Effects of HF on the Lithiation Behavior of the Silicon Anode in LiPF6 Organic Electrolyte Solution
Effects of HF on the Lithiation Behavior of the Silicon Anode in LiPF6 Organic Electrolyte Solution
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HF对硅负极在LiPF6有机电解质溶液中锂化行为的影响
DOI：
10.1021/acsomega.9b01665
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发表时间：
2020
期刊：
影响因子：
4.1
通讯作者：
Kohei Uosaki
中科院分区：
文献类型：
--
作者：
Huiwen Lin;Hidenori Noguchi;Kohei Uosaki
作为有机电解质中的主要杂质之一，HF可以与固体电解质中间相（SEI）中的碱性组分（例如，锂醇盐和碳酸锂）反应以形成更多的富LiF的SEI。在这里，HF对单晶Si（111）阳极的锂化行为的影响进行了研究，使用扫描电子显微镜，软X射线发射光谱，和无窗能量色散X射线光谱。当在碳酸亚丙酯溶剂中的1.0 M LiPF 6中形成Li-Si合金时，它具有分层结构，其中包含第一层结晶Li 15 Si 4（c-Li 15 Si 4）合金金字塔、第二层非晶Li 13 Si 4（a-Li 13 Si 4）合金和第三层Li扩散的LixSi合金。当电解质溶液中的HF浓度越高时，在第一层中形成的c-Li 15 Si 4合金的量越少。这表明，相对于电解质中的组分，Si锂化只能形成非晶态LixSi合金。该研究还解释了为什么在以前的一些研究中只观察到非晶LixSi合金的形成。
As one of the major impurities in the organic electrolyte, HF can react with the alkali components in the solid electrolyte interphase (SEI), such as lithium alkoxide and lithium carbonate, to form more LiF-rich SEI. Here, the effects of HF on the lithiation behavior of the single crystal Si(111) anode were studied using scanning electron microscopy, soft X-ray emission spectroscopy, and windowless energy-dispersive X-ray spectroscopy. When the Li–Si alloy is formed in 1.0 M LiPF6in the propylene carbonate solvent, it has a layered structure that contained the first layer of crystalline Li15Si4(c-Li15Si4) alloy pyramids, the second layer of amorphous Li13Si4(a-Li13Si4) alloy, and a third layer of Li-diffused LixSi alloy. When the more concentrated HF is in the electrolyte solution, less amount of the c-Li15Si4alloy is formed in the first layer. It suggests that the Si lithiation can form only amorphous LixSi alloy relative to the components in the electrolytes. The study also explains why only amorphous LixSi alloy formation was observed in some previous studies.