Alkali Metals Extraction Reactions with the Silicides Li15Si4 and Li3NaSi6: Amorphous Si versus allo-Si
Alkali Metals Extraction Reactions with the Silicides Li15Si4 and Li3NaSi6: Amorphous Si versus allo-Si
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DOI：
10.1021/cm503371e
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发表时间：
2014-11
影响因子：
8.6
通讯作者：
M. Zeilinger;Laura‐Alice Jantke;L. Scherf;F. Kiefer;G. Neubüser;L. Kienle;A. Karttunen;S. Konar;U. Häussermann;T. Fässler
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作者：
M. Zeilinger;Laura‐Alice Jantke;L. Scherf;F. Kiefer;G. Neubüser;L. Kienle;A. Karttunen;S. Konar;U. Häussermann;T. Fässler
分别用液氨和乙醇对硅化物Li 15 Si 4和Li 3 NaSi 6进行碱金属组分的化学萃取，洗涤后得到黑色的非晶硅粉末。所调查的反应是有趣的，相对于新的Si改性和脱锂过程中的Si阳极材料的形成。产物称为a-Si（来自Li 15 Si 4）和a-allo-Si（来自Li 3 NaSi 6）通过方法学的组合表征（X射线衍射、透射电子显微镜、差热分析、拉曼、原子吸收和能量色散X射线光谱），其揭示了（i）由尺寸约10 nm的球形颗粒构建的a-Si的多孔微观结构，（ii）两种材料的部分表面氧化和（iii）两种材料中纳米晶Si的存在。Li_3NaSi_6质子氧化的结果与早先报道的形成银的晶体块体同素异形体的结果不同。
The silicides Li15Si4 and Li3NaSi6 were subjected to chemical extraction of the alkali metal component by liquid ammonia and ethanol, respectively, which after washing yielded black powders of amorphous silicon. The investigated reactions are interesting with respect to both the formation of novel Si modifications and the delithiation process in Si anode materials. The products termed a-Si (from Li15Si4) and a-allo-Si (from Li3NaSi6) were characterized by a combination of methodologies (X-ray diffraction, transmission electron microscopy, differential thermal analysis, Raman, atomic absorption, and energy-dispersive X-ray spectroscopy) which revealed (i) a porous microstructure for a-Si built from spherically shaped particles with sizes around 10 nm, (ii) partial surface oxidation of both materials and (iii) the presence of nanocrystalline Si in both materials. The result of the protic oxidation of Li3NaSi6 is at variance with earlier findings reporting the formation of a crystalline bulk allotrope of sil...