Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1294704 | Journal of Power Sources | 2008 | 5 Pages |
Abstract
Structural changes of bare and AlPO4-coated LixCoO2 with a coating thickness of 20 and 200 nm are investigated at x = 0.24 and 0.1 after thermal annealing at 200, 300, and 400 °C using XRD and Co K-edge XANES (X-ray absorption near-edge structure) and EXAFS (extended X-ray absorption fine structure). Both the bare and coated cathodes exhibit faster phase transformation into spinel phases at lower annealing temperatures as x in LixCoO2 is decreased. Bare LixCoO2 cathodes exhibit phase transitions from LixCo2O4 to Co3O4 spinel as the annealing temperature is increased and the x is value decreased, which suggests a possible reaction according to (1/2)LixCo2O4 â xLi2CO3 + (1/3)Co3O4 + (2/3)O2. However, the coated cathodes sustain a LixCo2O4 phase even at 400 °C and x = 0.1. This indicates that the AlPO4 coating layer suppresses the LixCo2O4 phase decomposition into Co3O4.
Related Topics
Physical Sciences and Engineering
Chemistry
Electrochemistry
Authors
Yoojung Kim, Youngsik Hong, Kwang Sun Ryu, Min Gyu Kim, Jaephil Cho,