Preparation method of precursor with high specific surface area and large tap density

The invention belongs to the technical field of battery materials, and discloses a preparation method of a precursor of a lithium ion battery positive electrode material with high specific surface area and high tap density. The process of preparing the precursor through coprecipitation is carried out in three stages, a nickel-cobalt-manganese mixed metal salt solution, a precipitator solution and a complexing agent solution are added into a reaction kettle base solution in a parallel flow mode, and a first-stage reaction is carried out; after the reaction of the first stage is finished, immediately entering a second stage, increasing the flow of the nickel-cobalt-manganese mixed metal salt solution on the basis of the first stage, and simultaneously adding an oxidant solution in a parallel flow manner; after the reaction in the second stage is finished, immediately entering a third stage; and on the basis of the second stage, the flow of the nickel-cobalt-manganese mixed metal salt solution is increased, and