm. The polymer binder increases the adhesion force, such that the integrated conductive network is thus formed. Since the polymer binder is well compatible with the binder as the active material contained in the electrochemical element. The active material of the electrochemical element is thus tightly bound with the graphene conductive layer so as to minimize the contact resistance and greatly improve the performance of the electrochemical element.

Abstract: A graphene ink includes a dispersion solution with a surface tension between 35 and 55 mJ/m2, a polymer binder dissolved in the dispersion solution to form a colloidal solution, and a plurality of graphene sheets dispersed in the colloidal solution with a suspension concentration of 0.1˜5 wt %. The graphene ink has a viscosity less than 100 cp and a surface potential greater than 30 mV or less than ?30 mV. The graphene ink is first prepared and then processed by the steps of masking, spraying, solidifying and removing so as to form a graphene pattern by patterning the graphene ink on an electrical insulation substrate.