Analytical transmission electron microscopy investigation of electrochemically Li+?Na+ substituted LiNi0.5Mn1.5O4 electrode
Analytical transmission electron microscopy investigation of electrochemically Li+?Na+ substituted LiNi0.5Mn1.5O4 electrode
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Li-Na取代LiNi0.5Mn1.5O4电极的电化学分析透射电子显微镜研究
DOI：
10.1016/j.jssc.2022.123458
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发表时间：
2022
影响因子：
3.3
通讯作者：
Kojima Toshikatsu
中科院分区：
文献类型：
--
作者：
Kitta Mitsunori;Kataoka Riki;Kojima Toshikatsu
锂镍锰氧化物（LiNi0.5Mn1.5O4，LNMO）的电化学Li+-Na+碱性阳离子取代，其特征在于通过结构分析，先前已被报道。然而，缺乏详细的化学和电子特性的表征。在这项研究中，我们的特点是通过使用分析透射电子显微镜。能量色散X射线光谱（EDS）显示均匀的钠插入到一个单一的颗粒。电子能量损失谱（EELS）分析显示完全Li提取。Mn和NiL-边的能量损失近边结构（ELNES）表明，在Li+-Na +置换过程中，只有Ni作为Ni 2+惠Ni 4+参与氧化还原反应。使用EDS和EELS的元素组成比分析表明Na取代材料的化学式为Na 0.6Ni 0.5Mn 1.5O 3.8。在Na-插入过程中引起氧脱附，并且发现氧缺陷的形成对于LNMO材料的Li+-Na+取代机制是必不可少的。
The electrochemical Li+–Na+alkaline cation substitution of a lithium nickel manganese oxide (LiNi0.5Mn1.5O4, LNMO), which is characterized via structural analysis, has previously been reported. However, detail characterizations of the chemical and electronic features are lacking. In this study, we characterized that by using analytical transmission electron microscopy. Energy dispersive X-ray spectroscopy (EDS) revealed uniform Na-insertion into a single particle. Electron energy-loss spectroscopy (EELS) analysis exhibited complete Li-extraction. Energy loss near edge structure (ELNES) of Mn and NiL-edges indicated that only Ni contributes to the redox reaction as Ni2+⇔ Ni4+during the Li+–Na +substitution. The elemental composition ratio analysis using both EDS and EELS indicated Na0.6Ni0.5Mn1.5O3.8as a formula of the Na-substituted material. Oxygen desorption was provoked during the Na-insertion process, and oxygen defect formation was found to be essential for the Li+–Na+substitution mechanism of the LNMO material.