Cathode active material for lithium rechargeable battery and lithium rechargeable battery using the same

A cathode active material for a lithium rechargeable battery is provided. The cathode active material is used for a lithium rechargeable battery containing a cathode, an anode, and an electrolytic solution. The cathode active material is composed of 0.5 % by weight or less carbonate ion (CO 3 2- ) plus bicarbonate ion (HCO 3 - ) and 0.1 % by weight or less hydroxyl ion (OH - ). The swelling of lithium battery containing the cathode active material is substantially suppressed when is placed at 60°C or more.