Surface profilometric study of the kinetics of the intercalation of graphite

The kinetics of the intercalation of graphite was investigated by measuring the c-face surface profiles during the intercalation of Br₂ into highly-oriented pyrolytic graphite cylindrical discs at room temperature. A sharp intercalate front was observed to advance while the surface profile evolved from a bucket-shape to a V-shape, as predicted by the model of interface-controlled intercalation proposed by the authors [11]. The average magnitude of the steady velocity of the front was ~ 15 Å/see; the initial period was marked by a larger velocity attributed to an edge effect. The same behavior was observed during ICI intercalation at room temperature. During desorption, inverted surface profiles were obtained, indicating that desorption may be the reverse of intercalation. In the case of HNO₃ intercalation at room temperature, bowl-shaped surface profiles were observed. Preliminary profile measurements were made during ICI intercalation at 50°C, at which the intercalate layers are known to be disordered.