In situ X-ray diffraction studies of mixed LiMn2O4–LiNi1/3Co1/3Mn1/3O2 composite cathode in Li-ion cells during charge–discharge cycling
In situ X-ray diffraction studies of mixed LiMn2O4–LiNi1/3Co1/3Mn1/3O2 composite cathode in Li-ion cells during charge–discharge cycling
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DOI：
10.1016/j.jpowsour.2009.02.088
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发表时间：
2009-07
影响因子：
9.2
通讯作者：
K. Nam;W. Yoon;Hyunjung Shin;K. Chung;Seung-Don Choi;Xiao‐Qing Yang
中科院分区：
文献类型：
--
作者：
K. Nam;W. Yoon;Hyunjung Shin;K. Chung;Seung-Don Choi;Xiao‐Qing Yang
用原位X射线衍射仪研究了尖晶石LiMn2O4和层状LiNi1/3Co1/3Mn1/3O2以1：1wt%的比例混合在锂离子电池和锂离子电池中制成的复合正极在充放电过程中的结构变化。在首次充电至∼5.2V vs.Li/Li+的过程中，Li-Half电池复合阴极的原位X射线衍射谱跟踪了各组分的结构变化。在充电初期，锂的提取只发生在LiNi1/3Co1/3Mn1/3O2组分中。当电池电压达到∼4.0V vs.Li/Li+时，从尖晶石LiMn2O4组分中提取锂开始，并由于LiMn2O4具有更高的倍率能力而成为电池容量的主要贡献者。当电压超过4.3V时，LiNi1/3Co1/3Mn1/3O2组分发生了主要的结构变化，而LiMn2O4组分几乎没有变化。在使用MCMB阳极和复合阴极的锂离子电池中，在2.5~4.2V之间循环，结构变化以尖晶石LiMn2O4组分为主，与Li-Half电池相比，层状LiNi1/3Co1/3Mn1/3O2组分的变化要小得多。这些结果为我们提供了有关特定充放电状态下各组分对电池容量贡献的结构变化的有价值的信息，有助于设计和优化用于锂离子电池研究的尖晶石和层状材料的复合正极。
The structural changes of the composite cathode made by mixing spinel LiMn2O4and layered LiNi1/3Co1/3Mn1/3O2in 1:1wt% in both Li-half and Li-ion cells during charge/discharge are studied by in situ XRD. During the first charge up to ∼5.2V vs. Li/Li+, the in situ XRD spectra for the composite cathode in the Li-half cell track the structural changes of each component. At the early stage of charge, the lithium extraction takes place in the LiNi1/3Co1/3Mn1/3O2component only. When the cell voltage reaches at ∼4.0V vs. Li/Li+, lithium extraction from the spinel LiMn2O4component starts and becomes the major contributor for the cell capacity due to the higher rate capability of LiMn2O4. When the voltage passed 4.3V, the major structural changes are from the LiNi1/3Co1/3Mn1/3O2component, while the LiMn2O4component is almost unchanged. In the Li-ion cell using a MCMB anode and a composite cathode cycled between 2.5V and 4.2V, the structural changes are dominated by the spinel LiMn2O4component, with much less changes in the layered LiNi1/3Co1/3Mn1/3O2component, comparing with the Li-half cell results. These results give us valuable information about the structural changes relating to the contributions of each individual component to the cell capacity at certain charge/discharge state, which are helpful in designing and optimizing the composite cathode using spinel- and layered-type materials for Li-ion battery research.