▎ 摘　　要

NOVELTY - Preparation of large size graphene oxide or graphene includes mixing graphite and intercalation agent, adding expansion agent, soaking, and taking out to obtain graphene aggregates; putting into acid and oxidizing agent mixture, soaking or refluxing, filtering, and washing with deionized water to obtain graphene oxide aggregates; mixing with deionized water, mechanically stripping to obtain graphene oxide dispersion, and subjecting to reduction reaction with reducing agent or heat treatment to obtain graphene suspension or graphene film; and concentrating graphene suspension or freeze-drying. USE - Method for preparation of large size graphene oxide or graphene (claimed) used for efficient thermal management, flexible display, energy conversion and storage areas. ADVANTAGE - The product has large size and high conductivity. DETAILED DESCRIPTION - Preparation of large size graphene oxide or graphene comprises: (A) mixing graphite and intercalation agent at 0-130 degrees C for 5 minutes to 48 hours, adding expansion agent, soaking to 0-80 degrees C for 1 hour to 7 days, and taking out to obtain graphene aggregates; (B) putting into acid and oxidizing agent mixture, soaking for 0.1-50 hours or refluxing to 0-130 degrees C, filtering, and washing with deionized water to remove impurities to obtain graphene oxide aggregates; (C) mixing with deionized water, mechanically stripping to obtain graphene oxide dispersion, and subjecting to reduction reaction with reducing agent or heat treatment to obtain large size and high conductivity graphene suspension or graphene film; and (D) concentrating graphene suspension through evaporation or centrifugation to obtain high solid content graphene or graphene oxide slurry; or freeze-drying or spray drying. The graphene suspension has graphene oxide aggregate content of 0.1-50 mg/mL. The graphene film has thickness of 1-25 mu m.