Preparation method of carbon-coated foil for lithium ion battery

The invention relates to the technical field of carbon-coated foil preparation, and discloses a preparation method of a carbon-coated foil for a lithium ion battery. The preparation method comprises the following steps of S1, sequentially performing ultrasonic cleaning pool cleaning, spraying cleaning and drying on an aluminum foil repeatedly for 2-3 times, wherein the used cleaning liquid is water and an organic solvent, the aluminum foil is cleaned with water and then is cleaned with the organic solvent to obtain the cleaned aluminum foil; and S2, placing the cleaned aluminum foil in a vacuum heat treatment furnace for high-temperature annealing treatment, wherein the heating temperature is 250-350 DEG C, the heating time is 2.5-3.5 hours, and the aluminum foil is cooled to a normal temperature after being heated and is stored for standby application. The preparation method has the advantages that the cleanliness of an outer surface of the aluminum foil is guaranteed, the adhesion degree of the aluminum foi