Advantages of carbon-coated aluminum foil

During the charging and discharging process of aluminum foil, the passive layer on its surface can prevent the corrosion of electrolyte. It is often matched with positive electrode current collector materials such as LiCoO2, lithium manganese, ternary materials, and LiFePO4. However, conventional aluminum foil usually has the following limitations:

1. Aluminum foil has a certain rigidity, and the contact area with the positive electrode material in the electrode is limited, affecting the internal resistance of the positive electrode.

2. The bonding strength of aluminum foil with binders and active materials is limited. During cyclic charge and discharge, the continuous change in electrode volume causes loose particle material binding, leading to rapid decay in battery capacity and cycle life.

3. The oxidation decomposition products of the electrolyte undergo electrochemical reactions on the surface of the aluminum foil, causing and accelerating the corrosion of the aluminum foil.

Therefore, for high-end batteries, especially in the field of power batteries, the trend is to modify the aluminum foil. The main methods of aluminum foil modification are as follows:

1. Surface treatment (chemical etching, electrochemical etching, direct current anodizing, corona treatment);

2. Conductive coating (carbon coating, graphene coating, carbon nanotube coating, composite coating);

3. 3D porous structure (foam structure, nanobelt structure, nanocone structure, fiber weaving structure);

4. Composite modification treatment.

Among them, carbon coating is a commonly used modification method for aluminum foil.

Carbon-coated aluminum foil is a material used for the positive electrode current collector in lithium-ion batteries after adding a carbon coating layer on the surface of the aluminum foil. The carbon materials in the coating mainly include carbon black, graphite flakes, and graphene. After the carbon material powder is mixed with a certain film-forming agent, solvent, and additives, it is coated on the surface of the aluminum foil. After drying, a dense carbon coating layer is formed.

Compared to blank aluminum foil, carbon-coated aluminum foil improves the conductivity of the positive electrode and can reduce the internal resistance of the battery. For example, the conductivity of lithium iron phosphate itself is poor, and there is a lack of an electron-transmitting bridge between it and the aluminum foil. After the carbon coating treatment on the surface of the aluminum foil, the carbon coating layer can act as a bridge, tightly bonding the positive electrode active material to the aluminum foil, embedding the particles between each other, thereby improving the conductivity of the positive electrode, ultimately reducing the internal resistance of the battery. In addition, the carbon coating layer can make the surface of the aluminum foil evenly uneven, increasing the contact area between the active material in the electrolyte and the positive electrode current collector. Therefore, in the case of rapid charging and discharging at high current, electrons can be transferred faster, and the collection of current can be improved, which can improve the rate performance of the battery and help lithium batteries improve their efficiency and adapt to high-rate fast charging.

Its advantages are as follows:

1. Reduce the interface impedance of the current collector, lower polarization, and improve cycle life and rate performance.

2. Enhance the adhesion of the active material to the current collector, reduce the amount of binder used, and lower production cost.

3. Prevent the current collector from being corroded and oxidized, and extend the battery life.

In summary, carbon-coated aluminum foil has the advantages of increasing battery energy density, suppressing battery polarization, reducing battery internal resistance, and increasing battery cycle life. At present, it is mainly used in lithium iron phosphate batteries. In recent years, with the increasing demand for battery energy density, the market demand for carbon-coated aluminum foil has continued to grow, and currently, nearly ninety percent of power lithium batteries have adopted carbon-coated aluminum foil.

Production and processing of carbon coated aluminum foil 

The production and processing of carbon coated aluminum foil require efficient and precise machinery, such as the rotary die cutting machine. This cutting-edge equipment enables the precise cutting of carbon coated aluminum foil into various shapes and sizes, supporting the diverse needs of the new energy industry. 

The rotary die cutting machine features advanced technology, allowing for high-speed and accurate cutting, ensuring the quality and consistency of the final product. Its versatility enables the production of custom and standard shapes with efficiency and speed, meeting the demands of the rapidly evolving renewable energy sector.

Furthermore, the rotary die cutting machine plays a crucial role in optimizing the manufacturing process, enhancing productivity, and minimizing material waste. With its ability to handle large volumes of carbon coated aluminum foil, this machinery offers a sustainable and cost-effective solution for companies seeking to scale up their production while maintaining superior product quality.

In summary, the integration of a rotary die cutting machine into the production and processing of carbon coated aluminum foil presents a vital step towards advancing new energy technologies. Its precision, speed, and versatility make it an indispensable tool in meeting the growing demand for high-quality and sustainable energy solutions.