| 초록 |
The lithium transport through the graphite electrode in the coexistence of two staged-phases has been investigated in 1M LiAsF6-EC/DEC nonaqueous solution by using potentiostatic current transient technique supplemented by cyclic voltammetry and ac-impedance spectroscopy. The current peaks were observed in the cyclic voltammograms, indicating the occurrence of stage transformation in lithiated graphite. The smaller particle size of graphite is, the sharper are current peaks in cyclic voltammograms. The occurrence of current plateau in the potentiostatic current transients means that the stage transformation in lithiated graphite electrode is accompanied by the interface controlled phase boundary movement. The mobility of two staged-phases boundary and diffusivity of lithium ion through the graphite electrode were obtained from potentiostatic current transients and ac-impedance spectra, respectively as functions of particle size of graphite and electrode potential. The movement of two staged-phases boundary was discussed in terms of the stress developed by lattice mismatch between two staged-phases.
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