以雙自熔旋轉電極製備固態氧化物燃料電池陽極基材之探討

Abstract

傳統固態氧化物燃料電池(SOFC)所用的陽極Ni-YSZ複合材料，其缺點在於，所用燃料為碳氫化合物時，常有積碳現象發生而影響電池的效率。如要改善碳積現象可用部分Cu取代Ni；不過以Cu為基底的陽極其熱穩定性差，使用溫度只能在~600℃，不適合一般的SOFC操作溫度(800-1000℃) 。因此本研究之目的為改善陽極材料，發展以Cu為基底的雙金屬合金，利用Cu來提供良好的電子導電率及防止積碳現象，並用另一金屬加強維持其陽極熱穩定性及提高其效能。有別於一般陽極的製備方法是用合金粉末與陶瓷複合物混合成漿狀，本實驗以旋轉電極粉末冶金的方法製備陽極粉末;實驗所用的陽極材料分為Cu-Ni、Cu-Cr及Cu-Co三種成份。 本實驗之負極為Cu，正極為Ni、Cr或Co。製備出的合金粉末用SEM+EDX觀察其粉末橫截面，並且將粉末燒結後再次以顯微鏡觀察其燒結情況。而後將燒結的試片拿去做一連串的分析如下:以TMA測量其熱膨脹係數、氧化還原測試再以SEM觀察其孔隙度及微結構之變化、以水銀測孔儀測量其孔隙度、四點探針量測法測電阻、硬度機量測其硬度 實驗結果可發現控制好旋轉電極之實驗參數即可得到較多的雙層粉末且其燒結後試片之熱膨脹係數都可以與電解質相匹配，不容易發生崩裂毀損的現象，也可以使電池的使用壽命拉長。而由一連串的測試結果發現Cu-Ni、Cu-Co因熱穩定性佳所以為較理想之SOFC陽極材料。

The shortcomings of traditional solid oxide fuel cell (SOFC) used by the anode Ni-YSZ composite materials is that when the fuel used for hydrocarbons, carbon deposition phenomenon occurred often affect the efficiency of the battery. To avoid the carbon deposition phenomenon ，it is useful to replace Ni by Cu; But the thermal stability of Cu-based anode is extremely poor, the temperature can only be used in ~ 600 ℃, not suitable for general SOFC operating temperature (800-1000 ℃). Therefore the purpose of this study was developing Cu-based bi-metal material to improve the efficiency of SOFC anode. Using Cu to provide a good electronic conductivity and prevent the phenomenon of carbon deposition, and the function of another metal is maintain its anode thermal stability and enhance its efficiency. Unlike the general preparation of the anode is ceramic mixed alloy powder into a slurry ， this experiment used double consumable rotating electrodes equipment, a new kind of PM method to prepare the anode powder. The materials used in this experiment were Cu-Ni, Cu-Cr and Cu - Co three components. In this study，the negative is Cu, and the positive is Ni, Cr or Co. Observing the cross-section of the alloy powders prepared by double consumable rotating electrodes by SEM + EDX , then sintered the powder into stack to observe the microscope . Sintering samples will be test with a series of analysis as follows: The coefficient of thermal expansion by TMA, redox test to observe the porosity and micro-structure changes by SEM, measuring the porosity by mercury-measurement, four-point probe Measurement measured resistance, hardness by hardness measurement. The results can be found that controlling the rotating electrode experimental parameters can get more bi-layer powders and its specimens of the coefficient of thermal expansion can be matched with the electrolyte. So that reducing the damage and longer the lifetime of the cell. By a series of test it can be found that Cu-Ni, Cu-Co materials are ideal for SOFC anode materials.