Comparison of Several Acidified Chitosan/Nafion^® Composite Membranes for Fuel Cell Applications

Acidic groups, which act as proton carriers, convert chitosan (CS) into a polyelectrolyte by protonating its NH₂ groups. In this study, by employing this concept acidified CSs (CS acidified by phosphoric sulfuric, or acetic acid) were intentionally incorporated into a Nafion^® matrix to prepare composite membranes that exhibit improved proton conductivity for fuel cell applications. Using FT-IR measurements, we assessed the intermolecular interactions in the membranes. Additionally, these membranes showed excellent water retention abilities and ion exchange capacities (IEC), comparable to those of cast Nafion^®. Considering the excellent membrane performances, the low cost of the CS membrane material, and the facile synthetic approach, these novel membranes should be competent to apply in proton exchange membrane fuel cells (PEMFCs).