Negative electrode plate, preparation method thereof and electrochemical device

A method for preparation of a negative electrode plate, comprising the steps of:

• disposing a negative active material layer on at least one surface of a negative current collector;
• said negative active material layer comprises opposite first surface and second surface, wherein said first surface is disposed away from the negative current collector;
• and
• disposing an inorganic dielectric layer on the first surface of the negative active material layer by vapor deposition,
• wherein said inorganic dielectric layer comprises first dielectric layer and second dielectric layer;
• the first dielectric layer is located on an outer surface of the negative active material layer and has a thickness T1 of 30 nm≤T1≤1000 nm;
• the second dielectric layer is located on an inner wall of at least a portion of pores inside the negative active material layer and has a thickness T2 of 0 nm<T2≤500 nm,
• the second dielectric layer extends in the thickness direction from the first surface to the second surface;
• and extension depth H and the thickness T1 of the first dielectric layer satisfy:
• 0.5≤H/T1≤5.