Anode Materials For Solid Oxide Research Articles

Effects of high-valence Mo content on microstructure and properties of Ba2Fe2-xMoxO6-δ anode materials for solid oxide fuel cells

Double perovskites Ba2Fe2-xMoxO6-δ (BFMox, x = 1.0–0.3) were investigated as anodes of solid oxide fuel cells (SOFCs). In H2, all the BFMox samples exhibit sufficient electrical conductivities (σ > 2 S cm−1) at 600–800 °C. However, the BFMo0.7 and BFMo0.5 compositions exhibit relatively better redox stability than the others. Furthermore, using 250-μm-thick La0.9Sr0.1Ga0.8Mg0.2O3-δ as electrolyte and Ba0.6Sr0.4Co0.9Nb0.1O3-δ as cathode, the BFMo0.7 and BFMo0.5 anode cells also show higher electrochemical performances with peak power density attaining 905 and 908 mW cm−2, respectively, at 800 °C. Additi°nally, the BFMo0.7 and BFMo0.5 anodes show good electrochemical stability for long-term H2 oxidation. However, the BFMo0.7 anode exhibits an especially high thermal expansion coefficient (TEC) ∼61.9 × 10−6 K−1 at 25–886 °C in air, nearly three times larger than that of the BFMo0.5 anode under the same condition (TEC=∼14.8 ×10−6 K−1). In view of this, the BFMo0.5 is considered to be a preferred anode candidate for SOFC.

Structural and dielectric properties of Y3+ doped SrTiO3: a novel anode materials for solid oxide fuel cell

An ongoing and elusive task is to create single phase anode materials for solid oxide fuel cells (SOFC). Compared to the typical Ni-YSZ cermet anode, perovskite oxide based anode material has a number of benefits. Here, we present the structural and electrical characteristics of Y3+ doped SrTiO3 ceramics that are used as the anode in solid oxide fuel cells. The samples with nominal composition x = 0 and 0.05 were synthesized by high energy ball milling. The powder X-ray diffraction pattern reveals that the synthesized samples crystallize into cubic crystal structure with space group Pm3m for both the compositions. The samples were sintered at a temperature of 1300 °C for 6h. The sintered density of the samples was found to be greater than 97%. The temperature dependent dielectric measurement studies reveal that dielectric constant increases with yttrium doping and shows relaxer behavior. A higher dielectric constant and electrical conductivity was observed for the Y-doped sample which fulfill the basic requirement for anode materials of solid oxide fuel cells.

Influence of A-Site Modifications on the Electrical and Crystallographic Properties of Ln0.2Sr0.7-XCaxTi0.95Fe0.05O3-δ (Ln=La, Nd) Based Fuel Electrode for Solid Oxide Cell

