X-ray absorption spectroscopic study on La0.6Sr 0.4CoO3-δ cathode materials related with oxygen vacancy formation

Yuki Orikasa; Toshiaki Ina; Takayuki Nakao; Atsushi Mineshige; Koji Amezawa; Masatsugu Oishi; Hajime Arai; Zempachi Ogumi; Yoshiharu Uchimoto

doi:10.1021/jp2029642

X-ray absorption spectroscopic study on La_0.6Sr _0.4CoO_3-δ cathode materials related with oxygen vacancy formation

Yuki Orikasa, Toshiaki Ina, Takayuki Nakao, Atsushi Mineshige, Koji Amezawa, Masatsugu Oishi, Hajime Arai, Zempachi Ogumi, Yoshiharu Uchimoto

IMRAM - Division of Process and System Engineering

Research output: Contribution to journal › Article › peer-review

57 Citations (Scopus)

Abstract

The electronic structural changes of La_0.6Sr _0.4CoO_3-δ 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 La _0.6Sr_0.4CoO_3-δ 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).

Original language	English
Pages (from-to)	16433-16438
Number of pages	6
Journal	Journal of Physical Chemistry C
Volume	115
Issue number	33
DOIs	https://doi.org/10.1021/jp2029642
Publication status	Published - 2011 Aug 25

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title = "X-ray absorption spectroscopic study on La0.6Sr 0.4CoO3-δ cathode materials related with oxygen vacancy formation",

abstract = "The electronic structural changes of La0.6Sr 0.4CoO3-δ 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 La 0.6Sr0.4CoO3-δ 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).",

author = "Yuki Orikasa and Toshiaki Ina and Takayuki Nakao and Atsushi Mineshige and Koji Amezawa and Masatsugu Oishi and Hajime Arai and Zempachi Ogumi and Yoshiharu Uchimoto",

year = "2011",

month = aug,

day = "25",

doi = "10.1021/jp2029642",

language = "English",

volume = "115",

pages = "16433--16438",

journal = "Journal of Physical Chemistry C",

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T1 - X-ray absorption spectroscopic study on La0.6Sr 0.4CoO3-δ cathode materials related with oxygen vacancy formation

AU - Orikasa, Yuki

AU - Ina, Toshiaki

AU - Nakao, Takayuki

AU - Mineshige, Atsushi

AU - Amezawa, Koji

AU - Oishi, Masatsugu

AU - Arai, Hajime

AU - Ogumi, Zempachi

AU - Uchimoto, Yoshiharu

PY - 2011/8/25

Y1 - 2011/8/25

N2 - The electronic structural changes of La0.6Sr 0.4CoO3-δ 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 La 0.6Sr0.4CoO3-δ 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).

AB - The electronic structural changes of La0.6Sr 0.4CoO3-δ 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 La 0.6Sr0.4CoO3-δ 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).

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X-ray absorption spectroscopic study on La_0.6Sr _0.4CoO_3-δ cathode materials related with oxygen vacancy formation

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