燃料電池氣體擴散層中碳微孔層性質研究

Study of micro-porous layer in the catalyst-supporting layer of fuel cell

林威璋(Wei-Chang Lin)

指導教授 ： 鄭吉豐

中原大學/理學院/化學系/碩士(2006年)

https://doi.org/10.6840/CYCU.2006.00440

摘要

燃料電池可以供應無污染的能源給交通工具及電器用品，它將漸漸成為新的替代能源。氣體擴散層、氣體流場板及電流收集板被設計成為最佳電性的膜電極組。氣體擴散層通常是以多孔性的碳布或碳紙為基材，兩邊分別是電池的陽極及陰極，它必須是良好的導體以導通電流。另氣體擴散層必須具備良好的氣體傳輸性，將反應氣體平均分散至膜電極組上的觸媒層，而碳微孔層是質子交換膜燃料電池中介於碳布及觸媒層中間的重要角色。
本論文探討質子交換膜燃料電池氣體擴散層之碳微孔層特性，我們採用顆粒大小均勻之碳黑，與高反應比表面積之活性碳為兩種不同的碳材料。氣體擴散層應有的特點包括，導電度佳、水分及氣體的傳輸佳、防腐蝕等。直到現在，已有許多研究證實，改良氣體擴散層的碳微孔層性質可以促進燃料電池的性能提升。
我們利用I-V電性測試來比較各種碳材料製成的GDL電極。1800℃高溫燒結後的自製活性碳材料製成的GDL電極獲得最佳的電性表現，因為這個GDL電極微孔層的碳材料擁有中等的比表面積數值及石墨化結構。1800℃高溫燒結後的自製活性碳材料，雖然其顆粒大小均勻性不如碳黑，但是高反應表面積特性卻彌補此缺點，反而獲得比較好的電池功率表現。

關鍵字

膜電極組 ； 燃料電池 ； 氣體擴散層

並列摘要

Fuel cells can provide pollution-free energy for both transportation and electric utilities. The GDLs, flow fields, and current collectors are designed to maximize the current from a membrane electrode assembly. The GDLs, one next to the anode, the other next to the cathode are usually made of a porous carbon paper or carbon cloth. The layers have to be made of a material (like carbon) that can conduct the electrons, leaving the anode and entering the cathode. The porous nature of the material ensures effective diffusion of each reactant gas to the catalyst on the membrane electrode assembly. A carbon micro-porous layers between the carbon paper and catalyst layer played a crucial role in PEMFC.
To study the characteristics of micro-porous layer between the catalyst layer and the gas diffusion layer of PEMFC, two carbon materials were used. One carbon material was Vulcan XC-72 carbon-black with good pore-size distribution from inter-particle space and quite uniformity of particle size and the other one is activated carbon with high specific surface areas. Gas diffusion layers should have properties such as good electric conductivity, well water and gas transportation, corrosion resistance, etc. Until now, there have been many attempts to increase fuel cell performance by developing or modifying the gas diffusion layer (GDL). The influence of conductivity of carbon materials and specific surface areas of the gas diffusion layer has been investigated. The performance of PEMFC was significantly improved by adding of micro-porous layer.
The current–voltage characteristics of various GDL electrodes were compared. A maximum performance was achieved with the home-made activated-carbon when it was heated to 1800℃before brushed on carbon cloth. This result follows from the fact that the home-made activated-carbon has the medium surface area, the well graphitized structure among the carbon materials used in this study. It is interesting that the comparison with the GDL based on activated carbon treated at 1800℃ better than Vulcan XC-72 carbon-black.

並列關鍵字

GDL ； Fuel Cell ； MEA

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