Perovskite oxides, in particular SrTiO3–based compounds have attracted particular attention over the past years due to their decent conductivity, good dimensional stability and high tolerance and resistance towards sulfur poisoning and carbon depositions [1, 2]. Optimal doping and stoichiometry levels on A- (La, Nd etc.) and B-sites (Fe, Ni etc.) of SrTiO3 based compounds allow to improve catalytic activity, electrical conductivity and chemical stability [2]. In addition, doping of A-site with calcium is predicted to enhance the electronic conductivity because it should decrease the unit cell volume bringing the conduction orbitals of titanium closer to each other [3].In this research influence of chemical composition of A-site on electrical and electrochemical performance of Ln0.2Sr0.7-xCaxTi0.95Fe0.05O3-δ (Ln=La, Nd) (x=0.35, 0.45) (LSCTF-x, NSCTF-x) hydrogen electrode has been investigated. The crystal structure and microstructure have been studied using X-ray diffraction and SEM to confirm the phase purity and visualize the microstructure of studied electrode layers. To understand the influence of MIEC material composition on electrical conductivities of LSCFT and NSCTF, the DC four-probe conductivity measurements of porous electrode layers has been performed. Conductivities have been measured at two different atmospheres: 1% H2 + 3% H2O + 96% Ar and 97% H2 + 3% H2O. It has been shown that the both LSCTF and NSCTF materials behave like semiconductor and the conductivity is significantly dependent on composition. The maximal total electrical conductivity of porous electrode layers were 5.5 S cm− 1 and 4.8 S cm− 1 at 850 °C characteristic for the La0.2Sr0.25Ca0.45Ti0.95Fe0.05O3-δ (LSCTF-45) and Nd0.2Sr0.35Ca0.35Ti0.95Fe0.05O3-δ (NSCTF-35) materials, respectively, in 97% H2 + 3% H2O atmosphere. Keywords: solid oxide fuel cell; perovskite; fuel electrode; MIEC; LST. [1] X. Li, H. Zhao, X. Zhou, N. Xu, Z. Xie, N. Chen, Electrical conductivity and structural stability of La-doped SrTiO3 with A-site deficiency as anode materials for solid oxide fuel cells, international journal of hydrogen energy 35 (2010) 7913-7918.[2] A. Gondolini, E. Mercadelli, G. Constantin, L. Dessemond, V. Yurkiv, R. Costa, A. Sanson, On the manufacturing of low temperature activated Sr0.9La0.1TiO3-δ-Ce1-xGdxO2-δ anodes for solid oxide fuel cell, Journal of the European Ceramic Society, 38 (2018) 153–161.[3] A.D. Aljaberi, J.T.S. Irvine, Ca-substituted, A-site deficient perovskite La0.2Sr0.7TiO3 as a potential anode material for SOFCs. J. Mater. Chem. A 2013, 1, 5868-5874.

Influence of A-Site Deficiency and B-Site Composition on the Electrical and Crystallographic Properties of (La0.25Sr0.25Ca0.45)yTi0.95Ni0.05-xMnxO3-δ Solid Oxide Fuel Cell Anode

(La,Sr)TiO3-δ has attracted specific attention over the past years due to its superior dimensional stability, high conductivity, and significant tolerance against sulfur poisoning and carbon depositions. To increase the catalytic activity and chemical stability, many different doping levels and stoichiometries for LaxSr1-xTiO3-δ (LST) have been investigated [1, 2]. Doping of B-site with Mn has been shown to promote electroreduction under SOFC conditions [3]. Furthermore, Mn is known to accept lower coordination numbers in perovskites, especially for Mn3+ (3d4), and so may enhance oxide-ion migration [4]. In addition, MnO is clearly stable under fuel conditions unlike Co or Ni oxides [4].In this research influence of A-site deficiency and B-site chemical composition on electrical performance of La0.25Sr0.25Ca0.45Ti0.95Ni0.05-xMnxO3-δ (x=0-0.05) (LSCTNM-x) hydrogen electrode has been studied. The crystal structure and microstructure have been studied using X-ray diffraction and SEM to confirm the phase purity and visualize the microstructure of studied electrode layers. To understand the influence of MIEC material composition on electrical conductivities of LSCTNM, the DC four-probe conductivity measurements of porous electrode layers has been performed. Conductivities have been measured at two different atmospheres: 1% H2 + 1.7% H2O + 97.3% Ar and 98.3% H2 + 1.7% H2O. It has been shown that all materials with LSCTNM compositions behave like semiconductor and the conductivity is significantly dependent on composition. The maximal total electrical conductivity of porous electrode layers was characteristic for the LSCTNM materials with 10% A-site deficiency, in 98.3% H2 + 1.7% H2O atmosphere. Keywords: solid oxide fuel cell; conductivity; perovskite; fuel electrode; MIEC.[1] X. Li, H. Zhao, X. Zhou, N. Xu, Z. Xie, N. Chen, Electrical conductivity and structural stability of La-doped SrTiO3 with A-site deficiency as anode materials for solid oxide fuel cells, international journal of hydrogen energy 35 (2010) 7913-7918.[2] A. Gondolini, E. Mercadelli, G. Constantin, L. Dessemond, V. Yurkiv, R. Costa, A. Sanson, On the manufacturing of low temperature activated Sr0.9La0.1TiO3-δ-Ce1-xGdxO2-δ anodes for solid oxide fuel cell, Journal of the European Ceramic Society, 38 (2018) 153–161.[3] P. Holtappels, J. Bradley, J.T.S. Irvine, A. Kaiser, M. Mogensen, Electrochemical characterization of ceramic SOFC anodes, J. Electrochem. Soc. A 148 (2001) 923–929.[4] S. Tao, J.T.S. Irvine, A redox-stable efficient anode for solid-oxide fuel cells, nature materials, 2 (2003) 320-323.

