Direct determination of graphene amount in electrochemical deposited Cu-based composite foil and its enhanced mechanical property

The amount of graphene (Gr) in a composite plays a key role in enhancing the performance of the composite. In general, an indirect method, that is, by adjusting the concentration of Gr (or GO) in the electrolyte, is used to study the influence of the graphene content on the properties of copper (Cu)-Gr composite foil. In this paper, we firstly propose a direct and accurate approach, that is, by using an instrumental carbon and sulfur analyzer, to determine the amount of Gr in the direct current electrodeposited Cu-Gr composite foil, and also obtain the relationship between the amount of Gr in the composite foils and the concentration of GO in the electrolyte. Further, mechanical property measurements reveal that: (1) the variations in the mechanical properties (involving the elastic modulus, hardness and tensile strength) of the Cu-Gr foils along with the concentration of GO in the electrolyte exhibit similar tendencies to that of the Gr content in the Cu-Gr foils. (2) According to current experimental conditions, the optimal values of the mechanical properties and the amount of Gr in the foils appears at a GO concentration of 0.5 g L-1 in the electrolyte. (3) When the GO concentration is less than 0.5 g L-1, the values of the mechanical properties and the amount of Gr in the foils present an approximately linear relationship; and beyond 0.5 g L-1, the values become unstable and declining, which can be attributed to an agglomeration of excess GO in the electrolyte which makes it difficult to be co-deposited into the foil.