The article "High Temperature Proton Exchange Membranes Based on Polybenzimidazoles for Fuel Cells" by Qingfeng Li, Jens Oluf Jensen, Robert F. Savinell, and Niels J. Bjerrum, published in *Progress in Polymer Science* in 2009, reviews the development of high-temperature proton exchange membrane fuel cells (PEMFCs) using polybenzimidazole (PBI) membranes. The authors highlight the advantages of PBI membranes, such as high molecular weight, good solubility, and processability, which are crucial for mechanical stability and functionalization processing. They discuss various methods for synthesizing PBI, including heterogeneous and homogeneous synthesis, and the modification of PBI structures to enhance properties like acid-base interaction and proton conductivity. The article covers the fabrication of PBI membranes through solution casting from organic and acid solutions, emphasizing the importance of high molecular weight polymers for mechanical stability and high proton conductivities. Techniques for membrane casting from TFA, PPA, and DMAc solutions are described, along with the need for acid doping to achieve proton conductivity. The authors also explore methods to improve membrane properties, such as ionic and covalent cross-linking, and the preparation of composite membranes with inorganic-organic composites. Key findings include the successful demonstration of PBI-based PEMFCs operating at temperatures up to 200°C under ambient pressure, with minimal gas humidification requirements. The cells exhibit high CO tolerance, better heat utilization, and potential integration with fuel processing units. Long-term durability tests show degradation rates of 5 μV h−1 under continuous operation with hydrogen and air at 150–160°C. The article concludes with suggestions for further improvements, including optimizing thermal and chemical stability, acid management, and catalyst support.The article "High Temperature Proton Exchange Membranes Based on Polybenzimidazoles for Fuel Cells" by Qingfeng Li, Jens Oluf Jensen, Robert F. Savinell, and Niels J. Bjerrum, published in *Progress in Polymer Science* in 2009, reviews the development of high-temperature proton exchange membrane fuel cells (PEMFCs) using polybenzimidazole (PBI) membranes. The authors highlight the advantages of PBI membranes, such as high molecular weight, good solubility, and processability, which are crucial for mechanical stability and functionalization processing. They discuss various methods for synthesizing PBI, including heterogeneous and homogeneous synthesis, and the modification of PBI structures to enhance properties like acid-base interaction and proton conductivity. The article covers the fabrication of PBI membranes through solution casting from organic and acid solutions, emphasizing the importance of high molecular weight polymers for mechanical stability and high proton conductivities. Techniques for membrane casting from TFA, PPA, and DMAc solutions are described, along with the need for acid doping to achieve proton conductivity. The authors also explore methods to improve membrane properties, such as ionic and covalent cross-linking, and the preparation of composite membranes with inorganic-organic composites. Key findings include the successful demonstration of PBI-based PEMFCs operating at temperatures up to 200°C under ambient pressure, with minimal gas humidification requirements. The cells exhibit high CO tolerance, better heat utilization, and potential integration with fuel processing units. Long-term durability tests show degradation rates of 5 μV h−1 under continuous operation with hydrogen and air at 150–160°C. The article concludes with suggestions for further improvements, including optimizing thermal and chemical stability, acid management, and catalyst support.