Coke-resistant ferrite anode decorated with in-situ exsolved ceria for carbonaceous fuel oxidation

In this work, the perovskite-type La0.8Ce0.2FeO3 (LCF) is employed as a host oxide for the exsolution of ceria in air and the further doping on La site using Pr3+ (La0.7Pr0.1Ce0.2FeO3, LPCF) or Gd3+ (La0.7Gd0.1Ce0.2FeO3, LGCF) is used to achieve the exsolution of PrOx- and Gd2O3- doped ceria (PDC and GDC). The exsolution of (doped) ceria is accompanied by the segregation of Fe2O3 that can promote fuel oxidation. The resulting perovskites are used as potential anode materials for solid oxide fuel cells. At 800 °C, the LPCF with 1 wt% Ni infiltration cell on a LSGM (La0.9Sr0.1Ga0.8Mg0.2O3-δ) electrolyte yields the lowest Rp (polarization resistance) value (0.11 Ω cm2) and the highest cell performance (808 mW cm−2) in H2 fuel, but the cells with LCF and LGCF anode show a stable performance under hydrocarbon fuel conditions if Ni is infiltrated into the anode to assist the deprotonation. The parameters controlling the exsolution of the doped ceria and the catalysis for the hydrocarbon reforming are analyzed, proposing an intriguing path to achieving the exsolution of complex oxide on the surface of perovskite for the construct of a hierarchical electrode/catalyst for the applications in fuel conversion.

In situ growth of copper-iron bimetallic nanoparticles in A-site deficient Sr2Fe1.5Mo0.5O6-δ as an active anode material for solid oxide fuel cells

The design of active anode materials with abundant active sites for fuel oxidation reaction is highly desirable. In-situ exsolution of nanoparticles from perovskite oxides is an effective approach to maintain its nanoscale dimensions and provide efficient active sites. Herein, a promising anode material decorated with copper-iron bimetallic nanoparticles is prepared by in-situ exsolution from A-site deficient Sr1.9Fe1.5Mo0.5−xCuxO6-δ double perovskite. With the doping of Cu, the agglomeration of iron nanoparticles is highly inhibited under reducing environment and copper-iron bimetallic nanoparticles can be uniformly formed. Through high temperature reduction, Sr1.9Fe1.5Mo0.5O6-δ substrate is transferred to heterostructure consisting of a Ruddlesden-Popper phase (Sr3FeMoO6.5) and a perovskite phase. The in-situ exsolved copper-iron bimetallic nanoparticles on the heterostructure can provide abundant active sites for fuel oxidation and lead to an improvement of polarization resistance from 0.41 Ω·cm2 to 0.22 Ω·cm2 at 800 °C under H2. In addition, the maximum power density is increased to 574 mW cm−2, which is about 37% higher than that of Sr1.9Fe1.5Mo0.5O6-δ. The present study provides a potential strategy for developing efficient anode materials for solid oxide fuel cells.

