Effects of anode microporous layers made of carbon powder and nanotubes on water transport in direct methanol fuel cells
Effects of anode microporous layers made of carbon powder and nanotubes on water transport in direct methanol fuel cells
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DOI：
10.1016/j.jpowsour.2009.01.099
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发表时间：
2009-06
影响因子：
9.2
通讯作者：
Qixing Wu;T. Zhao;Rong Chen;Weiwei Yang
中科院分区：
文献类型：
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作者：
Qixing Wu;T. Zhao;Rong Chen;Weiwei Yang
实验研究了阳极扩散层（DL）的设计参数，包括背衬层（BL）中PTFE的负载量、微孔层（MPL）中碳和PTFE的负载量对水通过膜的传输和液体进料直接甲醇燃料电池（DMFC）性能的影响。结果表明，当进料甲醇浓度增加时，增加BL中的PTFE负载并引入MPL可以减少水穿过膜而不牺牲电池性能。研究还发现，改变MPL中PTFE的负载量对水渗透的影响很小，而增加MPL中碳的负载量可以显著降低水渗透通量。然而，由于存在大量泥浆裂缝，MPL减少水渗透的能力受到限制。为了进一步降低水渗透通量，提出了一种由多壁碳纳米管（MWCNTs）和聚四氟乙烯（PTFE）制成的无裂纹MPL。测试表明，具有纳米管MPL的DMFC比传统的碳粉末MPL具有更低的水渗透通量。更重要的是，纳米管MPL的使用允许DMFC以更高的甲醇浓度运行，从而增加燃料电池系统的能量密度。
The effects of the design parameters of the anode diffusion layer (DL), including the PTFE loading in the backing layer (BL), and the carbon and PTFE loading in the microporous layer (MPL), on water transport through the membrane and the performance of a liquid-feed direct methanol fuel cell (DMFC) are experimentally investigated. The results indicate that increasing the PTFE loading in the BL and introducing a MPL could decrease water crossover through the membrane without sacrificing cell performance when the feed methanol concentration is increased. It is also found that changing the PTFE loading in the MPL has little effect on water crossover, whereas increasing the carbon loading in the MPL could noticeably decrease the water-crossover flux. Nevertheless, the ability of the MPL to reduce water crossover is limited by the presence of a number of mud cracks. To reduce further the water-crossover flux, a crack-free MPL made of multi-walled carbon nanotubes (MWCNTs) and PTFE is proposed. Tests indicate that the DMFC with the nanotube MPL results in a much lower water-crossover flux than a conventional carbon-powder MPL. More importantly, the use of the nanotube MPL allows the DMFC to be operated with a higher methanol concentration, and thereby increases the fuel cell system energy density.