CVD-GROWTH SIMULATION OF PYROLYTIC CARBON ON SPHERONIZED GRAPHITE BY BENZENE PRECURSOR

Modeling of pyrolytic carbon (PyC) coating on spheronized graphite particles was performed. The model takes into account convective and radiative heat transfer, particle movement in a fluidized bed, benzene pyrolysis kinetics and carbon deposition in view of the adhesion coefficient. It has been shown that efficient benzene decomposition for PyC coating formation occurs at temperature of 1000–1100℃. A nitrogen pulse feed rate of 10 pulses min-1 maximizes particle concentration in the benzene active decomposition zone. A semi-empirical model predicting PyC coating thickness as a function of temperature and particle diameter was presented. The calculated layer thickness varies from 40 to 90 nm and is in good agreement with the experiment. The obtained anode material exhibits ≤ 5% loss in specific discharge capacity at 2C and recovers up to 99% capacity at 0.1C.