Phase stability and conductivity of Ba1−ySryCe1−xYxO3−δ solid oxide fuel cell electrolyte

The structure, phase stability, and electrical properties of BaCe_1−xY_xO_3−δ (x = 0-0.4) in humidity air and CO₂ atmosphere are investigated. XRD results indicate that the BaCe_0.9Y_0.1O_3−δ sample has a symmetric cubic structure, and its phase changes to tetragonal as the Y³⁺ doping amount increases to 20 mol%. The conductivity of BaCe_1−xY_xO_3−δ increases with temperature, and it depends on the amount of yttrium doping and the atmosphere. BaCe_0.8Y_0.2O_3−δ exhibits the highest conductivity of 0.026 S cm⁻¹ at 750 °C. The activation energy for conductivity depends on yttrium doping amount and temperature. The conductivity of BaCe_0.8Y_0.2O_3−δ is 0.025 S cm⁻¹ in CO₂ atmosphere at 750 °C which is 3.8% lower than that in air due to reactions with CO₂ and BaCO₃ and the CeO₂ impure phases formed. The structure of BaCe_0.8Y_0.2O_3−δ is unstable in water and decomposes to Ba(OH)₂ and CeO₂ phases. It is found that the activation energy of samples in CO₂ atmosphere is higher than that of sample in air. Sr-doped Ba_1−ySr_yCe_0.8Y_0.2O_3−δ (y = 0-0.2) is prepared to improve the phase stability of BaCe_0.8Y_0.2O_3−δ in water. The conductivity of Ba_0.9Sr_0.1Ce_0.8Y_0.2O_3−δ is 0.023 S cm⁻¹ at 750 °C which was 11% lower than that of BaCe_0.8Y_0.2O_3−δ, however, the phase stability of Ba_0.9Sr_0.1Ce_0.8Y_0.2O_3−δ is much better than that of BaCe_0.8Y_0.2O_3−δ in water.     

The effect of doping in the electrochemical performance of (Ln1−xMx)FeO3−δ SOFC cathodes

A family of iron perovskites with the general formula AFeO_3−δ (A = Ln_1−xM_x; Ln = La, Nd and/or Pr; M = Sr or/and Ca) has been prepared keeping fixed the A cation radius 〈r_A〉 and cation size mismatch to isolate the effect of divalent dopant concentration from the A-cation steric effects. The electrochemical behaviour of these compounds for their application as SOFC cathodes was evaluated by using I-V curve measurements and ac impedance spectroscopy over three electrodes electrolyte supported cells processed under identical conditions. In contrast with the bulk behaviour, trends are more difficult to observe due to microstructural effects, but results seem to indicate that the doping level, x, does not influence in a significant way the electrochemical performance of iron perovskites with identical 〈r_A〉 and σ²(r_A).     

New SrMo1−xCrxO3−δ perovskites as anodes in solid-oxide fuel cells

Oxides of composition SrMo_1−xCr_xO_3−δ (x = 0.1, 0.2) have been prepared, characterized and tested as anode materials in single solid-oxide fuel cells, yielding output powers higher than 700 mW cm⁻² at 850 °C with pure H₂ as a fuel. All the materials are suggested to present mixed ionic–electronic conductivity (MIEC) from neutron powder diffraction (NPD) experiments, complemented with transport measurements; the presence of a Mo⁴⁺/Mo⁵⁺ mixed valence at room temperature, combined with a huge metal-like electronic conductivity, as high as 340 S cm⁻¹ at T = 50 °C for x = 0.1, could make these oxides good materials for solid-oxide fuel cells. The magnitude of the electronic conductivity decreases with increasing Cr-doping content. The reversibility of the reduction–oxidation between the oxidized Sr(Mo,Cr)O_4−δ scheelite and the reduced Sr(Mo,Cr)O₃ perovskite phases was studied by thermogravimetric analysis, which exhibit the required cyclability for fuel cells. An adequate thermal expansion coefficient, without abrupt changes, and a chemical compatibility with electrolytes make these oxides good candidates for anodes in intermediate-temperature SOFC (IT-SOFCs).     

