Abstract
The electrophoretic deposition of the artificial graphite particle, KS-25, on Cu foil has been examined in an acetonitrile bath containing additives such as triethylamine (TEA), tetramethylguanidine (TMG), and pyridine (Py). The charge-discharge capability of carbon anode for the Li-ion secondary battery prepared by the electrophoretic deposition method was estimated. Graphite particles were deposited electrophoretically on the anode substrate. The amount of graphite particle on Cu foil increased with an increasing deposition voltage, deposition time, and TEA concentration and was controllable in the range from 0 to 10mg·cm-2. The carbon anode provided relatively flat charge and discharge potentials (0 to 0.3V vs. Li/Li+) and high current capability (310mAh·g-1). Compared with the carbon anode composed of artificial graphite particles having a smaller grain size (KS-6), improvement in charge-discharge efficiency of the carbon anode with KS-25 particles was able to be observed in several of the early cycles. Moreover, the relationship between the ζ-potential and additive concentration, as well as the relationship between the amount of graphite particles deposited on Cu substrate and pKa of additives, and the results of the XPS measurement of graphite particle surface suggested that the charging of the graphite particle surface was caused by the deprotonation of carboxyl and alcohol groups by additives such as TEA, TMG, and Py.
