▎ 摘　　要

NOVELTY - Secondarily oxidized expanded graphite is added to supersaturated solution of sodium acetate, solid sodium acetate, and crystalline sodium acetate solution and processed, to obtain crystals and graphite mixture. The crystals and graphite mixture are milled, and deionized water is added. The mixture is subjected to solid-liquid-separation, and residual solids and sodium acetate are removed, to obtain preliminarily dissociated graphite. The preliminarily-dissociated graphite is ultrasonically-dispersed using ethanol as medium at 100-1000 Hz for 1-10 hours, to obtain multilayered graphene. USE - Production of multilayer graphene used for nanomaterial. ADVANTAGE - The method enables production of multilayer graphene having high quality and stability. DETAILED DESCRIPTION - Natural crystalline flaky graphite and hydrogen peroxide in mass ratio of 1:0.07-0.15 are mixed for 15-30 minutes. Sulfuric acid is added and stirred for 30-60 seconds, to obtain intercalated graphite. The mass ratio of sulfuric acid and natural crystalline flaky graphite is 2-5:1. Intercalated graphite is washed with deionized water having pH value of more than 6, and dried at 1000 degrees C for 30-60 seconds, to obtain expanded graphite oxide. The expanded graphite oxide is subjected to electrochemical oxidation in a tank using high-purity graphite blocks as anode, ammonium nitrate solution with mass concentration of 20-50% as electrolyte and expanded graphite oxide as cathode, and electrolysis current density of 2-8 A is supplied. The mixture is solid-liquid-separated, and dried at 1000 degrees C for 30-60 seconds, to obtain secondarily oxidized expanded graphite. Secondarily oxidized expanded graphite is added to supersaturated solution of sodium acetate, solid sodium acetate, and crystalline sodium acetate solution and processed, to obtain crystals and graphite mixture. The crystals and graphite mixture are milled for 2-8 hours, and deionized water is added. The mixture is subjected to solid-liquid-separation, and residual solids and sodium acetate are removed, to obtain preliminarily dissociated graphite. The preliminarily dissociated graphite is ultrasonically-dispersed using ethanol as medium at 100-1000 Hz for 1-10 hours, to obtain multilayered graphene. The mass ratio of ethanol and preliminarily dissociated graphite is 1 L:10-40 g.