晶界
材料科学
透射电子显微镜
微观结构
扫描透射电子显微镜
电子能量损失谱
电极
粒度
分析化学(期刊)
矿物学
结晶学
冶金
化学
纳米技术
色谱法
物理化学
作者
Shijian Zheng,Rong Huang,Yoshinari Makimura,Yoshio Ukyo,Craig A. J. Fisher,Tsukasa Hirayama,Yuichi Ikuhara
出处
期刊:Journal of The Electrochemical Society
[The Electrochemical Society]
日期:2011-02-09
卷期号:158 (4): A357-A362
被引量:137
摘要
The microstructure of LiNi 0.8 Co 0.15 Al 0.05 O 2 positive electrode material before and after the first cycle was investigated by scanning transmission electron microscopy (STEM) and electron energy loss spectroscopy (EELS). STEM and EELS analysis shows that, before cycling, there are very thin layers of material at grain boundaries that contain a small amount of transition metal ions (particularly Ni) on Li sites. After the first cycle, the thickness of some grain boundary layers increases significantly, accompanied by formation of microcracks at grain boundaries. Also, from the grain interior to the grain boundary, the structure gradually changes from an ordered layer structure (α-NaFeO 2 -type) to a partially ordered structure and then to a disordered rock-salt structure. We posit that these microstructural changes are primarily responsible for the irreversible capacity during the first cycle.
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