鋰離子於正、負極界面遷移的反應對於鋰電池的效能及壽命息息相關，以往對於該反應的探討是藉由量測整個電池的阻抗來進行分析，但因為涉及的界面反應眾多，因此無法有效獨立各界面的貢獻。本研究利用自行開發可表面分析的雙電極掃描探針 (dual-electrode scanning probe, DESP)與縱向阻抗量測的單極探針，對鋰鈦氧 (Li4Ti5O12) 半電池進行界面阻抗分析，藉此將各層界面對整個電池的貢獻分離。
DESP透過兩針頭將電流侷限於鋰鈦氧表面，探討電極隨著循環反應的阻抗變化，從等效電路的擬合成功將活性材 (active material) 的貢獻從電極中獨立。量測結果顯示活性材阻抗在前6次循環會因為電極活化的現象而逐步下降，再於後續循環因電極衰退而上升。該現象與半電池在不同循環狀態下的電荷轉移阻抗變化相同，推論是造成電池活化的主要反應。
在半電池反應時鋰金屬會於表面生成一層成分複雜的固態電解質界面 (solid electrolyte interface，SEI) ，其結構組成與穩定性亦是造成電池衰退的重要因素。為了解SEI各層組成與阻抗之關聯性，本實驗透過化學分析電子光譜儀 (ESCA)鑑定SEI縱深成分，再以單極探針對SEI表面微區加工，針對不同組成的SEI進行縱向的阻抗分析。藉由ESCA分析結果的輔助，解析SEI各層成分對阻抗變化的貢獻，結果顯示SEI阻抗除了因厚度增加而上升之外，位於表層較薄的碳化物相比於內部較厚的氧化層是造成SEI阻抗遽增的主要原因。此外，在加工的過程中也觀察到SEI的去除並非均勻地層層向下，該現象是因各層的硬度不同所致，所觀察的硬度由小而大分別對應到最外層的多孔有機物而至內層的無機物。
本實驗以探針阻抗為基礎的量測技術對鋰離子電池界面進行分析，並利用微區加工進一步對SEI各層阻抗進行分離，上述技術的建立成功為成分複雜與非均勻組成的系統提供一個微觀的分析方式。

With the knowledge of the interfacial reactions between the electrolyte and electrodes, the mechanism of the lithium ion batteries (LIB) can be understood in detail. Researchers had studied the interfacial reactions by measuring the impedance of the whole cell. However, this information is related to several interfaces inside the cell, which makes it difficult to distinguish the impedance contributions. In this study, the impedance contribution of individual electrodes material was examined. A self-designed dual-electrode scanning probe (DESP) and local impedance measurement (LIM) of commercial AFM probes were adapted for the half-cell configuration.
Combining the DESP and the analysis method, the impedance of the active material could be distinguished from the Li4Ti5O12 (LTO) electrode. It is found that the electrode is activated initially and starts to decay after the sixth cycling, which results in the decrease but then increase in impedance. The same trend was also observed for the charge transfer resistance of the LTO half-cell, which shows that the activation of LTO indeed dominates cell performance. Except for the impedance, the composition and stability of the solid electrolyte interface (SEI) formed on the lithium foil during cycling, were also related to the decay of the cell. By scratching the SEI and analyzing the depth profiling of Electron Spectroscopy for Chemical Analysis (ESCA), the impedance contribution of each SEI layer could be measured. The results showed that positive correlation between the impedance and thickness of SEI, and the carbide layer among SEI played a significant role in the increasing impedance rather than the oxide layer. Besides, the removal depth of the SEI during each scratching was different with the same scratching parameters, which was due to the differences in hardness of each SEI layer.
In this work, the interface reactions of LIB were studied and the impedance of each layer was characterized. With the application of the techniques used in the experiment, we provide a way for analyzing the heterogeneous and complex composite materials.

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