本論文利用古典以及第一原理分子動力學模擬方法，進行研究混合多元鹽類於高溫熔融狀態下的運動行為，計算其離子傳導率以及熱傳導率結果，進行交互驗證以評估其熔融電解質對於熱電池效能之影響；最後再與現有文獻實驗結果進行比較，以檢驗不同方法的優缺點以及適合操作狀況。
熱電池與一般電化學電池最大不同地方，係為利用外部熱源，將電解質迅速加熱至高溫熔化狀態並激發此電池。影響熱電池效能關鍵因素除了陰陽極材料之外，最重要的為熔鹽電解質的離子傳導率與熱傳導率，此二項因素為最直接的影響發電性能。本研究利用建立系統等容定溫模型 (NVT constrain)，在離子傳導率的部分，同時使用古典分子動力學以及第一原理分子動力學搭配Nernst-Einstein relation作計算;在熱傳導率計算上使用反向非平衡態分子動力學方法 (RNEMD method)。不同於實驗，以施加溫差的方式提供熱通量，該方法則是利用提供已知的熱通量來觀察其溫度變化，相較於其他一般的非平衡態分子動力學方法 (NEMD method)或是平衡態分子動力學的Green-Kubo方法有更好的收斂性。
最後嘗試利用分子動力學方法模擬共晶材料模擬材料降溫熔融態至固態的過程，用以觀察其不連續的區域或點來評估熔點位置，以期能建立一個完整的熔融鹽模擬工具，作為未來選用電解質材料的重要參考，並可達到優化性能設計之目的。

The main propose of this thesis is to simulate blend molten salts by molecular dynamics (MD) and first principles molecular dynamics (FPMD) techniques. It is followed by calculating the ionic conductivity and thermal conductivity in order to analyze how the molten electrolyte affect the operation of a thermal battery. Furthermore, we compare our simulation results with literatures to verify the pros and cons of different methods.
According to the literature survey, whether a thermal battery is good or not is based on the discharging life and efficiency. The important factors to the battery efficiency are ionic conductivity and thermal conductivity. They both will affect the ionic transportation. The battery life time and the melting point are also influential factors. In the simulation of ionic conductivity, we use both classical molecular dynamics and first principles molecular dynamics to simulate the behavior at high temperature. Then we calculate the ionic conductivity with Nernst-Einstein relation and thermal conductivity with reversed non-equilibrium molecular dynamics (RNEMD) algorithm. Comparing to some other non-equilibrium molecular dynamics (NEMD) methods, RNEMD has been found to have better convergence.
Finally, we try to simulate the process of cooling down temperature of eutectic-salts electrolyte and observe the region of discontinuation to evaluate the melting point. It is expected to build a complete software tool for molten salt simulation to replace the costive in experiments and to optimize the battery design in a more efficient way.

目錄
摘要 I
Abstract II
第一章 緒論 V
1.1 前言 1
1.2 熱電池簡介 2
1.2.1熱電池基本構造 3
1.2.2電極材料 3
1.2.3電解質材料 4
1.3 文獻回顧 5
1.3.1離子傳導率 6
1.3.2熱傳導率 6
1.3.3熔點 7
1.4 研究動機與目的 7
第二章 研究方法 9
2.1分子動力學模擬 (Molecular Dynamics, MD) 9
2.1.1 古典分子動力學 9
2.1.1.1 分子動力學理論 9
2.1.1.2基本勢能函數 11
2.1.2 第一原理分子動力學 (First Principles Molecular Dynamics, FPMD) 19
2.2週期性邊界條件 (Periodic Boundary Condititons, PBC) 27
2.3 Ewald Summation 28
2.4溫控器 (Thermostat): 31
2.4.1 Nose-Hoover Thermostat 31
2.4.2 Nose-Hoover-Langevin (NHL) Dynamics 33
2.5 運動方程式 34
2.6 其他常見的勢能模型 35
第三章 模型建構與模擬方法 37
3.1模擬流程 37
3.2模擬工具 38
3.2.1建立模型 39
3.2.2古典分子動力學 41
3.2.3 CASTEP與自洽場計算原理 43
3.2.4數據後處理 44
第四章 結果與討論 51
4.1 離子傳導率 51
4.1.1 古典分子動力學 51
4.1.2 第一原理分子動力學 53
4.2 熱傳導率 59
4.3 熔點 62
第五章 結論 65
5.1結論 65
5.2未來工作建議 66

