Preparation of coal-based graphite anode materials and study on their electrochemical performance
Taking anthracite as a precursor,the influences of coalification degree,ash content and graphitization temperature on the graphitization of anthracite are studied,and the"structure-effect"relationship between microstructure and electrochemical properties of coal-based graphite are also explored.It is found that anthracite with a high coalification degree is beneficial to the growth of microcrystals of coal-based graphite,and can reach a higher graphitization degree at the same temperature.After graphitization at 2,400℃,the graphitization degree of Taixi coal reaches 80.3%,while the graphitization degree of Jincheng coal is only 74.5%.The ash in anthracite plays a catalytic role in graphitization.The anthracite samples that have not been deashed show a high degree of graphitization at lower temperature,and deliver a higher first charge-discharge capacity.However,the existence of ash will also affect the lamellar structure of coal-based graphite,resulting in a large number of folds in graphite lamellae,which will lead to the decline of cycle stability and rate performance of coal-based graphite.With the increasing temperature,the graphitization degree of coal-based graphite increases,the graphite lamellar structure develops gradually,and its electrochemical performance is greatly improved.The graphite that is prepared through graphitization of deashed Taixi coal at 2,800℃exhibits 370.8 mAh·g-1 of first discharge capacity at 0.2 C.
万方数据
维普
