Polybenzimidazole (PBI)-based membranes for fuel cell, water electrolysis and desalination

Polybenzimidazole (PBI)-based membranes have been extensively utilized due to their exceptional physical properties, including ionic conductivity, thermal and mechanical robustness, stability at elevated temperatures, and low fuel crossover. These membranes play a crucial role in high-temperature proton exchange membrane fuel cells (HT-PEMFCs) for efficient proton exchange, anion exchange membrane fuel cells (AEMFCs), alkaline water electrolysis (AEMWE) for renewable green hydrogen (H2) production, redox flow batteries, electrodialysis, desalination and water treatment, and other electrochemical devices. This review paper provides the detailed insights into the recent development of PBI membranes as an efficient PEMs for PEMFCs, PBI nanocomposite mixed matrix membranes (PBI-MMMs), PBI-based AEMs for AEMFCs and AEMWE, PBI ion exchange membranes for redox flow batteries and PBI membranes for desalination applications. The development strategies of PBI membranes by various structural modification, blending, cross-linking and organic-inorganic composites have been discussed critically. The effects of temperatures, electrolyte doping time, type of electrolytes and electrolytes concentration on the membranes electrochemical performances also have been directed in-depth. The physical properties, characteristics and performances of PBI-based membranes are discussed in terms of ion conductivity, ion exchange capacity, mechanical properties, generated power densities from these reported membranes. Also, future perspectives on further research and development have been discussed.