▎ 摘　　要

NOVELTY - Graphite is added to N-methylpyrrolidone, ultrasonically processed, and obtained N-methylpyrrolidone graphene dispersion is centrifuged and redispersed in N-methylpyrrolidone to obtain N-methylpyrrolidone graphene dispersion. Dispersion is ultrasonically processed, and solid is removed to obtain N-methylpyrrolidone graphene dispersion having uniform controlled diameter size. Obtained dispersion is filtered, dried, redispersed in ethanol, ultrasonically processed, and filtered to obtain graphene ethanol solution. USE - Manufacture of graphene ethanol solution used in graphene coating, and manufacture of graphene composite material, lithium ion battery, supercapacitor, conductive ink, solar battery and touch screen. ADVANTAGE - The method efficiently provides graphene ethanol solution having high stability, concentration and conductivity. DETAILED DESCRIPTION - Graphite is added to N-methylpyrrolidone, and ultrasonically processed in ultrasonic power of 300-500 W for 60-150 minutes to obtain N-methylpyrrolidone graphene dispersion. The ratio of graphite with respect to N- methylpyrrolidone is 1 mg:1 ml. The obtained dispersion is centrifuged at 5000 rpm for 40 minutes, and the supernatant is removed. The resultant solid is centrifuged and re-dispersed in N-methylpyrrolidone to obtain 0.5-2 wt.% N-methylpyrrolidone graphene dispersion. The obtained dispersion is ultrasonically processed in ultrasonic power of 300-500 W for 30-40 minutes, centrifuged at 2000 rpm for 30 minutes, and the solid is removed to obtain N-methylpyrrolidone graphene dispersion having uniform controlled diameter size. The obtained dispersion is filtered, and the resultant solid is dried at 60 degrees C in vacuum and redispersed in ethanol, such that the ratio of graphene solid with respect to ethanol is 1 mg:50 ml. The obtained product is ultrasonically processed for 10-15 minutes, and the dispersion is filtered and further processed ultrasonically to obtain 1-10 mg/ml graphene ethanol solution.