Why do lithium batteries use copper foil as the anode current collector?

Why do lithium batteries use copper foil as the anode current collector?

The lithium battery utilizes lithium ions stored in the positive electrode material and electrons to reversely move during charging and discharging to achieve normal operation. The main structures are a positive electrode, a negative electrode and an electrolyte. In addition to the main four parts, the current collector for storing the positive and negative materials is also an important component of the lithium battery. Its main function is to collect the current generated by the battery active material to form a larger current for external output.

According to the working principle and structural design of the lithium ion battery, the positive and negative materials should be coated on the conductive current collector, so the current collector should be in full contact with the active material, and the internal resistance should be as small as possible.

Copper foil and Aluminum Foil have good conductivity, have formed oxidized protective film, soft texture is favorable for bonding, mature manufacturing technology and relatively low price, so they are selected as the main material of lithium battery current collector.

The positive electrode potential of the lithium battery is high, the oxide layer of the aluminum foil is relatively dense, and the current collector can be prevented from being oxidized, and the lithium intercalation reaction occurs at a high potential, the copper foil is not suitable for positive current collector , so the positive current collector is generally made of aluminum foil.

The potential of the negative electrode is low, the aluminum foil is easy to form an aluminum-lithium alloy at a low potential, and the negative electrode current collector is generally made of copper foil, and the copper foil and the aluminum foil do not have interchangeability.