▎ 摘　　要

NOVELTY - Preparing graphene-type materials based on biomass waste comprises (i) heating and calcining biomass waste under the protection of protective gas at 600-1500 degrees C for 1-5 hours to obtain carbonized biomass material; (ii) stirring and mixing the carbonized biomass material with the activator, drying at 80 degrees C and heating and calcining under the protection of protective gas at 400-1500 degrees C for 1-5 hours to obtain the activated mixture; (iii) placing the activated mixture in a hydrothermal reaction vessel filled with an acid solution and reacting at 120-220 degrees C for 6-12 hours to obtain a hydrothermal oxidation mixture; (iv) cleaning the hydrothermal oxidation mixture and ultrasonically peeling to obtain a dispersion liquid of biomass-based graphene-type materials; and (v) freeze-drying dispersion of the biomass-based graphene-based material. USE - The material is useful as an electrode material in a supercapacitor (claimed). ADVANTAGE - The material has high nitrogen content, one-dimensional tubular structure and excellent electrochemical performance and is economical. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for material prepared by above mentioned method.