高結晶性天然鱗片石墨用於鋁離子電池之電化學分析及機制研究

Abstract

隨著能源問題日漸嚴重，對於電能儲存的開發越來越受到重視。次世代的電池目標是低成本、高充放電速率、高穩定性且具有高能量及功率密度。為了達到以上目標，我們發展出具有高安全性的鋁離子電池系統。鋁金屬的氧化還原由三個電子進行，所以鋁金屬能提供更高的能量密度，且具有無汙染等優點。 先前本團隊研究利用天然鱗片石墨作為鋁離子電池的陰極，具有高電量、高電位平台，且在長圈數的循環下電量並無衰退，而本研究主要探討為鋁離子電池在進行充放電的過程中，石墨與氯鋁酸鹽離子間的關係，因此利用各種不同電位下探討其中的反應機制，藉由in-situ XRD、in-situ Raman、XAS等分析證明氯鋁酸鹽離子嵌入嵌出於石墨層間，最後再以用密度泛函理論(DFT)和第一計算來模擬AlCl4-陰離子與石墨間的行為表現。 另外，對鋁離子電池做參數的調整，例如改變石墨負載量、不同材質隔離膜及觀察在不同環境溫度下對鋁離子電池的電化學表現。

With the energy issues, electrochemical energy storage is an important issue for future technology development. The goals of the next generational battery are low cost, high-rate charging, high stability, high energy and power density. To meet this requirement, we developed aluminum ion battery which is a high safety and low cost battery system. With three-electron redox anode reaction, aluminum ion battery has higher energy and power density. For the environmental issues, the battery system is without pollution and poison. In our early work, we used natural flake graphite as cathode for AIB. The performance of the graphite cathode was high capacity, high voltage plateau and without decay after thousands of cycles. The purpose of this study was to investigate the interaction of AlCl4- and graphite cathode during charging. We dug deeper on the reaction mechanisms with in situ XRD, in-situ Raman and XAS. Finally, we used DFT and first principle method to confirm the reaction between graphite and AlCl4-. Besides, we observed the performance of AIB with different graphite loading, different kind of separators and charging at various temperatures.