- 學位論文
高溫型固態氧化物燃料單元電池之製程研究
Preparation of Single Cell of Solid Oxide Fuel Cell
摘要
燃料電池是一種利用電化學反應的發電裝置，燃料電池與一般電池不同，可不經燃燒過程，可直接將化學能轉換成電能，是眾所矚目的新一代的替代能源技術。固態氧化物燃料電池 (Solid Oxide Fuel Cell) 為其中一種裝置，它具有無污染、高發電效能的優點，但是由於成本高且須於高溫下操作，對材料的匹配性要求較高，故運用上仍有所限制。本論文之研究主要針對高溫型固態氧化物燃料電池中之主要元件製造，其中包含電解質、陽極、陰極所組成的單元電池的燒結。實驗粉末採用目前商業生產中最常使用的高溫型材料，電解質為8mol％釔安定氧化鋯（Yttria-stablized Zirconia，簡稱8YSZ）；陽極為NiO-YSZ；陰極為20LSM-YSZ，主要通過兩方面的探討來獲得平坦且性能良好的陽極支撐型單元電池元件。首先，通過改變不同Binder成分及比例來調整不同材料燒結後的收縮率，以達到最佳的匹配性﹔其次，按所選擇的Binder配方製備陽極和電解質層薄帶，並通過疊層、熱壓壓合在一起，並探討不同溫度下材料共燒後的顯微組織及性能。實驗結果發現，當使用高聚合度和低聚合度的高分子材料混合作Binder時，可使8YSZ粉末的電解質材料與添加30vol%的NiO-YSZ的陽極材料有最好的燒結匹配性。且陽極與電解質層的共燒溫度為1375℃時，陽極可達到32.45%最高的孔隙率，電解質層的相對密度可達到96.40%。實驗得到厚度20μm緻密的電解質層及厚度680μm的陽極NiO-YSZ層平整之結構。將共燒後之平整試片再於電解質層面網印上厚度約60μm之陰極20LSM-YSZ層，於1100℃至1300℃之間燒結處理，得到完整之SOFC單元電池結構，再於700℃氫氣氣氛下作NiO還原成Ni之處理。在測試溫度900℃、5 vol% 氫氣-氮氣混合氣體流量80 ml/min 時，水氣潤濕或無潤濕的條件下，其測得功率密度為0.09W/cm2。
並列摘要
The Solid Oxide Fuel Cell (SOFC) is an electrochemical device, which converts chemical energy directly into electrical energy without an intermediate step of conversion to heat. Fuel cell technology is an extremely promising method for electrical power generation due to its ability to achieve very high efficiency with very low level of pollutant. There are a lot of challenges in application due to its high operation temperature. In this study we plan to manufacture a planar Solid Oxide Fuel Cell (SOFC) which contains anode, cathode and electrode. NiO-YSZ, 8YSZ, 20LSM are chosen for study due to their common use in commercial production. Firstly, we change the constituent and ratio of Binder to study the shrinkage ratio of different materials﹔ Secondly, we fabricate the anode and electrolyte green foil follow the recipe, press them as a substrate then co-sinter at different temperature. The microstructure and the characteristics are referred for the appropriate sinter temperature, such as the porosity ratio of the anode and the relative density of the electrolyte. We find that when the high polymerization degree and low polymerization degree macromolecule are mixed for Binder, 8YSZ powder for electrolyte material and 30vol% carbon doped NiO-YSZ for anode material show good compatibility under sintering at 1375℃. The porosity ratio of the anode is 32.45% and the relative density of electrolyte reach to 96.40%. We manufacture a flat substrate with 680μm anode and 20μm electrolyte. Then the cathode material 20YSM-YSZ is printed on the electrolyte by screen printing and sintered at 1100℃~1300℃. At last the cell is annealled under 700℃ in hydrogen atmosphere. When the testing temperature is 900℃, the energy density of complete single cell reach to 0.09W/cm2 in 5vol% hydrogen and nitrogen mixed gas with 80 ml/min flow rate.