Carbon Coated Copper Foil

The first step is the extraction and refining of copper. After the extraction of copper ore, through steps like crushing, grinding, and flotation, copper concentrate with about 30% copper content can be obtained. These copper concentrates then undergo a refining process, including smelting, converter refining, and electrolysis, ultimately yielding electrolytic copper with a purity as high as 99.99%.

Next comes the manufacturing process of copper foil, which can be divided into two types depending on the manufacturing method: Electrolytic copper foil and rolled copper foil.

Electrolytic copper foil is made through an electrolytic process. In an electrolytic cell, the copper anode gradually dissolves under the action of the electrolyte, and the copper ions, driven by the current, move towards the cathode and form copper deposits on the cathode surface. The thickness of electrolytic copper foil usually ranges from 5 to 200 micrometers, which can be precisely controlled according to the needs of printed circuit board (PCB) technology (Yu, 1988).

Rolled copper foil, on the other hand, is made mechanically. Starting from a copper sheet several millimeters thick, it is gradually thinned by rolling, eventually producing copper foil with a thickness at the micrometer level (Coombs Jr., 2007). This type of copper foil has a smoother surface than electrolytic copper foil, but its manufacturing process consumes more energy.

After the copper foil is manufactured, it usually needs to undergo post-processing, including annealing, surface treatment, etc., to improve its performance. For instance, annealing can enhance the ductility and toughness of copper foil, while surface treatment (such as oxidation or coating) can enhance the corrosion resistance and adhesion of copper foil.