What is coating Dark streaks? and how to avoid it?

Dark streaks occur due to uneven thickness of the coating on the surface of the electrode during the coating process, resulting in color differences and appearing as dark streaks in the visual appearance. The uneven thickness can be caused by two main factors:

(1) Foreign objects or irregularities on the blade edge(Slot die edge) during the coating process, leading to uneven thickness on the surface of the electrode.

(2) Linear traces that occur before or after the roller press. This can be attributed to particles that were not cleared from the blade edge(Slot die edge) or small dried slurry material stuck on the blade edge(Slot die edge).