Hydrothermal synthesis of orthorhombic LiCoxMn1-xO2 and their structural changes during cycling
Hydrothermal synthesis of orthorhombic LiCoxMn1-xO2 and their structural changes during cycling
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DOI：
10.1149/1.1504453
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发表时间：
2002-10
影响因子：
3.9
通讯作者：
Seung‐Taek Myung;S. Komaba;N. Kumagai
中科院分区：
文献类型：
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作者：
Seung‐Taek Myung;S. Komaba;N. Kumagai
采用水热法合成了Co掺杂的正交相LiMnO 2粉体以（CoxMn 1-x）3 O 4为前驱体，在170°C下与氢氧化锂水溶液反应，合成了具有良好化学计量比的正交相结构的CoxMn 1-x氧化物（LiCoxMn 1-xO 2，Pmnm），具有较宽的取代范围（0 ≤ x ≤ 0.14）.制备的粉体为单晶颗粒氧化物，用高分辨透射电子显微镜直接观察到LiCo0.14Mn0.86O2的层间距约为5.7A的层状结构。在LiCoxMn 1-xO 2中掺入x = 0.1的Co，可显著改善其作为锂离子电池正极的循环性能。Co在o-LiMnO 2中Mn位的取代不仅改善了其结构完整性，而且提高了其在长期循环中的容量保持率。这种新的水热合成方法有望成为制备锂离子二次电池高容量正极材料的一种优良的替代粉体制备方法。
Co-doped orthorhombic LiMnO 2 powders were synthesized by the hydrothermal treatment of tetragonal (Co x Mn 1-x ) 3 O 4 as a precursor with aqueous lithium hydroxide solution at 170°C, The X-ray diffraction and chemical analyses of the hydrothermal products confirmed a well-ordered stoichiometric orthorhombic structure (LiCo x Mn 1-x O 2 , Pmnm) with the wide substitution range of 0 ≤ x ≤ 0.14. The prepared powders were single-crystallite particle oxides, and the layer structure of about 5.7 A spacing for LiCo 0.14 Mn 0.86 O 2 was directly observed by high-resolution transmission electron microscopy. The Co doping of x = 0.1 in LiCo x Mn 1-x O 2 was effective in improving the cycling performance as a Li-ion battery cathode substantially. The Co substitution in Mn sites of o-LiMnO 2 was not only to improve the structural integrity, but also to enhance high capacity retention upon extensive cycling. This new hydrothermal synthesis is expected to be an excellent alternative powder preparation method of high-capacity cathode materials to be used for Li-ion secondary batteries.