Bio-based flame-retardant lithium ion battery diaphragm and preparation method thereof

The invention discloses a bio-based flame-retardant lithium ion battery diaphragm and a preparation method thereof, and relates to the technical field of electrical materials. When the bio-based flame-retardant lithium ion battery diaphragm is prepared, microcrystalline cellulose and epichlorohydrin react firstly and then react with dimethylallylamine to prepare modified cellulose; the preparation method comprises the following steps: reacting allyltriphenylphosphonium bromide with heptamethylcyclotetrasiloxane, and then reacting with a vinyl double-end socket to prepare double-end vinyl phosphorus-containing polysiloxane; and mixing the modified cellulose, double-end vinyl phosphorus-containing polysiloxane, N, N-dimethylacetamide and azodiisobutyronitrile to prepare a membrane casting solution, and blade-coating and curing the membrane casting solution to prepare the bio-based flame-retardant lithium ion battery diaphragm. The bio-based flame-retardant lithium ion battery diaphragm prepared by the invention