Pore Scale Simulation of Transport and Electrochemical Reactions in Reconstructed PEMFC Catalyst Layers
Pore Scale Simulation of Transport and Electrochemical Reactions in Reconstructed PEMFC Catalyst Layers
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DOI：
10.1149/1.3478207
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发表时间：
2010-01-01
影响因子：
3.9
通讯作者：
Djilali, Ned
中科院分区：
文献类型：
--
作者：
Lange, Kyle J.;Sui, Pang-Chieh;Djilali, Ned
采用介尺度模拟方法对质子交换膜燃料电池（PEMFC）阴极催化剂层的传输和电化学过程进行了模拟。模型中考虑了氧、质子和电子的输运。许多模拟运行与各种不同的参数上的随机重构的微结构的分辨率为2 nm。努森扩散在限制氧通过催化剂层的传输中起重要作用。在催化剂层中使用较大的碳球增加了氧气通过催化剂层的有效扩散率。当使用更大的球体、使用球体的正态分布或使用更高的重叠容差时，有效质子传导率增加。增加重叠容限或重叠概率会导致有效电子电导率的增加。当在靠近气体扩散层的催化剂层的一部分中考虑电化学反应时，决定氧消耗的关键参数是碳球半径。在给定的碳体积分数下，在包含具有较小半径的球体的微结构中的氧消耗更大，因为存在更多的表面积可用于电化学反应。(C)2010年电化学学会。[DOI：10.1149/1.3478207]保留所有权利。
A mesoscale simulation is developed to simulate transport and electrochemistry in a small section of a proton exchange membrane fuel cell (PEMFC) cathode catalyst layer. Oxygen, proton, and electron transport are considered in the model. Many simulations are run with a wide variety of different parameters on stochastically reconstructed microstructures with a resolution of 2 nm. Knudsen diffusion plays an important role in limiting the transport of oxygen through the catalyst layer. Using larger carbon spheres in the catalyst layer increases the effective diffusivity of oxygen through the catalyst layer. The effective proton conductivity increases when larger spheres are used, a normal distribution of spheres is used, or a higher overlap tolerance is used. Increasing the overlap tolerance or overlap probability results in an increase in the effective electron conductivity. When electrochemical reactions are considered in a part of the catalyst layer that is close to the gas diffusion layer, the critical parameter that determines oxygen consumption is the carbon sphere radius. Oxygen consumption at a given carbon volume fraction is larger in microstructures containing spheres with smaller radii, because there is more surface area available for electrochemical reactions. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3478207] All rights reserved.