Environmental Energy Technologies Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
Phys Chem Chem Phys. 2012 Mar 28;14(12):4296-302. doi: 10.1039/c2cp23686a. Epub 2012 Feb 15.
In this study, the high resolution hydrogen-deuterium contrast radiography method was applied to elucidate the impact of the micro-porous layer (MPL) on water distribution in the porous fuel cell media. At the steady state, deuterium replaced hydrogen in the anode stream, and the large difference in neutron attenuation of the D(2)O produced at the cathode was used to track the produced water. It was found that the water content peaked in the cathode-side diffusion media (DM) for the cell without MPL, but with an MPL on the anode and cathode DM, the peak water amount was pushed toward the anode, resulting in a relatively flattened water profile through components and demonstrating a liquid barrier effect. Additionally, the dynamic water behavior in diffusion media was analyzed to understand the effect of a MPL and operating conditions. The water content in the DM changed with applied current, although there is a significant amount of residual liquid content that does not appear to be part of capillary channels. The effect of the MPL on irreducible saturation in DM and cell performance was also investigated.
在这项研究中，高分辨率氘氚对比度射线照相法被应用于阐明微多孔层（MPL）对多孔燃料电池介质中水分分布的影响。在稳定状态下，氘取代了阳极流中的氢，并且在阴极处产生的 D（2）O 的中子衰减差异很大，用于跟踪产生的水。结果发现，对于没有 MPL 的电池，水含量在阴极侧扩散介质（DM）中达到峰值，但在阳极和阴极 DM 上有 MPL 时，峰值水量被推向阳极，从而在组件中形成相对平坦的水分布，并表现出液体阻挡效应。此外，还分析了扩散介质中的动态水行为，以了解 MPL 和操作条件的影响。DM 中的含水量随施加的电流而变化，尽管存在大量的残留液体含量，这些液体似乎不属于毛细通道的一部分。还研究了 MPL 对 DM 和电池性能中不可还原饱和度的影响。
