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  • 學位論文

以GNP法合成固態氧化物燃料電池BSCF摻雜鈣之陰極材料

Synthesis of (Ba0.5Sr0.5)1-XCaXCo0.8Fe0.2O3-δ Cathode Material of SOFC by GNP methode

指導教授 : 余炳盛

摘要


燃料電池為目前最有發展性的能源利用方式之ㄧ,其中以陰極材料鋇鍶鈷鐵氧化物(BaySr1-yCoxFe1-xO3-δ)具有高電子導率及高催化特性,為一般常用的固態氧化物燃料電池(SOFCs)之陰極材料,但BaySr1-yCoxFe1-xO3-δ仍有:熱膨脹係數高、導電度低、材料價格昂貴等缺點。故本研究選用此成分為基礎並利用異質摻雜方式進行材料改質,使用溶膠-凝膠燃燒合成法(GNP法),合成Ba0.5Sr0.5Co0.8Fe0.2O3-δ摻雜Ca之鈣鈦礦相新型固態氧化物燃料電池陰極材料鋇鍶鈣鈷鐵氧化物(Ba0.5-Sr0.5)1-XCaXCo0.8Fe0.2O3-δ,以期提升電池的發電效率。 本研究以GNP法輔以950℃煆燒3小時,可成功合成純相鈣鈦礦結構之BSCaCF粉末,且產物經ICP-AES分析,顯示其成分與原始化學劑量比相符。由於摻雜物為鈣,其離子半徑較鋇、鍶小,因此,摻雜標準物經由XRD分析後可明顯發現其繞射峰往小角度偏移,利用Unitcell計算不同鈣添加量之晶格參數,可發現鈣摻雜A位10%到25%之晶格參數由3.9751 Å變小至3.9356 Å,當鈣摻雜量超過25%後晶格參數不再變化,且有雜相產生,推測鈣於A位摻雜量最大約為20%。本研究選用3種常見電解質材料SDC、GDC、YSZ與(Ba0.5-Sr0.5)0.9Ca0.1Co0.8Fe0.2O3-δ進行化學匹配實驗,由結果顯示SDC及GDC與(Ba0.5-Sr0.5)0.9Ca0.1Co0.8Fe0.2O3-δ經900℃熱處理仍無二次相產生,擁有良好的化學匹配度。利用4點探針法量測其導電度,發現其最高導電度於600℃可達59 Scm-1,相對於未摻雜鈣之陰極材料Ba0.5-Sr0.5Co0.8Fe0.2O3-δ,其電性有明顯提升。其熱膨脹係數量測,於800℃熱處理下為17.29 × 10-6 K-1,與未摻雜鈣之BSCF熱膨脹係數19.7× 10-6 K-1相比,明顯下降。與傳統之BSCF相比,目前所觀察到之性質皆明顯改善,此有助於BSCaCF成為新型的固態氧化物燃料電池陰極材料。

並列摘要


Solid oxide fuel cell (SOFC) is a high-efficiency energy conversion device equipped with promising potential for development. Of the cathode materials for SOFC, BSCF (BaySr1-yCoxFe1-xO3-δ) is frequently used thanks to its excellent electron conductivity and superior catalysis characteristic. BSCF, however, reports several disadvantages, such as high thermal expansion coefficient, low electric conduction, and high cost. Using heterogeneous doping to facilitate changes in material characteristics, this thesis aims at synthesizing calcium-doped Ba0.5Sr0.5Co0.8Fe0.2O3-δ by the sol-gel combustion synthetic (GNP) method to form a new type of perovskite cathode material for improving the power generating ability of SOFC. By GNP method, the study successfully synthesized single-phase perovskite-type powdered BSCaCF, and the stoichiometry was verified by ICP-AES analysis. As the doping Ca has an ionic radius smaller than those of barium and strontium, results of XRD analysis indicated that the diffraction peaks of BSCaCF shifted to small angles. Using Unitcell to calculate the lattice parameters at various additions of the doping calcium showed that the lattice parameters of Ca doping at A site from 10% to 25% decreased from 3.9751 Å to 3.9356 Å. The lattice parameters stopped changing and impurity took place when the Ca doping exceeded 25%. The maximum amount of Ca doping at A site was accordingly estimated to be approximately 20%. The study selected three common electrolytes SDC, GDC and YSZ to perform chemical matching experiments with (Ba0.5-Sr0.5)0.9Ca0.1Co0.8Fe0.2O3-δ. The results identified SDC and GDC as good matches with (Ba0.5-Sr0.5)0.9Ca0.1Co0.8Fe0.2O3-δ as there was still no secondary phase when they were heat treated at 900ºC. Using 4-point probe method to measure the conductivity found that the highest conductivity was 59 Scm-1 at 600 ºC. Compared to the cathode material Ba0.5Sr0.5Co0.8Fe0.2O3-δ with no calcium doping, the electrical properties reported significant improvement. The thermal expansion coefficient of the calcium-doped cathode read 17.29 x 10-6 K-1 when heat treated at 800 ºC, showing an obvious decrease as compared to the thermal expansion coefficient of the undopped BSCF (19.7 × 10-6 K-1). As the above experiment results demonstrate, BSCaCF emerges as a more promising new SOFC cathode material than the traditional BSCF.

並列關鍵字

SOFC GNP method BaSrCaCoFe Pervoskite

參考文獻


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被引用紀錄


邵泓翔(2011)。以田口方法探討材料合成與其性質表現以新式八元鈣鈦礦結構固態氧化物燃料電池陰極材料為例〔碩士論文,國立臺北科技大學〕。華藝線上圖書館。https://www.airitilibrary.com/Article/Detail?DocID=U0006-2707201122475300

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