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Steam electrolysis by means of reversible Fuel Cells is a promising concept for compensating the intermittency of renewable energy sources. Several tests on SOFC stacks operated in reverse mode (SOEC) reported faster degradation than in power production mode. Although not completely clarified, the degradation mechanisms appear partly related to the higher steam concentration at the electrode compartments. This work introduces a novel type of cell with dual anionic-protonic conductivity, which allows the separation of the steam compartment from the electrodes compartments. The concept is presented together with a set of experimental results pointing out the potential advantages of this approach.

Whereas significant advances have been reported in the performances of solid oxide fuel cells, some work has still to be done to reduce the costs connected to the overall processing of these systems. Tape casting and screen-printing are the most common techniques used for the fabrication of large area SOFCs. The production of the bilayer anode-electrolyte entirely by tape casting, or by tape casting coupled with screen-printing, are two of the most economical and reliable shaping alternatives. The work presents two unconventional approaches to these techniques applied to the production of anode-supported half-cell (NiOGDC/GDC), namely the use of water-based screen printing inks and an innovative lamination process done at room temperature and low pressure. These variations of the common multilayer production scheme, potentially allow overcoming two of the drawbacks connected with them: the use of organics for the production of screen printing inks and high temperature or glues for the lamination of tapes. Both approaches allowed producing crack-free large area half cells with dense GDC electrolyte.

Gadolinia-doped ceria (Ce0.8Gd0.2O2-d, GDC) is an alternative electrolyte for Intermediate Temperature Solid Oxide Fuel Cells (IT-SOFC). Nanostructured materials have recently attracted extensive attention because of their high reactivity that allowed milder sintering conditions. Although several methods were proposed for the synthesis of ultrafine powders, most of them generally require a subsequent calcination step. The aim of this work was to produce ultrafine, pure GDC powders using a standard chemical route (aqueous sol-gel) coupled with non-conventional heating processes (infrared heating). Nanocrystalline non-agglomerated GDC particles were successfully produced under mild conditions (170{degree sign}C, 1h) without the intermediate decomposition and/or calcining steps. Moreover the GDC obtained through the optimization of the IR-assisted sol-gel synthesis parameters exhibited values of ionic conductivity higher than the ones showed by commercial and conventional sol-gel produced powders of similar composition.

Solid oxide fuel cell technology offers substantial advantages for clean and efficient power generation. However, the high working temperatures impose severe restrictions on the materials selection. The key to prolong the stack lifetime, widen the selection of materials and reduce the costs lies in lowering the working temperature. Two main approaches have been applied for this purpose: testing materials based on Gd doped CeO2, having higher ionic conductivity at lower temperatures, and decreasing the electrolyte thickness. At present, different methods have been studied for the deposition of fully dense thin coatings. Among them, the radio frequency magnetron sputtering technique is a powerful and versatile tool to deposit mixed oxide thin films in a wide thickness range (100 nm/10 um). In this report, the results about the deposition by RF magnetron sputtering of 1/5 um GDC films on anodic substrates will be presented.

This study reports the effect of copper oxide on the sintering mechanism of Ce0.8Gd0.2O2-d (GDC) studied through dilatometric and microstructural analyses. The addition of 3% CuO into GDC greatly improves its sinterability lowering the sintering temperature of more than 300{degree sign}C and increasing its maximum shrinkage rate. The early-stage sintering has been modeled showing a mechanism substantially different from the one generally accepted for CoO.

Solid Oxide Fuel Cells have still many technical problems related to its high operating temperature (800–1000 °C). The most recent studies deal with reducing the operation temperature increasing at the same time the durability of the device. The use of La0.8Sr0.2Ga0.8Mg0.2O3-δ(LSGM) perovskite as electrolyte, could be a very promising solution for IT-SOFC operating at 600°C. In this work, LSGM bilayers constituted by a thicker porous layer (namely the anode scaffold) and a dense electrolyte were produced by tape casting. The critical issues to obtain flexible and crack-free green tapes suitable for lamination were carefully examined. In particular, the nature and amount of pore former needed to obtain an anode scaffold with a porous network suitable for the catalysts impregnation process were deeply investigated.

In this paper we present the combine modeling and experimental study of electrochemical hydrogen oxidation at an alternative perovskite based mixed-conducting SOFC anode. Two types of button cells without and with addition of nickel (Ni) were fabricated based on La0.1Sr0.9TiO3-α(LST)-CGO composite anodes and dense YSZ electrolytes. Electrochemical experiments were performed using symmetrical cell configuration in H2/H2O fuel mixture systematically varying applied potentials and operating temperatures. The previously developed model, which includes thermal chemistry at each surface, charge-transfer processes and reactive porous media transport, was employed. It was found that in the case of conventional LST based anodes heterogeneous and charge transfer chemistry at LST surface has capacitive behavior and alters the impedance spectra. However, if nickel is added the influence of LST surface chemistry is diminished leading to an improvement of cell performance.

The present paper refers to an innovative SOFC concept named EVOLVE after a running FP7 project which integrates advanced materials and an inventive anode current collector made from a NiCrAl preoxidized foam impregnated with a conductive perovskite. Even if the concept is the beneficial combination of Metal supported cell (MSC) and Anode supported cell (ASC) technologies, strong improvements in terms of reliability and durability are expected. In order to enhance anode efficiency, the 3D microstructure needs to be precisely described at the microscopic scale. ISTEC has produced LST-GDC active anode layers using screen printing process. Back-scattered electrons (BSE) SEM images that contain relevant microstructure information have been realized by Centre des Matériaux. All the original images have been enhanced by Centre de Morphologie Mathématique using a series of morphological operators to remove artefacts. Finally, a 3D pluri-Gaussian model has been generated from 2D images, and then computed to predict volume fraction of the 3 phases, 3D tortuosity, gas permeation and ionic conductivities.

Gadolinia-doped ceria (Ce0.8Gd0.2O2-δ, GDC) is an alternative electrolyte for Intermediate Temperature Solid Oxide Fuel Cells (IT-SOFC). Nanostructured materials have recently attracted extensive attention because of their high reactivity that allowed milder sintering conditions. Although several methods were proposed for the synthesis of ultrafine powders, most of them generally require a subsequent calcination step. The aim of this work was to produce ultrafine, pure GDC powders using a standard chemical route (aqueous sol-gel) coupled with non-conventional heating processes (infrared heating). Nanocrystalline non-agglomerated GDC particles were successfully produced under mild conditions (170{degree sign}C, 1h) without the intermediate decomposition and/or calcining steps. Moreover the GDC obtained through the optimization of the IR-assisted sol-gel synthesis parameters exhibited values of ionic conductivity higher than the ones showed by commercial and conventional sol-gel produced powders of similar composition.

This study reports the effect of copper oxide on the sintering mechanism of Ce0.8Gd0.2O2-δ (GDC) studied through dilatometric and microstructural analyses. The addition of 3% CuO into GDC greatly improves its sinterability lowering the sintering temperature of more than 300{degree sign}C and increasing its maximum shrinkage rate. The early-stage sintering has been modeled showing a mechanism substantially different from the one generally accepted for CoO.