Modeling Electrochemical Performance of the Hierarchical Morphology of Precious Group Metal-Free Cathode for Polymer Electrolyte Fuel Cell
Modeling Electrochemical Performance of the Hierarchical Morphology of Precious Group Metal-Free Cathode for Polymer Electrolyte Fuel Cell
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DOI：
10.1149/2.0041712jes
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发表时间：
2017-01-01
影响因子：
3.9
通讯作者：
Litster, S.
中科院分区：
文献类型：
--
作者：
Babu, S. Komini;Chung, H. T.;Litster, S.
本文提出了一种聚合物电解质燃料电池（PEFC）的二维（2D）计算模型，该模型具有无铂族金属（PGM-free）催化剂阴极，可以通过消除昂贵的铂催化剂来显着降低PEFC的成本。由于其相对较低的体积活性，无pgm阴极比其基于pt的对应物厚一个数量级。因此需要更大的电极厚度来达到足够的功率密度，这需要仔细注意在更厚的阴极上的传输损失。该模型用于将阴极的成分和形貌与PEFC性能联系起来。该模型是一个完整的细胞连续体模型，包括一个先进的凝聚体模型，用于阴极的微观结构一致的表示。该方法的一个独特之处是整合了从无pgm阴极的纳米级分辨率x射线计算机断层扫描（纳米ct）成像中提取的形态学和输运参数统计数据。用不同负载量的无pgm阴极的实验结果验证了模型的正确性。我们的主要发现是需要通过减少扭曲度或增加体积导电性来增加阴极疏水性和增加离聚体导电性。我们进一步使用该模型来评估未来催化剂的体积活性和活性位点密度目标。c作者(s) (c) 2017。由ECS出版。版权所有。
This paper presents a two-dimensional (2D) computational model of a polymer electrolyte fuel cell (PEFC) with a platinum group metal-free (PGM-free) catalyst cathode that can significantly reduce PEFC costs by eliminating the need for expensive platinum catalysts. Due to their comparatively low volumetric activity, PGM-free cathodes are an order of magnitude thicker than their Pt-based counterpart. The resulting need for greater electrode thickness to achieve sufficient power density requires careful attention to the transport losses across the thicker cathodes. The presented model is used to correlate the composition and morphology of the cathode to PEFC performance. The model is a complete cell, continuum model that includes an advanced agglomerate model for a microstructurally consistent representation of the cathode. A unique feature of the approach is the integration of morphology and transport parameter statistics extracted from nano-scale resolution X-ray computed tomography (nano-CT) imaging of PGM-free cathodes. The model was validated with experimental results of PGM-free cathodes with varying Nafion loading. Our key findings are a need for increased cathode hydrophobicity and increased ionomer conductivity through either reduced tortuosity or increased bulk conductivity. We further use the model to evaluate targets for the volumetric activity and active site density for future catalysts. c The Author(s) (C) 2017. Published by ECS. All rights reserved.