Advancing ionomer design to boost interfacial and thin-film proton conductivity via styrene-calix[4]arene-based ionomers
Advancing ionomer design to boost interfacial and thin-film proton conductivity via styrene-calix[4]arene-based ionomers
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DOI：
10.1016/j.xcrp.2023.101282
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发表时间：
2023-02
影响因子：
8.9
通讯作者：
S. Chatterjee;Oghenetega Allen Obewhere;E. Zamani;R. Keloth;Seefat Farzin;M. Morton;A. Sarella
中科院分区：
文献类型：
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作者：
S. Chatterjee;Oghenetega Allen Obewhere;E. Zamani;R. Keloth;Seefat Farzin;M. Morton;A. Sarella
亚微米厚的离子传导聚合物（离聚物）层通常在基底/催化剂界面处具有差的离子传导性。质子交换膜燃料电池的质子导电性差，阴极的电化学反应缓慢。为了解决这个问题，在这里，我们报告一类聚苯乙烯基离聚物具有亚纳米尺寸，磺化大环杯[4]芳烃基侧基（PS-杯）。在与基于离聚物的粘合剂层的厚度相当的膜中，PS-calix膜的电导率（约41 mS/cm）比目前最先进的离聚物Nafion的电导率高13倍。我们观察到类似的改善质子导电性时，PS-杯接口与Pt纳米粒子，证明PS-杯在催化剂油墨的潜力。利用一个有利的界面化学成分，PS-杯增强质子传导在膜-基底界面，一个缺点的Nafion。此外，PS-杯膜中的水比本体水和限制在Nafion膜中的水扩散得更快，这表明亚纳米尺寸的杯[4]芳烃空腔在创建独特的水/离子传输路径中发挥了重要作用。
Sub-micrometer-thick ion-conducting polymer (ionomer) layers often suffer from poor ionic conductivity at the substrate/catalyst interface. The weak proton conductivity makes the electrochemical reaction at the cathode of proton-exchange-membrane fuel cells sluggish. To address this, here we report on a class of polystyrene-based ionomers having sub-nanometer-sized, sulfonated macrocyclic calix[4]arene-based pendants (PS-calix). In films with thickness comparable to that of ionomer-based binder layers, the conductivity of PS-calix film (∼41 mS/cm) is ∼13 times higher than that of the current state-of-the-art ionomer, Nafion. We observe a similar improvement in proton conductivity when PS-calix interfaces with Pt nanoparticles, demonstrating the potential of PS-calix in catalyst ink. Leveraging a favorable interfacial chemical composition, PS-calix enhances proton conduction at the film-substrate interface, a shortcoming of Nafion. Moreover, the water in PS-calix films diffuses faster than bulk water and the water confined in Nafion films, suggesting an important role played by sub-nanometer-sized calix[4]arene cavities in creating unique water/ion transport pathways.