▎ 摘　　要

NOVELTY - Preparation of graphene, involves pretreating waste graphite electrode, placing the graphite powder in liquid phase purification stripping liquid, forming upper layer as graphene-containing suspension liquid, and lower layer composed of coarse graphite and insoluble impurities particles, separating to obtain graphene-containing suspension liquid phase, centrifuging to obtain micron-sized particles, sub-micron particles and nanoparticles-containing suspension, subjecting graphene-containing suspension to solid-liquid separation, washing and drying to obtain final product. USE - Method for preparing graphene. ADVANTAGE - The method enables preparation of graphene with large specific surface area and low energy consumption. DETAILED DESCRIPTION - Method for preparing graphene, involves (S1) pretreating waste graphite electrode, purifying, stripping the liquid layer to enhance the surface layer from abandoned graphite electrode, grinding the surface layer into graphite powder with particle size of 20-60 mu m, placing the graphite powder in liquid phase purification stripping liquid, carrying out purification and stripping strengthening treatment, adjusting pH value to 0.5-2, leaving still, layering, forming upper layer as graphene-containing suspension liquid, and lower layer composed of coarse graphite and insoluble impurities particles, separating to obtain graphene-containing suspension liquid phase, centrifuging to obtain micron-sized particles, sub-micron particles and nanoparticles-containing suspension, (S3) subjecting graphene-containing suspension to solid-liquid separation, washing and drying to obtain final product. The liquid phase purification stripping solution contains aluminum ion salt composed of aluminum element and graphite powder in mass ratio of 1:10-50. The waste graphite electrode is waste graphite electrode or waste sodium ion battery graphite electrode produced by molten electrolytic process. The nanoparticles-containing suspension is graphene-containing suspension.