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Abstract−The electrochemical characteristics of artificial graphite coated with petroleum pitch were investigated as
anode material in lithium ion batteries. Petroleum pitch with various softening points (SP 150, 200 and 250 o
C) was
prepared to coat the surface of artificial graphite using tetrahydrofuran as the solvent. Scanning electron microscopy
and transmission electron microscopy were used to confirm the coating properties of the prepared anode materials.
The electrochemical characteristics of the batteries were investigated by initial charge/discharge, cycle, rate performance,
cyclic voltammetry and electrochemical impedance spectroscopy tests in the electrolyte of 1.0 M LiPF6 (EC : DEC=
1 : 1 vol%). With the goal of optimizing the pitch coating process of graphite as an anode material, both the composition ratios of artificial graphite to petroleum pitch and the carbonization temperatures were varied. The best battery
anode performance was found to be 10 wt% coated carbon with heat treatment at 1,000 o
C on the artificial graphite
using petroleum pitch with SP 250 o
C. Pitch-derived amorphous carbon coating effectively decreases irreversible capacity and increases the cycle stability. The prepared anode materials have good initial efficiency (92.9%), discharge capacity (343 mAh/g), cycle stability (97%), and rate performance of 10 C/0.1 C (84.1%).
Keywords; Li-ion Batteries, Anode Materials, Petroleum Pitch, Coating, Graphit
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