▎ 摘　　要

NOVELTY - A porous graphene material is prepared by grinding coal tar, adding transition metal oxide nanopowder and solid potassium hydroxide, grinding, ball milling, purging with nitrogen gas, heating, extracting, naturally cooling, grinding, pickling, washing with distilled water, and drying. USE - Method for preparing porous graphene material used as supercapacitor (claimed). ADVANTAGE - The method is simple, safe, low-cost and suitable for industrial production. The graphene material having pore diameter of 2.53-5.91 nm, specific surface area of 664-1862 m2/g and specific pore volume of 0.51-1.60 cm3/g is low-cost. DETAILED DESCRIPTION - A porous graphene material is prepared by grinding 15.6-33.3 wt.% coal tar to particle size of less than or equal to 74 mu m, adding 44.4-62.2 wt.% transition metal oxide nanopowder and 22.2 wt.% solid potassium hydroxide having total mass of 27 g, grinding for 1-2 hours, ball milling for 20-30 minutes at speed of 303-500 revolutions/minute, purging with nitrogen gas for 5-15 minutes, heating at 150 degrees C for 0.5 hour under - 0.1 MPa pressure with rate of 5 degrees C/minute and at 800-850 degrees C for 1 hour, extracting under - 0.05 to - 0.1 MPa pressure, naturally cooling to room temperature, grinding, pickling, washing with distilled water, and drying.