| 摘要: | 本研究旨在建立適用於中溫操作條件下質子陶瓷燃料電池(Protonic Ceramic Fuel Cell, PCFC)之高性能陰極結構設計，系統性探討具三重導體特性之PBSCF應用於陰極與功能層的可行性，並優化其微觀結構與電化學性能表現。整體研究依照材料組合與製程參數調控的邏輯，分為三大階段進行探討：
第一部分固定陰極材料為LSCF，設計BCZY-LSCF、BCZY-PBSCF複合功能層組合，其中搭配LSCF複合功能層之組合在800 °C下最大功率密度為693.8 mW/cm²，比起PBSCF複合功能層提升約47.4%。
第二部分則固定陰極材料為PBSCF，分別搭配BCZY-LSCF、BCZY-PBSCF複合功能層，以及設計無功能層(w/o Interlayer)的比較，比較各組合在導電特性、熱膨脹匹配性與微觀結構上的差異。實驗結果顯示，PBSCF搭配LSCF複合功能層之陰極結構，在電子、氧離子與質子等傳輸通道上具良好協調性，其中LSCF提供穩定的電子與氧離子傳導能力，BCZY提供質子傳導途徑，與PBSCF的三重導電特性形成連續且互補的傳輸路徑，有效提升界面電荷轉移效率與氧還原反應活性面積，整體表現優於其他材料組合。
第三部分針對性能最佳組合，進一步調整陰極與黏結劑的比例，透過調整陰極醬料配比，改善微觀孔隙連通性與氣體擴散路徑，進一步強化電極在中溫條件下的反應動力學與電化學表現。研究結果顯示，採用陰極粉末與黏結劑比例為3:2之組合，有最佳的電化學性能，其功率密度提升至1073 mW/cm²，歐姆阻抗(RΩ)與極化阻抗(Rp)分別為0.306 Ω·cm²與0.016 Ω·cm²。整體實驗結果驗證三重導體材料於中溫PCFC陰極結構設計中的潛力，並建立一套以材料導電特性整合與界面相容性為核心的設計邏輯，輔以微觀結構觀察與電化學數據驗證，作為未來中溫燃料電池陰極結構設計之具體參考。
;This study aims to develop a high-performance cathode structural design for protonic ceramic fuel cells (PCFCs) operating under intermediate temperatures. A systematic investigation was conducted on the applicability of the triple-conducting oxide PrBa₀.₅Sr₀.₅Co₂O₅+δ (PBSCF) as both the cathode and cathode functional layer (CFL) material. The research focused on optimizing the microstructure and electrochemical performance of the integrated cathode system through tailored material combinations and process parameters. The study was divided into three major phases:
In the first phase, La₀.₆Sr₀.₄Co₀.₂Fe₀.₈O₃−δ (LSCF) was selected as the cathode, and various composite functional layers, including BCZY-LSCF and BCZY-PBSCF, were evaluated. The objective was to assess the feasibility of incorporating PBSCF as a CFL component by examining its conductivity and interfacial behavior, particularly its influence on electrolyte (BCZY) compatibility and thermal expansion matching. Among the tested configurations, the LSCF cathode with a BCZY-LSCF functional layer achieved the highest peak power density of 693.8 mW/cm² at 800 °C, which is approximately 47.4% higher than that of the BCZY-PBSCF counterpart.
In the second phase, PBSCF was employed as the cathode material and combined with either BCZY-LSCF or BCZY-PBSCF functional layers. A configuration without any CFL (w/o interlayer) was also tested for comparison. Electrochemical analysis revealed that the PBSCF cathode with a BCZY-LSCF functional layer exhibited superior structural and functional synergy across all charge transport pathways—including electrons, oxygen ions, and protons. In this structure, LSCF contributed robust electronic and oxygen-ion conductivity, BCZY facilitated proton conduction, and PBSCF′s triple-conducting nature established a continuous and complementary transport network. This integration significantly improved interfacial charge transfer and oxygen reduction reaction (ORR) activity, outperforming other material combinations.
The third phase further optimized the best-performing configuration by adjusting the cathode-to-binder ratio. By modifying the ink formulation, the pore structure and gas diffusion pathways were enhanced, leading to improved reaction kinetics and electrochemical performance at intermediate temperatures. The optimal ratio of cathode powder to binder (3:2) yielded the highest performance, achieving a peak power density of 1073 mW/cm², with an ohmic resistance (RΩ) of 0.306 Ω·cm² and a polarization resistance (Rp) of 0.016 Ω·cm².
Overall, this work demonstrates the potential of triple-conducting oxides in PCFC cathode designs and proposes a comprehensive strategy based on conductive compatibility and interfacial integration, supported by microstructural observations and electrochemical characterizations. The findings provide valuable insights and a rational framework for the future development of high-performance cathode architectures for intermediate-temperature fuel cells. |