1. Sandia National Laboratories.
2. Guidotti, R.A. and P. Masset, Thermally activated (“thermal”) battery technology: Part I: An overview. Journal of Power Sources, 2006. 161(2): p. 1443-1449.
3. Masset, P. and R.A. Guidotti, Thermal activated (thermal) battery technology: Part II. Molten salt electrolytes. Journal of Power Sources, 2007. 164(1): p. 397-414.
4. Masset, P., Iodide-based electrolytes: A promising alternative for thermal batteries. Journal of Power Sources, 2006. 160(1): p. 688-697.
5. Masset, P., A. Henry, J.-Y. Poinso, and J.-C. Poignet, Ionic conductivity measurements of molten iodide-based electrolytes. Journal of Power Sources, 2006. 160(1): p. 752-757.
6. Sangster, M.J.L. and M. Dixon, Interionic potentials in alkali halides and their use in simulations of the molten salts. Advances in Physics, 1976. 25(3): p. 247-342.
7. Galamba, N., C.A.N. de Castro, and J.F. Ely, Thermal conductivity of molten alkali halides from equilibrium molecular dynamics simulations. Journal of Chemical Physics, 2004. 120(18): p. 8676-8682.
8. Ohtori, N., T. Oono, and K. Takase, Thermal conductivity of molten alkali halides: Temperature and density dependence. Journal of Chemical Physics, 2009. 130(4).
9. Galamba, N., C.A.N. de Castro, and J.F. Ely, Equilibrium and nonequilibrium molecular dynamics simulations of the thermal conductivity of molten alkali halides. Journal of Chemical Physics, 2007. 126(20).
10. Müller-Plathe, F., A simple nonequilibrium molecular dynamics method for calculating the thermal conductivity. The Journal of Chemical Physics, 1997. 106(14): p. 6082-6085.
11. Galamba, N. and B.J. Costa Cabral, First principles molecular dynamics of molten NaCl. J Chem Phys, 2007. 126(12): p. 124502.
12. Galamba, N. and B.J. Costa Cabral, First principles molecular dynamics of molten NaI: structure, self-diffusion, polarization effects, and charge transfer. J Chem Phys, 2007. 127(9): p. 094506.
13. Anwar, J., D. Frenkel, and M.G. Noro, Calculation of the melting point of NaCl by molecular simulation. The Journal of Chemical Physics, 2003. 118(2): p. 728-735.
14. Alfè, D., Melting Curve of MgO from First-Principles Simulations. Physical Review Letters, 2005. 94(23): p. 235701.
15. Fujiwara, S., M. Inaba, and A. Tasaka, New molten salt systems for high-temperature molten salt batteries: LiF–LiCl–LiBr-based quaternary systems. Journal of Power Sources, 2010. 195(22): p. 7691-7700.
16. Chen, W.-H., C.-H. Wu, and H.-C. Cheng, Modified Nos\&\#233;-Hoover thermostat for solid state for constant temperature molecular dynamics simulation. J. Comput. Phys., 2011. 230(16): p. 6354-6366.
17. http://cbio.bmt.tue.nl/pumma/index.php/Theory/Potentials.
18. Somoza, M. Morse potential with a harmonic potential for comparison. 2006; Available from: http://en.wikipedia.org/wiki/Morse_potential#mediaviewer/File:Morse-potential.png.
19. Perdew, J.P., K. Burke, and M. Ernzerhof, Generalized Gradient Approximation Made Simple. Physical Review Letters, 1996. 77(18): p. 3865-3868.
20. Payne, M.C., M.P. Teter, D.C. Allan, T.A. Arias, and J.D. Joannopoulos, Iterative Minimization Techniques for Abinitio Total-Energy Calculations - Molecular-Dynamics and Conjugate Gradients. Reviews of Modern Physics, 1992. 64(4): p. 1045-1097.
21. http://isaacs.sourceforge.net/phys/pbc.html.
22. Darden, T., D. York, and L. Pedersen, Particle mesh Ewald: An N [center-dot] log(N) method for Ewald sums in large systems. The Journal of Chemical Physics, 1993. 98(12): p. 10089-10092.
23. Nose, S., A unified formulation of the constant temperature molecular dynamics methods. The Journal of Chemical Physics, 1984. 81(1): p. 511-519.
24. Hoover, W.G., Canonical dynamics: Equilibrium phase-space distributions. Physical Review A, 1985. 31(3): p. 1695-1697.
25. Samoletov, A., C. Dettmann, and M.J. Chaplain, Thermostats for “Slow” Configurational Modes. Journal of Statistical Physics, 2007. 128(6): p. 1321-1336.
26. Leimkuhler, B., E. Noorizadeh, and O. Penrose, Comparing the Efficiencies of Stochastic Isothermal Molecular Dynamics Methods. Journal of Statistical Physics, 2011. 143(5): p. 921-942.
27. Sun, H., COMPASS:  An ab Initio Force-Field Optimized for Condensed-Phase ApplicationsOverview with Details on Alkane and Benzene Compounds. The Journal of Physical Chemistry B, 1998. 102(38): p. 7338-7364.
28. Cri. how the radial distribution function is calculated. 2012; Available from: http://en.wikipedia.org/wiki/Radial_distribution_function#mediaviewer/File:Rdf_schematic.jpg.
29. Kundu, A., A. Dhar, and O. Narayan, The Green–Kubo formula for heat conduction in open systems. Journal of Statistical Mechanics: Theory and Experiment, 2009. 2009(03): p. L03001.
30. Syozo Fujiwaara, O.J., MOLTEN SALT AND THERNAL BATTERY. 2012, Panasonic Corporation, Osaka(JP).