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碳中介孔中氧气扩散的综合分子动力学研究:设计燃料电池催化剂的洞察力支持

Nobuaki Kikkawa¹, Masayuki Kimura²

¹Toyota Central RD Laboratories, Inc., Yokomichi 41-1, Nagakute 480-1192, Aichi Japan.

Langmuir : the ACS journal of surfaces and colloids

|January 10, 2024

概括

在中孔碳中氧气扩散受到孔腔封闭和离子体存在的显著阻碍. 分子动力学模拟揭示了优化碳支的策略,以提高燃料电池性能.

科学领域:

材料科学材料科学材料科学
电化学电化学电化学
计算化学的计算化学

背景情况:

半孔碳支持聚合物电解质燃料电池中的催化剂.
介质孔通过防止离子体吸附来提高性能,但可以阻碍质量传输.
了解毛孔中的分子行为是优化燃料电池催化剂层的关键.

研究的目的:

在各种条件下,研究碳中位孔中的氧气扩散.
阐明孔隙结构和离子体存在对氧气运输的影响.
为设计改进的半孔碳支物提供洞察力.

主要方法:

使用了分子动力学模拟.
计算氧气扩散系数,考虑孔径长度,直径,填充率和离子体含水量.
使用表面自由能量理论分析孔腔封闭.

主要成果:

由于毛孔封闭,氧气扩散减少了两倍.
在存在离子体时,观察到扩散的额外减少1到2个数量级.
孔腔封闭可以通过表面自由能量来预测,这表明较短的狭窄孔隙.

结论:

半孔碳的设计应该旨在防止毛孔封闭,例如,通过缩短狭窄的毛孔.
通过创建密集的接口,离子体的存在显著减缓了氧气扩散.
优化碳表面和离子体结构可以防止界面密集,并改善氧气运输.

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