Transport Properties of Nafion Membranes in Electrochemically Regenerative Hydrogen/Halogen Cells

An investigation has been carried out on the transport properties of Nafion membranes as related to electrochemically regenerative hydrogen/halogen energy storage systems. Included are a determination of membrane conductivity as a function of concentration and temperature and determination of hydrogen, chlorine, and bromine permeation rates and diffusivities in various and environments at various temperatures. Transport properties of the membrane are related to the water content of the membrane. In the case of bromine, negatively charged complex formation results in lower permeation rates than expected. Results indicate that hydrogen/chlorine cells should have voltaic efficiencies in excess of 75% at current densities of ∼300 mA/cm 2 and coulombic losses in the vicinity of 2%.