隨著科技日漸的進步，人們對於能源的需求也越來越大，並且致力於研究出更高能量密度的儲能裝置，而鋰離子電池因其高能量密度而有許多團隊在進行研究。其中陽極的部分雖然市售的Li4Ti5O12以及碳都有很好的循環壽命，但是受限於本身的電容量太低，所提供的能量密度如今已不符合人們的需求，而Fe2O3不僅無毒性，而且本身的穩定性良好以及地殼上的含量非常豐富，再加上工作電壓不高且有理論電容量高達1005 mA h g−1，是一個及有淺力的陽極材料。
但是Fe2O3受限於其傳導性差，且在充放電過程中的轉變反應會造成96%的體積膨脹，使得電容量在循環壽命上受到限制。而本實驗即是利用摻雜釩離子進入Fe2O3，欲利用釩離子較大的半徑，摻雜進Fe2O3的結構中使晶格結構變大，有助於鋰離子在晶格中的傳導，並且佔據住晶格中的位置，讓Fe2O3在充放電過後依舊能維持住本身的結構，不會有結構崩塌而造成電池死亡的現象發生。
而結果的確如預期，摻雜釩離子過後的Fe2O3的確不會因為結構崩塌而造成電性上的損失，不僅在0.1 C的定速率下循環100圈還能維持有1303.8 mA h g−1的電容量，在變速率下也有比較好的電性表現。

α- Fe2O3, which is the most stable phase of iron oxide, has a theoretical capacity of 1005 mA h g−1 which is much higher than the commercial materials like LTO and graphite. However, the drastic volume change, about 96%, occurs in the conversion reaction during lithiation/delithiation from α- LixFe2O3(rhombohedral structure) to Li2Fe2O3(cubic structure) for α- Fe2O3.
The present work attempted to dope different amount of vanadium in hematite as the anode materials for lithium battery. The results show that doping vanadium in hematite can help sustaining the Li2Fe2O3 structure during lithiuation/delithiation, preventing the structure of Li2Fe2O3 from collapse after cycling. Moreover, with increasing amount of vanadium doped, the diffusivity of lithium ion in the Li2Fe2O3 structure increases which improves the shortcoming of poor ionic counductivity of the transition oxides. However, the partical sizes, observed by scanning electron microscope, increases as increasing amount of vanadium doped. Both factors influence the electrochemical performance of the vanadium doped hematite as the anode of lithium ion battery.
Comparing to Fe2O3 without V doping, Fe2O3 doped with 10% V showed an improved electrochemical performance in long cycling performance. At current densities of 0.1 C, V-doped Fe2O3 exhibited an initial capacity of 1049 mA h g−1, and the capacity was rising up to 1303.8 mA h g−1 after 100 cycles.

第1章 緒論 1
1.1 鋰電池的發展與應用 1
1.2 α- Fe2O3 3
1.2.1 α- Fe2O3的優缺點 3
1.2.2 α- Fe2O3充放電機制 3
第2章 文獻回顧 4
2.1 奈米顆粒α- Fe2O3 4
2.2 包覆導電分子 5
2.3 複合物 6
2.4 摻雜不參與反應元素 8
第3章 實驗步驟與相關儀器 12
3.1 研究動機 12
3.2 實驗藥品 12
3.3 材料製備 13
3.3.1 以水熱法合成α- Fe2O3活物 13
3.3.2 以水熱法合成摻雜釩離子α- Fe2O3活物 13
3.4 電極製備 14
3.5 電池組裝 15
3.6 材料鑑定分析 15
3.6.1 XRD結晶繞射分析 15
3.6.2 場發掃描式電子顯微鏡 15
3.6.3 X-ray 光電子能譜分析 16
3.7 材料電性分析 16
3.7.1 循環壽命測試 16
3.7.2 循環伏安測試 16
3.7.3 交流阻抗測試 16
第4章 實驗結果與討論 17
4.1 α- Fe2O3與摻雜釩離子α- Fe2O3粉末 17
4.1.1 X-ray繞射分析 17
4.1.2 SEM顯微結構分析 19
4.1.3 XPS分析 22
4.2 電性表現 24
4.2.1 等速率循環壽命 24
4.2.2 變速率循環壽命 27
4.2.3 放電平台分析 28
4.3 電化學表現 30
4.3.1 循環伏安法分析 30
4.3.2 利用循環伏安法討論擴散速率 33
4.3.3 晶粒大小與擴散速率對於電性的影響 36
4.3.4 交流阻抗分析 39
第5章 結論 41
第6章 未來展望 42
第7章 參考文獻 43

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