NZP型化合物是一種以NaZr2(PO4)3為代表的材料，以ZrO6八面體與PO4四面體共角連接形成開放性的架狀結構。本研究探討MZr4(PO4)6, (M=Mg, Ca, Sr, Ba) 陶瓷材料之晶體結構與導電率的關係。先利用液相輔助固相反應法製備粉末，以二階段煅燒合成單一相之MgZr4(PO4)6、CaZr4(PO4)6、SrZr4(PO4)6、BaZr4(PO4)6，但後者無法合成出單一相。因為NZP型化合物普遍存在著燒結不易緻密化的問題，利用Na2O做為助燒結劑，讓燒結體相對密度可以達到96%以上。由於NZP型化合物利用陽離子在結構中穿梭來導電，而在離子通道中會有氧離子組成之瓶頸 (bottleneck) 限制陽離子的通過，利用高溫XRD及無機晶體結構資料庫 (ICSD) 的數據進行Rietveld refinement結構精修，接著利用軟體做晶體結構的繪圖，討論不同溫度、成分對於瓶頸大小的影響。最後使用直流電量測陶瓷體的導電率，可以發現室溫下每個成分的導電率都差不多，而升溫後以MgZr4(PO4)6的導電率最好，在各溫度下與瓶頸截面積做比較可以發現，CaZr4(PO4)6之瓶頸截面積最小而導電率也最低，而各成分間導電率的關係也和瓶頸截面積成正比。

NZP compound is a material represented by NaZr2(PO4)3. Its opening framework structure is made by ZrO6 tetrahedra and PO4 octahedra connecting by sharing corner. To discuss the relationship between crystal structure and ionic conductivity of MZr4(PO4)6 (M=Mg, Ca, Sr, Ba), we synthesize the powder of NZP compounds by solution-assisted solid-state reaction method. In this study, we synthesize single phase MgZr4(PO4)6, CaZr4(PO4)6, SrZr4(PO4)6, BaZr4(PO4)6 by two-stage calcining, but BaZr4(PO4)6 compound would residue BaZrP2O8 as secondary phase. NZP compounds contains 0.2 mole ratio Na2O as sintering aids to achieve relative density above 96%. The bottleneck made by oxygen ions restricts cations path through. Different temperature and different composition would affect bottleneck size. We adopted the Rietveld refinement approach and Diamond software to calculate the bottleneck size of the ionic channel. The electrical conductivity of ceramic body is measured with direct current analysis. We found the conductivity of each compound are nearly the same at room temperature. The conductivity of MgZr4(PO4)6 is the best when temperature rise up. To compare temperature with the bottleneck size, CaZr4(PO4)6 has the smallest bottleneck size and also the least conductivity. The relationship between conductivity and bottleneck size in each compound is positive correlation.

[1] A. K. Sethi, The European Edisons: Volta, Tesla, and Tigerstedt. Springer, 2016.
[2] 方程毅. (2014). 【材料應用】從手機到電動車：無處不見的鋰電池.
[3] W. A. v. S. B. Scrosati, Advances in lithium-ion batteries. Springer Science & Business Media, 2002.
[4] L. O. Hagman, P. Kierkegaard, P. Karvonen, A. Virtanen, and J. Paasivirta, "The crystal structure of NaMe2 IV (PO4) 3; MeIV= Ge, Ti, Zr," Acta Chem. Scand, vol. 22, no. 6, pp. 1822-32, 1968.
[5] H.-P. Hong, "Crystal structures and crystal chemistry in the system Na1+ xZr2SixP3− xO12," Materials Research Bulletin, vol. 11, no. 2, pp. 173-182, 1976.
[6] C.-Y. Huang, Thermal expansion behavior of sodium zirconium phosphate structure-type materials. The Pennsylvania State University, 1990.
[7] R. Roy, D. Agrawal, J. Alamo, and R. Roy, "[CTP]: A new structural family of near-zero expansion ceramics," Materials research bulletin, vol. 19, no. 4, pp. 471-477, 1984.
[8] R. Rajagopalan, Z. Zhang, Y. Tang, C. Jia, X. Ji, and H. Wang, "Understanding crystal structures, ion diffusion mechanisms and sodium storage behaviors of NASICON materials," Energy Storage Materials, 2020.
