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An investigation of components degradation in a polymer electrolyte membrane (PEM) electrolyzer technology for naval application is carried out. In naval applications, an electrolyzer has to work using treated seawater obtained on board. Electrolyzer performance is evaluated in terms of hydrogen production per unit of electrical energy input starting from a seawater desalination plant simulating the conditions on board of the ship. A desalinator plant, tailored for the specific application, is designed to produce water having a low ionic conductivity ( ® ) is used to test MEAs and electrolyzer components on the basis of specific international norms (ASTM standard). Both materials and components are characterized by electrochemical and physico-chemical analysis before and after the DCTC ® treatment.

Polymer electrolyte fuel cells (PEFCs) fed by hydrogen were investigated with the aim of highlighting their behaviour during grid connected (GC) operation. Starting from the analysis of the systems working under practical conditions on the utility grid, the study was addressed to the materials degradation during GC applications. Endurance tests on 5 kW pre-commercial PEFC fuel cell systems were carried out at direct current constant load and in GC configuration. An evidence of disturbance on the FC system power output was observed. The study was focused on Low Frequency (LF) 100 Hz noise (current ripple) that can mainly affect the fuel cell performance and lifetime. In order to evaluate the issues that occurred on the active components of a PEMFC, when subjected to a current ripple, electrochemical characterizations were performed on single cells of 5 cm2 subjected to a dynamic load. Post mortem physico-chemical analyses showed materials degradation on the cathode catalyst associated to the current ripple.

An optimization study of components and assembling characteristics for a proton exchange membrane (PEM) short stack electrolyzer (3 cells of 100 cm 2 geometrical area) was carried out. The electrochemical properties were investigated by polarization, impedance spectroscopy and chrono-potentiometric measurements. A decrease of the ohmic contact resistance between the bipolar plates and the electrode backing layer was obtained by using an appropriate thickness for the gas diffusion layers/current collectors as well as by an optimization of stack compression. The amount of H 2 produced was ∼90 l h −1 at 60 A (600 mA cm −2 ) and 75 °C under 300 W of applied electrical power. No significant leakage or gas recombination was observed. The stack electrical efficiency was 75% and 88%, at 60 A and 75 °C, with respect to the low and high heating value of hydrogen, respectively.

A nanosized IrO 2 anode electrocatalyst was prepared by a sulfite-complex route for application in a proton exchange membrane (PEM) water electrolyzer. The physico-chemical properties of the IrO 2 catalyst were studied by termogravimetry–differential scanning calorimetry (TG–DSC), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). The electrochemical activity of this catalyst for oxygen evolution was investigated in a single cell PEM electrolyzer consisting of a Pt/C cathode and a Nafion ® membrane. A current density of 1.26 A cm −2 was obtained at 1.8 V and a stable behavior during steady-state operation at 80 °C was recorded. The Tafel plots for the overall electrochemical process indicated a slope of about 80 mV dec −1 in a temperature range from 25 °C to 80 °C. The kinetic and ohmic activation energies for the electrochemical process were 70.46 kJ mol −1 and 13.45 kJ mol −1 , respectively. A short stack (3 cells of 100 cm 2 geometrical area) PEM electrolyzer was investigated by linear voltammetry, impedance spectroscopy and chrono-amperometric measurements. The amount of H 2 produced was 80 l h −1 at 60 A under 330 W of applied electrical power. The stack electrical efficiency at 60 A and 75 °C was 70% and 81% with respect to the low and high heating value of hydrogen, respectively.