經由文獻的整理，鍺酸鑭基磷灰石結構中會由於不同的鑭配比，而造成不一樣的結構，使導電度有上升或下降的趨勢，不同的鑭配比會使摻雜進入鍺位置的離子，出現不同的固溶極限。
本研究利用固態反應法合成導電度高的鎢摻雜鍺酸鑭基電解質材料，藉由不同添加量之W6+ 取代La10-yGe6-xWxO27+x-1.5y中的Ge4+ 的位置，在不同鑭配比下將鎢摻雜入，利用無超出固溶極限的成分及超出固溶極限的成分，繪製出一結構區域圖，同時探討各成分的晶體結構與導電度，並推論出間隙氧離子可能的移動空間。
實驗結果顯示在La9Ge6-xWxO25.5+x系統中含有第二相La2Ge2O7，當鎢添加量達到x=0.1時，就已超出固溶範圍出現含鎢成分的新雜相；在La10Ge6-xWxO27+x系統中含有微量第二相La2GeO5，當鎢添加量到達x=0.4時，出現含有鎢成分的新雜相La6W2O16，代表其超出固溶範圍，由此得知鍺酸鑭系統會由於鑭配比上升或下降而出現第二相，且系統中鑭配比越高具有越高的固溶度。
La10Ge6-xWxO27+x系統中，各成分在1450°C/3h的燒結條件下，相對密度可達到98%，此系統隨著摻雜量上升，單位晶胞體積也隨之上升，摻雜量到達 x=0.3時，結構從三斜晶系 (Pī) 轉變成六方晶系 (P63/m)，藉由觀察結構內將結構中最大的開口空間La2-O3長邊和導電度進行比較，發現和導電度呈正相關。

Lanthanum germanate apatite will have different structures due to different lanthanum content, which will cause the conductivity to increase or decrease. The lanthanum content causes ions doped into the Ge4+ site to exhibit different solid solution limits. In this study, the W6+-doped lanthanum germanate powders were synthesized using the solid-state reaction method. The results show that second phase La2Ge2O7 is contained in the La9Ge6-xWxO25.5+x system and second phase La2GeO5 is contained in the La10Ge6-xWxO27+x system. In La9Ge6-xWxO25.5+x system, the formation of the secondary phase La2W1.25O6.75 was obtained in the compositional range of x ≥ 0.1. In La10Ge6-xWxO27+x system, the formation of the secondary phase La6W2O16 was obtained in the compositional range of x ≥ 0.4. After drawing a structure field map of W6+-doped lanthanum germanate system, we can observe that as the lanthanum content increases, the solid solution range increases. Crystal strictures of La10Ge6-xWxO27+x system inducated that x=0, 0.1, 0.2 has a triclinic structure (Pī) and x=0.3 has a hexagonal structure (P63/m). The results of the conductivity of sintered bulks and crystal structure analysis indicate that the longer distance between the La2 and O3 atoms (La2-O3 longer distance) is related to conductivity.

[1] 台灣電力公司資訊揭露，火力營運現況與績效-近10 年火力發電量，
台灣電力公司, 2020.
https://www.taipower.com.tw/tc/page.aspx?mid=202&cid=129&cchk=675cea43-9c45-4ae1-80c6-4f18b3b38d8e
[2] S. Nakayama, H. Aono, and Y. Sadaoka, “Ionic Conductivity of Ln10(SiO4)6O3 (Ln= La, Nd, Sm, Gd and Dy),” Chemistry letters, vol.24, no.6, pp.431-432,1995.
[3] S. Nakayama, T. Kageyama, H. Aono, and Y. Sadaoka, “Ionic conductivity of lanthanoid silicates, Ln10(SiO4)6O3 (Ln= La, Nd, Sm, Gd, Dy, Y, Ho, Er and Yb),” Journal of Materials Chemistry, vol.5, no.11, pp.1801-1805, 1995.
