氧化鉍基鈣鈦礦陰極材料用於中溫型燃料電池之研究

Abstract

本研究選擇鉍鍶鐵及鉍鍶鈷鐵鈣鈦礦之陰極材料，運用於中溫型燃料電池 (600°C – 800°C)，使用X光繞射、電導率量測、離導率量測、熱膨脹，以及全電池電能輸出量測予以分析。從XRD分析中，成功利用EDTA-檸檬酸鰲合法製備出單一相鈣鈦礦結構粉體。其中，鍶摻雜鐵酸鉍的燒結樣品中，以50 %鍶摻雜鐵酸鉍的樣品在800°C時的電導率及離導率分別為1.5 S cm-1、0.011 S cm-1為最佳；在鍶鈷共摻雜鐵酸鉍燒結樣品中，以鍶摻雜50 %、鈷摻雜20 %的樣品在800°C時電導率及離導率分別為5.4 S cm-1、0.032 S cm-1為最佳。熱分析的結果顯示，鍶摻雜鐵酸鉍的熱膨脹係數隨鍶摻雜的量增加而增加，其從10.0 ppm K-1至15.1ppm K-1。而以鍶鈷共摻雜鐵酸鉍樣品中，熱膨脹係數以鈷摻雜20 % 達到最大，其值為19.1 ppm K-1。S50C20 在所有樣品中擁有最低的極化電阻值，0.1 Ω cm2。以鑭鍶鈷鐵作為陰極的單一陽極支撐全電池為標準電池，其I-V量測的結果中，以S50及S50C20為陰極組成的全電池，輸出分別為361 mW cm-2、405 mW cm-2，其皆高於標準電池的輸出，353 mW cm-2。

Two series perovskites, Bi1-xSrxFeO3-δ (x = 0.1-0.5) and Bi0.5Sr0.5CoyFe1-yO3-δ (y = 0-0.2), have been synthesized by EDTA-citric complexing method and characterized in intermediate-temperature range (600 to 800°C) by X-ray diffraction, electrical property study, thermal analysis and cell testing. The results show single-phase perovskite structure offering CTE values from 10.0 to 19.1 ppmk-1. Two samples S50 and S50C20 perform maximal electrical and ionic conductivities among the series. Polarization resistance from Nyquist plot depicts that S50C20 has a lowest value of 0.10 Ω.cm2. The cells with S50 or S50C20 cathode comparing to the standard cell with La0.6Sr0.4Co0.2Fe0.8O3-δ cathode show the power density 361 mWcm-2,405 mW cm-2 and 353 mW cm-2,respectively. The cells with Bi-base cathodes have a power density higher then that of STD cell.