Figure 1. Scanning electron micrographs of the graphene that solves the
problems regarding insufficient exfoliation of the graphite powder and
deterioration in the electrical conductivity and thermal conductivity.
The high-resolution scanning electron micrographs are illustrated in
Figure 2 for the graphene that solves the problems regarding
insufficient exfoliation of the graphite powder and deterioration in the
electrical conductivity and thermal conductivity. The raw graphene
powder can contain graphene nanoparticles consisting of stacks of
graphene sheets having a platelet shape. The graphene particles may have
an average thickness of about 6-8 nm and a typical surface area of about
80 to 200 square meters per gram. The graphene particles have an average
particle diameter of about 8-20 microns. Graphene nanoplatelets may have
naturally occurring functional groups like ethers, carboxyl, or
hydroxyls that can react with atmospheric humidity to form acids or
other compounds. These functional groups are present on the edges of the
particles and their weight fraction varies with particle size. The
liquid precursor is a suspension containing graphene solids. The amount
and concentration of the graphene raw material liquid precursor can
depend on the desired amount, concentration, and use of the resultant
product of the process. A smaller distribution of graphene, for example,
from about 0.05 percent by weight to about 60 percent by weight relative
to the total weight of a liquid dispersion containing the graphene,
would more easily disperse at the submicron level in the liquid
dispersion, when compared to a greater weight fraction of graphene in
the liquid dispersion. Smaller dispersions result in ease of addition of
graphene to other desirable emulsions, for example, to enhance the
uniform coating matrix for protection attributes graphene can provide to
the coating. A non-limiting example of the silica that can be used is
fumed silica. Silica fume is an ultrafine powder collected as a
by-product of the silicon and ferrosilicon alloy production. It may
consist of amorphous spherical particles with an average particle
diameter of about 80-280 nm, for example, about 200 nm, without the
branching of the pyrogenic product. The concentration of silica, for
example, fumed silica, can be in the range of about 0.08 percent by
weight to 28 percent by weight in the liquid precursor or any subrange
thereof, for example, about 0.2-20 percent by weight, about 3-6 percent
by weight, or about 4-6 percent by weight. A concentration of fumed
silica in the range of about 0.2-20 percent by weight can modify
nonpolar solvents to have a viscosity of higher than 80 Sabol seconds,
for example, to form ringing gels.