Gas Permeability of Modified Perfluorinated Proton-Exchange Sulfonic-Acid Membranes Operating in a Hydrogen–Air Fuel Cell

The gas permeability of perfluorinated proton-exchange MF-4SK membranes modified with an inert fluoropolymer and zirconium hydrophosphate is studied under operating conditions of a low-temperature hydrogen–air fuel cell; electrochemical methods of cyclic and staircase voltammetry are used. The adequacy of the methods used for the estimating of the hydrogen crossover current is demonstrated using different-thickness membranes. The relationship between the membrane hydrogen permeability and the diffusion permeability for the electrolyte solution is studied for membranes modified with zirconium hydrophosphate. The optimal content of the inert fluoropolymer and zirconium hydrophosphate in the proton-exchange perfluorinated MF-4SK membrane is found; it provided an improvement in the power characteristics of the fuel cell and reduced the hydrogen permeability.