Preparation method of positive sizing agent of lithium ion battery, positive electrode sheet and lithium ion battery

The invention discloses a preparation method of a positive sizing agent of a lithium ion battery, a positive electrode sheet and the lithium ion battery. The preparation method of the positive sizing agent comprises the following step: (1), mixing an oily solvent, a water adhesive and a water solvent, and uniformly stirring so as to obtain a primary sizing agent; (2) adding a conductive agent into the primary sizing agent in the step (1), mixing and stirring uniformly so as to obtain a secondary sizing agent; and (3) adding active substances in the secondary sizing agent obtained in the step (2) so as to obtain the positive sizing agent of the lithium ion battery, wherein the weight ratio of the water solvent to the oily solvent to the water adhesive to the conductive agent to the active substances is (100-150) to (0.1-2.0) to (3-7) to (2-6) to (85-96). The positive sizing agent prepared by adopting the method disclosed by the invention is good in dispersing performance, strong in stability, and easy for dressing; the electrode sheet is good in uniformity and better than conventional oily electrode sheets in flexibility, so that the use cost of a conventional oily positive electrode is effectively reduced, the battery capacity of the lithium ion battery is increased, and the multiplying charging and discharging performances and the cycle performance of the lithium ion battery can be improved.