Unfolding the Mechanism of Sodium Insertion in Anatase TiO2 Nanoparticles
Unfolding the Mechanism of Sodium Insertion in Anatase TiO2 Nanoparticles
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DOI：
10.1002/aenm.201401142
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发表时间：
2015-01-21
影响因子：
27.8
通讯作者：
Passerini, Stefano
中科院分区：
文献类型：
--
作者：
Wu, Liming;Bresser, Dominic;Passerini, Stefano
通常认为，钠离子电池化学表现出与更频繁研究的锂离子化学相似的行为。然而，这项工作表明，至少在锐钛矿型二氧化钛的情况下，存在着巨大的、相当令人惊讶的差异。通过原位X射线衍射、非原位X射线光电子能谱、扫描电子显微镜和拉曼光谱研究表明，虽然通常更还原的锂离子可逆地插入锐钛矿型二氧化钛晶格中，但钠离子似乎部分还原了相当稳定的氧化物，形成了金属钛、氧化钠和无定形钛酸钠。然而，一旦锐钛矿型二氧化钛的电化学转化完成，新形成的材料具有非常稳定的长期循环性能、出色的高倍率性能和优异的库仑效率，使其成为一种非常有前途的钠离子电池负极材料。
It is frequently assumed that sodium-ion battery chemistry exhibits a behavior that is similar to the more frequently investigated lithium-ion chemistry. However, in this work it is shown that there are great, and rather surprising, differences, at least in the case of anatase TiO2. While the generally more reducing lithium ion is reversibly inserted in the anatase TiO2 lattice, sodium ions appear to partially reduce the rather stable oxide and form metallic titanium, sodium oxide, and amorphous sodium titanate, as revealed by means of in situ X-ray diffraction, ex situ X-ray photoelectron spectroscopy, scanning electron microscopy, and Raman spectroscopy. Nevertheless, once the electrochemical transformation of anatase TiO2 is completed, the newly formed material presents a very stable long-term cycling performance, excellent high rate capability, and superior coulombic efficiency, highlighting it as a very promising anode material for sodium-ion battery applications.