Changes in the structure and physical properties of the solid solution LiNi1−xMnxO2 with variation in its composition
Changes in the structure and physical properties of the solid solution LiNi1−xMnxO2 with variation in its composition
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DOI：
10.1039/b211558a
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发表时间：
2003-02
影响因子：
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通讯作者：
H. Kobayashi;H. Sakaebe;H. Kageyama;K. Tatsumi;Y. Arachi;T. Kamiyama
中科院分区：
文献类型：
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作者：
H. Kobayashi;H. Sakaebe;H. Kageyama;K. Tatsumi;Y. Arachi;T. Kamiyama
合成了层状氧化物LiNi 1 − xMnxO 2（x = 0.1-0.5），并使用同步加速器X射线衍射、TOF中子衍射、SQUID磁力仪、ICP光谱、XAFS和电化学测量进行了表征。所有样品均为单相，采用α-NaFeO 2结构; LiNi 1 − xMnxO 2可以表示为Li（Ni 2 + xNi 3 +1− 2xMn 4 +x）O2。使用同步加速器和中子衍射数据的结构分析表明，LiNi 0.5Mn 0.5O2的晶格参数为a = 2.892 A和c = 14.302 A，并且化学组成可以通过参考维科夫位置3a和3b表示为[Li 0.91 Ni 0.09]3a[Li0.09Mn0.5Ni0.41] 3bO 2。LiNi 1 − xMnxO 2的晶格参数a和c以及3a位的Ni含量随着Mn含量的增加而增加，直到x = 0.4，然后在x = 0.4和0.5之间几乎没有变化。随着x的增加，观察到Ni-O距离的增加。随着Ni ~（2+）和Mn ~（4+）含量的增加，在x = 0.4-0.5范围内明显出现铁磁性。Li/LiNi 1 − xMnxO 2电池的放电容量从190 mAh g−1（x = 0.1）降低到140 mAh g−1（x = 0.5）。
The layered oxides LiNi1−xMnxO2 (x = 0.1–0.5) were synthesized and characterized using synchrotron X-ray diffraction, TOF neutron diffraction, SQUID magnetometry, ICP spectroscopy, XAFS, and electrochemical measurements. All the samples were single-phase and adopted the α-NaFeO2 structure; LiNi1−xMnxO2 can be represented as Li(Ni2+xNi3+1−2xMn4+x)O2. Structural analysis using synchrotron and neutron diffraction data demonstrated that the lattice parameters of LiNi0.5Mn0.5O2 are a = 2.892 A and c = 14.302 A and that the chemical composition can be expressed by referring to the Wyckoff positions 3a and 3b as [Li0.91Ni0.09]3a[Li0.09Mn0.5Ni0.41]3bO2. The lattice parameters a and c and the fraction of Ni at the 3a site of LiNi1−xMnxO2 increased with Mn content up to the x = 0.4 composition and then showed little change between x = 0.4 and 0.5. An increase in the Ni–O distance was observed with increasing x. The appearance of ferromagnetism was clearly observed at x = 0.4–0.5 as the Ni2+ and Mn4+ content increased. The discharge capacity of the Li/LiNi1−xMnxO2 cell decreased from 190 mAh g−1 (x = 0.1) to 140 mAh g−1 (x = 0.5).