Evaluation of aromatic ionomer separators for use in advanced alkaline water electrolyzers

Abstract The solution properties of newly developed aromatic carboxylate polymers of various equivalent weights have been investigated in the context of their application as separators for water electrolyzers. Sorption and ion transport experiments in dilute and concentrated alkali solutions were performed. Results show large water and electrolyte uptake for these polymer films. In addition, relatively large Na + self-diffusion coefficients have been formed in both electrolyte environments. Furthermore, dc membrane conductance measurements were carried out as a function of current density (0.5–10 kA m −2 ), temperature (100–180°C) and electrolyte environment. The conductance behavior of the aromatic carboxylate ionomers is quite different from that found for nonporous 1150 equivalent weight (EW) Nafion membranes. This difference is caused primarily by the microporous structure of the aromatic carboxylates, which results in large specific conductances.