高效率且高充放電速率之鋁離子二次電池的研究與電化學分析

Abstract

新型二次電池可應用於個人電子產品或大型機具中。鋁離子二次電池的氧化還原反應由三個電子進行轉換，所以能提供非常高的電容。它具有低成本、低可燃性的優點，但由於正極材料的不穩定、低放電電位、無明顯放電平台以及電量快速衰退等問題，導致近三十年沒有顯著的發展。近期一篇期刊討論到相關的鋁離子電池發展，但電量卻只有約70mAh/g。我們提出以鋁金屬作為負極、天然石墨作為正極材料的鋁離子電池。這種電池的工作原理，在負極是鋁金屬的沉積與溶解反應，正極則是負離子的嵌入與嵌出。實際測試後，發現電容量可高達108mAh/g、庫倫效率可達98%以上且1200次充放電後，電量並沒有出現明顯的衰退。The development of new rechargeable battery systems could fuel various energy applications, from personal electronics to grid storage. Rechargeable aluminium based batteries offer the possibilities of low cost and low flammability, together with three electron redox properties leading to high capacity. However, research efforts over the past 30 years have encountered numerous problems, such as cathode material disintegration, low cell discharge voltage, capacitive behaviour without discharge voltage plateaus and insufficient cycle life with rapid capacity decay.Recently,Nature Publishing Group published a paper about Al-ion battery,but the specific capacity is only 70mAh/g. We present a rechargeable aluminium battery with high-rate capability that uses an aluminium metal anode and natural graphite cathode. The battery operates through the electrochemical depositionand dissolution of aluminium at the anode, and intercalation/de-intercalation of chloroaluminate anions in the graphite.The specific capacity is about 108mAh/g, a Coulombic efficiency of approximately 98% and without any decay after 1000 cycles.