Constructing High-Performance Proton Transport Channels in High-Temperature Proton Exchange Membranes by Introducing Triazole Groups
Jianfa Liu, Shichao Wang, Lei Wang
Abstract
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 °C under H2/O2, 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.