▎ 摘　　要

NOVELTY - Electromagnetically shielded light graphene film comprises 0.005-0.1 gm/cm3 dense film that has carbon content (in terms of mass percentage) of not less than 95 wt.% and plane oriented graphene sheet of average size greater than or equal to 100 mu m. The planes overlap by pi - pi conjugated bond that contains layered graphene structure and each layer is made of 1-4 graphene sheets with pores between the sheets. The average pore size in the cross section is 10 nm2-400 mu m2 and the porosity is 70% or more. The defects in the graphene sheet is ID/TG less than or equal to 0.01. USE - Electromagnetically shielded light graphene film. ADVANTAGE - The electromagnetically shielded light graphene film is efficient and has good conductivity. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for: (1) a method for preparing electromagnetically shielded light graphene film which involves utilizing graphene oxide of average size greater than or equal to 100 mu m to prepare concentration of 0.1-100 mg/ml aqueous graphene oxide solution; (2) adding 0.1-5 wt.% of inorganic salt, organic small molecules or macromolecules and dispersing the particles by ultrasonic action; (3) preparing graphite oxide film by film-forming method and reducing the obtained product with a reducing agent like hydrazine hydrate; (4) restoring the graphene film under inert gas atmosphere by heating with the speed of 0.1-1 degrees C/min rate to reach 500-800 degrees C and insulating the product for 0.5-2 hours; (5) insulating the obtained product under inert gas atmosphere with 1-3 degrees C/minute rate of heating up to 1000-1300 degrees C for 0.5-3 hours; (6) insulating the obtained product under inert gas atmosphere with 5-8 degrees C/minute rate of heating up to 2500-3000 degrees C for 0.5-4 hours; (7) cooling the obtained product to obtain a highly efficient electromagnetically shielded light graphene film; (8) a method for preparing graphene oxide which involves using modified-Hummer method to obtain diluted graphite oxide solution and filtering the solution through a 140 mesh sieve to obtain the graphite oxide sheet; (9) mixing the obtained product in ice water according to volume ratio 1:10 and allowing the solution to stand for 2 hours; (10) adding hydrogen peroxide dropwise where, hydrogen peroxide has mass fraction of 30 wt.%; (11) mixing the solution until the mixture stops changing color which shows that the potassium permanganate has been completely removed from the liquid; (12) adding dropwise concentrated hydrochloric acid in 12 mole/l concentration into the obtained mixture until the flocculent graphite oxide disappears and filtering the obtained solution through the 140 mesh sieve to obtain graphite oxide wafer; and (13) placing the graphite oxide wafer on a shaker and washing the components with a stirring speed of 20-80 revolutions/minute to peel of the large pieces of graphite oxide wafer of average size greater than 87 mu m and distribution coefficient between 0.2-0.5.