The invention relates to a pole piece and a lithium ion battery. The pole piece comprises a body and a ceramic coating. The body has a first surface and a second surface, which are opposite to each other; at least one of the first surface and the second surface is laminated by the ceramic coating; and the thickness of the ceramic coating protruding from the first surface and/or the second surfaceis 10 micrometers-100 micrometers. The ceramic coating acts as a diaphragm between positive and negative pole pieces, so that there is no need to provide the diaphragm between the positive and negative pole pieces, and diaphragm-free winding can be carried out; the ceramic coating, serving as the diaphragm between the positive and negative pole pieces, has excellent heat resistance and strong wetting electrolyte performance, and has uniform porosity distribution, thereby helping to improve thermal stability and cycle life of the prepared battery; and since the thickness of the ceramic coatingprotruding from the first surface and/or the second surface is 10 micrometers-100 micrometers, when in the thickness range, the ceramic coating is better in heat resistance and wetting electrolyte performance, and in the thickness range, the porosity distribution is uniform.