鋰二次電池陽極碳材料之新製作研究(Ⅲ)

The graphite is precipitated by the
different carbon solubility due to a variety of
temperatures in the phase diagram. This
graphite composite including the fullerenes
and carbon nano tube is different from the
simple graphite in the phase diagram.
Besides, it is needed to discuss with the
precipitated graphite by adding different
boron contents. The character and structure
of precipitated graphite were studied by
X-ray diffraction, Raman spectra and
FE-SEM. The data obtained by X-ray
diffraction was refined by Rietveld method,
And as a result, the graphitization degree has
been calculated with Maire and Mering
method。G4 (added 10000ppm boron) has the
highest graphitization degree is of 93.04%.
Carbon nano tube was observed around the
graphite’s surface by FT-SEM. The size is
from several microns to several tens of
nanometers. For these graphites, they are
suitable for the use as anode material in the
Li-ion second battery. And the
electrochemical measurements were carried
out with Cyclic Voltammetry and Impedance
spectra. G2 (added 300ppm boron) has the
highest energy density (518mAhg-1). This
value exhibited it is higher than the perfect
graphite theoretical value (372 mAhg-1)。