▎ 摘　　要

NOVELTY - Preparation of graphene-supported hollow manganese dioxide composite material involves dispersing water and graphene oxide for 1-24 hours to obtain graphene oxide colloid, mixing manganese salt solution and graphene oxide colloid to obtain mixed suspension (A), stirring water and L-lysine to obtain L-lysine solution, mixing L-lysine solution and mixed suspension (A) to obtain mixed suspension (B), stirring water and sodium borohydride to obtain sodium borohydride solution, mixing sodium borohydride solution and mixed suspension (B) to obtain mixed suspension (C), hydrothermally reacting at 150-250 degrees C for 15-25 hours, filtering, washing to obtain oxide composite material, dispersing oxide composite material to obtain suspension (S1), mixing suspension (S1) and potassium permanganate solution, filtering, washing, re-dispersing in water to obtain suspension (S2), mixing suspension (S2) and hydrochloric acid solution, filtering, washing, and drying. USE - Preparation of graphene-supported hollow manganese dioxide composite material. ADVANTAGE - The method is simple, and provides graphene-loaded hollow manganese dioxide composite material with high specific capacitance, long cycle life and excellent electroconductivity. DETAILED DESCRIPTION - Preparation of graphene-supported hollow manganese dioxide composite material involves ultrasonically dispersing water and graphene oxide in mass ratio of (1000-2000):1 for 1-24 hours to obtain graphene oxide colloid, stirring water and manganese salt in ratio of (500-2000):1 to obtain manganese salt solution, mixing manganese salt solution and graphene oxide colloid in volume ratio of (0.5-4):1, stirring at 25-40 degrees C for 1-10 hours to obtain mixed suspension (A), stirring water and L-lysine in ratio of (100-400):1 to obtain L-lysine solution, mixing L-lysine solution and mixed suspension (A) in volume ratio of (0.5-1.5):1, stirring at 25-40 degrees C for 0.5-2 hours to obtain mixed suspension (B), stirring water and sodium borohydride in mass ratio of (1000-2000):1 to obtain sodium borohydride solution, mixing sodium borohydride solution and mixed suspension (B) in volume ratio of (0.5-2):1, stirring at 25-40 degrees C for 0.5-1 hour to obtain mixed suspension (C), putting mixed suspension (C) into PTFE-lined hydrothermal reactor, keeping at 150-250 degrees C for 15-25 hours, filtering, washing to obtain oxide composite material, dispersing oxide composite material in water at manganese concentration of 0.02-0.05 mol/L to obtain suspension (S1), mixing suspension (S1) and potassium permanganate solution in volume ratio of (10-200):1, stirring at 25-40 degrees C for 1-4 hours, filtering, washing to obtain graphene-supported manganese dioxide composite material, re-dispersing in water at manganese concentration of 0.01-0.04 mol/L to obtain suspension (S2), mixing suspension (S2) and hydrochloric acid solution in volume ratio of (1-100):1, stirring for 1-4 hours, filtering, washing, and drying. The concentration of potassium permanganate solution is 0.01-0.1 mol/L. The concentration of hydrochloric acid solution is 0.01-12 mol/L.