▎ 摘　　要

NOVELTY - Preparation of graphene-hard carbon composite material involves adding graphite oxide in water, ultrasonically dispersing, adjusting pH of obtained graphene oxide suspension to 2-5, adding phenol and formaldehyde to the graphene oxide suspension, stirring, heating such that polymerization reaction of phenol and formaldehyde is carried out, placing obtained graphene oxide and phenolic resin composite material in inert gas atmosphere, heating at rate of 5-25 degrees C/minute to 800-900 degrees C for 0.5-2 hours, and cooling. USE - Preparation of graphene-hard carbon composite material used for preparing electrochemical capacitor (all claimed). ADVANTAGE - The method enables preparation of graphene-hard carbon composite material with specific surface area of 800-1174 m2/g. DETAILED DESCRIPTION - Preparation of graphene-hard carbon composite material involves adding graphite oxide in water, ultrasonically dispersing, adjusting pH of obtained graphene oxide suspension to 2-5, adding phenol and formaldehyde to the graphene oxide suspension, stirring, heating such that polymerization reaction of phenol and formaldehyde is carried out, placing obtained graphene oxide and phenolic resin composite material in inert gas atmosphere, heating at rate of 5-25 degrees C/minute to 800-900 degrees C for 0.5-2 hours, and cooling. The mass ratio of graphene oxide and phenol is 5:0.5-3. The mass ratio of phenol and formaldehyde is 1.1-1.3:1. INDEPENDENT CLAIMS are included for the following: (1) electrochemical capacitor; and (2) preparation of electrochemical capacitor.