Operando observation of patterned nickel - gadolinium doped ceria solid oxide fuel cell anode

Nickel (Ni) - gadolinium doped ceria (GDC) is one of the promising anode materials for solid oxide fuel cells (SOFCs). However, they are not as stable as Ni - yttria-stabilized zirconia (YSZ) anodes at reducing atmosphere, since both Ni and GDC migrate and porous microstructure changes. The degradation behavior of the Ni-GDC anode is thus more complex than that of Ni-YSZ. In the present study, novel operando observations of the morphological changes of patterned Ni on a GDC substrate as well as conventional ex-situ measurements are conducted under SOFC operation. Both Ni and GDC moved dynamically in the range of several tens of microns during 51 h operation, where the three phase boundary (TPB) length dynamically changed during the operation. Nano-size GDC particles appeared on the Ni surface and the GDC surface was strongly roughened, which were the distinctive morphological changes of the patterned Ni-GDC anode.

Cu-Ce0.8Sm0.2O2-δ anode for electrochemical oxidation of methanol in solid oxide fuel cell: Improved activity by La and Nd doping

CuCe0.8La0.1Sm0.1O2-δ and CuCe0.8Nd0.1Sm0.1O2-δ are studied as anode materials for solid oxide fuel cells with methanol as fuel. The oxygen surface exchange and bulk diffusion coefficients of Ce0.8Sm0.2O2-δ both increase with La and Nd doping. The CH3OH temperature-programmed surface reaction results show that the addition of La and Nd accelerates the chemical oxidation of CH3OH. Furthermore, compared with CuCe0.8Sm0.2O2-δ, the anodes with La and Nd show higher resistance to coking in CH3OH atmosphere. The Cu-based cermet anode exhibits a low catalytic activity for the electrochemical oxidation of H2, and a single cell supported by a Ce0.8Sm0.2O2-δ‑carbonate composite electrolyte with CuCe0.8Sm0.2O2-δ anode exhibits a maximum power density of 160 mW cm−2 at 650 °C using dry hydrogen as fuel. However, the maximum power density reaches 550 mW cm−2 when CH3OH is used as fuel, and further increases to 730 and 830 mW cm−2 with the addition of La and Nd in the anode, respectively. The results indicate that with the promotion of the oxygen activity, the Cu-based cermet is a promising anode material for solid oxide fuel cells using CH3OH as fuel.

Highly Active and Stable a-Site Deficient La0.4Sr0.4Ti0.94Ni0.06O3-δ SOFC Anode Material with in-Situ Exsolved of Ni Nanoparticles

La-doped strontium titanates with a perovskite structure are promising candidates of the anode materials for solid oxide fuel cells (SOFCs) owing to their good chemical compatibility with other components and superior redox-stability. Among these La-doped SrTiO3 (LST), A-site deficient LST materials have attracted much interest due to their improved electrochemical characteristics. Recently, exsolution in A-site deficient LST has been intensively studied, because catalytic active and durable metal nanoparticles can be exsolved on the LST surface. In this study, we developed the A-site deficient Ni-doped La0.4Sr0.4TiO3 (LSTN)-Ce0.9Gd0.1O1.95 (GDC) composite anodes, and investigate their electrochemical performance and redox stability on La0.8Sr0.2Ga0.8Mg0.2O3-δ (LSGM) electrolyte-based SOFCs. The maximum power density(MPD) of LSTN44-GDC anode based cell was 0.698 mW cm-2 at 900℃ in wet H2 fuel (3% H2O). Also, during redox cyclic tests combined with long-term stability test, The LSTN44-GDC cell maintained its performance without any degradation. All these results demonstrate that the A-site deficient LSTN-GDC is a promising material for an efficient and stable SOFC anode.

A mini-review of carbon-resistant anode materials for solid oxide fuel cells

A comprehensive overview is presented of recent developments as well as trends of carbon-resistant anode materials using hydrocarbon as fuel.

