▎ 摘　　要

NOVELTY - A graphene composite material is prepared by stirring graphite with concentrated sulfuric acid and fuming nitric acid mixed solution by adding intercalation agent to obtain a mixed solution. The mixed solution is filtered by using filter paper to obtain a filtered solution followed by adding hydrochloric acid to the filtered solution till sulfate residue disappears to obtain residual mixture. The residual mixture is washed using de-ionized water. The residual mixture is dried to obtain expandable graphite, which is placed in a high temperature furnace under protective gas. USE - Graphene composite material for use in positive and negative pole materials of a lithium battery. ADVANTAGE - The material has high electric conductivity, high thermal conductivity, high concentration and better dispersion property, and provides the battery with reduced internal resistance, improved power density, improved energy density, high safety and better durability. DETAILED DESCRIPTION - A graphene composite material is prepared by stirring 1-3 pts. wt. graphite with 15-17 pts. wt. concentrated sulfuric acid and fuming nitric acid mixed solution at 0-10 degrees C for 10-100 hours by adding 1-3 pts. wt. intercalation agent to obtain a mixed solution. The mixed solution is filtered by using filter paper to obtain a filtered solution followed by adding 10 wt.% hydrochloric acid to the filtered solution till sulfate residue disappears to obtain residual mixture. The residual mixture is washed using de-ionized water till pH of 5-7 to be obtained. The residual mixture is dried at 50-90 degrees C to obtain an expandable graphite. The expandable graphite is placed in a high temperature furnace at 800-1200 degrees C under protective gas for 1-8 minutes to obtain expansion graphite followed by stirring 5-7 pts. wt. dispersing agent with 102-105 pts. wt. carrier liquid to obtain a dissolved solution. The dissolved solution is stirred with 1-3 pts. wt. anionic surfactant and 0.1-0.5 pts. wt. defoamer at 40-60 degrees C to obtain mixed solution. The expansion graphite is added in mixed solution to carry out cleavage by using a high-shearing cleavage device to obtain a workpiece. The 1-5 pts. wt. workpiece is added with 1-5 pts. wt. binder and 90-98 pts. wt. lithium electrode active material to obtain slurry mixture. The slurry mixture is coated on electrodes to prepare graphene composite material.