Temperature Dependent Local Structure of NaxCoO2 Cathode Material for Rechargeable Sodium-Ion Batteries

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• 作者：Wojciech Olszewski ; Marta Ávila Pérez ; Carlo Marini ; Eugenio Paris ; Xianfen Wang ; Tatsumi Iwao ; Masashi Okubo ; Atsuo Yamada ; Takashi Mizokawa ; Naurang Lal Saini ; Laura Simonelli
• 刊名：Journal of Physical Chemistry C
• 出版年：2016
• 出版时间：March 3, 2016
• 年：2016
• 卷：120
• 期：8
• 页码：4227-4232
• 全文大小：384K
• ISSN：1932-7455

文摘

We have investigated the local structure of differently charged Na_xCoO₂ cathode material as a function of temperature by Co K-edge X-ray absorption fine structure (EXAFS) measurements. We have found that the charge/discharge process has a direct effect on the bond characteristics of the cathode in the Na-ion batteries. The results reveal that the local Co–O bonds get softer, while the Co–Co bonds hardly show any change during discharge (sodiation). The present study underlines the key role of local atomic displacements in diffusion and the reversibility of ions in cathodes for batteries and points toward the feasibility of Na_xCoO₂ to be used as a cathode material. The results are discussed in comparison with the lithiation/delithiation of Li_xCoO₂ battery materials.