ABSTRACT
Exfoliation phenomena of graphite have been known since the graphite intercala-
tion compounds were found. Exfoliated graphite consists of particles exfoliated
preferentially along the normal to graphite basal plane of the original flakes.
A representative micrograph is shown in Fig. 1.1(a). These particles have often
been called worm-like. How to exfoliate the flakes of natural graphite was first
described in a US patent in 1891[1] and preparation of graphite films from
exfoliated graphite in 1916.[2] This unique material has been produced in industrial
scale predominantly for the raw materials of flexible graphite sheets. Therefore,
exfoliation phenomena were studied mostly in order to improve the properties
and performances of flexible graphite sheets. In the industry, it has been produced
from residue compounds, mostly with sulfuric acid, that are formed through the
mild decomposition of graphite intercalation compounds (GICs).
