固態氧化物燃料電池(Solid Oxide Fuel Cell, SOFC)為高溫型燃料電池，特色為功率密度高，其中電解質的離子導電特性扮演重要的角色，常見的電解質材料主要以螢石結構(fluorite structure)為主的氧化鋯基與氧化鈰基為主要的發展材料，故本文以此兩種材料系統作為我們研究探討方向。
首先對氧化鋯基材料研究，本實驗使用1 mol% 氧化釔穩定氧化鉍（Yttria-stabilized bismuth oxide, YSB）摻雜於氧化釔穩定氧化鋯 (Yttria-stabilized zirconia, YSZ)為電解質材料(以下簡稱為1YBZ)，並以微波燒結(Microwave Sintering, MS)的方式來製備電解質試片，希望藉由YSB的添加，可以降低YSZ的燒結溫度，並提升其離子導電率，更希望利用微波燒結來消除m相氧化鋯（monoclinic ZrO2 ,m-ZrO2）的產生。
實驗結果得到添加1 mol% YSB，可使YSZ的燒結溫度由1500℃降至1100~1200℃；在結構方面，1YBZ的主相仍為立方結構之富YSZ 相，使用傳統高溫爐燒結方式時，YSZ母相會有單斜相ZrO2的產生，而使用微波燒結，不但可以縮短燒結時間，更可以消除單斜相ZrO2的現象；在導電率方面，1YBZ的材料系統，使用MS在燒結溫度1200℃持溫2小時的條件下，800℃的離子導電率為0.019 S/cm，高於為8YSZ（8 mol% Y2O3-92 mol% ZrO2）離子導電率0.013S/cm。在還原方面，1YBZ電解質在40％氫氣還原下7小時功率密度還能維持在40~42mW/cm2之間。
氧化鈰研究結果方面，由於氧化鈰在低氧分壓及高溫條件下，Ce4+易被還原成Ce3+，造成電解質的效能和應用性降低，故嘗試在氧化鈰基材上面使用網印的方式，塗覆不同漸進層的多層複合(GDC)1-x(YSZ)x結構，除了希望能提升GDC電解質的抗還原特性，更可以解決GDC和YSZ之間的匹配性問題。
實驗結果可以看出，在微觀結構方面，以漸進層方式製備複合電解質的確可以改善GDC與8YSZ之間熱膨脹係數的缺失。在離子導電性方面，卻因為晶界效應及界面阻抗的影響比GDC大，所以複合電解質的離子導電性較GDC電解質差。最後在還原方面，使用GDC電解質及GDC/(GDC)1-x(YSZ)x複合電解質做成單電池，在800℃、持溫7小時下測量其功率密度，在通入15%的氫氣，且陽極和陰極皆使用網印的方式塗覆純白金膠的條件下，GDC 電解質的單電池功率密度降低的非常快，從21.89 mW/cm2降低至 7.16 mW/cm2；但在GDC基材表面上使用適當的抗還原層改質後的GDC/(GDC)1-x(YSZ)x複合電解質，卻還能使58.49mW/cm2維持在47.30 mW/cm2，此結果印證了複合電解質可以抑制GDC還原的問題。

Featuring high efficiency of power generation, Solid Oxide Fuel Cell (SOFC) was considered as high-temperature fuel cell, in which the ion conductivity of an electrolyte was one of popular topics in this field. Fluorite-based materials such as doped zirconia and doped ceria caught many researchers attention. This thesis focused on these two materials systems for detailed discussion.
First, doping 1 mol% Yttria-stabilized Bismuth oxide, YSB, into Yttria-stabilized Zirconia, YSZ, was chosen as the material system, and the microwave sintering, MS, was chosen as sintering method. The purpose of doping YSB was to decrease the sintering temperature of YSZ as well as increase ion conductivity. Furthermore, the generation of m-phase of zirconia was expected to be eliminated after MS. The result showed that the sintering temperature decreased from 1500℃ to 1100~1200℃. In aspect of structure, 1YBZ remained YSZ-rich cubic phase, and the m-phase of zirconia was detected at the matrix of YSZ under furnace heating condition. On the other hand, using MS not only reduced sintering time but also eliminated the m-phase. Moreover, the specimen of the former was sintered at 1200℃for 2 hours; the measured ion conductivity was 0.019 S/cm at 800℃, which is higher than 0.013 for 8YSZ. For reduction resistance, the measured power density of the electrolyte originally was 40mW/cm2. After the exposure to 40% H2 atmosphere for 7 hours, the power density would be maintained to 40~42 mW/cm2.
Second, according to previous research, ceria-based electrolyte had poor reduction resistance, which was under low oxygen pressure and high temperature condition. The reduction, Ce4+ to Ce3+, should be avoided for stable power density output for long-term operation. In this study, a multilayer structure of (GDC)1-x(YSZ)x was screen-printed onto GDC, called composite GDC, for the purpose of increasing anti-reduction ability of the electrolyte and solving mismatch between the layer and electrolyte. The result showed that the ion conductivity of the composite GDC was poorer than that of GDC only possibly due to the grainboundry effect as well as higher interface impedance. After the exposure to 15% H2 atmosphere for 7 hours , the power density of GDC only decreased drastically from 21.89 mW/cm2 to 7.16 mW/cm2. On the other hand, under the same condition for the composite GDC, the power density remained 47.3 mW/cm2 compared to 58.49 mW/cm2 before the reduction test. This result proved that the method of screen-printing the multilayer structure of (GDC)1-x(YSZ)x onto GDC was a feasible solution.

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