Lithium-ion cells are not immune to corrosion, which can affect their performance and lifespan.
One of the critical components of a lithium-ion cell is the current collector, which is typically made of copper or aluminum. The current collector's main function is to conduct electrons between the battery's electrodes and the external circuit. However, corrosion of the current collector can lead to a decrease in conductivity and, ultimately, battery failure.
Corrosion of the current collector can occur due to several factors, including exposure to moisture, oxygen, and acidic electrolytes. Moisture can seep into the battery through the seals or vents, leading to the formation of oxides on the surface of the current collector. Similarly, oxygen can react with the metal to form metal oxides, which can also reduce conductivity. In acidic electrolytes, the metal can dissolve, leading to the formation of metal ions and ultimately, corrosion.
To mitigate the effects of corrosion on the current collector, several strategies are employed in the design of lithium-ion batteries. One common approach is to use surface coatings that provide a barrier between the metal and the surrounding environment. For example, a thin layer of polymer or ceramic can be applied to the current collector to protect it from moisture and oxygen.