當今儲存電能技術之發展趨勢，乃是結合快速充放電的超級電容與高能量密度的超級電池設計，同時提升功率密度與能量密度，進一步提升電容量以及考慮製造成本降低，其中陰極材料是決定超級鋰離子電池性能相當關鍵的一環，因此本研究提出新陰極材料並事先評估其性能即為研究重點目標。
本研究提出之陰極材料為α-MoO3(α-三氧化鉬)，此材料具有比惰性電極碳更高之還原電位，其分子結構為層狀結構，鋰離子易於嵌入其中，可儲存較高的鋰離子濃度，故理論上具有高比電容值1117mAhg-1(目前市場約150-200 mAhg-1)，此外其材料成本相當低(約為目前40%)，是極具潛力的新進陰極材料；然而其原先材料電子導電度低、鋰離子擴散速率普通以及鋰離子嵌入遷出過程中材料體積變化大，限制其使用及壽命；本論文提出在氧化物陰極材料製造氧空缺以改善離子導電率，並增進電池充放電效能，故本研究內容將是α-MoO3之氧空缺與電池充放電過程模擬及性能分析。
本論文利用固態物理第一原理來分析氧空缺對於鋰離子嵌入α-MoO3之影響，在無氧空缺情況下，其開路電壓為2.8 V，並觀察到鋰離子嵌入過程中沿著材料表面(010)擴散，計算擴散能障為0.551 eV；根據原子鍵結強度之不同，本研究建立多種氧空缺結構，模擬分析鋰離子嵌入過程，預測結果其開路電壓能提升至3.0 V，且擴散能障降至約0.301 eV，意即其材料於鋰離子嵌入遷出過程中，體積變化減小，有助於壽命提升，而離子導電度比原先提升約6000倍，達到1.18x10-7cm2/s，為現今材料NCM之200倍成長，改善了原先材料應用於鋰離子電池陰極之性能。
本論文提出透過建立氧空缺方法來改善鋰離子陰極材料性能，在可見未來，鋰離子電池陰極材料發展會逐漸轉換成過渡金屬氧化物，此固態物理第一原理模擬可用以提前預測效能，並開發更高性能之鋰離子超級電池。

Super-batteries are designed to combine the advantages of high power density supercapacitors and the original high energy density of lithium ion batteries (LiBs). At the same time, further rising the capacity and lower down the production cost are also very important. The key technology is the cathode materials selection to increase the conductivity as well as to further endure the high temperature due to high rate of charge and discharge. This research aims to develop the simulation technology to predict the cathode properties and to detail the ionic transport phenomena.
α-MoO3(α-Molybdenum Oxide) has a great potential to be the new cathode material due to its extraordinary specific theoretical capacity 1117 mAh/g, comparing with the current status at 150-200 mAh/g of commercial batteries. However, low diffusivity and modest reaction kinetics limit its widespread use. This research proposes to create oxygen vacancies in the metal oxides is beneficial to diffusivity and enhance charge/discharge rate.
This thesis employs solid state physics based first principles calculation to analyze the influence of oxygen vacancy on the α-MoO3 during Li+ intercalation process. Comparing with the original α-MoO3, the oxygen vacancy can decrease the diffusion barrier from 0.551 eV to 0.301 eV, and increase the ionic diffusivity around 6000 times to 1.18x10-7cm2/s, which is 200 times higher than the commercial nickel-cobalt-manganese cathode (NCM, 5x10-10 cm2/s). That means oxygen vacancy technology is able to dramatically promote the charge/discharge rate and also longer the battery lifetime, which are the criteria to develop a future super-battery.

摘要 I
Abstract II
誌謝 III
第一章 緒論 1
1.1 前言 1
1.2 研究動機 6
1.3 研究目標 7
第二章 研究理論 8
2.1 First Principles Computation 8
2.1.1 Schrödinger Equation 8
2.1.2 Plane Wave 10
2.1.3 Bloch Theorem 11
2.1.3.1 Reciprocal Lattice 12
2.1.3.2 First Brillouin Zone 13
2.1.4 Pseudopotential 13
2.1.5 Born-Oppenheimer Approximation 14
2.1.6 Hartree-Fock Equation 15
2.1.7 Hohenberg-Kohn Theorem 16
2.1.8 Kohn-Sham Equation 17
2.1.9 Local Density Approximation (LDA) 19
2.1.10 Generalized Gradient Approximation (GGA) 19
2.1.10.1 Perdew-Wang 91 (PW91) 20
2.1.10.2 Perdew-Burke Ernzerhof (PBE) 21
2.1.11 Self-Consistent Field Method (SCF) 21
2.2 Van der Waals Force 23
2.2.1 DFT-D2 24
2.2.2 DFT-D3 24
2.3 DFT+U 26
2.4 Binding Energy 27
2.5 Nudged Elastic Band (NEB) 27
2.6 Diffusion Coefficient 30
第三章 模擬方法及參數設定 31
3.1材料性質及模擬流程 31
3.2 Vienna Ab-initio Simulations Package (VASP) 34
3.2.1 輸入檔案 34
3.2.2 輸出檔案 35
3.2.3 結構最佳化與電子性質計算 35
3.3 α-MoO3晶胞能量及收斂性測試 36
3.4 Adsorption Locator 41
3.4.1 LiMoO3晶胞能量及收斂性測試 41
3.5 Diffusion Path 43
3.6 Build Oxygen Vacancy 44
3.6.1 Reduced α-MoO3晶胞能量及收斂性測試 44
3.6.2 Reduced LiMoO3晶胞能量及收斂性測試 47
第四章 結果與討論 50
4.1 結構最佳化分析 50
4.1.1 α-MoO3及LiMoO3結構最佳化 50
4.1.2 Reduced α-MoO3及LiMoO3結構最佳化 55
4.2 開路電壓計算 57
4.3 鋰離子擴散路徑 59
4.4 擴散係數 66
第五章 結論與未來研究方向 68
5.1 結論 68
5.2 未來研究方向 69
參考文獻 70

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