An investigation of proton conductivity of PVA, PBI and SPEEK polymer membranes using molecular dynamics simulation

Abstract

The conductivity and diffusion of hydronium ions at 298 K in PVA (Polyvinyl alcohol), PBI (Polybenzimidazole) and SPEEK (Sulfonated polyether ether ketone) as known membranes of PEMFCs have been investigated using molecular dynamics simulation method throughout this work. The simulation results show that the diffusion of hydronium ions in these polymer membranes depends on the polymer structure and water concentration in the membrane. On the other hand, RDF analysis results also show that the tendency of hydronium ions to polymer atoms strongly depends on the water concentration. So their tendency to polymer chains decreases with increasing the water concentration in PBI and PVA. Based on the results of this investigation, the conductivity of hydronium ions in PVA is more than the two other membranes (=19.83 ms/cm in 30 wt % of water).