Progress of high temperature polybenzimidazole proton exchange membrane: a systematic review

Proton exchange membrane (PEM) is the core component of proton fuel cell. Generally speaking, ordinary PEM has the poor barrier to fuel (especially liquid fuel) and proton conduction has a strong dependence on water molecules. Compared with ordinary PEM, high temperature fuel cell works in high temperature non-water environment, which overcomes the above problems. Besides, the system is complex with low impurity and much simpler flow field design. Polybenzimidazole (PBI) not only meets the requirements of high temperature, but also has higher proton conductivity than ordinary PEM, i.e., is the best material for high temperature PEM. From this point of view, the properties and fabrication of PBI are systematically reviewed. Specifically, the factors influencing the performance of acid doped PBI high temperature PEM as well as existing problems (high temperature degradation as well as chemical oxidative degradation) are demonstrated. Furthermore, the corresponding solutions and future direction are put forward.