▎ 摘　　要

NOVELTY - Preparing three-dimensional porous graphene sheet involves using cryogenic graphite method, seperating inner shell of the biomass, crushing, and sieving to selecting powder below 100 microns. The powder obtained is placed in a tube furnace and carbonized at a temperature of 350-900 degrees C slowly under protection of nitrogen to obtain biochar after cooling. The biochar obtained is mixed with the catalyst, ground, and slowly heated at 850-1000 degrees C under a nitrogen atmosphere to complete graphitized, removed, and cooled. The sample is washed with deionized water to neutrality. USE - Method for preparing three-dimensional porous graphene sheet used for preparing a super capacitor (claimed). ADVANTAGE - The method enables to prepare three-dimensional porous graphene sheet in eco-friendly mannaer, has high purity, excellent crystal lattice, high electrical conductivity, high specific surface area, provides the graphene material synthesis a very ideal synthesis process. DETAILED DESCRIPTION - Preparing three-dimensional porous graphene sheet invoves using cryogenic graphite method, seperating inner shell of the biomass, crushing, and sieving to selecting powder below 100 microns. The powder obtained is placed in a tube furnace and carbonized at a temperature of 350-900 degrees C slowly under protection of nitrogen to obtain biochar after cooling. The biochar obtained is mixed with the catalyst, ground, and slowly heated at 850-1000 degrees C under a nitrogen atmosphere to complete graphitized, removed, and cooled. The sample is washed with deionized water to neutrality. The sample is placed in dilute hydrochloric acid and stirred. The sample obtained is again washed with deionized water to neutrality, and dried product to obtain final product.