X-ray Absorption Spectroscopic Study on La0.6Sr0.4CoO3鈭捨?/sub> Cathode Materials Related with Oxygen Vacancy Formation
详细信息 查看全文
- 作者：Yuki Orikasa ; Toshiaki Ina ; Takayuki Nakao ; Atsushi Mineshige ; Koji Amezawa ; Masatsugu Oishi ; Hajime Arai ; Zempachi Ogumi ; Yoshiharu Uchimoto
- 刊名：Journal of Physical Chemistry C
- 出版年：2011
- 出版时间：August 25, 2011
- 年：2011
- 卷：115
- 期：33
- 页码：16433-16438
- 全文大小：919K
- 年卷期：v.115,no.33(August 25, 2011)
- ISSN：1932-7455
文摘
The electronic structural changes of La0.6Sr0.4CoO3鈭捨?/sub> cathodes with oxygen vacancy formation by reducing oxygen partial pressures, p(O2)'s were investigated in detail using X-ray absorption spectroscopy to understand metallic-like electronic conduction mechanism. The oxygen nonstoichiometry of La0.6Sr0.4CoO3鈭捨?/sub> was controlled by annealing the samples under various p(O2)'s and quenched to room temperature. Co K-edge X-ray absorption near edge structure (XANES) spectra revealed that the Co average valence decreased with decreasing p(O2), which was also confirmed by iodometric titration. The Co L-edge XANES spectra were hardly changed with changing p(O2)'s. Meanwhile, the peak area of the O K-edge XANES spectra strongly depended on p(O2). This result revealed the strong hybridization between the O 2p and Co 3d states. It was concluded the introduction of oxygen vacancies narrowed the hybridized orbital of O 2p and Co 3d states, resulted in a decrease in the mobility as well as the concentration of electron holes with decreasing p(O2).