Method for preparing multi-layer graphene

The invention relates to a method for preparing multi-layer graphene. The method comprises the following steps: (a) dissolving carboxymethyl cellulose and polyethylene glycol in deionized water, and stirring the solution until the solution is clear to obtain a dispersant; (b) adding expanded graphite into the dispersant which is cooled to room temperature along with stirring to obtain a suspension; and (c) adding the suspension into a nano-grinder for grinding to obtain the multi-layer graphene. The preparation method is simple, environment-friendly, low in price and non-toxic, can be used for preparing the graphene with maintained electron structure and crystal perfection and preparing a large amount of multi-layer graphene.