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| 題名: | (A,Li)2Ti2O7 (A = Y、Gd) 固態電解質的製備與離子導電性研究 |
| 其他題名: | Preparation and ionic conductivity of (A,Li)2Ti2O7 (A = Y、Gd) solid electrolyte |
| 作者: | 謝欣諭;Shieh, Shin-yu |
| 貢獻者: | 淡江大學化學學系碩士班
高惠春 |
| 關鍵詞: | 固態電解質;焦綠石結構;離子導體;solid state electrolyte;pyrochlore structure;ionic conductivity;lithium ion;solid oxide fuel cell;crystal structure |
| 日期: | 2010 |
| 上傳時間: | 2010-09-23 16:13:07 (UTC+8) |
| 摘要: | (A2-xLix)Ti2O7-x (A1LT, x = 0.04 – 0.11) (A = Y、Gd)，兩系列樣品分別在1150和1250 oC下燒結10 h。比較A1LT和 A2-xTi2O7 (AT)系列樣品的晶胞參數，發現在相同取代量x的情況下，A1LT系列的晶胞參數會大於AT系列的晶胞參數，這表示Li+成功的取代至A1LT樣品A site的位子。利用添加兩倍的Li2O至A1LT系列樣品，即為(A2-xLi3x)Ti2O7 (A3LT)系列，A3LT與A1LT在相同取代量x的條件下，會有相同的晶胞參數。因此，添加額外的Li2O可當作助熔劑的功用，藉由固態共熔點的產生而降低A3LT樣品的熔點，使A3LT材料獲得改善，且有較大的晶粒。添加Li2O當助熔劑至A1LT系列樣品和燒結時的溫度控制，可使(A2-xLix)Ti2O7-x (A1LT, x = 0.04 – 0.11) (A = Y 、Gd)系列在相同的燒結溫度(分別為1150和1250 oC 10 h)，樣品的相對緻密度均在90 % 以上。Y3LY系列中取代量為x = 0.06樣品在700 ℃時的導電度時為4.07 × 10-4S.cm-1;而根據報導指出，相較於Y2Ti2O7樣品在700度C的導電度為2.03X10-4S.cm-1，卻要以1600度C燒結。
Two series of (A2-xLix)Ti2O7-x (A1LT, x = 0.04 – 0.11) with A = Y and Gd were sintered at 1150 and 1250 oC respectively for 10 h in the static air atmosphere. Unit cell a-axis of the A1LT is longer than that of the A2-xTi2O7 (AT) with the same amount of x and the same A site cation, indicating a successful substitution of the Li+ ion into the A site of A1LT. Addition of extra Li2O (2x) into A1LT, the nominal composition becomes (A2-xLi3x)Ti2O7 (A3LT), which has the same unit cell a-axis as A1LT with the same amount of x. Therefore, the extra Li2O added in the A3LT is probably acting as a self flux to lower the melting point of the mixture. As a result, materials become more compact and grains grow bigger. Adding Li2O as a flux and the heating history is carefully controlled, compact samples of (A2-xLix)Ti2O7-x (A1LT, x = 0.04 – 0.11) with A = Y and Gd with relative density higher than 90% can be obtained at a temperature as low as 1150C and 1250C respectively. One compound of Y3LT with x=0.06 prepared at 1150C had an AC conductivity of 4.07 x10-4S/cm at 700C, the ionic conductivity is comparable to a Y2Ti2O7 prepared at 1600C that is 2.03x10-4 S/cm reported. |
| 顯示於類別: | [化學學系暨研究所] 學位論文
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