▎ 摘　　要

NOVELTY - A hydrophilic graphene thin film is prepared by adding deionized water to graphene oxide powder with mass ratio of 1:100-1000, ultrasonically dispersing for 0.5-2 hours to obtain uniformly dispersed graphene oxide suspension, adding 0.1-5 g iron powder and 5-100 ml 5-50 mass% hydrochloric acid solution to obtained graphene oxide suspension, mechanically stirring at room temperature for 60 minutes, standing for 1 hour, continuously adding 5-50 mass% hydrochloric acid solution until iron powder is completely removed, separating by filtration, and cleaning multiple times. USE - Preparation of hydrophilic graphene thin film for supercapacitor. ADVANTAGE - Graphene thin film has reduced contact angle, increased wettability and specific surface area, and improved hydrophilicity and capacitive deionization ability, and does not generate secondary pollution. DETAILED DESCRIPTION - A hydrophilic graphene thin film is prepared by adding deionized water to graphene oxide powder with mass ratio of 1:100-1000, ultrasonically dispersing for 0.5-2 hours to obtain uniformly dispersed graphene oxide suspension, adding 0.1-5 g iron powder and 5-100 ml 5-50 mass% hydrochloric acid solution to obtained graphene oxide suspension, mechanically stirring at room temperature for 60 minutes, standing for 1 hour, continuously adding 5-50 mass% hydrochloric acid solution until iron powder is completely removed, separating by filtration, cleaning multiple times using deionized water and ethanol solution, drying in oven at 433 K for 6 hours, taking out, adding sulfonating agent to dried product with mass ratio of 1:1-10, placing in ice bath for 2 hours, cleaning with deionized water, collecting by vacuum filtration, ultrasonically dispersing in water, adding reducing agent with mass ratio 1:1-10, setting at 473 K condition while continuously stirring for 12 hours, filtering, washing, vacuum drying to obtain hydrophilic graphene powder in which sulfonating agent is benzene sulfonic acid diazonium salt or styrene sulfonic acid sodium salt, and reducing agent is sodium borohydride or hydrazine hydrate, adding 30 mass% graphite powder and 10 mass% PTFE to 60 mass% hydrophilic graphene powder, uniformly mixing, and tabletting through pressing into graphene sheet to obtain hydrophilic graphene thin film electrode. DESCRIPTION OF DRAWING(S) - The drawing shows an electric absorption comparison graph of hydrophilic graphene thin film electrode and unsulfonated graphene thin film electrode in sodium solution.