Pole piece, lithium ion battery and preparation method

The invention belongs to the field of batteries, and particularly relates to a pole piece, a lithium ion battery and a preparation method. The pole piece comprises a current collector and active substance layers arranged on the two sides of the current collector. The active material layer comprises two layers, namely a first active layer close to the current collector and a second active layer far away from the current collector; the particle size of the first active material is smaller than that of the second active material; the proportion of the first binder in the first active layer is greater than that of the second binder in the second active layer; according to the design of the pole piece, the binding power of the pole piece is improved through the high binder content of the first active layer, the diameter of the capillary tube on the upper layer of the pole piece is increased through the large-particle active substance of the second active layer, the pressure of the capillary tube liquid level is re