Abstract: An ion-conducting polymer wherein at least 80% of the repeat units comprise an ion-conducting region and a spacer region is disclosed. The ion-conducting region has an aromatic backbone of one or more aromatic groups, wherein at least one ion-conducting functional group is attached to each aromatic group. The spacer region has an aromatic backbone of at least four aromatic groups, wherein no ion-conducting functional groups are attached to the aromatic backbone. The polymer is suitable for use as a fuel cell membrane, and can be incorporated into membrane electrode assemblies.

Abstract: A novel process for the manufacture of a gas diffusion electrode comprising the steps of a) application of a catalyst ink to a gas diffusion substrate; b) firing; c) application of a proton-conducting polymer solution; and d) drying; characterised in that the proton-conducting polymer solution comprises one or more solvents selected from the group of solvents with structure (A) wherein R1, R2 and R3 are independently chosen from H, methyl, ethyl, n-propyl and isopropyl is disclosed. A novel process for the manufacture of a membrane electrode assembly is also disclosed.