NOVELTY - The method involves peeling a positive electrode active material from a positive electrode substrate by immersing a battery dismantling object obtained by dismantling a lithium ion battery in a surfactant solution, and stirring the lithium ion battery by a stirring media. Concentration of the surfactant solution is in a range of 1.5 to 10 weight percent, where the surfactant is nonionic surfactant that comprises polyoxyalkylene ether group, and time for a stirring process is made into more than 1 hour.    USE - Method for peeling a positive electrode active material from a positive electrode substrate e.g. positive electrode foil such as aluminum foil, to collect a valuable metal e.g. nickel, cobalt and lithium, from a lithium ion battery utilized in an electric equipment e.g. digital camera and mobile telephone, and as a power supply for a motor vehicle and a small household appliance, and as a backup power supply for a computer.    ADVANTAGE - The positive electrode active material is peeled from the positive electrode substrate by immersing the battery dismantling object obtained by dismantling the lithium ion battery in the surfactant solution, and stirring the lithium ion battery, thus reducing the valuable metal contained in the positive electrode active material and eluting the positive electrode active material of the lithium ion battery in a solution, and hence eliminating collection loss of the valuable metal by peeling the positive electrode active material in an effective manner.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for a method for collecting a valuable metal from a lithium ion battery.    DESCRIPTION OF DRAWING(S) - The drawing shows a flow diagram illustrating a process of a method for collection of a valuable metal from a lithium ion battery.'(Drawing includes non-English language text)'    Crushing/pulverization process (S1)    Washing process (S2)    Positive electrode active material peeling process (S3)    Neutralization process (S5)    Sulfuration process (S6)