氣體擴散層是電極的重要組成材料,主要進行著反應物的傳遞、生成物的轉移以及電子的傳導。擴散層的性能直接或間接影響電池的歐姆極化、擴散極化、甲醇穿透。本研究主要目的是建立甲醇燃料電池氣體擴散層的材料與質傳特性參數之分析方法。 藉由標準的量測方法,分析氣體擴散層材料改質後其物理特性如厚度、導電性、親疏水性、氣體滲透率的變化。進一步以capillary flow porometer分析孔結構特性的變化 ,探討其孔洞分佈及最大孔洞,並比較質傳特性的變化如何影響甲醇燃料電池的性能與效率。 實驗結果顯示由於改質陽極氣體擴散層厚度增加和孔隙度減少,雖然在低甲醇濃度下因為質傳阻抗增加,導致性能降低。但在較高甲醇濃度操作下,由於燃料中甲醇較多提高反應效率,而且甲醇穿透現象有效地被阻擋,故電池性能進而提升。
Direct methanol fuel cell (DMFC) gas diffusion layers (GDLs) play important parts in diffusing gas , discharging products , and conducting electricity, etc.。The performance of GDL effects losses of ohmic polarization、concentration polarization and methanol crossover directly or indirectly。To develop analysis method of property parameters for DMFC GDL material with mass transport is the main purpose of this paper。 To investigate physical properties change of reformed gas diffusion layer like thickness、resistance、contact angle and gas permeability with standard measurement methods。Advanced using capillary flow porometer to analysis the change of pore structure for pore distribution and maximum pore diameter then compare with mass transport properties change and how they effect the performance and efficiency of DMFC。 The results show increased thickness and decreased porosity of reformed anode GDL causes lower performance under lower concentration of methanol due to the increased of concentration polarization , but higher performance under high concentration of methanol is observed because the methanol crossover is blocked。