Model-guided design of a high performance and durability Ni nanofiber/ceria matrix solid oxide fuel cell electrode

Mixed ionic electronic conductors (MIECs) have attracted increasing attention as anode materials for solid oxide fuel cells (SOFCs) and they hold great promise for lowering the operation temperature of SOFCs. However, there has been a lack of understanding of the performance-limiting factors and guidelines for rational design of composite metal-MIEC electrodes. Using a newly-developed approach based on 3D-tomography and electrochemical impedance spectroscopy, here for the first time we quantify the contribution of the dual-phase boundary (DPB) relative to the three-phase boundary (TPB) reaction pathway on real MIEC electrodes. A new design strategy is developed for Ni/gadolinium doped ceria (CGO) electrodes (a typical MIEC electrode) based on the quantitative analyses and a novel Ni/CGO fiber–matrix structure is proposed and fabricated by combining electrospinning and tape-casting methods using commercial powders. With only 11.5 vol% nickel, the designer Ni/CGO fiber–matrix electrode shows 32% and 67% lower polarization resistance than a nano-Ni impregnated CGO scaffold electrode and conventional cermet electrode respectively. The results in this paper demonstrate quantitatively using real electrode structures that enhancing DPB and hydrogen kinetics are more efficient strategies to enhance electrode performance than simply increasing TPB.

The effect of Mo concentration on the electrical properties of CaV1-xMoxO3-δ (x=0.2 ÷ 0.6) anode materials for solid oxide fuel cells

A perovskite-like CaV1-xMoxO3-δ (x = 0.2 ÷ 0.6) were prepared by a formate solution method with the final annealing at 1473 K in an H2 atmosphere. X-ray diffraction analysis was used for sample characterisation. Metal-like electric conductivity was observed using a 4-probe DC technique from 573 to 1123 K in dry H2. Magnetic susceptibility measurements showed the absence of localised V and Mo valence electrons. The Seebeck coefficient was measured between temperatures of 573–1123 K in dry H2, supporting the hypothesis that electronic conductivity is predominant. Thermal expansion coefficients (TEC) are obtained by dilatometry from 373 to 1123 K in dry H2. TEC values increase with temperature from 10 ppm to 15 ppm K−1 and decrease with Mo concentration.

In situ embedding of CoFe nanocatalysts into Sr3FeMoO7 matrix as high-performance anode materials for solid oxide fuel cells

Anode materials with excellent catalytic activity, good stability, and enhanced tolerance to carbon deposition are highly desired for solid oxide fuel cells (SOFCs). Herein, CoFe (CF) nanoalloy catalysts are homogeneously in-situ embedded on Sr3FeMoO7 (RP-SFM) efficient electrically conductive perovskite matrix through reduction of Sr2FeMo2/3Co1/3O6−δ precursor. The particle size of CoFe alloy is in the range of 10–50 nm, and the electrical conductivity enhances from about 8 to 17 S cm−1 to 49-63 S cm−1 after Sr2FeMo2/3Co1/3O6−δ reduction. The maximum power density of SOFCs with the RP-SFM@CF-SDC(Sm0.2Ce0·8O1.9) composite anode in H2 fuel reaches to 2.12 W cm−2 at 850 °C, which is about 1.4 times than that of the SOFCs with traditional Ni-SDC anode. Moreover, the RP-SFM@CF-SDC anodes also demonstrate excellent resistance to carbon deposition and high power density when C3H8 hydrocarbon is used as fuel. The improved catalytic activity results from the efficient electronic/ion conductive paths, abundant CoFe active sites, together with the enlarged trip phase boundaries (TPBs).

Theoretical investigation on H2 oxidation mechanisms over pristine and Sm-doped CeO2(1 1 1) surfaces

Samarium-doped transition metal oxides are recognized as promising anode materials for solid oxide fuel cell (SOFC). The adsorption and oxidation of hydrogen on both pristine and Sm-doped CeO2(1 1 1) are studied using Hubbard-U density functional theory (DFT + U). Our calculations suggest that a H atom could bind to the doped Sm atom through a secondary bonding, weaker than covalent bonding but stronger than Van der Waals force. This special HSm interaction facilitates H2 dissociation (and H2O formation) step by dramatically reducing the energy barrier from 1.092 (3.540) eV to 0.532 (0.158) eV when compared with pristine CeO2(1 1 1), indicating that Sm doping could significantly improve the catalytic activity of CeO2 for H2 oxidation. Microkinetic modeling further confirms the crucial role played by doped Sm, and the Sm-mediated pathway is dominant at medium and low temperature (300–800 K), contributing to good low-temperature performance of CeO2-based anode in SOFC.

