Simultaneous Reduction of Co3+ and Mn4+ in P2-Na2/3Co2/3Mn1/3O2 As Evidenced by X-ray Absorption Spectroscopy during Electrochemical Sodium Intercalation

被引：96

作者：

Cheng, Ju-Hsiang ^{[1
]}

Pan, Chun-Jern ^{[1
]}

Lee, Jyh-Fu ^{[2
]}

Chen, Jin-Ming ^{[2
]}

Guignard, Marie ^{[3
]}

Delmas, C. ^{[3
]}

Carlier, Dany ^{[3
]}

Hwang, Bing-Joe ^{[1
,2
]}

机构：

[1] NTUST, Dept Chem Engn, Taipei 106, Taiwan

[2] NSRRC, Hsinchu 30076, Taiwan

[3] Univ Bordeaux, CNRS, ICMCB, UPR 9048, F-33600 Pessac, France

来源：

CHEMISTRY OF MATERIALS | 2014年 / 26卷 / 02期

关键词：

CATHODE MATERIAL; ELECTRONIC-STRUCTURE; BEHAVIOR; EDGE;

D O I：

10.1021/cm403597h

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

Sodium intercalation in P2-Na2/3Co2/3Mn1/3O2 (obtained by a coprecipitation method) was investigated by ex situ and in situ X-ray absorption spectroscopy. The electronic transitions at the O K-edge and the charge compensation mechanism, during the sodium intercalation process, were elucidated by combining Density Function Theory (DFT) calculations and X-ray absorption spectroscopy (XAS) data. The pre-edge of the oxygen K-edge moves to higher energy while the integrated intensity dramatically decreases, indicating that the population of holes in O 2p states is reduced with increasing numbers of sodium ions. From the K-edge and L-edge observations, the oxidation states of pristine Co and Mn were determined to be +III and +IV, respectively. The absorption energy shifts to lower positions during the discharging process for both the Co and the Mn edges, suggesting that the redox pairs, that is, Co3+/Co2+ and Mn4+/Mn3+, are both involved in the reaction.

引用

页码：1219 / 1225

页数：7

共 28 条

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