本研究利用銀與靜電紡絲技術製備之La0.6Sr0.4Co0.2Fe0.8O3-δ(LSCF)奈米纖維均勻混合後，作為質子傳輸型固態氧化物燃料電池之複合陰極。銀價格低廉且具有優良的導電性與催化性，但是銀顆粒在高溫下容易粗化，造成陰極孔隙率降低，導致固態氧化物燃料電池陰極性能降低。故本研究將銀與LSCF奈米纖維均勻混合形成複合陰極，藉由測量不同混合比例下銀與LSCF奈米纖維之電池性能，及電化學交流阻抗頻譜量測，以釐清陰極端中氣體、氧離子、電子與質子之反應機制。 實驗結果顯示，六種組成比例參數中，以50%Ag-50%LSCF(Fiber)具有最佳電池性能，在800 ℃下最大功率密度值為212.90 mW/cm2，而參考試片100%Ag在800 ℃下最大功率密度值為138.04 mW/cm2，電池性能提升54%；於800 ℃下，50%Ag-50%LSCF(Fiber)之極化阻抗為0.076 Ω∙cm2，而100%Ag之極化阻抗為0.339 Ω∙cm2，故LSCF奈米纖維能夠有效提升電池性能與降低極化阻抗，同時提升全電池之長時間性能穩定性。 本文同時提出銀添加LSCF奈米纖維提升電池性能之機制：藉由LSCF奈米纖維抑制銀顆粒成長，同時擔任銀顆粒之間氧離子與電子之傳輸路徑。 ;In this study, silver and La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) nanofibers prepared by electrospinning technology are evenly mixed and used as composite cathodes for proton-conducting solid oxide fuel cells (P-SOFCs). Silver is inexpensive and has excellent conductivity, however, the easy agglomeration of silver particles at high temperature reduces the cathode porosity resulting poor P-SOFC performance. We expect to improve the performance of solid oxide fuel cells using the blending of silver and LSCF nanofibers as composite cathodes in cells. In this study, cell performance (I-V curve) and electrochemical impedance spectroscopy (EIS) clarify the reaction mechanism of gas, oxygen ions, electrons and protons transport in the cathode. The experimental results show that there exists the best cell performance in the 50%Ag-50%LSCF(Fiber) among six composition ratios. Results show that at 800 ℃, 50%Ag-50%LSCF(Fiber) exhibits higher cell performance and lower polarization impedance of 212.90 mW/cm2 and 0.076 Ω·cm2 compared to other proportions along with 100% Ag reference cell. Therefore, adding LSCF nanofibers can effectively improve the cell performance and long-term stability. Mixing silver and LSCF nanofibers uniformly, LSCF nanofibers can effectively inhibit the agglomeration of silver particles, and simultaneously act as a transport path of oxygen ions and electrons between silver particles, so that LSCF nanofibers can be practically used in solid oxide fuel cells.