[4] S. Nakayama, and M. Sakamoto, “Electrical properties of new type high oxide ionic conductor RE10Si6O27 (RE= La, Pr, Nd, Sm, Gd, Dy),” Journal of the European Ceramic Society, vol.18, no.10, pp.1413-1418, 1998.
[5] 曾儒雅，鈮摻雜對鍺酸鑭基磷灰石電解質晶體結構之研究，國立成功大學資源工程學系碩士論文，2013。
[6] 林立武，鎢摻雜之鍺酸鑭基磷灰石離子導體之晶體結構與電性，國立成功大學資源工程學系碩士論文，2014。
[7] 林鈺烜，鎳摻雜之鍺酸鑭基磷灰石離子導體之晶體結構與電性，國立成功大學資源工程學系碩士論文，2015。
[8] 陳正威，鍺酸鑭基磷灰石離子導體之晶體結構與電性，國立成功大學資源工程學系碩士論文，2016。
[9] E. Kendrick, and P. Slater, “Synthesis of Ga-doped Ge-based apatites: Effect of dopant and cell symmetry on oxide ion conductivity,” Materials Research Bulletin, vol.43, no.12, pp.3627-3632, 2008.
[10] C.Guo, T.Cai, W.Zhang, C.Tian, and Y.Zeng, “Synthesis and characterizationof Al3+-doped La9.33Ge6O26 intermediate temperature electrolyte for SOFCs,” Materials Science and Engineering: B, vol.171, no.1-3, pp.50-55,2010.
[11] S.-F. Wang, Y.-F. Hsu, and W.-J. Lin, “Effects of Nb5+, Mo6+, and W6+ dopants on the germanate-based apatites as electrolyte for use in solid oxide fuel cells,” International journal of hydrogen energy, vol.38, no.27, pp.12015-12023,2013.
[12] S.-F. Wang, Y.-W. Chen, Y.-F. Hsu, P.-H. Li, and C.-Y. Huang, “Gallium-doped lanthanum germanates as electrolyte material of solid oxide fuel cells,” Journal of the Ceramic Society of Japan, vol.123, no.1436, pp.222-228, 2015.
[13] S.-F. Wang, Y.-F. Hsu, W.-J. Lin, and K. Kobayashi, “Transition metal-doped lanthanum germanate apatites as electrolyte materials of solid oxide fuel cells,” Solid State Ionics, vol.247, pp.48-55, 2013.
[14] S. F. Wang, Y. F. Hsu, W. J. Lin, and K. Kobayashi, “Doped Germanate‐Based Apatites as Electrolyte for Use in Solid Oxide Fuel Cells,” Fuel Cells, vol.14,no.2, pp.144-152, 2014.
[15] A. Kirubakaran, S. Jain, and R. K. Nema, “A review on fuel cell technologies and power electronic interface,” Renewable & Sustainable Energy Reviews, vol.13, no.9, pp.2430-2440, Dec. 2009.
[16] 湯智羽、蔡淑儀、方冠榮，屎灰復燃─綠能燃料電池的發展，科學發展564 期，p. 38，2019 年 12 月。
https://ejournal.stpi.narl.org.tw/sd/download?source=1081207.pdf&vlId=81c00b94ab824d3f8bae19957ea839e0&nd=1&ds=1
[17] 陽哲化，固態氧化物燃料電池 (SOFC) 原理與檢測，，國立台北科技大學製造科技所，2006。
https://myweb.ntut.edu.tw/~wwwemo/download/shri/sofc-1.pdf
[18] A. Weber, and E. Ivers-Tiffée, “Materials and concepts for solid oxide fuel cells (SOFCs) in stationary and mobile applications,” Journal of power sources,vol.127, no.1-2, pp.273-283, 2004.
[19] 韋文誠，固態燃料電池技術，高立圖書，2013。
[20] A. Orera, and P. Slater, “New chemical systems for solid oxide fuel cells,” Chemistry of Materials, vol.22, no.3, pp.675-690, 2010.
