The invention provides a PVDF-coated
lithium-
ion battery separator and a preparation method thereof. The PVDF-coated
lithium-
ion battery separator comprises a base film and a
coating, wherein the
coating coats a single side or double sides of the base film; the
coating is obtained by coating and
drying slurry; and the coating is 0.1-0.5 micron in thickness and contains evenly arranged PVDF spherical particles. According to the PVDF-coated
lithium-
ion battery separator, a traditional technology that an existing PVDF-coated lithium-ion battery separator takes oil substances of
acetone and the like as solvents is abandoned. Water is adopted as the
solvent of a PVDF material; and no a
thickening agent is added, so that the low-
viscosity water-based PVDF coating
slurry is obtained; an ultra-thin coating of which the PVDF particles are regularly arranged and which is relatively loose is obtained after the
slurry is coated; the ultra-thin coating improves the
hardness of a
pole piece and the effective utilization space of the battery when effectively bonded to the lithium-ion battery separator and the
pole piece; and the ventilation loss caused by the thickness of the coating is reduced.