Electrochemical performance of Nd1.95NiO4+δ cathode supported microtubular solid oxide fuel cells

Nd1.95NiO4+δ (NNO) cathode supported microtubular cells were fabricated and characterized. This material presents superior oxygen transport properties in comparison with other commonly used cathode materials. The supporting tubes were fabricated by cold isostatic pressing (CIP) using NNO powders and corn starch as pore former. The electrolyte (GDC, gadolinia doped ceria based) was deposited by wet powder spraying (WPS) on top of pre-sintered tubes and then co-sintered. Finally, a NiO/GDC suspension was dip-coated and sintered as the anode. Optimization of the cell fabrication process is shown. Power densities at 750°C of ~40 mWcm-2 at 0.5V were achieved. These results are the first electrochemical measurements reported using NNO cathode-supported microtubular cells. Further developments of the fabrication process are needed for this type of cells in order to compete with the standard microtubular solid oxide fuel cells (SOFC).The authors thank grant MAT2009-14324-C02-01 and MAT2012-30763, financed by the Spanish Government (Ministerio de Ciencia e Innovación) and Feder program of the European Community, for funding the project.Peer Reviewe

Fabrication and performance of Nd1.95NiO4+δ (NNO) cathode supported microtubular solid oxide fuel cells

Trabajo presentado al 10th European Solid Oxide Fuell Cell Forum celebrado en Lucerna (Suiza) del 26 al 29 de Junio de 2012.Microtubular SOFC present significant advantages in comparison with the traditional planar SOFC configuration. In particular, the tubular design facilitates sealing and also reduces thermal gradients. As a consequence, rapid starts up times are possible. In addition, another advantage of the microtubular configuration is their higher power density per unit volume. Due to these properties, those devices are especially attractive for portable applications. There has been a great interest in microtubular SOFCs in the recent years, mainly using anode supported cells. Electrolyte supported cells have also been reported, but there are relatively few investigations using the cathode as the support. In the present paper, Nd1.95NiO4+δ (NNO) has been chosen as the cathode support, as it presents superior oxygen transport properties in comparison with other commonly used cathode materials, such as LSCF or LSM, and these material has been proven as an excellent cathode for SOFC and SOEC applications. Results on the fabrication and characterization of NNO cathode supported SOFC will be presented. The tubes were fabricated by cold isostatic pressing (CIP) using NNO powders and corn starch as the pore former. The electrolyte (GDC based) was deposited by wet powder spray (WPS) on top of the pre-sintered tubes and then co-sintered. Finally, a NiOGDC paste was dip-coated as the anode. Optimization of the fabrication process as well as the electrochemical performance of single cells will be further discussed.The authors thank grant MAT2009-14324-C02-01, financed by the Spanish Government (Ministerio de Ciencia e Innovación) and Feder program of the European Community, for funding the project. M.A.L.-B. thanks the JAE program (CSIC) for financial support.Peer Reviewe

Nd-nickelate solid oxide fuel cell cathode sensitivity to Cr and Si contamination

The stability of Nd-nickelate, considered as an alternative solid oxide fuel cell (SOFC) cathode material, was evaluated in this work on its tolerance towards contaminants

Fabrication and Characterisation of Cathode Support-tubes for Micro-tubular SOFC Application

Tubes of diameter <5mm of a nickelate cathode material of composition Nd1.95NiO4 were prepared by cold-isostatic pressing (CIP) and extrusion. These tubes are intended as cathode support structure for micro-tubular SOFCs at reduced working temperatures around 700°C. The characteristics of these tubes - porosity, pore size, geometric dimensions and surface roughness - were measured by various techniques such as mercury intrusion, SEM-Imaging and with an in-house built diffusion setup. Diffusion measurements yielded average pore sizes of 0.12 μm for CIP-ed tubes and 0.22 μm for extruded tubes. Estimation of the loss due to oxygen diffusion has shown that the wall thickness of CIP-ed tubes must be reduced prior to coating processes in order to limit oxygen concentration overpotential loss during operation

EORTC Cancer in the Elderly Task Force guidelines for the use of colony-stimulating factors in elderly patients with cancer

