Preparation method of graphene material of supercapacitor

The invention relates to a preparation method of graphene material of a supercapacitor. The preparation method comprises the following steps of: step one, preparation of expanded graphene, comprising the steps of placing 1-2 parts by weight of graphite oxide into a heating container, sealing the heating container, rapidly warming and heating for 30-120s, preparing 0.5-1 part by weight of the expanded graphene; and step two, preparation of activated graphene. The invention has the beneficial effects that the graphene material prepared by adopting the preparation method provided by the invention improves cellular structure of graphene on the basis that composition of the graphene is not changed, thus the graphene material is more beneficial to charge storage, the specific capacity of a graphene supercapacitor is improved, the specific volume of the supercapacitor in organic electrolyte reaches up to 200F/g, and energy density can reach up to 40Wh/kg; meanwhile, the preparation method provided by the invention has simple technological process and low cost.