合成質子傳導型電解質與奈米纖維陽極 功能層於H+-SOFC之應用研究

Synthesis and Characterization of Proton-conducting Electrolytes and Nano-fiber Anode Functional Layer for H+-SOFC Applications

黃俞碩(Yu-Shuo Huang)

指導教授 ： 李勝偉

國立中央大學/工學院/材料科學與工程研究所/碩士(2015年)

摘要

態氧化物燃料電池電解質材料之化學穩定性、燒結緻密性、相均勻性以及離子傳導性，本實驗利用溶膠-凝膠製備以BaCe0.8Y0.2O3-δ為基礎之電解質材料，此氧化物在中溫(600-800℃)範圍內具有穩定之質子傳導性，但由於此材料之高溫化學穩定性及燒結緻密性不佳，因此必須添加Sr及Zr來抑制生成不純相，為了增進燒結緻密性，故本研究利用成分交換法均勻混合Ba1Ce0.8Y0.2O3-δ及Ba0.6Sr0.4Ce0.4Zr0.4Y0.2O3-δ，於1600℃下燒結4小時，使成分均勻擴散形成單相Ba0.8Sr0.2Ce0.6Zr0.2Y0.2O3-δ，並觀察其顯微結構以及利用拉曼圖譜分析此材料於高溫CO2環境下之化學穩定性，並作成單電池Pt /電解質/ Pt測量電解質之電導率及電池能量密度。之後以陽極支撐的方式製作電池，將電解質減薄至50 μm以下，縮短質子傳遞路徑，另外加入陽極功能層(functional layer) SrCe0.8Y0.2O3-δ奈米纖維結構來達到增加陽極與電解質間之表面積，以利燃料催化得更完全，進而提升電池電化學表現及能量密度。

關鍵字

溶膠-凝膠法 ； 固態氧化物燃料電池 ； 電解質 ； 奈米纖維 ； 陽極功能層

並列摘要

This study reports the synthesis of proton-conducting Ba1-xSrxCe0.8-xZrxY0.2O3-δ (x =0, 0.2, 0.4) ceramics by using a combination of citrate-EDTA complexing sol-gel process and the composition-exchange method. Compared to the sintered oxides of similar composition prepared from conventional sol-gel powders,Ba0.8Sr0.2Ce0.6Zr0.2Y0.2O3-δoxides synthesized by sol-gel combined with the composition-exchange method are found to exhibit improved sinterability, higher conductivity, more homogeneous phase. Among all sintered oxides in this study, the Ba0.8Sr0.2Ce0.6Zr0.2Y0.2O3-δpellet fabricated by this new method has the highest conductivity, 0.017 S/cm at 800℃, which is higher than those pressed from conventional sol-gel powders. Based on the experimental results, we discuss the mechanism for improvement in these properties in terms of calcined particle characteristics. This work demonstrates thatBa0.8Sr0.2Ce0.6Zr0.2Y0.2O3-δoxides synthesized by sol-gel combined with the composition-exchange method would be a promising electrolyte for H+-SOFC applications.
A SrCe0.8Y0.2O3-δ-NiO anode functional layer was added between the Ba0.8Sr0.2Ce0.6Zr0.2Y0.2O3-δelectrolyte and the Ba0.8Sr0.2Ce0.6Zr0.2Y0.2O3-δ-NiO anode substrate to investigate its effect on the performance of single cells. Anode-supported electrolyte fuel cells were fabricated and tested. The single cell without SrCe0.8Y0.2O3-δ-NiO anode functional layer generated maximum power densities of 201.08 mWcm−2 at 800 °C. Electrochemical impedance spectroscopy (EIS) measurements for three cells revealed that the addition of the anode functional layer reduced the contact resistance as well as the polarization resistance for the cell, resulting thus in the improved cell performance.

並列關鍵字

Sol-gel ； SOFC ； proton-conducting ； electrolyte ； nanofiber ； anode functional layer

參考文獻

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