Effect of carbon coating on thermal stability of natural graphite spheres used as anode materials in lithium-ion batteries

To investigate the effect of non-graphitic carbon coatings on the thermal stability of spherical natural graphite at elevated temperature, differential scanning calorimetry (DSC) and X-ray diffraction (XRD) measurements are performed. Data from DSC studies show that the thermal stability of the surface modified natural graphite electrode is improved. The surface modification results in a decrease in the BET surface specific area. An improvement in coulombic efficiency and a reduction in irreversible capacity are also observed for the carbon-coated natural graphite. X-ray diffraction analysis confirms that carbon coating alleviates the release of intercalated lithium from natural graphite at an elevated temperature and acts as a protective layer against electrolyte attack.