Constructing High-Performance Proton Transport Channels in HighTemperature Proton Exchange Membranes by Introducing Triazole Groups

Recently, constructing proton transport channels has been considered an effective method to improve proton conductivity of high-temperature proton exchange membranes (PEM) with low phosphoric acid (PA)-doping levels. To construct proton transport channels, a metal-organic framework (MOF) is introduced into a polymer matrix. However, the MOF has poor compatibility with the polymer matrix as an inorganic substance. In this study, organic triazole-grafted poly(vinylbenzyl chloride) is synthesized and introduced into a cross-linked OPBI membrane to construct proton transport channels. Scanning electron microscopy (SEM) images show a homogeneous microstructure. Furthermore, proton transport channels are constructed in the membrane by introducing numerous triazole groups. The cross-linked OPBI has twice the proton conductivity of the linear OPBI, even with a low PA-doping level. All cross-linked membranes with a triazole group outperform OPBI membranes in terms of mechanical properties. The maximum power density of a single-cell test reaches 563 mW cm(-2) at 160 degrees C under H-2/O-2, and it can be maintained for 500 h under a constant load of current discharge without manifest voltage degradation. These impressive results indicate that the moderately cross-linked membrane with triazole groups is one of the potential materials for PEM applications.

Automated summary

This study successfully constructed proton transport channels in high-temperature proton exchange membranes by synthesizing organic triazole-grafted polymers and introducing them into cross-linked OPBI membranes. The membranes with triazole groups showed improved proton conductivity and mechanical properties compared to traditional OPBI membranes. These results indicate that moderately cross-linked membranes with triazole groups are promising materials for PEM applications.