▎ 摘　　要

NOVELTY - Graphene slurry comprises expanded graphite and cellulose derivative, where the graphene in graphene slurry comprises mixture of single layer and few layers of graphene prepared by taking expanded graphite as raw material, and the graphene layer comprises technical indexes of number of graphene layers is 1-3 layers, and the diameter is 3-7 mu m. USE - The graphene slurry is useful in the preparation of electrothermal coating, which is used in electric heating film and electric heating device for electric heating (all claimed), and in electric heating material applications. ADVANTAGE - The graphene slurry ensures electrothermal coating with excellent flexibility, temperature and heat resistance and strong electrical conductivity. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: (1) a method for preparing graphene slurry, involving dissolving cellulose derivative in solvent to obtain cellulose derivative solution, adding expanded graphite, and uniformly mixing to obtain expanded graphite dispersion, performing high pressure homogenization treatment on expanded graphite dispersion to obtain graphene slurry; (2) an electrothermal coating comprising 10-50 wt.% graphene slurry, 5-30 wt.% aqueous polymer resin, 5-20 wt.% silica sol, 0.1-1 wt.% aqueous wetting dispersant, 5-20 wt.% inorganic filler, 0.1-2 wt.% film-forming additive, 0.1-1 wt.% thickener, 0.1-1 wt.% defoamer, 0.1-2 wt.% leveling agent and remaining of deionized water; (3) a method for preparing electrothermal coating, involving uniformly mixing above-mentioned components to obtain the coating; (4) a electric heating film prepared by coating electrothermal coating on film-forming carrier comprising polyimide film, non-woven fabric, polyethylene film and/or polyester film; and (5) an electric heating device comprising above-mentioned electric heating film, or coating electric heating device with electrothermal coating.