A new symmetric solid-oxide fuel cell with La0.8Sr0.2Sc0.2Mn0.8O3-δ perovskite oxide as both the anode and cathode (original) (raw)
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Journal of Applied Electrochemistry, 2010
A series of La 0.75 Sr 0.25 Cr 0.9 M 0.1 O 3 (M = Mn, Fe, Co, Ni) perovskite compounds was synthesized by a modified citrate sol-gel route and employed as anode electrodes on YSZ electrolyte supported SOFC cells. Materials and anode electrodes were characterized for their chemical composition, crystal structure and film morphology. The electrochemical performance of the prepared anodes was evaluated in button cells under SOFC operation with CO/CO 2 mixtures in the temperature range of 900-1000°C. It was shown that the performance of the perovskite materials in terms of maximum power density follows the sequence Fe [ Ni [ Co [ Mn, based on the substitution cation into the B-site. No carbon deposition was observed under the operating conditions examined, even for prolonged (120 h) exposure to the reaction mixture.
Synthesis and characterization of Perovskites based oxides for solid oxides fuel cells materials
2008
Double perovskite structure with composition of Sr2Mg1-xMnxMoO6 (SMMMO) and Sr2Mg1-xFexMoO6 (SMFMO) for anode materials in solid oxide fuel cell have been synthesized by means of solid state reaction and sol gel method, respectively. Crystal structure of those materials were characterized by X-ray diffraction technique and refined using Rietveld method implemented in the Rietica program and their conductivity were determined by DC conductivity measurement technique. The higher Mn concentration the lower the cell volume of SMMO, whilst for SMFO the higher Fe content the larger the cell. For SMMO the ionic conductivity tends to increase with increased Mn, whilst for SMFMO conductivity decreases as Fe concentration increases.
In this study the characteristics of two La0.6Sr0.4Co0.2Fe0.8O3 (LSCF) powders, one obtained from an in-house synthesized by co-precipitation method and a commercial one from Fuel Cell Materials Co. (USA), were compared. The co-precipitated powder was processed by using ammonium carbonate as precipitating agent with a NH4+/NO3- molar ratio of 2 and calcination at 1000C for 1 h. Phase composition, morphology and particle size distribution of powders were systematically studied using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and laser particle size analysis (LPSA), respectively. The synthesized and commercial LSCF powders were overlaid on Yttria-stabilized zirconia (YSZ) electrolyte having a gadolinium-doped ceria (GDC) interlayer. Electrochemical Impedance Spectroscopy (EIS) measurement was carried out at various operating temperatures in the range of 600-850C. XRD and FESEM analysis revealed that single phase nano-crystalline LSCF powder with a m...
2015
In this study the characteristics of two different kinds of La0.6Sr0.4Co0.2Fe0.8O3 (LSCF) powders, one in-house synthesized powder by a co-precipitation method and another one purchased from Fuel Cell Materials Co. (FCM Co., USA), were compared. The co-precipitated powder was prepared by using ammonium carbonate as precipitant with a NH4+/NO3- molar ratio of 2 and calcination at 1000C for 1 h. Phase composition, morphology and particle size distribution of powders were systematically studied using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and laser particle size analysis (LPSA), respectively. The synthesized and commercial LSCF powders were overlaid on Yttria-stabilized zirconia (YSZ) electrolyte having a gadolinium-doped ceria (GDC) interlayer. Electrochemical Impedance Spectroscopy (EIS) measurement was carried out at various operating temperatures in the range of 600-850C. XRD and FESEM analysis revealed that single phase nano-crystalline LSCF...
Angewandte Chemie, 2014
A class of double-perovskite compounds display fast oxygen ion diffusion and high catalytic activity toward oxygen reduction while maintaining excellent compatibility with the electrolyte. The astoundingly extended stability of NdBa 1Àx Ca x Co 2 O 5+d (NBCaCO) under both air and CO 2containing atmosphere is reported along with excellent electrochemical performance by only Ca doping into the A site of NdBaCo 2 O 5+d (NBCO). The enhanced stability can be ascribed to both the increased electron affinity of mobile oxygen species with Ca, determined through density functional theory calculations and the increased redox stability from the coulometric titration. Figure 3. Electrochemical performances and long-term stability data. a) I-V curves and the corresponding power densities of test cells at 600 8C. b) Longterm stability measurement at a constant cell voltage of 0.6 V at 550 8C.