Novel SrCo1−yNbyO3−δ cathodes for intermediate-temperature solid oxide fuel cells

Perovskite oxides SrCo_1−yNb_yO_3−δ (SCNy, y = 0.00-0.20) are investigated as potential cathode materials for intermediate-temperature solid oxide fuel cells (IT-SOFCs) on La_0.9Sr_0.1Ga_0.8Mg_0.2O_3−δ (LSGM) electrolyte. Compared to the undoped SrCoO_3−δ, the Nb doping significantly improves the thermal stability and enhances the electrical conductivity of the SCNy oxides. The cubic phase of the SCNy oxides with high thermal stability can be totally obtained when the Nb doping content y ≥ 0.10. Among the investigated compositions, the SrCo_0.9Nb_0.1O_3−δ oxide exhibits the highest electrical conductivity of 461-145 S cm⁻¹ over the temperature range of 300-800 °C in air. The SCNy cathode has a good chemical compatibility with the LSGM electrolyte for temperatures up to 1050 °C for 5 h. The area specific resistances of SCNy with y = 0.10, 0.15 and 0.20 cathodes on LSGM electrolyte are 0.083, 0.099 and 0.110 Ω cm² at 700 °C, respectively. At y = 0.10, 0.15 and 0.20, the maximum power densities of a single-cell with SCNy cathodes on 300-μm thick LSGM electrolyte achieve 675, 642 and 625 mW cm⁻² at 800 °C, respectively. These results indicate that SCNy perovskite oxides with cubic phase are potential cathode materials for application in IT-SOFCs.     

Electrical performance and structural analysis of La1−xBaxGa0.8Mg0.2O3−δ solid electrolyte

The aim of this study was to develop La_1−xBa_xGa_1−yMg_yO_3−δ (x = 0.03–0.1, y = 0.2–0.25) (LBGM) electrolytes for intermediate-temperature solid-oxide fuel cells (SOFCs); these electrolytes were synthesized via a solid-state reaction. In the study, the La_1−xBa_xGa_1−yMg_yO_3−δ samples crystallized in an orthorhombic (Imma) structure, and a BaLaGa₃O₇ phase was detected for x ≥ 0.08 at a fixed y = 0.2. The solubility limit of the Ba ions increased with an increase in the Mg content in the matrix. Two active Raman bands at ca. 677 and 739 cm⁻¹ were observed, and they were attributed to the oxygen vacancies. The La_0.95Ba_0.05Ga_0.75Mg_0.25O_3−δ sample had a higher conductivity ca. 0.1 S/cm at 800 °C, and an activation energy of ca. 0.83–1.27 eV at 500–800 °C. The thermal expansion coefficient (TEC) of the LBGM samples at 200–800 °C was in the range of 10 × 10⁻⁶ to 14 × 10⁻⁶/°C.     

(La,Pr)0.8Sr0.2FeO3−δ–Sm0.2Ce0.8O2−δ composite cathode for proton-conducting solid oxide fuel cells