[21] DoITPoMS: Online Materials Science Learning Resources, Fuel cells,University of Cambridge, 2006.
https://www.doitpoms.ac.uk/tlplib/fuel-cells/sofc_electrolyte.php
[22] J. Zhu, and A. Thomas, “Perovskite-type mixed oxides as catalytic material for NO removal,” Applied Catalysis B: Environmental, vol.92, no.3-4, pp.225-233, 2009.
[23] E. Kendrick, M. S. Islam, and P. R. Slater,“Developing apatites for solid oxide fuel cells: insight into structural, transport and doping properties,” Journal of Materials Chemistry, vol.17, no.30, pp.3104-3111, 2007.
[24] S. Nakayama, M. Sakamoto, M. Higuchi, K. Kodaira, M. Sato, S. Kakita, T.Suzuki, and K. Itoh, “Oxide ionic conductivity of apatite type Nd9·33(SiO4) 6O2 single crystal,” Journal of the European Ceramic Society, vol.19, no.4, pp.507-510, 1999.
[25] E. Kendrick, and P. Slater, “Synthesis of hexagonal lanthanum germanate apatites through site selective isovalent doping with yttrium,” Materials Research Bulletin, vol.43, no.8-9, pp.2509-2513, 2008.
[26] P. R. Slater, J. E. H. Sansom, and J. R. Tolchard, “Development of apatite-type oxide ion conductors,” Chemical Record, vol.4, no.6, pp.373-384, 2004.
[27] H. Arikawa, H. Nishiguchi, T. Ishihara, and Y. Takita, “Oxide ion conductivity in Sr-doped La10Ge6O27 apatite oxide,” Solid State Ionics, vol. 136, pp. 31-37,
2000.
[28] R. D. Shannon, “Revised effective ionic radii and systematic studies of interatomic distances in halides and chalcogenides,” Acta crystallographica section A: crystal physics, diffraction, theoretical and general crystallography,vol.32, no.5, pp.751-767, 1976.
[29] Allen C. Larson and Robert B. Von Dreele, “ General Structure Analysis System (GSAS),” Los Alamos National Laboratory Report LAUR 86-748,2004.
[30] R. A. Young, The Rietveld method, International Union of Crystallography,1993.
[31] W. Liu, S. Yamaguchi, T. Tsuchiya, S. Miyoshi, K. Kobayashi, and W. Pan,“Sol–gel synthesis and ionic conductivity of oxyapatite-type La9.33+xSi6O26+1.5x,” Journal of power sources, vol. 235, pp. 62-66, 2013.
[32] A. Orera, T. Baikie, P. Panchmatia, T. J. White, J. Hanna, M. E. Smith, M. S.Islam, E. Kendrick, and P. R. Slater, “Strategies for the Optimisation of the Oxide Ion Conductivities of Apatite‐Type Germanates,” Fuel Cells, vol.11, no.1, pp.10-16, 2011.
[33] A. Orera, T. Baikie, E. Kendrick, J. F. Shin, S. Pramana, R. Smith, T. White,M. Sanjuán, and P. Slater, “Apatite germanates doped with tungsten:synthesis,structure, and conductivity,” Dalton Transactions, vol. 40, no. 15, pp. 3903-3908, 2011.
[34] S. F. Wang, Y. X. Liu, Y. F. Hsu, C. J. Li, and P. Jasinski, “Effects of La content on the densification, microstructure, and conductivity of doped La10−xGe6O26±δ Telectrolytes,” International Journal of Applied Ceramic Technology, vol.14,no.1, pp.84-93, 2017.
[35] E. Abram, C. Kirk, D. Sinclair, and A. West, “Synthesis and characterisation of lanthanum germanate-based apatite phases,” Solid State Ionics, vol. 176, no.
23-24, pp. 1941-1947, 2005.