膨脹性石墨對鋁離子電池之電化學表現研究

Abstract

鋁不僅是產量最高的金屬在大氣也不會有甚麼反應，屬於安全也較便於處理的金屬。在氧化還原過程中牽涉到三個電子的轉移，其密度(2.7 g*cm-3)遠大於鋰(0.53 g*cm-3)，故其體積容量(8.06 Ah*mL-1)也是遠大於鋰(2.04 Ah*mL-1)，表示在相同體積下的鋁可以提供的電量約有鋰提供的四倍多。 在我們團隊的前作中，研究出天然鱗片石墨適用於鋁離子電池中的陰極材料，具有高電量及穩定性的特點。本作中研究前驅物為鱗片石墨的膨脹性石墨，在高電流密度(1000 mA/g)時亦具有高電量與穩定性，比較充放電曲線圖與循環伏安圖的反應後發現和前作一樣。臨場XRD與臨場拉曼可以得知充放電過程中氯鋁酸根有嵌入嵌出石墨層。SEM圖分析了充放電前後材料的結構差異。

Aluminum is not only the most abundant metal on Earth, but also safe to deal with in comparison to other kind of metal-ion battery. It contains the transfer of three electrons in redox reaction of aluminum. Furthermore, the density of aluminum is around four times larger than the one of lithium, indicating that under the same volume, aluminum provides almost four times greater volumetric capacity than lithium. In our previous study, we found that the aluminum-ion batteries with natural flake graphite as cathode material contains high capacity and high stability. In this work, we investigate the cathodic performance of expanded graphite with natural flake graphite as the precursor. We discovered that under a high current density of 1000 mA/g, the battery also contains high capacity and high stability.Moreover, the galvanostatic curves and the cyclic voltammogram of this work are the same as the previous one.From in-situ XRD and in-situ raman spectroscopy, it shows the intercalation/deintercalation of AlCl4- ions into/out of to expanded graphite. The SEM image also reveal the structural difference of expanded graphite between before and after charging-discharging.