Molecular Dynamics Simulation of Polyhedral Silsesquioxane Nanoparticles on Cathodes of Polymer Electrolyte Membrane Fuel Cells,ACS Applied Nano Materials

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Molecular Dynamics Simulation of Polyhedral Silsesquioxane Nanoparticles on Cathodes of Polymer Electrolyte Membrane Fuel Cells
ACS Applied Nano Materials ( IF 5.3 ) Pub Date : 2023-06-08 , DOI: 10.1021/acsanm.3c01534
Qiong Xue ₁ , Dai-Jun Yang ₁ , Ruo-fan Zhang ₁ , Bing Li ₁ , Ping-Wen Ming ₁ , Cun-Man Zhang ₁

Affiliation

The effect of octahedral cage-structured polyhedral oligomeric silsesquioxane (POSS) on the cathode catalyst layer (CCL) for polymer electrolyte membrane fuel cells (PEMFCs) is investigated via molecular dynamics simulations. A model of CCL is constructed consisting of Pt/C substrate/ionomer–POSS/water–gas. The pair correlation function analysis shows that the dense cover of ionomer chains on the Pt surface and the interaction between sulfonate groups and water molecules are weakened by POSS. At high hydration, the effective water content in the ionomer–POSS phase is drastically reduced with increasing POSS content. Interestingly, at low hydration, the effective water content is slightly improved as the POSS content increases. This water retention effect is probably due to the trapping of water molecules in the POSS cage. The diffusion coefficients of O₂ and H₃O⁺ are effectively increased. The method of inserting nanocages into ionomer can avoid the formation of a high-density ionomer film at the Pt/ionomer interface. Moreover, POSS-modified CCLs possess a self-balance of water content, thus achieving enhanced multicomponent transport involving proton, water, and oxygen transfer. It provides a strategy for designing high-performance PEMFC, particularly for fuel cell vehicles due to the self-balance property under changing humidity.

中文翻译：

聚合物电解质膜燃料电池阴极上多面体倍半硅氧烷纳米粒子的分子动力学模拟

通过分子动力学模拟研究了八面体笼状结构多面体低聚倍半硅氧烷（POSS）对聚合物电解质膜燃料电池（PEMFC）阴极催化剂层（CCL）的影响。构建了由 Pt/C 基材/离聚物-POSS/水-气组成的 CCL 模型。对相关函数分析表明，POSS 削弱了 Pt 表面离聚物链的致密覆盖以及磺酸盐基团与水分子之间的相互作用。在高水合情况下，离聚物-POSS 相中的有效水含量随着 POSS 含量的增加而急剧降低。有趣的是，在低水合情况下，随着 POSS 含量的增加，有效含水量略有提高。这种保水效应可能是由于 POSS 笼中水分子的捕获所致。₂和H ₃ O ⁺有效增加。将纳米笼插入离聚物的方法可以避免在Pt/离聚物界面处形成高密度离聚物薄膜。此外，POSS改性的CCL具有水含量的自平衡，从而实现增强的多组分传输，包括质子、水和氧的传输。由于湿度变化下的自平衡特性，它为设计高性能质子交换膜燃料电池（尤其是燃料电池汽车）提供了一种策略。

更新日期：2023-06-08

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