Electrode plate and surface treatment method thereof

A surface treatment method of an electrode plate, comprising the following steps:

• step 1:
• providing an electrode plate, wherein the electrode plate comprises a magnesium-aluminum alloy material layer;
• annealing the electrode plate to make a part of a magnesium element be precipitated from the magnesium-aluminum alloy material layer to form a magnesium film on a surface of the magnesium-aluminum alloy material layer;
• step 2:
• arranging the electrode plate in a closed chamber, introducing a plasma containing fluorine ions into the closed chamber and the magnesium film on asurface of the electrode plate chemically reacts with fluorine ions and form a magnesium fluoride film on the surface of the electrode plate;
• wherein in the step 2, when the magnesium film completely reacts, the magnesium film is converted into the magnesium fluoride film entirely;
• wherein in the step 1, an annealing temperature of the electrode plate is from 500° C. to 700° C., and a heat preservation time is from 30 minutes to 2 hours;
• wherein in the magnesium-aluminum alloy material layer, a content of the magnesium element is from 0.2 wt % to 2 wt %;
• wherein a thickness of the magnesium film obtained in the step 1 is from 5 to 10 μm.