隨著現代社會對能源的需求日愈增加，發展綠色能源及儲能裝置的必要性也隨之上升，其中鋰離子電池因其賦有高能量密度之特性使其成為備受矚目的議題，為了追求更高能量及更好的穩定性，以過渡金屬為基底的氧化物負極材料被廣為開發，然而現今開發之鋰離子電極在充放電循環過程中存在著體積變化與結構改變等潛在問題，進而使鋰離子電池存在著性能上與安全上的疑慮。本研究以新穎的高熵材料嘗試做為鋰離子電池之負極，並驗證其電化學性能及穩定循環測試:本實驗中採取水熱法進行材料合成，使用鉻、錳、鐵、鎳此四個過渡金屬元素為基礎，再摻入不同的金屬元素合成不含鈷之尖晶石結構高熵氧化物，並組成電極進而驗證材料在鋰離子電池中的表現。其中，摻入銅之高熵氧化物電極，在經過350圈充放電後，仍保有高達將近100%的電容量維持率；另外透過改變製程中的退火溫度進一步調控高熵氧化物電極之顆粒尺寸及結晶度，在經過250次充放電循環後，維持了99%的電容量，且在2000 mA g–1下，仍留有450 mA h g–1之電容量；其後本實驗同時採取了水熱法及熱溶劑法合成摻有鋅之高熵氧化物電極，發現其中含有Mn3O4雜相之高熵氧化物，相較純單相有著更好地穩定性表現。

With the ever-growing demand for energy in modern society, the need to develop sustainable energy and energy storage devices has also increased. Among them, lithium-ion batteries have become a popular option due to their high energy density. In order to pursue higher energy and better stability, oxide anode materials based on transition metals have been widely developed. However, lithium-ion electrodes developed nowadays have potential problems such as volume changes and structural changes during the charge and discharge cycle, which become concerns about its battery performances and safety issues. In this study, a novel high entropy material was used as the negative electrode of a lithium-ion battery, and its electrochemical performance and stable cycle test were verified. In this experiment, the hydrothermal method was used for material synthesis. Based on four transition metals of chromium, manganese, iron, and nickel, different metal elements are added to synthesize cobalt-free high entropy oxides with spinel structure. The electrode fabrication and battery measurement were carried out to investigate the performance of the materials as lithium-ion anodes. Among them, the high entropy oxide doped with copper maintained a capacity retention of nearly 100% after 350 cycles. In addition, the particle size and crystallinity of the high entropy oxide were further controlled by tuning the post annealing temperature in the synthesis process. The obtained electrode achieved 99% capacity retention after 250 cycles, and also exhibited capacity of 450 mA h g-1 at 2000 mA g-1. After that, the high entropy oxides doped with zinc was synthesized using both hydrothermal and solvothermal methods. It was found that the electrode with the mixed phases of high entropy spinel oxide and Mn3O4 showed a better stability performance than the pure high entropy spinel oxide electrode.

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