Preparation and characterization of NiO based nano-ceramic composites as alternative anode materials for solid oxide fuel cells (SOFCs)

Solid oxide fuel cell (SOFC) is being developed all over the world at present as a future energy conversion device. The alternative anode materials are also being studied in order to develop efficient low temperature SOFCs (LTSOFCs) operating below 800o C. Ni‐based cermets are still the most promising anode materials and some targeted modifications are needed to improve the coking resistance and to enhance their electro-catalytic activity relatively at low temperature (~600 – 700 oC) range. Present work is aimed to develop alternate anode materials such as, NiO-Ce0.9Gd0.1O2-δ-Ce0.9Y0.1O2-δ, NiO-Ce0.8Gd0.2O2-δ-Ce0.8Y0.2O2-δ, NiO-Ce0.9Gd0.1O2-δ-Ce0.9Sm0.1O2-δ, NiO-Ce0.8Gd0.2O2-δ-Ce0.8Sm0.2O2-δ, NiO-Ce0.9Gd0.1O2-δ and NiO-Ce0.8Gd0.2O2-δ for by simple chemical precipitation route and characterize them towards application in SOFC systems. The precursor materials used in this synthesis were cerium nitrate hexahydrate, gadolinium nitrate, yttrium nitrate, samarium nitrate [as basic materials] and sodium hydroxide [as precipitator material]. C-TAB (cetyl trimethylammonium bromide) was used as a surfactant in order to avoid the agglomeration of the nanoparticles. The influence of Gd, Y and Sm doping on the phase structure development of ceria was investigated. The prepared anode materials were characterized by TGA, XRD, FTIR, particle size analysis, SEM and EDAX. The electrical characteristics of the materials were studied by electrochemical impedance spectroscopy. The results obtained were discussed in order to use the materials as alternate anode materials for SOFCs.

Co-substituted Sr2Fe1.5Mo0.5O6-δ as anode materials for solid oxide fuel cells: Achieving high performance via nanoparticle exsolution

Co-Substituted Sr2Fe1.5Mo0.5O6-δ (Sr2Fe1.3Co0.2Mo0.5O6-δ) double perovskite oxides have been prepared and evaluated as anode materials of solid oxide fuel cells (SOFCs). In reducing atmosphere, active cobalt metal nanoparticles are in situ exsolved from the parent double perovskite oxides, which are characterized by XRD, XPS, SEM and TEM. Sr2Fe1.3Co0.2Mo0.5O6-δ show the highest electrical conductivity of 13.9 S cm−1 at 600 °C and the lowest polarization resistance of 0.15 Ω cm2 at 850 °C in 5% H2–95% N2. When hydrogen, syngas and methane are filled as fuel, a maximum power density of 1.09, 0.981 and 0.29 W cm−2 could be achieved at 850 °C, respectively. Further, after continuously operated in hydrogen for 115 hs, in syngas for 190 hs and in methane for 300 hs, there are no negligible degradations. Synergistic effect between perovskite oxide and exsolved Co nanoparticles contributes to the improved SOFCs performances. The protocol developed in this research provides a new strategy to optimize anodic activities of double perovskite oxides, and broadens our horizons in rational design of heterogeneous ceramics for other applications.

