新穎金屬摻雜燒綠石電解質材料於中溫型固態氧化物燃料電池之應用及研製

Abstract

全球氣候變暖和能源危機是人類目前面臨的關鍵問題。固態氧化物燃料電池能夠發揮降低碳污染和轉化電力高效率的關鍵作用；然而，相對高的工作溫度（>900°C）導致電池壽命表現不佳、需求的材料以及封裝成本過高是目前研究最大的考量因素。在此，我們以五種的製程方法：其中三種以陽極支撐電池結構，另外兩種採用電解質支撐電池結構，分別對應大面積及小面積的電池需求。刮刀塗佈成形法被發現可以製造出最可靠的電解質陶瓷薄膜；約100m的YSZ和200m的LSGM電解質片，可用於組成全電池，測量其他由本實驗室開發的新型陰、陽極材料。更進一步，該膜的尺寸可以達到1010到5050 cm2，未來有機會進行電池堆疊的應用。此外，我們還開發了兩種新的氧離子導體材料，La2(Zr1-xWx)2O7以及Gd2(Zr1-xInx)2O7，並分析摻雜金屬的相位寬度、元素組成、元素分散均勻性、元素的價態及其個別在晶體結構中填佔的位置。使用PXRD、SEM-EDX、TEM-EDX、ICP-AES、XPS和XANES進行一系列的分析。我們觀察到該混合摻雜物皆與B位置的Zr混合填佔，並更進一步量測氧離子電導率後，在W摻雜La2(Zr1-xWx)2O7 x = 0.15時，在700°C有最大值0.026 S/cm；在Gd2(Zr1-xInx)2O7 x = 0.2時，在500°C有最大值1.710-4 S/cm。這兩種離子導體在還原氣氛下是相當穩定的。最後，我們製造的Ni-La2(Zr0.85W0.15)2O7（1200°C）| LSGM（200m）| LSCF-SDC單電池片在700°C有最佳效率0.2 W/cm2表現；而Ni-Gd2(Zr0.8In0.2)2O7 | Gd2(Zr0.8In0.2)2O7（300m）| LSCF-SDC單電池片在700°C輸出功率則為1.1510-3 W/cm2。由實驗結果得知，La2(Zr1-xWx)2O7和Gd2(Zr1-xInx)2O7有潛力作為中溫型固體氧化物燃料電池的新型電解質材料。

Global warming and the energy crisis are critical problems that humans are currently confronting. The solid oxide fuel cells, SOFC, play a key role in decreasing carbon pollution and transforming electricity with high efficiency; however, their high operating temperature (> 900°C) causes a high degradation rate of cells and high cost for materials. Herein, we reveal five fabrication methods; three kinds involve anode-supported cells and two employ electrolyte-supported cells. Tape-casting was found to fabricate the most reliable electrolyte film; ~100 μm YSZ and ~200 μm commercial LSGM film were used for measuring other novel anode materials developed by other labs. Moreover, the size of the film can reach 1010 to 5050 cm2 for approaching stack application. In addition, we also developed two kinds of new materials, La2(Zr1-xWx)2O7 and Gd2(Zr1-xInx)2O7, and analyzed phase width, element compositions, valence of the elements, elemental dispersion and occupied sites of the dopants by PXRD, SEM-EDX, TEM-EDX, ICP-AES, XPS and XANES. We observed the mixed dopant occupied the B-site zirconium, and found increasing ionic conductivity: 0.026 S/cm at 700oC for the composition W x=0.15 and 1.710-4 S/cm at 500oC for In x = 0.2. Both of these ion conductors are stable under a reduction atmosphere. Lastly, we fabricated the single cell of Ni-La2(Zr0.85W0.15)2O7 (1200oC) | LSGM(200m) | LSCF-SDC which showed better power efficiency, 0.2 W/cm2 at 700oC, while Ni-Gd2(Zr0.8In0.2)2O7 | Gd2(Zr0.8In0.2)2O7(300m) | LSCF-SDC power output was 1.1510-3 W/cm2 at 700oC. The results show that the La2(Zr1-xWx)2O7 and Gd2(Zr1-xInx)2O7 may have good potential for becoming the electrolyte for IT-SOFCs.