▎ 摘　　要

NOVELTY - Preparing three-dimensional porous graphene sheets using low-temperature double-salt compound comprises (i) taking dried coconut shells and placing in a pulverizer to make them powdered, (ii) taking the crushed coconut shell and placing in a tube furnace in an argon atmosphere for carbonizing, (iii) mixing the carbonized material with potassium carbonate and sodium carbonate according to the mass ratio, (iv) placing the mixed material in the step (iii) under a tube furnace in an argon atmosphere, heating to 600-1000 degrees C at specific heating rate for activation reaction, then cooling to room temperature before taking out, (v) using hydrochloric acid solution and deionized water for cleaning and stirring the activated material until the solution becomes neutral, and(vi) drying the product obtained in the step (v) to obtain three-dimensional porous graphene sheets. USE - The method is useful for preparing three-dimensional porous graphene sheets using low-temperature double-salt compound. ADVANTAGE - The method: reduces energy consumption; and provides solutions for other biomass-derived graphitized carbon. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for: (1) electrode material, comprising graphene sheet for preparing a three-dimensional porous graphene sheet by using a low-temperature double-salt compound; and (2) supercapacitor prepared by using the electrode material.