Mixed rare-earth (La, Pr)_0.8Sr_0.2FeO_3−δ–Sm_0.2Ce_0.8O_2−δ (LPSF–SDC) composite cathode was investigated for proton-conducting solid oxide fuel cells based on protonic BaZr_0.1Ce_0.7Y_0.2O_3−δ (BZCY) electrolyte. The powders of La_0.8−xPr_xSr_0.2FeO_3−δ (x = 0, 0.2, 0.4, 0.6), Sm_0.2Ce_0.8O_2−δ (SDC) and BaZr_0.1Ce_0.7Y_0.2O_3−δ (BZCY) were synthesized by a citric acid-nitrates self-propagating combustion method. The XRD results indicate that La_0.8−xPr_xSr_0.2FeO_3−δ samples calcined at 950 °C exhibit perovskite structure and there are no interactions between LPSF0.2 and SDC at 1100 °C. The average thermal expansion coefficient (TEC) of LPSF0.2–SDC, BZCY and NiO-BZCY is 12.50 × 10⁻⁶ K⁻¹, 13.51 × 10⁻⁶ K⁻¹ and 13.47 × 10⁻⁶ K⁻¹, respectively, which can provide good thermal compatibility between electrodes and electrolyte. An anode-supported single cell of NiO-BZCY|BZCY|LPSF0.2–SDC was successfully fabricated and operated from 700 °C to 550 °C with humidified hydrogen (∼3% H₂O) as fuel and the static air as oxidant. A high maximum power density of 488 mW cm⁻², an open-circuit potential of 0.95 V, and a low electrode polarization resistance of 0.071 Ω cm² were achieved at 700 °C. Preliminary results demonstrate that LPSF0.2–SDC composite is a promising cathode material for proton-conducting solid oxide fuel cells.     

Fabrication of anode-supported protonic ceramic fuel cell with Ba(Zr0.85Y0.15)O3−δ–Ba(Ce0.9Y0.1)O3−δ dual-layer electrolyte

We fabricated a uniquely designed anode-supported-type protonic ceramic fuel cell (PCFC) with a dual-electrolyte layer containing BaCe_0.9Y_0.1O_3−δ (BCY) as the higher-proton-conducting phase and BaZr_0.85Y_0.15O_3−δ (BZY) as the chemically stable protecting phase. In order to overcome the poor sinterability of the BZY electrolytes, which is a critical limitation in making thin and dense dual-electrolyte layers for anode-supported PCFCs, we employed aid-assisted enhanced sintering of BZY by adding 1 mol% of CuO. We also promoted the densification of the BZY layer by utilizing the higher sinterability of BCY that is attached to the top of the BZY layer. By properly adjusting the shrinkage behaviors of both the anode substrate and the dual-electrolyte layers, we were able to fabricate a fairly dense BZY/BCY dual-layer electrolyte with a thickness of less than 20 μm. In this paper, the novel strategies used to fabricate the PCFC based on dual-electrolyte layers are reported.     

Pd-substituted (La,Sr)CrO3−δ-Ce0.9Gd0.1O2−δ solid oxide fuel cell anodes exhibiting regenerative behavior

Composite anodes consisting of Pd-substituted (La,Sr)CrO_3−δ mixed with 50 wt% Ce_0.9Gd_0.1O_2−δ were tested in La_0.9Sr_0.1Ga_0.8Mg_0.2O_3−δ-electrolyte supported fuel cells at 800 °C with humidified H₂ fuel. Low anode polarization resistance was observed during the first several hours of operation, explained by the nucleation of Pd nano-particles on perovskite particle surfaces. Anode performance then degraded gradually before stabilizing. Redox cycling repeatedly restored the anodes to their initial peak performance, followed again by degradation. This regenerative behavior was explained by the observation that the Pd nano-particles were removed by oxidation, and then re-nucleated upon reduction.     

Synthesis and properties of La0.6Sr0.4CoO3−δ nanopowder

Uniform nanopowders of La_0.6Sr_0.4CoO_3−δ (LSC) were synthesized by the combined citrate–EDTA method. The precursor solution was prepared from nitrates of the constituent metal ion, citric acid and EDTA with a pH value controlled by ammonia. The obtained product was characterized by TG/DTA, XRD, SEM, and BET measurements. The single perovskite phase could form completely after sintering at the temperature of 900 °C. There was no significant effect of the precursor solution pH value on the perovskite phase formation temperature; however, LSC powders prepared from the precursors with different pH values showed specific shapes. The morphology of La_0.6Sr_0.4CoO_3−δ powder was also optimized with proper surfactant addition. The sintered La_0.6Sr_0.4CoO_3−δ bulk samples exhibited an electrical conductivity of 1867 S cm⁻¹ in air at 800 °C. The impedance spectra of a symmetric LSC cathode on a GDC electrolyte substrate were measured and polarization resistance (R_p) values of 0.17 Ω cm² at 700 °C and 0.07 Ω cm² at 750 °C in air were obtained.     

