Method for producing positive electrode slurry, positive electrode, secondary battery, and electrochemical device

The invention relates to a manufacturing method of positive electrode slurry, which comprises the following steps: adding lithium iron phosphate, a conductive agent, a binder and a first part of solvent into a first stirring module of double-screw stirring equipment, and stirring to obtain first stirred slurry; the first part of solvent contains NMP; introducing the first stirring slurry into a second stirring module of the double-screw stirring equipment, and adding a positive electrode additive and a second part of solvent for high-solid-content kneading to obtain second stirring slurry; wherein the second part of solvent contains NMP, the second stirring module contains at least 2-6 stirring sub-modules, and the positive electrode additive simultaneously contains a polar group and a non-polar group; and S3, introducing the second stirring slurry into a third stirring module of the double-screw stirring equipment, adding a third part of solvent, and carrying out slurry stretching dispersion to obtain the po