摻雜鋁、鐵、鎵對鍺酸鑭基電解質應用於固態氧化物燃料電池之影響

Effects of Al3+, Fe3+ and Ga3+ dopants on the germanate-based apatites as electrolyte for use in solid oxide fuel cells

李沛勳(Pei-Hsun Li)

指導教授 ： 王錫福

國立臺北科技大學/工程學院/材料科學與工程研究所/碩士(2014年)

摘要

本研究是利用固態合成法製備磷灰石結構鍺酸鑭基SOFC電解質材料，主要是利用不同摻雜半徑的離子取代La9.5Ge6O25.25中部分Ge4+，藉以開發最佳導電率之電解質材料，希望能夠取代8YSZ。本實驗將磷灰石結構鍺酸鑭基分別摻雜Al2O3、Fe2O3及Ga2O3，透過固態合成法製備鍺酸鑭基電解質粉末。配合不同的摻雜劑利用不同的製程參數進行燒結，並測量其電性，期望能找出最佳成分配比及製程條件。研究結果發現，摻雜FeO2有二次相生成，而摻雜Al2O3造成導電率過低，因此此兩種摻雜物不利應用於鍺酸鑭基電解質材料。在摻雜組成為La9.5Ge5.7Ga0.3O26.1導電率較佳，在量測溫度800oC時導電率和8YSZ相近，在量測溫度為800oC時，具有最佳導電率(0.031 S/cm)。

關鍵字

鍺酸鑭 ； 電解質 ； 磷灰石 ； 固態氧化物燃料電池

並列摘要

The purpose of this study was to develop apatite-type lanthanum germanate-based solid electrolytes for SOFC (Solid Oxide Fuel Cell). In order to achieve the best conductivity of the electrolyte materials applications, these ceramics were doped with various ions radii that was different from Ge4+ ion and to substitute part of the ion Ge4+ in La9.5Ge6O25.25. Various dopants including Al2O3、Fe2O3 and Ga2O3 were added into to apatite-type lanthanum germanate-based solid electrolytes, respectively. These lanthanum germanate-based solid electrolyte powders were synthesized by solid state reaction. These specimens were sintered at various temperatures and periods of time, then the conductivity of the specimens were measured. The results showed that, the secondary phase of LaFeO3 is formed by doping FeO2, the electrical conductivity is reduced significantly by doping Al2O3. Therefore, the two kinds of dopant were unfavorable used in the lanthanum germanate-based electrolytes. The La9.5Ge5.7Ga0.3O26.1 possesses the best conductivity (0.031 S/cm) at 800oC.

並列關鍵字

lanthanum germanate ； electrolyte ； apatite ； SOFC

參考文獻

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