Numerical modeling of novel cage‐like cross‐linked membranes for enhanced proton conductivity in a high temperature‐polymer electrolyte membrane fuel cell

Abstract

AbstractPhosphoric acid (PA)‐doped polybenzimidazole (PBI) membranes have encountered several problems associated with high cost, chemical instability, poor solubility in organic solvents, and higher doping level which results in poor mechanical properties and faster degradation of the membrane. Alternative membranes with high proton conductivity and mechanical strength for high‐temperature applications are of great interest, one such membrane being cPBI‐IL X. The cage‐like cross‐linked structure of these membranes shows a dual proton transport path due to which proton conductivity is elevated. The ionic liquid content of these membranes improves the PA absorbing capability and shortens the proton transfer path. These membranes exhibit the highest proton conductivity of 13.3 S/m and better durability compared to existing PBI Membranes. A mathematical model is developed and validated versus published experimental results to account for the proton conductivity of these membranes. The developed model is further investigated for a detailed understanding of polarization phenomena and species distribution.