The fabrication of proton exchange membranes (PEMs) with excellent conductivity and low methanol permeability is critical but challenging for the further development of high-performance direct methanol fuel cells (DMFCs). In this work, two ionic hydrogen-bonded organic frameworks (iHOF-14 and iHOF-15) are obtained from 1,3,5-tris(4-phosphonophenyl)benzene and guanidine hydrochloride under the control of dimethylamine cations. Due to the abundant hydrogen bonding network, iHOF-14 and iHOF-15 exhibit good proton conductivity of over 10–2 S cm−1. In addition, we dope the iHOFs into Nafion matrix to get the PEMs with richer proton transport pathways and good methanol barrier properties. At 100 °C and 98 % RH, the conductivity of 9 %-iHOF-14/Nafion and 9 %-iHOF-15/Nafion reaches up to 1.53 × 10–1 and 1.78 × 10–1 S cm−1, respectively. The 72 h permeation experiment results show that the methanol permeability of the composite membranes is 73.7 % lower than that of the recast Nafion. The maximum power densities of hybrid membranes for DMFCs reach about 80 mW cm−2, which is 1.5 times higher compared to the recast Nafion. This work not only enriches the high proton conductivity of arylphosphonate iHOFs, but also expands iHOFs/Nafion PEMs materials for DMFCs.

中文翻译：

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用于 DMFC 的二甲胺调谐芳基膦酸胍 iHOF 和超质子传导 Nafion 杂化膜


制造具有优异导电性和低甲醇渗透性的质子交换膜（PEM）对于高性能直接甲醇燃料电池（DMFC）的进一步开发至关重要，但也具有挑战性。在这项工作中，在二甲胺阳离子的控制下，由1,3,5-三(4-膦酰基苯基)苯和盐酸胍获得了两个离子氢键有机骨架(iHOF-14和iHOF-15)。由于丰富的氢键网络，iHOF-14 和 iHOF-15 表现出超过 10–2 S cm−1 的良好质子电导率。此外，我们将iHOFs掺杂到Nafion基质中，以获得具有更丰富的质子传输途径和良好的甲醇阻隔性能的PEMs。在 100 °C 和 98 % RH 下，9 %-iHOF-14/Nafion 和 9 %-iHOF-15/Nafion 的电导率分别达到 1.53 × 10–1 和 1.78 × 10–1 S cm−1。 72 h渗透实验结果表明，复合膜的甲醇渗透率比重铸Nafion降低了73.7%。 DMFC 混合膜的最大功率密度达到约 80 mW cm−2，比重铸 Nafion 高 1.5 倍。这项工作不仅丰富了芳基膦酸酯iHOFs的高质子电导率，而且拓展了iHOFs/Nafion PEMs材料在DMFC中的应用。