| 摘要: | 本研究旨在評估質子傳導型固態氧化物燃料電池 (PC-SOFCs) 以氫氣和甲烷混合氣體作為陽極燃料時的電化學性能。傳統PC-SOFCs主要使用純氫燃料，但甲烷作為更具經濟效益且蘊藏豐富的替代燃料，其應用潛力值得探討。然而，甲烷燃料亦面臨積碳及重整效率等挑戰。
實驗中，系統性地探討了不同甲烷比例（0%、15%、30%、45%、60%、75%、90%）對PC-SOFCs性能的影響。透過量測開路電壓 (OCV)、最大功率密度 (MPD) 及電化學阻抗譜 (EIS)，全面分析燃料組成的變化。
結果顯示，操作溫度是影響電池性能的關鍵因素。在600°C時，通入15%甲烷的MPD並無明顯衰退。然而，在500°C的低溫下，性能則隨著甲烷濃度增加而急遽衰減，MPD由553 mW/cm²大幅下降，在90%甲烷時只剩下50 mW/cm²，EIS與DRT分析明確指出，性能衰退源於歐姆、活化與濃差極化的全面增加，其中與陽極表面反應動力學相關的中頻阻抗 (RM ) 增長最為顯著，證實甲烷裂解與積碳是主要衰退機制。
最後，本研究發現，此積碳造成的性能衰退具有可回復性。在通入含3%水氣的氫氣處理後，電池性能與阻抗均能恢復至初始水平。此研究結果系統性地揭示了溫度對甲烷燃料PCFC性能的影響，並證實了積碳的可移除性，為未來開發抗積碳陽極提供了重要的依據。
;This study aims to evaluate the electrochemical performance of proton-conducting solid oxide fuel cells (PCFCs) using methane-hydrogen mixtures as the anode fuel. While conventional PCFCs primarily operate on pure hydrogen, methane is a promising alternative fuel due to its economic advantages and natural abundance. However, the direct utilization of methane faces challenges such as carbon deposition (coking) and reforming efficiency.
In this work, the effect of different methane proportions (0%, 15%, 30%, 45%, 60%, 75%, 90%) on the performance of PCFC was systematically investigated. The impact of the fuel composition changes was comprehensively analyzed by measuring the open-circuit voltage (OCV), maximum power density (MPD), and electrochemical impedance spectroscopy (EIS).
The results indicate that operating temperature is a critical factor influencing cell performance. At 600°C, the MPD showed no significant degradation when operating on 15% methane. However, at a lower temperature of 500°C, the performance degraded sharply with increasing methane concentration, with the MPD plummeting from 553 mW/cm² to only 50 mW/cm² at 90% methane. EIS and Distribution of Relaxation Times (DRT) analysis revealed that the performance degradation originated from a comprehensive increase in ohmic, activation, and concentration polarizations. Among these, the mid-frequency resistance (RM) related to the anode surface reaction kinetics showed the most significant growth, confirming that methane cracking and carbon deposition are the primary degradation mechanisms.
Finally, this study found that the performance degradation caused by coking is reversible. After a treatment with humidified hydrogen (3% H₂O), both the cell performance and impedance could be restored to their initial levels. These findings systematically reveal the influence of temperature on the performance of methane-fueled PCFCs and demonstrate the removability of carbon deposits, providing an important basis for the future development of coking-resistant anodes. |
