鋰金屬二次電池不論在業界或是學術界，都被視為未來20-50年內的主要動力來源之一，其因使用的鋰金屬擁有較高的理論電容量(3,860 mAh/g)、較低的電化學還原電位(-3.04 V vs. SHE)，成為高能量密度儲能設備的首選材料，此外能提升電池能量密度亦是設計簡單的無陽極系統，可省去陽極的活性材料留下集電器，故能將電池的體積和重量得以最小化，不僅製程手法簡單也能降低材料成本，並且有望開拓更廣的應用前景。但因無陽極電池可逆性差，可能會與電解液產生副反應，使陰極有限的鋰逐漸被消耗，降低了電池的循環壽命，同時也存在安全問題，成為當前棘手的問題。
為了解決無陽極電池系統的潛在缺陷，我們必須了解鋰枝晶複雜的生長機制，因此在本工作中，實現強大的影像分析技術，用於釐清電池內部的電化學現象，而專門設計和改良原位電池載具，以獨特的真空方形電池設計，確保電池在傳輸至SEM腔體時，能夠絕對隔絕環境中的水、氧，實驗中將使用截面平整的方形電池進行量測，相對於市售常見的圓形鈕扣電池有較大的觀測平台，透過無窗口的觀測方法，將電子束直接打在待測樣品上可提高影像的解析度，依照實驗需求可適時調控環境溫度、供應穩定的電流，獲得當前及時的影像資訊。
研究中將對電池施加不同電流密度，觀察PEO機械強度對鋰生長的抑制效果，此外將利用Li||SS、Li||Cu兩種系統，比較鋰生長形貌差異的因素，並且使用映射(Mapping)，針對PEO中的C元素的分布型態，進行動態表徵分析，了解PEO與沉積鋰交互作用的結果，此強大的分析結果可對未來在開發新型的儲能系統提供更關鍵、詳盡的優化資訊。

Rechargeable lithium metal batteries, recognized as the major energy storage systems in the next 20-50 years by both the industry and academia, have attracted significantly research interests. This can be attributed to the high theoretical capacity (3,860 mAh/g) and low reduction potential (-3.04 V vs. SHE) of metallic lithium. With the intrinsic properties mentioned above, lithium metal batteries have become the preferred high energy density energy storage devices. Anode-free lithium metal batteries (AFLMBs) are reported to further improve the energy density of the battery effectively via a simplified cell configuration, namely the absence of the initial Li anode. In other words, the remained anode electrode of the cell is the bare current collector. Thus, the modified cell configuration minimizes the volume and weight of the AFLMB, leading to ease of battery fabrication and cost. It is expected that AFLMBs will develop a broad application prospects in the near future.
However, the anode-free lithium metal battery has poor reversibility and may cause side reactions related to the electrolyte. The limited active lithium in the cathode material is gradually consumed upon cycling, which significantly restrict the cycle life. Moreover, the growth of lithium dendrites on the current collector also gives rise to safety concerns, which has become one of the most critical issues impeding the practical application of AFLMBs.
In this regard, the implement of in-situ electron microscopy will can provide the most direct evidence and understanding of the lithium growth behavior under different testing conditions. In this work, realize powerful image analysis technology to clarify the electrochemical phenomena inside the battery. The unique design of the vacuum square holder ensures the isolation of battery materialst from H2O and O2 in the environment during the transferr to the SEM chamber. For the in-situ SEM experiments, a homemade square battery with a flat cross-sectional surface is fabricated for measurement, it has a larger observation platform than the common coin cell. Through the windowless observation method, the electron beam can directly interact with the sample to improve the image resolution. According to the experimental requirements, we can regulate the ambient temperature and stabilize the current supply source, and obtain real-time image information.
In this work, polyethylene oxide (PEO)-based solid polymer electrolyte (SPE) is employed to monitor and study the effect of dendrite suppresion at different current densities. In addition, two of cell configuration, namely Li||SS and Li||Cu cells, are used to compare the difference of lithium growth morphology. Moreover, EDS mapping further reveal the elemental distribution of carbon in PEO during Li deposition and dissolution in real-time, providing dynamic understanding of the interaction between PEO and the deposited Li. To conclude, the newly designed in-situ SEM setup and the obtained in-depth information of the Li growth behavior in PEO SPE can provid new insights into the development of all-solid-state Li-metal batteries.

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