D. Alliata et al., Anion intercalation into highly oriented pyrolytic graphite studied by electrochemical atomic force microscopy, ELECTROCH C, 1(1), 1999, pp. 5-9
Knowledge of the dimensional changes occurring during electrochemical proce
sses is fundamental for understanding of the electrochemical intercalation/
insertion mechanism and for evaluation of potential application in electroc
hemical devices. We studied a highly oriented pyrolitic graphite (HOPG) ele
ctrode in perchloric acid, as a model to elucidate the mechanism of electro
chemical anion intercalation in graphite. The aim of the work is the local
and time dependent investigation of dimensional changes of the host materia
l during electrochemical intercalation processes on the nanometer scale. We
used atomic force microscopy (AFM), combined with cyclic voltammetry, as t
he in situ tool of analysis during intercalation and deintercalation of per
chlorate anions. According to the AFM measurements, the HOPG interlayer spa
cing increases by 32% in agreement with the formation of stage IV of graphi
te intercalation compounds, when perchlorate anions intercalate. In additio
n, the local aspect of the process has been demonstrated by revealing coexi
sting regions with different kinetics for intercalation and deintercalation
processes. (C) 1999 Elsevier Science S.A. All rights reserved.