Novel Ni cermets for anode-supported proton ceramic fuel cells

Ni cermets have been widely investigated as anode materials for solid oxide fuel cells (SOFCs), particularly for those based on O2−-conducting electrolytes, e.g., yttria-stabilized zirconia (YSZ). However, proton ceramic fuel cells (PCFCs) are increasingly attracting research attention, considered to be another developmental step in high-temperature fuel cell technologies. Ni cermets with a ceramic matrix capable of performing proton transfer are believed to be prospective anode materials for PCFCs. This work is aimed at investigating materials that can be used as supporting anodes with LaScO3-based proton-conducting electrolytes. La0.95Sr0.05ScO3−δ (LSS5) as a potential ceramic component was synthesized by solid-phase and co-precipitation methods. Ni-LSS5 composites were obtained by solid-state mixing of the respective powders followed by reduction in hydrogen. Effects of the LSS5 powder production technique and sintering temperature (1400, 1450, and 1500 °С) on the microstructural features and phase composition were studied using both oxidized and reduced samples. The temperature dependencies of resistivity, as well as of thermal and chemical expansions, were investigated in situ. It is found that the electrical conductivity and chemical expansion of Ni-LSS is largely determined by its porosity rather than by the selected synthesis method. The materials under study are shown to exhibit relatively small values of chemical expansion and resistivity, making them promising for application in anode-supported PCFCs with LaScO3-based proton-conducting electrolytes.

Electron doping of Sr2FeMoO6−δ as high performance anode materials for solid oxide fuel cells

Electron doping-induced structure modification of double-perovskite anode material with enhanced electrocatalytic activities for methane oxidation in solid oxide fuel cells.

Comparative electrochemical investigation of zinc based nano-composite anode materials for solid oxide fuel cell

The structural and electrochemical properties of zinc based nano-composites anode materials with a composition of X0.25Ti0.05Zn0.70 (where X = Cu, Mn, Ag) have been investigated in this present study. The proposed X0.25Ti0.05Zn0.70 oxide materials have been synthesized through sol-gel method. The doping effect of Cu, Mn, and Ag on TiZn oxides were analyzed in terms of electronic conduction and power density in hydrogen atmosphere at comparatively low temperature in the range of 650 °C. The crystal structure and surface morphology were examined by X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis techniques. The XRD patterns of composites depict that the average crystalline sizes lie in the range of 20–100 nm. Four-probe DC conductivity technique was used to measure the conductivity of the materials and maximum electrical conductivity of Ag0.25Ti0.05Zn0.70 oxide was found to be 7.81 S/cm at 650 °C. The band gap and absorption spectra were determined by ultra-violet visible (UV–Vis) and Fourier Transform Infrared spectroscopy (FTIR) techniques respectively. The maximum power density was achieved to be 354 mW/cm2 at 650 °C by Ag0.25Ti0.05Zn0.70 oxide anode with SDC (electrolyte) and BSCF (conventional cathode) materials.

Molybdenum-based double perovskites A2CrMoO6−δ (A = Ca, Sr, Ba) as anode materials for solid oxide fuel cells

The development of sulfur-tolerant anode materials is vital for solid-oxide fuel cells (SOFCs) that use conventional fossil fuels as fuel source to decrease emissions and increase energy-conversion efficiency. In this work, A2CrMoO6–δ (A = Ca, Sr, Ba) double perovskite materials are synthesized and evaluated as potential SOFC anode materials to assess their electrocatalytic activity and sulfur tolerance. All samples exhibit well-matched thermal expansion coefficient and satisfactory chemical compatibility with La0.9Sr0.1Ga0.8Mg0.2O3–δ (LSGM) electrolyte over the measured temperature range. Among the compositions investigated, the B-site partially disordered Sr2CrMoO6–δ (SCM) double perovskite exhibits superior electrical conductivity, cycle stability, and polarization resistance on LSGM electrolyte because of its high-symmetry structure and appropriate oxygen-vacancy concentration. The relatively stable single-cell performance in 100 ppm H2S/H2 demonstrates that the behavior of SCM anode is more stable than that of nickel–yttria-stabilized zirconia. Postexposure characterization by X-ray diffraction is further conducted to evaluate SCM as potential sulfur-tolerant SOFC anode.