In situ esr study of the hno_3-intercalate diffusion process in graphite intercalation compounds

摘要

In situ conduction electron spin resonance (CESR), contactless conductivity and X-ray diffrac- tion studies of HNO_3 molecule intercalation into highly oriented pyrolytic graphite (HOPG) plates are presented. The CESR lineshape, linewidth, intensity and position analysis allow us to establish: a) individual reaction steps, b) two different intercalation mechanisms: a slow diffusion of the intercalate through faces parallel to the c-axis in the whole thickness of sample and a relatively faster nucleation of a new phase in near surface galleries; and c) an estimate of the constant of the two-dimensional diffusion of intercalate throgh the sample after its insertion into HOPG.