%0 Journal Article
%K conductivity
%K nafion
%K Domain spacing
%K HBr
%K SAXS
%K Uptake
%A Ahmet Kusoglu
%A Kyu-Taek Cho
%A Rafael A Prato
%A Adam Z Weber
%B Solid State Ionics
%D 2013
%R 10.1016/j.ssi.2013.05.008
%T Structural and transport properties of Nafion in hydrobromic-acid solutions
%8 06/2013
%! Solid State Ionics
%X <p>Proton-exchange membranes are key solid-state ion carriers in many relevant energy technologies including flow batteries, fuel cells, and solar-fuel generators. In many of these systems, the membranes are in contact with electrolyte solutions. In this paper, we focus on the impact of different HBr, a flow-battery and exemplary acid electrolyte, external concentrations on the conductivity of Nafion, a perfluorosulfonic acid membrane that is commonly used in many energy-related applications. The peak and then decrease in conductivity is correlated with measured changes in the water and HBr content within the membrane. In addition, small-angle x-ray scattering is used to probe the nanostructure to correlate how the interactions of the bromide ion with the fixed sulfonic-acid sites impact conductivity and hydrophilic domain distance. It is also shown that membrane pretreatment has a large impact on the underlying structure/function relationship. The obtained data and results are useful for delineation of optimal operating regimes for flow batteries and similar technologies as well as in understanding underlying structure/function relationships of ionomers in electrolyte solutions.</p>