Journal of Power Sources, 2010
This paper exploits the suitability of three perovskite materials Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3−ı (BSCF), GdBaCo 2 O 5+ı (GBC) and Ba 0.5 Sr 0.5 Mn 0.7 Fe 0.3 O 3−ı (BSMF) as SOFC cathodes in the single-chamber configuration operating at the intermediate temperature range. TG analysis showed high thermal stability depending on the crystalline phases of the materials. The catalytic activity of these three materials for hydrocarbon conversion was investigated under a realistic feed, i.e. with hydrocarbon, oxygen, water and carbon dioxide. Electrochemical impedance spectroscopy of the various cathodes tested in symmetric cell configuration revealed a B-site dependence of the electrode catalytic activity for oxygen reduction. High temperature (1000 • C) powder reactivity tests over a gadolinium doped-ceria (CGO) and perovskite cathode revealed excellent chemical compatibility of BSMF and CGO. Catalytic tests associated with thermal and structural characterization attest to the suitability of these materials in the single-chamber configuration.
Latest development of double perovskite electrode materials for solid oxide fuel cells: a review
Frontiers in Energy, 2019
Recently, the development and fabrication of electrode component of the solid oxide fuel cell (SOFC) have gained a significant importance, especially after the advent of electrode supported SOFCs. The function of the electrode involves the facilitation of fuel gas diffusion, oxidation of the fuel, transport of electrons, and transport of the byproduct of the electrochemical reaction. Impressive progress has been made in the development of alternative electrode materials with mixed conducting properties and a few of the other composite cermets. During the operation of a SOFC, it is necessary to avoid carburization and sulfidation problems. The present review focuses on the various aspects pertaining to a potential electrode material, the double perovskite, as an anode and cathode in the SOFC. More than 150 SOFCs electrode compositions which had been investigated in the literature have been analyzed. An evaluation has been performed in terms of phase, structure, diffraction pattern, electrical conductivity, and power density. Various methods adopted to determine the quality of electrode component have been provided in detail. This review comprises the literature values to suggest possible direction for future research.
Perovskite-type Cathode Material for Intermediate Temperature Solid Oxide Fuel Cells
2020
Solid oxide fuel cells (SOFCs) are an alternative energy device that transforms chemical energy to electrical energy without the conventional combustion step. SOFCs can do this with an efficiency of 60-80%. However, the temperature of operation (800-1000 o C) reduces the lifetime and puts sever restrictions on the material available for use. Ideally SOFCs would need to operate at a more intermediate temperature (IT) range between (500-750 o C) to maintain their fuel flexibility and have a reasonable lifetime to compete with conventional energy methods but, the reduction in temperature results in sluggish oxygen reduction reaction (ORR) activity for conventional SOFC cathodes. Due to the sluggish ORR of conventional cathodes, new materials are being introduced and studied to act as cathodes for SOFCs. The primary criteria for an SOFC cathode are the ability to act as a mixed ionic electronic conductor (MIEC), stability in an oxygen atmosphere, a porous microstructure, high catalytic activity towards the oxygen reduction reaction (ORR) and thermal cyclability. One material that has received attention is the perovskite-type structure because of its high tunability through doping while maintaining the same structure. The effect of Cu-substitution in Ba0.5Sr0.5Fe1-xCuxO3-δ (BSFCux, 0 ≤ x ≤ 0.20) on the phase, microstructure, cyclability and electrochemical performance was investigated using a series of methods to determine the feasibility of this material acting as a solid oxide fuel cell (SOFC) cathode. Powder X-ray diffraction showed the formation of a cubic perovskite (space group: Pm-3m, No. 221). This material has illustrated cyclable oxygen uptake and releasing properties that were studied using TGA. The microstructure was studied using SEM which showed a porous structure along with minor changes based on copper content. The symmetrical cells Ba0.5Sr0.5Fe1iii xCuxO3-δ+LSGM|LSGM|Ba0.5Sr0.5Fe1-xCuxO3-δ+LSGM were tested for their electrochemical performance using EIS in ambient air. A trend of decreasing area specific resistance (ASR) with decreasing copper content was observed. 4-probe DC measurements were used to study the conductivity of Ba0.5Sr0.5Fe1-xCuxO3-δ in varying atmospheres. These measurements showed an increase in conductivity with increasing copper content and an increase in conductivity with an increasing pO2. The effect of sintering temperature (900-1100 °C) on the electrochemical performance and microstructure was studied for Ba0.5Sr0.5Fe0.95Cu0.05O3-δ+LSGM and Ba0.5Sr0.5Fe0.8Cu0.2O3-δ+LSGM. Plots of log ASR vs. pO2 were used to evaluate the rate determining steps in the oxygen reduction/oxygen evolution reactions (ORR/OER).