OPTIMIZATION OF CARBON COATINGS

摘要

Several synthetic additives have been used to improve the carbon coatings on LiFePO4 electrode materials. Pyromellitic acid (PA) added prior to calcination decreases the D/G ratios of the carbon produced in situ, while the use of both iron nitrate and PA results in increased sp2 character. Thus, the carbon coatings are structured with a greater fraction of graphitic character. The production of structured carbon coatings results in higher pressed pellet conductivities of LiFePO4/C composites and improved electrochemical performance of cells containing these cathode materials, although the carbon content is not necessarily increased. The combination of both ferrocene and PA used during LiFePO4 synthesis causes more carbon to be retained, although the structural characteristics are similar to that produced from the same amount of PA alone.