Increasing age is not, in itself, a contraindication to cancer chemotherapy. Myelosuppression, however, a common adverse consequence of the administration of many standard-dose chemotherapy regimens to both young and elderly patients with cancer, increases with age. The risk of development of febrile neutropenia may contribute to a reluctance to administer chemotherapy in the elderly patient population. We conducted a detailed literature search (1992-2002) to derive evidence-based conclusions on the value of prophylactic colony-stimulating factor (CSF) administration in elderly patients receiving chemotherapy. Sufficient evidence allows us to affirm that prophylactic granulocyte colony-stimulating factor (G-CSF) reduces the incidence of chemotherapy-induced neutropenia, febrile neutropenia and infections in elderly patients receiving myelotoxic chemotherapy for non-Hodgkin's lymphoma (NHL), small-cell lung cancer (SCLC) or urothelial tumours. Lack of available trial data does not allow similar conclusions to be drawn for other cancers studied, but it is likely that similar benefits would accrue from the use of prophylactic G-CSF. There is insufficient evidence to extend this recommendation to include the use of granulocyte-macrophage colony-stimulating factor (GM-CSF). There are insufficient data available to allow the evaluation of the impact of prophylactic CSF on the incidence of toxic deaths in elderly patients with cancer and this is a crucial question for geriatric oncology practice. There is no evidence in elderly patients that the delivery of standard-dose chemotherapy on schedule improves efficacy measures. The data show that febrile neutropenic events are more likely to occur during the first and second cycles of chemotherapy, thus prophylactic measures should be considered early in the course of treatment. Furthermore, since systematic dose reduction can impact on outcome, primary prophylactic use of G-CSF for all elderly patients receiving curative myelotoxic chemotherapy (cyclophosphamide, doxorubicin, vincristine and prednisolone (CHOP) or CHOP-like) is indicated and we suggest a risk-adapted strategy with primary prophylactic G-CSF administration in high-risk patients. Dose intensification, through dose interval reduction, facilitated by prophylactic G-CSF, improved survival in elderly patients with some specific diseases. There is a need for further well-designed studies to identify the elderly patients who will benefit most from prophylactic G-CSF. To achieve this, we strongly urge the design of and participation in further trials. © 2003 Elsevier Ltd. All rights reserved.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Cathode-supported micro-tubular SOFCs based on Nd1.95NiO4+δ: Fabrication and characterisation of dip-coated electrolyte layers

Fabrication conditions to obtain dense electrolyte double layers on a porous micro-tubular cathode substrate were investigated. Porous tubes of a nickelate material, Nd1.95NiO4 + δ, were fabricated by cold-isostatic pressing (CIP) and sintering. Thin films of electrolyte powders Ce0.9Gd0.1O1.95 (GDC) and Zr0.89Sc0.1Ce0.01O1.95 (SSZ) were applied by dip-coating in aqueous suspensions. Electrolyte powders had been attrition-milled to decrease their particle size and densification temperature. The quantity of polyacrylic acid (PAA) as dispersant was optimised by ζ-potential measurements. The densification behaviour was studied by dilatometry and SEM-imaging. A sintering temperature of 1250 °C was found to densify GDC whereas SSZ-layers remained slightly porous

Three-dimensional microstructural mapping of poisoning phases in the Neodymium Nickelate solid oxide fuel cell cathode

Nd-Nickelate (NNO), Nd1.95NiO4+delta, an alternative solid oxide fuel cell cathode material, has been imaged and mapped in 3D using synchrotron-based x-ray nanotomography. The NNO cathode material, which suffered from silicon contamination during fabrication, was found to contain the desired NNO, plus two distinct poisoning phases. The likely composition and description of the poisoning phases are presented, as well as a detailed description of the microstructural mapping and material characterization. The insulating poisoning phases are likely to have deleterious implications for the cell, as they have a tendency to form a coating layer on the NNO surface, significantly decreasing its active area. Additional losses may be expected due to the poisoning phases inhibiting ionic and electronic transport pathways, increasing cathode polarization resistance. (C) 2013 Elsevier B.V. All rights reserved