▎ 摘　　要

NOVELTY - Preparation of supercapacitor electrode material involves cutting the resultant polyimide film into small pieces, placing in a reactor, adding aqueous ammonia solution having pH of 11, sealing, heating to 180 degrees C, performing high-pressure hydrothermal reaction for 4 hours, naturally cooling, filtering the resultant yellow solution, immersing the graphene film in obtained yellow solution containing a hydrolyzed polyimide molecules at 80 degrees C for 4 hours, removing the resultant film, soaking in deionized water, and washing. USE - Preparation of electrode material used for supercapacitor. ADVANTAGE - The method enables efficient preparation of electrode material by economical process. The high-performance supercapacitor obtained using the electrode material has improved specific capacity and energy density. DETAILED DESCRIPTION - Preparation of supercapacitor electrode material involves cutting the resultant polyimide film into small pieces, placing in a reactor, adding aqueous ammonia solution having pH of 11, sealing, heating to 180 degrees C, performing high-pressure hydrothermal reaction for 4 hours, naturally cooling the resultant reaction mixture, filtering the resultant yellow solution, immersing the graphene film in obtained yellow solution containing a hydrolyzed polyimide molecules at 80 degrees C for 4 hours, removing the resultant film, soaking in deionized water, and washing. The graphene film is prepared by pouring the mixed solution (S) into a polytetrafluoroethylene mold having a squared-shaped flat bottom, flattening the liquid surface, naturally drying in a dust-free cabinet, obtaining composite film with uniform thickness, adjust the depth and size of the mold, obtaining reduced graphene oxide film with large size and thickness, naturally drying, placing the film in a 100 mL-reactor containing 1.5-3.5 L/mL aqueous ammonia at concentration of 25-28 wt.%, performing hydrothermal reduction at 180 degrees C for 3 hours, cooling, removing the film, and water washing. The mixed solution (S) is prepared by mixing highly-concentrated liquid crystalline graphene oxide and ammonium carbonate, or ammonium sulfate, ammonium acetate, and urea, and sodium chloride in mass ratio of 1:3:3, in water, adjusting the graphene oxide concentration in the resultant solution to 6 mg/mL, performing magnetic stirring and ultrasonic vibration, leaving still for 3-5 days, to obtain stable soluble dispersion.