▎ 摘　　要

NOVELTY - A preparation method of carbon nitride-graphene composite material, involves (1) mixing trithiocyanuric acid, thiourea and water, and baking to obtain block-shaped object, crushing the block-shaped object, heating and keeping the temperature to obtain sulfur-doped porous honeycomb-shaped carbon nitride, and (2) dispersing the sulfur-doped porous honeycomb-shaped carbon nitride obtained in the step (1) to obtain carbon nitride solution, mixing with graphene-hydrochloric acid dispersion liquid to obtain a finished product. USE - Preparation method of carbon nitride-graphene composite material for preparing supercapacitor (all claimed) used in hybrid power vehicle, portable electronic device, power backup device and electrochemical energy storage device. ADVANTAGE - The carbon nitride-graphene composite material has high specific capacity, high surface reaction activity and strong conductivity. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: 1.a carbon nitride-graphene composite material; 2.an application of the carbon nitride-graphene composite material in preparation of capacitor; and 3.a supercapacitor which comprises active material, adhesive, current collector and electrolyte, where the active material comprises carbon nitride-graphene composite material.