▎ 摘　　要

NOVELTY - Preparing acrylic multi-element copolymer i.e. octane-2,4,6-tricarboxylate derivative (I) comprises (i) mixing emulsifier into deionized water to obtain emulsion A, placing in three-necked flask equipped with a stirrer, a nitrogen flow device and a temperature controller, (ii) adding initiator into acrylate monomer mixture to obtain emulsion B, adding emulsion B into emulsion A to obtain emulsion C, (iii) stirring the emulsion C, performing ultrasonic cell pulverization under ice-water bath, taking it out cooling to room temperature to obtain a monomer miniemulsion, (iv) passing in nitrogen to exhaust oxygen, carrying out polymerization reaction, then adding hydroquinone, adjusting the pH and obtaining a uniform and stable acrylic multi-element copolymer emulsion, (v) taking acrylic multi-element copolymer emulsion for demulsification precipitation to obtain the copolymer solids, filtering, washing the copolymer solids with methanol, drying to obtain final product. USE - (I) is useful as additive in positive pole piece (claimed). ADVANTAGE - The acrylic acid multi-element copolymer and its preparation method and its application in the positive pole piece can improve the bonding effect between the carbon-coated anode active material, the binder and the conductive agent, improve the safety performance and electrical performance of lithium batteries. DETAILED DESCRIPTION - Preparing acrylic multi-element copolymer i.e. octane-2,4,6-tricarboxylate deroivative formula (I) comprises (i) adding emulsifier into deionized water and mixing to obtain emulsion A, placing the emulsion A in a three-necked flask equipped with a stirrer, a nitrogen flow device and a temperature controller, (ii) adding initiator into R1, R2 and R3-containing acrylate monomer mixture to obtain emulsion B, adding emulsion B dropwise into emulsion A through a constant pressure dropping funnel to obtain emulsion C, (iii) stirring the emulsion C, performing ultrasonic cell pulverization under ice-water bath conditions, taking it out and allowing it to stand to return to room temperature to obtain a monomer miniemulsion, (iv) passing in nitrogen to exhaust oxygen, heating in a constant temperature water bath to initiate the polymerization reaction, completing the reaction, adding hydroquinone, adjusting the pH value to 7 and obtaining a uniform and stable acrylic multi-element copolymer emulsion, (v) taking the acrylic multi-element copolymer emulsion for demulsification precipitation to obtain the copolymer solids, after filtration, washing the copolymer solids with methanol, then drying the obtained copolymer solids at room temperature and vacuum to a constant weight to obtain final product. R1 = linear alkylene, branched alkylene or 5-22C alkyl structure; R2 = amino group or H; R3 = fluoroalkane; and x, y and z = 0-10,000,000. Provided that: x, y, and z are not 0 at the same time. An INDEPENDENT CLAIM is also included for: (1) (I) prepared by above method; (2) positive pole piece, where the positive pole piece comprises a positive current collector, the anode current collector is coated with anode slurry, the concentration of anode slurry is 92-98 wt.% positive active material, 0.5-2 wt.% conductive agent, 1-10 wt.% binder and additives, the total mass of the agent and the additive is 100% and the concentration of the binder and the additive is 70-90:10-30%, where the additive is (I); and (3) method for preparing a positive pole piece, comprising (a) mixing the binder with the solvent, stirring at 500-1000 revolutions/minute for 2-5 hours at 25-60 degrees C and making the glue liquid with 10-15% solid content, (b) adding the anode active material, the conductive agent, and the additives into the stirring tank in order, stirring for 0.1-0.5 hours to obtain the mixture A, (c) adding the glue solution to the mixture A, stirring for 0.5-1 hours at a stirring speed of 500-1000 revolutions/minute and stirring at 25-40 degrees C to obtain a mixture B, (d) adding a solvent into the resulting mixture B to adjust the solid content to 60-65%, stirring for 1-3 hours at a stirring speed of 500-1000 revolutions/minute to obtain a mixture C, (e) testing the viscosity of mixture C, stirring at 2000-4000 revolutions/minute for 0.5-1 hours if the viscosity is between 8000-12000 mPa.s, adding a solvent if the viscosity is higher than 12000 mPa.s to dilute it until the viscosity of the mixture C is 8000-12000 mPa.s, mixing, finally, stirring at 1000-2000 revolutions/minute for 0.5-1 hour under vacuum conditions, where the vacuum condition is that the degree of vacuum is -0.1 to -0.01 Mpa to obtain the anode slurry of the lithium ion battery and (f) uniformly coating the prepared anode slurry on the anode current collector with a doctor blade, drying in a blast drying oven at 80-120 degrees C, finally, rolling the dried anode current collector and cutting to form a positive pole piece.