1) Surface treatment (chemical etching, electrochemical etching, DC anodizing, corona treatment);
2) Conductive coating (surface coating carbon, graphene coating, carbon nanotube coating, composite coating);
3) 3D porous structure (foam structure, nanobelt structure, nano cone mechanism, fiber weaving mechanism);
4) Composite modification treatment.
Among them, carbon coating on the surface is a common modification method for aluminum foil.
Carbon-coated aluminum foil is a material used for the positive electrode collector of 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 prepared into a slurry with a certain film-forming agent, solvent, and auxiliary agent, it is coated on the surface of the aluminum foil, and a dense carbon coating layer is formed after drying.
Modification method of aluminum foil
Compared with blank aluminum foil, carbon-coated aluminum foil improves the conductivity of the positive electrode sheet 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 a bridge for electron transmission between the aluminum foil and the aluminum foil. Tightly bonded, the particles are embedded in each other, which improves the conductivity of the positive electrode sheet and ultimately reduces the internal resistance of the battery.
In addition, the carbon coating can make the surface of the aluminum foil uniform and uneven, and increase the contact area between the active material in the electrolyte and the positive electrode current collector, so that electrons can be transferred faster and current can be collected during high-current rapid charge and discharge, which can improve the performance of the battery. The high-rate charge and discharge performance help lithium batteries to improve their use efficiency and adapt to high-rate fast charging.
