Why use aluminum foil for the positive electrode of lithium batteries and copper foil for the negative electrode?

First, copper and aluminum foil has good conductivity, soft texture and low price. Among the general materials, metal materials are the most conductive materials. Among the metal materials, copper foil and aluminum foil are cheap and conductive. Regarding winding, the pole pieces used to prepare the battery must have a certain degree of flexibility to ensure that the pole pieces do not suffer from brittleness during winding. Among the metal materials, copper aluminum foil is also a softer metal. Finally, consider the cost of battery preparation. Relatively speaking, the price of copper and aluminum foil is relatively cheap. Second, copper and aluminum foil is relatively stable in the air. Aluminum is easy to chemically react with oxygen in the air to form a dense oxide film on the surface of aluminum to prevent further reactions of aluminum. This thin oxide film also has a certain protective purpose for aluminum in the electrolyte. Copper itself is relatively stable in air, and basically does not react in dry air. The third is that the positive and negative potentials of lithium batteries determine that the positive electrode uses aluminum foil and the negative electrode uses copper foil, not the other way around. The positive electrode potential is high, the copper foil is easily oxidized under high potential, while the oxidation potential of aluminum is high, and the surface of the aluminum foil has a dense oxide film, which also has a better protection for the internal aluminum. Fourth, the positive electrode potential of lithium batteries is high, and the oxide layer of aluminum foil is relatively dense, which can prevent the current collector from oxidizing, while copper will undergo lithium intercalation reaction at high potential. Low potential, aluminum foil is easy to form aluminum-lithium alloy at low potential. Copper foil is generally used as the negative current collector, and there is no interchangeability between copper foil and aluminum foil. Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete it. Previous article: Under what circumstances will mobile phone lithium batteries explode?