Atomic Structure of Li2MnO3 after Partial Delithiation and Re-Lithiation
Atomic Structure of Li2MnO3 after Partial Delithiation and Re-Lithiation
复制标题
部分脱锂和再锂化后Li2MnO3的原子结构
DOI：
10.1002/aenm.201200842
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发表时间：
2013-10-01
影响因子：
27.8
通讯作者：
Chen, Liquan
中科院分区：
文献类型：
--
作者：
Wang, Rui;He, Xiaoqing;Chen, Liquan
Li_2MnO_3是高能量密度锂离子电池正极材料xLi（2）MnO（3）中心点（1-x）LiMO_2的母体化合物。Li 2 MnO 3具有非常高的理论容量，为458 mA h g（-1），用于提取2 Li。然而，Li 2 MnO 3和富锂锰基正极材料的脱锂和锂化行为以及相应的结构演变机制仍然不是很清楚。利用球差校正扫描透射电子显微镜（STEM）对Li 2 MnO 3部分脱锂和再锂化前后的原子结构进行了观察。Li 2 MnO 3中的所有原子都可以在环形亮场图像中直接可视化。因此，证实了在电化学脱锂之后，锂可以从LiMn 2平面中提取，并且一些锰原子可以迁移到Li层中。此外，当Mn原子在（001）面内的位置约为0时，Mn原子可以在（001）面内可逆地移动。18.6%的锂被提取，12.4%的锂被重新插入。在第一次循环中，在Li1.63MnO3的某些区域中也观察到LiMnO 2畴。Li1.63MnO3和Li 2 MnO中氧的位置和占有率没有显著差异
Li2MnO3 is the parent compound of the well-studied Li-rich Mn-based cathode materials xLi(2)MnO(3)center dot(1-x)LiMO2 for high-energy-density Li-ion batteries. Li2MnO3 has a very high theoretical capacity of 458 mA h g(-1) for extracting 2 Li. However, the delithiation and lithiation behaviors and the corresponding structure evolution mechanism in both Li2MnO3 and Li-rich Mn-based cathode materials are still not very clear. In this research, the atomic structures of Li2MnO3 before and after partial delithiation and relithiation are observed with spherical aberration-corrected scanning transmission electron microscopy (STEM). All atoms in Li2MnO3 can be visualized directly in annular bright-field images. It is confirmed accordingly that the lithium can be extracted from the LiMn2 planes and some manganese atoms can migrate into the Li layer after electrochemical delithiation. In addition, the manganese atoms can move reversibly in the (001) plane when ca. 18.6% lithium is extracted and 12.4% lithium is re-inserted. LiMnO2 domains are also observed in some areas in Li1.63MnO3 at the first cycle. As for the position and occupancy of oxygen, no significant difference is found between Li1.63MnO3 and Li2MnO