Treatment process for a positive electrode active material for lithium-ion secondary battery

A treatment process for a positive electrode active material for a lithium-ion secondary battery, comprising:

• cleaning a positive electrode active material for the lithium-ion secondary battery by a cleaning fluid containing ammonia,
• separating the cleaning fluid to solid and liquid,
• calcining a solid component at 600° C. to 700° C. in an oxygen atmosphere,
• cleaning another positive electrode active material for the lithium-ion secondary battery by a new cleaning fluid with a recovered liquid separated at said separating of the cleaning fluid,
• separating the new cleaning fluid to solid and liquid again, and
• calcining a solid component separated from the new cleaning fluid at 600° C. to 700° C. in an oxygen atmosphere,
• wherein the new cleaning fluid has a conductivity of 11.6 mS/cm or less,
• the positive electrode active material for the lithium-ion secondary battery treated is used as a positive electrode material of the lithium-ion secondary battery,
• a discharge capacity of 4.25 V to 3.5 V of the lithium-ion secondary battery is 99% or above relative to a discharge capacity before being cleaned,
• a quantity of the positive electrode active material to be cleaned is 30-50% by weight relative to a quantity of the cleaning fluid, and
• the positive electrode active material becomes a slurry in the cleaning fluid, and after being stirred in a slurry state, the positive electrode active material is left still as it is for 20 minutes to one hour at a room temperature to approximately 30° C.