[9] 陳建中, "Crystal Stucture and Thermal Expansion Bhavior of MZr4P6O24 (M=Ca, Sr, Ba)," 碩士, 資源工程學系, 國立成功大學, 台南市, 1996.
[10] N. Anantharamulu, K. K. Rao, G. Rambabu, B. V. Kumar, V. Radha, and M. Vithal, "A wide-ranging review on Nasicon type materials," Journal of materials science, vol. 46, no. 9, pp. 2821-2837, 2011.
[11] J. B. Goodenough, H.-P. Hong, and J. Kafalas, "Fast Na+-ion transport in skeleton structures," Materials Research Bulletin, vol. 11, no. 2, pp. 203-220, 1976.
[12] Z. Zou et al., "Relationships between Na+ distribution, concerted migration, and diffusion properties in rhombohedral NASICON," Advanced Energy Materials, vol. 10, no. 30, p. 2001486, 2020.
[13] A. Ahmad, T. Wheat, A. Kuriakose, J. Canaday, and A. McDonald, "Dependence of the properties of Nasicons on their composition and processing," Solid State Ionics, vol. 24, no. 1, pp. 89-97, 1987.
[14] U. Von Alpen, M. Bell, and H. Höfer, "Compositional dependence of the electrochemical and structural parameters in the Nasicon system (Na1+ xSixZr2P3− xO12)," Solid State Ionics, vol. 3, pp. 215-218, 1981.
[15] H. Aono and E. Suginoto, "Ionic Conductivity and Sinterability of NASICON‐Type Ceramics: The Systems NaM2 (PO4) 3+ yNa2O (M= Ge, Ti, Hf, and Zr)," Journal of the American Ceramic Society, vol. 79, no. 10, pp. 2786-2788, 1996.
[16] S. Ikeda, M. Takahashi, J. Ishikawa, and K. Ito, "Solid electrolytes with multivalent cation conduction. 1. Conducting species in Mg- Zr- PO4 system," Solid State Ionics, vol. 23, no. 1-2, pp. 125-129, 1987.
[17] J. Boilot, J. Salanie, G. Desplanches, and D. Le Potier, "Phase transformation in Na1+ xSixZr­P­3-xO12 compounds," Materials Research Bulletin, vol. 14, no. 11, pp. 1469-1477, 1979.
[18] D. Quon, T. Wheat, and W. Nesbitt, "Synthesis, characterization and fabrication of Na1+ xZr2SixP3− xO12," Materials Research Bulletin, vol. 15, no. 11, pp. 1533-1539, 1980.
[19] T. Ota, P. Jin, and I. Yamai, "Low thermal expansion and low thermal expansion anisotropy ceramic of Sr0.5 Zr2(PO4)3 system," Journal of materials science, vol. 24, no. 12, pp. 4239-4245, 1989.
[20] E. Breval and D. K. Agrawal, "Synthesis of [NZP]‐structure‐type materials by the combustion reaction method," Journal of the American Ceramic Society, vol. 81, no. 7, pp. 1729-1735, 1998.
[21] P. Yadav and M. Bhatnagar, "Structural studies of NASICON material of different compositions by sol–gel method," Ceramics International, vol. 38, no. 2, pp. 1731-1735, 2012.
[22] D. Agrawal and V. S. Stubican, "Synthesis and sintering of Ca0. 5Zr2P3O12-a low thermal expansion material," Materials Research Bulletin, vol. 20, no. 2, pp. 99-106, 1985.
[23] A. Kuriakose, T. Wheat, A. Ahmad, and J. Dirocco, "Synthesis, sintering, and microstructure of NASICONS," Journal of the American Ceramic Society, vol. 67, no. 3, pp. 179-183, 1984.
[24] 黃詩涵, "以液相輔助固相反應法製備鋯磷矽酸鈉之離子導體及其阻抗分析," 碩士, 資源工程學系, 國立成功大學, 台南市, 2019.
[25] 林佳慧, "NASICON化合物中MZr2(PO4)3 (M=Li, Na, K, Cs)之晶體結構與離子導電率," 碩士, 資源工程學系, 國立成功大學, 台南市, 2020.
[26] C. Rashmi and O. Shrivastava, "Synthesis and crystal structure of nanocrystalline phase: Ca1− xMxZr4P6O24 (M= Sr, Ba and x= 0.0–1.0)," Solid State Sciences, vol. 13, no. 2, pp. 444-454, 2011.