An impedance study of amorphous thin oxide films grown on sputtered Al-Nb alloys is presented. The characterization of the electronic properties of mixed amorphous oxide on the basis of the theory of amorphous semiconductor Schottky barrier has been carried out for anodic film on Al-92at.%Nb in a very detailed manner. The semiconductor to insulator transition of formed oxides as a function of the alloy composition at fixed final voltage has been supported by differential admittance study. A possible rationale for this transition has been suggested taking into account the changes of solid state properties, optical bandgap and electronic structure of the films, derived from the fitting of the differential admittance curves at different frequencies.

In this work, new doped Nafion membranes with enhanced proton conductivity were prepared to be used as proton exchange membranes in fuel cells. New dopants derived from arylmono-or bisphosphonic acid were prepared and incorporated into the new membranes using impregnation or casting methods. Proton conductivities were assessed by Electrochemical Impedance Spectroscopy (EIS), at different temperatures and relative humidity (RH) conditions, in order to evaluate the influence of the structure and the method of the preparation on proton transport. The membranes prepared by casting showed higher proton conductivities than commercial Nafion membrane at all temperatures and relative humidity conditions studied. The [1,4-phenylenebis(hydroxymethanetriyl)]tetrakis(phosphonic acid) (BP2) showed the best proton conductivity with a value of 87 mS cm −1. The values obtained for the activation energy (E a) for proton conduction suggests that transport occurs via both Grotthuss and vehicular mechanisms.

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Azolebisphosphonates were prepared and used as dopants to obtain new Nafion doped membranes, which exhibited higher proton conductivities than that of Nafion.