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Impact of lithium composition on the thermoelectric properties of the layered cobalt oxide system LixCoO2
| Title: | Impact of lithium composition on the thermoelectric properties of the layered cobalt oxide system LixCoO2 |
| Authors: | Motohashi, T. Browse this author | | Sugimoto, Y. Browse this author | | Masubuchi, Y. Browse this author | | Sasagawa, T. Browse this author | | Koshibae, W. Browse this author | | Tohyama, T. Browse this author | | Yamauchi, H. Browse this author | | Kikkawa, S. Browse this author |
| Issue Date: | 15-May-2011 |
| Publisher: | American Physical Society |
| Journal Title: | Physical Review B |
| Volume: | 83 |
| Issue: | 19 |
| Start Page: | 195128 |
| Publisher DOI: | 10.1103/PhysRevB.83.195128 |
| Abstract: | Thermoelectric properties of the layered cobalt oxide system LixCoO2 were investigated in a wide range of Li compositions, 0.98 ≥ x ≥ 0.35. Single-phase bulk samples of LixCoO2 were successfully obtained through electrochemical deintercalation of Li from the pristine LiCoO2 phase. While LixCoO2 with x ≥ 0.94 is semiconductive, the highly Li-deficient phase (0.75 ≥ x ≥ 0.35) exhibits metallic conductivity. The magnitude of the Seebeck coefficient at 293 K (S293K) significantly depends on the Li content (x). The S293K value is as large as +70 up to +100μV/K for x ≥ 0.94, and it rapidly decreases from +90μV/K to +10μV/K as x is lowered within a Li composition range of 0.75 ≥ x ≥ 0.50. This behavior is in sharp contrast to the results of x ≤ 0.40 for which the S293K value is small and independent of x (+10μV/K), indicating that a discontinuous change in the thermoelectric characteristics takes place at x = 0.40-0.50. The unusually large Seebeck coefficient and metallic conductivity are found to coexist in a narrow range of Li composition at about x = 0.75. The coexistence, which leads to an enhanced thermoelectric power factor, may be attributed to unusual electronic structure of the two-dimensional CoO2 block. |
| Rights: | ©2011 American Physical Society |
| Type: | article |
| URI: | http://hdl.handle.net/2115/45609 |
| Appears in Collections: | 工学院・工学研究院 (Graduate School of Engineering / Faculty of Engineering) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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Submitter: 本橋 輝樹
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