Li 1+ x Mn 2– x O 4尖晶石中x = 0.05和0.10的形貌和表面反应性关系：组合的第一性原理和实验研究,ACS Applied Materials & Interfaces

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Li _{1+ x} Mn _{2– x} O ₄尖晶石中x = 0.05和0.10的形貌和表面反应性关系：组合的第一性原理和实验研究
ACS Applied Materials & Interfaces ( IF 8.3 ) Pub Date : 2017-12-15 00:00:00 , DOI: 10.1021/acsami.7b15249
Ambroise Quesne-Turin _{1,

2,

3} , Germain Vallverdu _{1,

3} , Delphine Flahaut _{1,

3} , Joachim Allouche ₁ , Laurence Croguennec _{2,

3} , Michel Ménétrier _{2,

3} , Isabelle Baraille _{1,

3}

Affiliation

本文集中在两个尖晶石样品与不同的化学计量和晶体形态，所述表面的反应性，即锂_{1+ X}锰_{2- X} ø ₄与X = 0.05和0.10。LiMn ₂ O ₄化合物非常适合作为便携式设备大功率锂离子电池的正极。使用实验和理论方法对样品进行了研究。从实验的角度来看，它们通过X射线衍射，扫描电子显微镜和X射线光电子能谱（XPS）分析进行了深度表征。然后，通过（SO ₂）气体探针，在受控条件下进行XPS表征。同时进行第一性原理计算，以研究理想LiMn ₂ O ₄材料的电子性能和相关表面的反应性。结果使我们得出结论，样品的反应性主要由酸碱性反应性和亚硫酸盐物质的形成所决定。但是，在x = 0.05的样品上，同时获得了亚硫酸盐和硫酸盐物质，后者的程度较小，对应于氧化还原反应性。结合实验和理论结果，该氧化还原反应性可能与大量Mn ⁴⁺的存在有关材料的最后表面层上的阳离子与特定的表面方向相关。

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Morphology and Surface Reactivity Relationship in the Li1+xMn2–xO4 Spinel with x = 0.05 and 0.10: A Combined First-Principle and Experimental Study

This article focuses on the surface reactivity of two spinel samples with different stoichiometries and crystal morphologies, namely Li_1+xMn_2–xO₄ with x = 0.05 and 0.10. LiMn₂O₄ compounds are good candidates as positive electrode of high-power lithium-ion batteries for portable devices. The samples were investigated using both experimental and theoretical approaches. On the experimental point of view, they were characterized in depth from X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy (XPS) analyses. Then, the reactivity was investigated through the adsorption of (SO₂) gaseous probes, in controlled conditions, followed by XPS characterization. First-principle calculations were conducted simultaneously to investigate the electronic properties and the reactivity of relevant surfaces of an ideal LiMn₂O₄ material. The results allow us to conclude that the reactivity of the samples is dominated by an acido-basic reactivity and the formation of sulfite species. Nonetheless, on the x = 0.05 sample, both sulfite and sulfate species are obtained, the later, in lesser extent, corresponding to a redox reactivity. Combining experimental and theoretical results, this redox reactivity could be associated with the presence of a larger quantity of Mn⁴⁺ cations on the last surface layers of the material linked to a specific surface orientation.

更新日期：2017-12-15

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