Recycling process for active material of waste cathode piece of lithium ion battery

The invention discloses a recycling process for an active material of the waste cathode piece of a lithium ion battery. The key points of the technical scheme of the invention are as follows: (1) allowing a release agent to contact with the waste anode piece in the manner of spraying, drip washing, dipping or soaking, and keeping the contact state at the temperature of minus 10 to 120 DEG C for 0.1-36 hours; (2) screening or picking out aluminum foil, filtering or centrifuging the release agent mixture containing the active material, and washing to separate out the solid active material and the liquid release agent; (3) drying the solid active material at the temperature of 40-250 DEG C, adding a lithium source to the dried solid active material, and after thorough mixing, conducting three-step calcining; (4) after the three-step calcining, naturally reducing the furnace temperature, and then collecting the solid material which is the recycled cathode active material. The cathode active material recycled in the invention has the same structure, shape and composition as the material for preparing the cathode of the lithium ion battery, and the electrochemical properties of the cathode active material are stable.