Lithium ion secondary battery and a lithium ion secondary battery thickening inhibitor

PROBLEM TO BE SOLVED: To provide a manufacturing method of a positive electrode plate for lithium ion secondary batteries capable of preventing complicated processing and low yield and preventing gelation of positive electrode material slurry, in view of the problem in which: preparing the slurry so as not to show strong alkalinity during the process requires not only strict pH control but also a process in which positive electrode material is once dispersed in water and, after that, undergoes desiccation; and accordingly, these lead to the complicated processing and thus low yield.SOLUTION: A positive electrode for lithium ion secondary batteries includes: positive electrode active material which can occlude and discharge lithium ions; nitrile group-containing polymer; and binder.