鋰鐵鈦磷酸鹽之晶體結構與離子導電度性質研究;Syntheses, Crystal Structures and Ionic Conductivity Properties of Lithium Iron Titanium Phosphates

Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/71298

Title:	鋰鐵鈦磷酸鹽之晶體結構與離子導電度性質研究;Syntheses, Crystal Structures and Ionic Conductivity Properties of Lithium Iron Titanium Phosphates
Authors:	邱郁雯;Chiu,Yu-Wen
Contributors:	化學學系
Keywords:	水熱合成法;溶膠凝膠法;鋰鐵鈦磷酸鹽;電化學測量
Date:	2016-07-13
Issue Date:	2016-10-13 12:41:16 (UTC+8)
Publisher:	國立中央大學
Abstract:	本論文使用高溫高壓水熱合成法，合成出 3 個的鋰鈦磷酸鹽化合物 : LiTi2(PO4)3 (A1)、Li1+xTi2-xFex(PO4)3 (x=0.8) (A2)、 Li1+xTi2-xFex(PO4)3 (A3)，藉由單晶 X 光繞射方法鑑定出化合物的晶體結構，並使用粉末 X 光繞射確定樣品純度以供後續分析，再以 X 光能量散佈分析、感應耦合電漿原子發射光譜儀、穆斯堡爾光譜儀等儀器進行定量及鐵離子周圍環境之分析。 A1 和 A3 為 NASICON 結構，它們皆為三方晶系，空間群為 R-3c，結構中的 2 個 MO6 與 3 個 PO4 會以共角的方式式連接成一個燈籠狀結構單元，其燈籠狀結構單元又以平形的方向互相作排列，鋰離子座落於八員環中。 A2 為 anti-NASICON 結構，其為正交晶系，空間群為 Pbcn. A2 也是由燈籠狀結構單元所組成，其燈籠狀結構單元的組成與 A1 (A3) 相同，不同的是其燈籠狀結構單元是以反平形的方向作排列，而鋰離子座落於六員環中。並且使用溶膠-凝膠法合成出鋰鐵鈦磷酸鹽化合物 : Li1+xTi2-xFex(PO4)3 (x=0.5) (A4, LFTP)，藉由粉末 X 光繞射鑑定其為NASICON結構。A4 可做為穩定的鋰電池之電解質材料，其離子導電度可達到 1 x 10-3 S· cm-1，將 A4 導入陰極材料，其放電電容量可達到 14.6 mAh。 ;Three lithium titanium phosphates, LiTi2(PO4)3 (A1), Li1+xTi2-xFex(PO4)3 (x=0.8) (A2), Li1+xTi2-xFex(PO4)3 (A3), were synthesized by the high-temperature, high-pressure hydrothermal method, and structurally characterized by powder and single X-ray diffraction. These compounds were further characterized by XRF, ICP-OES and Mössbauer spectroscopy. A1 and A3 adopt the NASICON structure with the trigonal space group R-3c. They both consist of lantern structure units which are composed of two MO6 octahedra and three PO4 tetrahedra by corner-sharing, and the units are connected in aparallel way. The lithium cations are located in the eight-membered rings. A2 adopts the anti-NASICON structure with the orthorhombic space group Pbcn, and consist of the same lantern units. But the lantern units are connected in an anti-parallel way and lithium cations are located in the six-membered rings which have different environment from A1(A3). A lithium iron titanium phosphate Li1+xTi2-xFex(PO4)3 (x=0.5) (A4, LFTP) with the NASICON structure has been synthesized by sol-gel method and characterized by powder X-ray diffraction. It is found that A4 displays good stability as electrolyte material for lithium battery. The ionic conductivity is 1 x 10-3 S· cm-1 and discharge capacity is 14.6 mAh.
Appears in Collections:	[Graduate Institute of Chemistry] Electronic Thesis & Dissertation

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