Visualization of Inhomogeneous Reaction Distribution in the Model LiCoO2 Composite Electrode of Lithium Ion Batteries
Visualization of Inhomogeneous Reaction Distribution in the Model LiCoO2 Composite Electrode of Lithium Ion Batteries
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DOI：
10.1021/acs.jpcc.6b12133
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发表时间：
2017-01
影响因子：
3.7
通讯作者：
Takashi Nakamura;Toshiki Watanabe;Y. Kimura;K. Amezawa;K. Nitta;H. Tanida;K. Ohara;Y. Uchimoto;Z. Ogumi
中科院分区：
文献类型：
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作者：
Takashi Nakamura;Toshiki Watanabe;Y. Kimura;K. Amezawa;K. Nitta;H. Tanida;K. Ohara;Y. Uchimoto;Z. Ogumi
采用二维x射线吸收光谱法从Co k边x射线吸收光谱中峰顶能量的位移来观察LiCoO2复合电极中的反应分布。利用将LiCoO2复合电极夹在铝箔和聚酰亚胺离子阻断层之间的模型电极，评估了离子传输对非均相反应的影响。当模型电极以6、9和12 mA cm-2的电流充电时，观察到的容量分别为51、20和12 mAh g-1， Co k边缘x射线吸收光谱中峰顶能量的位移显示的带电区域分别在距离电极边缘约700、500和200 μm的范围内形成。观察到的反应分布表明，由于电化学过程的电位损失较大，电化学活性区随着电流密度的增加而减小。
Two-dimensional X-ray absorption spectroscopy was carried out to observe the reaction distribution in a LiCoO2 composite electrode from the shift of the peak top energy in Co K-edge X-ray absorption spectra. The influence of ionic transportation to the inhomogeneous reaction was evaluated by using the model electrode, which sandwiched the LiCoO2 composite electrode between an aluminum foil and a polyimide ion blocking layer. When the model electrode was charged with the currents of 6, 9, and 12 mA cm–2, the observed capacities were 51, 20, and 12 mAh g–1 and the charged areas visualized from the shift of the peak top energy in Co K-edge X-ray absorption spectra were formed within ca. 700, 500, and 200 μm from the edge of the electrode, respectively. The observed reaction distribution indicated that the electrochemically active region decreases with increasing the current density because of the large potential loss of the electrochemical processes.