▎ 摘　　要

NOVELTY - Preparation of lithium ion battery composite separator involves mixing 1-50 mg/mL, preferably 1 mg/mL aqueous graphene oxide solution and 1-5 mg/mL, preferably 1 mg/mL nanocellulose aqueous solution in a mass ratio of 1-5:1, preferably 1:5, adding ion conductive polymer, mixing to obtain polyolefin membrane, modifying to obtain polyolefin-based separator modification layer, and drying in dry box. The total concentration of aqueous graphene oxide solution and nanocellulose aqueous solution is 5-30 %mass. The number of layers of graphene oxide is 1-5 layers. The nanocellulose is derived from natural wood pulp plant fibers, and has average particle diameter (D50) of 25 nm. The ion conductive polymer is polyvinylpyrrolidone, polyvinyl alcohol, polyethylene glycol, carboxymethyl cellulose, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, polyacrylamide, polyacrylic acid, polymaleic anhydride and/or polyquaternium. USE - Preparation of lithium ion battery composite separator. ADVANTAGE - The method enables simple, convenient and economical preparation of separator having excellent wettability, ion conductivity, safety, and charge and discharge cycle characteristics. The separator effectively inhibits the growth of lithium metal dendrites in lithium ion batteries.