In Situ Observation of Lithiation and Delithiation Reactions of a Silicon Thin Film Electrode for All-Solid-State Lithium-Ion Batteries by X-ray Photoelectron Spectroscopy
In Situ Observation of Lithiation and Delithiation Reactions of a Silicon Thin Film Electrode for All-Solid-State Lithium-Ion Batteries by X-ray Photoelectron Spectroscopy
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DOI：
10.1021/acs.jpclett.0c01906
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发表时间：
2020-08-20
影响因子：
5.7
通讯作者：
Masuda, Takuya
中科院分区：
文献类型：
--
作者：
Endo, Raimu;Ohnishi, Tsuyoshi;Masuda, Takuya
用X射线光电子能谱（XPS）原位研究了沉积在Li6.6La3Zr1.6Ta0.4O12固体电解质上的非晶Si电极的电化学锂化/脱锂过程。在第一次锂化之后，宽的Li峰出现在Si表面，并且对应于体Si和Si低价氧化物的峰显著地向较低的结合能偏移。Li峰的出现和Si峰的位移证实了由于Si和天然低价氧化物的锂化而形成锂硅化物和锂硅酸盐。通过电化学响应和光电子能谱的定量分析，推测硅化锂的组成为Li_（3.44）Si。峰拟合分析显示由于副反应而形成Li 2 O和Li 2CO 3。在随后的脱锂时，对应于Li3.44Si相的峰移回到较高的结合能以形成Li0.15Si相，而硅酸锂、Li 2 O和Li 2CO 3保持为不可逆物质。因此，成功地观察到伴随锂化/脱锂过程的电化学反应。
In situ X-ray photoelectron spectroscopy is applied to electrochemical lithiation/delithiation processes of an amorphous Si electrode sputter-deposited on a Li6.6La3Zr1.6Ta0.4O12 solid electrolyte. After the first lithiation, a broad Li peak appears at the Si surface, and peaks corresponding to bulk Si and Si suboxide significantly shift to lower binding energy. The appearance of the Li peak and shift of the Si peaks confirm the formation of lithium-silicide and lithium-silicates due to the lithiation of Si and native suboxide. The composition of lithium-silicide is estimated to be Li3.44Si by quantitative analysis of electrochemical response and photoelectron spectra. Peak fitting analysis shows the formation of Li2O and Li2CO3 due to side reactions. Upon the following delithiation, the peak corresponding to Li3.44Si phase shifts back to higher binding energy to form Li0.15Si phase, while lithium-silicates, Li2O, and Li2CO3 remained as irreversible species. Thus, electrochemical reactions accompanied with lithiation/delithiation processes are successfully observed.