▎ 摘　　要

NOVELTY - Preparing lithium-ion battery composite separator comprises ultrasonically dispersing graphite oxide in ethanol, and adding a reducing agent and a binder to obtain a graphene oxide hydrogel. The hydrogel is coated on the surface of the base film. The separator is placed in an oven at 50°C for 1 hour to evaporate the solvent to obtain the lithium-ion battery composite separator. USE - Method for preparing lithium-ion battery composite separator used in consumer electronic product and electric vehicle. ADVANTAGE - The composite separator has better wettability compared with the polyolefin-based separator electrolyte, and improved ionic conductivity, where the characteristic structure of graphene hydrogel molecules can improve the high temperature shrinkage resistance of the separator and optimize the thermal stability of the separator. The prepared separator has a contact angle of ≤ 11°, an ion conductivity of ≤ 0.6 ms.cm-1at 160℃, a thermal shrinkage rate in the machine direction and transverse direction (MD/TD) direction of 4%, a closed cell temperature of ≤ 134℃, and a membrane rupture temperature of ≥ 159℃.