Measurement of liquid water content in cathode gas diffusion electrode of polymer electrolyte fuel cell
Measurement of liquid water content in cathode gas diffusion electrode of polymer electrolyte fuel cell
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DOI：
10.1016/j.jpowsour.2009.12.073
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发表时间：
2010-06-01
影响因子：
9.2
通讯作者：
Hirai, Shuichiro
中科院分区：
文献类型：
--
作者：
Nishida, Kosuke;Murakami, Takeshi;Hirai, Shuichiro
聚合物电解质燃料电池(PEFC)阴极气体扩散电极(GDE)中的水管理是高性能运行的关键，因为液态水凝结在多孔气体扩散层(GDL)和催化层(CL)中，阻碍了氧气向活性反应部位的传输。在本研究中，通过重量法对低温PEFC阴极GDE内的平均液态水含量进行了实验和定量估算，并研究了阴极GDE内的积水速率与电池电压的关系。利用光学诊断技术对阴极处的液态水行为进行了可视化，并讨论了操作条件和GDL结构对阴极GDE中水输运的影响。研究发现，在燃料电池开始运行后，由于CL处的水产生，阴极GDE中的液态水含量显著增加。在高电流密度下，尽管阴极GDE中的水分含量较低，但电池电压在开始运行后会突然下降。当GDL厚度增加时，阴极CL附近会积聚大量水，燃料电池在运行后立即关闭。在本文的最后，为了防止水淹和提高燃料电池的性能，提出了具有多个除水槽的阴极GDL的结构。这种槽结构有效地促进了积聚在活性催化剂位置附近的液态水的去除。(C)2009爱思唯尔B.V.保留所有权利。
Water management in cathode gas diffusion electrode (GDE) of polymer electrolyte fuel cell (PEFC) is essential for high performance operation, because liquid water condensed in porous gas diffusion layer (GDL) and catalyst layer (CL) blocks oxygen transport to active reaction sites. In this study, the average liquid water content inside the cathode GDE of a low-temperature PEFC is experimentally and quantitatively estimated by the weight measurement, and the relationship between the water accumulation rate in the cathode GDE and the cell voltage is investigated. The liquid water behavior at the cathode is also visualized using an optical diagnostic, and the effects of operating conditions and GDL structures on the water transport in the cathode GDE are discussed. It is found that the liquid water content in the cathode GDE increases remarkably after starting the fuel cell operation due to the water production at the CL. At a high current density, the cell voltage drops suddenly after starting the operation in spite of a low water content in the cathode GDE. When the GDL thickness is increased, much water accumulates near the cathode CL and the fuel cell shuts down immediately after the operation. In the final section of this paper, the structure of cathode GDL that has several grooves for water removal is proposed to prevent water flooding and improve fuel cell performance. This groove structure is effective to promote the removal of the liquid water accumulated near the active catalyst sites. (C) 2009 Elsevier B.V. All rights reserved.