Search results for " fuel cell"
showing 10 items of 169 documents
Strontium and iron-doped barium cobaltite prepared by solution combustion synthesis: exploring a mixed-fuel approach for tailored intermediate temper…
2013
Ba0.5Sr0.5Co0.8Fe0.2O3-? (BSCF) powders were prepared by solution combustion synthesis using single and double fuels. The effect of the fuel mixture on the main properties of this well-known solid oxide fuel cell cathode material with high oxygen ion and electronic conduction was investigated in detail. Results showed that the fuel mixture significantly affected the area-specific resistance of the BSCF cathode materials, by controlling the oxygen deficiency and stabilizing the Co2+ oxidation state. It was demonstrated that high fuel-to-metal cations molar ratios and high reducing power of the combustion fuel mixture are mainly responsible for the decreasing of the area-specific resistance o…
Effect of metallacarborane salt H[COSANE] doping on the performance properties of polybenzimidazole membranes for high temperature PEMFCs
2020
[EN] In this paper, a series of composite proton exchange membranes comprising a cobaltacarborane protonated H[Co(C2B9H11)(2)] named (H[COSANE]) and polybenzimidazole (PBI) for a high temperature proton exchange membrane fuel cell (PEMFC) is reported, with the aim of enhancing the proton conductivity of PBI membranes doped with phosphoric acid. The effects of the anion [Co(C2B9H11)(2)] concentration in three different polymeric matrices based on the PBI structure, poly(2,2 '-(m-phenylene)-5,5 '-bibenzimidazole) (PBI-1), poly[2,2 '-(p-oxydiphenylene)-5,5 '-bibenzimidazole] (PBI-2) and poly(2,2 '-(p-hexafluoroisopropylidene)-5,5 '-bibenzimidazole) (PBI-3), have been investigated. The conducti…
First principles modeling of Ag adsorption on the LaMnO3 (001) surfaces
2015
Abstract Doping of oxide surfaces with Ag atoms could improve their catalytic properties, e.g. for solid oxide fuel cell and oxygen permeation membrane applications. We present results of the ab initio calculations of Ag adsorption on the LaMnO 3 (LMO) (001) surfaces. The energetically most favorable adsorption sites for low coverage of Ag atoms and monolayer on both MnO 2 - and LaO-terminations have been determined. The electron charge transfer between Ag and substrate and interatomic distances have been analyzed. The Ag atom migration along the MnO 2 surface is ~ 0.5 eV which could lead to a fast clustering of adsorbates at moderate temperatures whereas the adhesion energy of silver monol…
Characterization process to measure the electrical contact resistance of Gas Diffusion Layers under mechanical static compressive loads
2016
AEM2016. International conference on Advanced Energy Materials, University of Surrey, Guildford, ROYAUME-UNI, 12-/09/2016 - 14/09/2016; Recent research has identified the mechanical properties of the fuel cell internal components (in particular, the Gas Diffusion Layers - GDLs) as key-parameters to obtain high final performances of the generator. The mechanical compression modulus of these components, the stability of their mechanical properties with respect to temperature and humidity, and their ability to interact with water have an impact on the electrical contact resistances in the stack and, by consequence, on the overall performance of the electric generator. Reducing the losses by co…
Enhanced Conductivity of Composite Membranes Based on Sulfonated Poly(Ether Ether Ketone) (SPEEK) with Zeolitic Imidazolate Frameworks (ZIFs)
2018
The zeolitic imidazolate frameworks (ZIFs) ZIF-8, ZIF-67, and a Zn/Co bimetallic mixture (ZMix) were synthesized and used as fillers in the preparation of composite sulfonated poly(ether ether ketone) (SPEEK) membranes. The presence of the ZIFs in the polymeric matrix enhanced proton transport relative to that observed for SPEEK or ZIFs alone. The real and imaginary parts of the complex conductivity were obtained by electrochemical impedance spectroscopy (EIS), and the temperature and frequency dependence of the real part of the conductivity were analyzed. The results at different temperatures show that the direct current (dc) conductivity was three orders of magnitude higher for composite …
Nanoscale membrane electrode assemblies based on porous anodic alumina for hydrogen–oxygen fuel cell
2007
In this paper, we demonstrate that nanoscale membrane electrode assemblies, functioning in a H 2/O 2 fuel cell, can be fabricated by impregnation of anodic alumina porous membranes with Nafion® and phosphotungstic acid. Porous anodic alumina is potentially a promising material for thin-film micro power sources because of its ability to be manipulated in micro-machining operations. Alumina membranes (Whatman, 50 μm thick, and pore diameters of 200 nm) impregnated with the proton conductor were characterized by means of scanning electron microscopy, X-ray diffraction, and thermal analysis. The electrochemical characterization of the membrane electrode assemblies was carried out by recording t…
Metallic interconnects for solid oxide fuel cell: Performance of reactive element oxide coating during long time exposure
2011
One of challenges in improving the performance and cost-effectiveness of SOFCs (solid oxide fuel cells) is the development of suitable interconnects materials. Chromia-forming alloys and especially ferritic stainless steels, like Crofer22APU, are considered to be among the most promising candidate materials as interconnects in SOFC stacks. However, the performance of chromia-forming materials can be limited by the low electronic conductivity of the oxide scale (high ASR – area specific resistance – value). Such degradation are unacceptable regarding the long-term operation (>40 000 h). A previous study 1 demonstrated that in air, the addition of a nanometric reactive element oxide (La2O3) l…
New prototypes for the isolation of the anodic chambers in microbial fuel cells
2016
This work has been focused on the assessment of new prototypes of MFC in which a more strict separation of the anode and cathode compartments is looked for, in order to attain strict anaerobic conditions in the anode chamber and hence, avoid lack of efficiency due to the prevalence of non-electrogenic competing microorganisms and to optimize composition of the anolyte and catholyte. A cylinder reactor with an inner chamber with graphite bars acting as anodes and the outer one with a stainless steel tube acting as cathode was used in three different configurations and results obtained during lifetests are compared in terms of electricity production, cathode oxygen consumption and anode COD d…
Comparison of Cu-B Alloy and Stainless Steel as Electrode Material for Microbial Fuel Cell
2019
The microbial fuel cell (MFC) is a technical devices that electricity produces during wastewater treatment. One of the problems of MFCs is a low current density. Thus, it is necessary to search for new electrodes for MFC. The comparison of Cu-B alloy and stainless steel as catalyst for MFCs cathode is presented in this paper. The research included measurements of the concentration of COD, NH4+ and NO3− in three types of reactors: without aeration, with aeration and with using a MFC (with Cu-B and stainless steel cathode). It has been shown that effectiveness of MFC with Cu-B electrode is higher than effectiveness of MFC with stainless steel electrode.
Centrifugal Water Pump Driven With a DC Motor Powered by an Emulator of MK5-E Proton Exchange Membrane Fuel Cell Stacks
2004
Direct Current (DC) motors can be directly powered by Proton Exchange Membrane Fuel Cell (PEMFC) Stacks, to obtain plants with little maintenance and good reliability. To obtain a suitable efficiency working plant, it’s necessary to correctly match the load in order to operate in proximity to the best power line of the FC stacks generator. Otherwise by a proper field current regulation of a separately excited DC motor directly powered by a FC stacks generator, it is possible to extract from the generator itself the correct power for every temperature level. The present interest for this problem has advised the Authors to perform an experimental investigation, whose results are reported in t…