| 摘要: | 本研究利用BaCe0.6Zr0.2Y0.2O3-δ/BaCe0.8Y0.2O3-δ/BaCe0.6Zr0.2Y0.2O3-δ三明治結構(Sandwich structure)來保護中間層，此種電解質材料主要應用於質子傳導型固態氧化物燃料電池，利用固態反應法來製作BaCe0.8Y0.2O3-δ(BCY) 與BaCe0.6Zr0.2Y0.2O3-δ(BCZY) 粉末，再利用刮刀塗佈法做成個別電解質片，堆疊成所需結構後水壓與燒結成試片。藉由SEM、XRD來進行材料與結構分析。
用SEM觀察三個試片剖面，其中BCY、BCZY與三明治結構分別厚度為66.67um、68.63um、73.52um，且其剖面為緊密結構，。
第二部分用XRD來確認鈣鈦礦相，單相之鈣鈦礦立方晶結構，主要出現6個明顯的主峰訊號，分別為(110)、(200)、(211)、(220)、(310)和(222)(JCPDS #89-2485)，並且沒有其他二次相訊號，因此燒結後所製備試片為單相之鈣鈦礦立方晶結構；接著在600℃ CO2氣氛下做毒化反應測其化學穩定性，BCY在持溫2小時即產生二次相，BCZY於16小時才產生微弱的二次相訊號，說明BCZY於三明治結構可以有效保護中間BCY層。
最後量測其電導率，在還未毒化前BCY、BCZY與三明治結構在800℃下分別為0.0027、0.0018與0.0026(S/cm)，經過CO2 16小時後量測的電導率曲線，BCY電解質在化學穩定性表現時就比較差，電導率因二次相影響有顯著的下降(800℃,~0.0006S/cm)，BCZY則因其化學穩定性佳，與毒化前一樣(800℃,~0.0018S/cm)，Sandwich則略為下降，但因外層有BCZY保護，所以下降幅度有限(800℃,~0.0019S/cm)，但因在量測時到接觸阻抗影響，其數值與理論數值有所差異。
;To protect proton-conducting solid oxide fuel cells (H+-SOFCs) from CO2 poisoning and to have basically ion conductivity, the sandwich structure of BaCe0.6Zr0.2Y0.2O3-δ/BaCe0.8Y0.2O3-δ/BaCe0.6Zr0.2Y0.2O3-δ was used in this study. BaCe0.8Y0.2O3-δ (BCY) and BaCe0.6Zr0.2Y0.2O3-δ (BCZY) powders were synthesized by solid-state reaction method (SSR). After sintering, BCY, BCZY and the sandwich samples were analyzed by scanning electron microscope (SEM), x-ray diffraction (XRD) and conductivity measurements.
The SEM images showed that the electrolytes were highly dense after sintering at 1550℃ for 12 hrs, indicating that the fuel leakage could be ignored. The thicknesses of BCY, BCZY and the sandwich structures were well controlled. The six main peaks (110), (200), (211), (220), (310), and (222) shown in the XRD patterns confirmed the perovskite phase. After poisoning treatment in CO2 atmosphere at 600℃, BCZY and the sandwich structure showed higher stability than that of BCY.
The conductivity of the sandwich structure (800℃,0.0026 S/cm) was found to locate between BCY (800℃,0.0027 S/cm) and BCZY (800℃,0.0018 S/cm). After poisoning treatment, the BCY conductive value obviously decreased (800℃,~0.0006S/cm) since the second phase hindered its ion transferring. The sandwich structure almost maintain its conductivity because its protection layers slowed down the pensioning process (800℃,~0.0019S/cm). However, all conductive values were smaller than the values in the previous study. It would be attributed to the contact resistances between electrolyte and metal contacts. |
