▎ 摘　　要

NOVELTY - A nitrogen-containing multi-stage porous carbon/graphene composite material preparing method involves adding chitosan and acetic acid solution to graphene oxide dispersion liquid and stirring to obtain intermediate product. The intermediate product is added with glutaraldehyde and dispersed to obtain a transparent hydrogel. The transparent hydrogel is subjected to fractional freezing treatment and freeze-dried. The gel material is transferred to a tube furnace, cooled, ground, heated and cooled to obtain product. The product is washed and dried to obtain the finished product. USE - Method for preparing nitrogen-containing multi-stage porous carbon/graphene composite material for producing supercapacitor electrode that is utilized in field of supercapacitor (all claimed). ADVANTAGE - The method enables preparing nitrogen-containing multi-stage porous carbon/graphene composite material with high specific surface area, multi-level porous structure, excellent specific capacitance performance, high power density and very high performance. DETAILED DESCRIPTION - A nitrogen-containing multi-stage porous carbon/graphene composite material preparing method involves adding chitosan and acetic acid solution to graphene oxide dispersion liquid and stirring at room temperature to obtain intermediate product of fused graphene and chitosan. The intermediate product is added with glutaraldehyde aqueous solution, dispersed uniformly and allowed to stand at room temperature for crosslinking completely to obtain a transparent hydrogel. The transparent hydrogel is subjected to fractional freezing treatment at 4 degrees C, 0 degrees C and -20 degrees C, and freeze-dried in a freeze dryer to obtain chitosan/graphene gas gel material with multiple-hole structure. The chitosan/graphene gas gel material is transferred to a tube furnace at 700-900 degrees C under a heating rate of 1-5 degrees C/minute in a nitrogen atmosphere, cooled naturally to room temperature for 60-120 minutes, ground homogeneously with potassium hydroxide and potassium carbonate, transferred to a tube furnace, heated to 600-800 degrees C under a heating rate of 1-5 degrees C/minute in a nitrogen atmosphere and cooled naturally to room temperature for 60-120 minutes to obtain product. The product is washed with hydrochloric acid and distilled water to neutral and dried to obtain the finished product. INDEPENDENT CLAIMS are also included for the following: (1) a nitrogen-containing multi-stage porous carbon/graphene composite material prepared by the method (2) a method for producing a supercapacitor electrode.