A simple and effective process for Sr0.995Ce0.95Y0.05O3−δ and BaCe0.9Nd0.1O3−δ solid electrolyte ceramics

A simple and effective reaction-sintering process for Sr_0.995Ce_0.95Y_0.05O_3−δ and BaCe_0.9Nd_0.1O_3−δ solid electrolyte ceramics was investigated in this study. Without any calcination involved, the mixture of raw materials was pressed and sintered directly. Sr_0.995Ce_0.95Y_0.05O_3−δ ceramics with 98.4% of the theoretical density were obtained after being sintered at 1350 °C for 2 h. A total conductivity 1.42 mS cm⁻¹ at 900 °C could be obtained in Sr_0.995Ce_0.95Y_0.05O_3−δ sintered at 1500 °C for 4 h. BaCe_0.9Nd_0.1O_3−δ ceramics with 91.7% of the theoretical density were obtained after being sintered at 1500 °C for 2 h. A total conductivity 11.54 mS cm⁻¹ at 900 °C could be obtained in BaCe_0.9Nd_0.1O_3−δ sintered at 1350 °C for 6 h. The reaction-sintering process has proven a simple and effective method to obtain useful Sr_0.995Ce_0.95Y_0.05O_3−δ and BaCe_0.9Nd_0.1O_3−δ ceramics for solid electrolyte applications in solid oxide fuel cells.     

Structure, chemical stability and mixed proton-electron conductivity in BaZr0.9−xPrxGd0.1O3−δ

BaZr_0.9−xPr_xGd_0.1O_3−δ (x = 0.3 and 0.6) was prepared by combustion synthesis and characterised with respect to conductivity and stability in an attempt to combine the desirable properties of the end members. The polycrystalline materials exhibit a cubic or pseudo-cubic structure as determined by X-ray synchrotron radiation and transmission electron microscopy. The chemical stability of the compositions is strongly dependent on the praseodymium content, the materials with more Pr present lower stability. Electron holes dominate the conductivity under oxidising atmospheres in BaZr_0.3Pr_0.6Gd_0.1O_3−δ, while BaZr_0.6Pr_0.3Gd_0.1O_3−δ exhibits a mixed electron hole-proton conducting behaviour. Substitution of Zr by Pr in acceptor-doped BaZrO₃ decreases the sintering temperature and increases the grain growth rate.     

SrCo1−xSbxO3−δ perovskite oxides as cathode materials in solid oxide fuel cells

The SrCo_1−xSb_xO_3−δ (x = 0.05, 0.1, 0.15 and 0.2) system was tested as possible cathode for solid oxide fuel cells (SOFCs). X-ray diffraction results show the stabilization of a tetragonal P4/mmm structure with Sb contents between x = 0.05 and x = 0.15. At x = 0.2 a phase transition takes place and the material is defined in the cubic Pm-3m space group. In comparison with the undoped hexagonal SrCoO₃ phase, the obtained compounds present high thermal stability without abrupt changes in the expansion coefficient. In addition, a great enhancement of the electrical conductivity was observed at low and intermediate temperatures (T ≤ 800 °C). The sample with x = 0.05 displays the highest conductivity value that reaches 500 S cm⁻¹ at 400 °C and is over 160 S cm⁻¹ in the usual working conditions of a cathode in SOFC (650-900 °C). Moreover, the impedance spectra of the SrCo_1−xSb_xO_3−δ/Ce_0.8Nd_0.2O_2−δ/SrCo_1−xSb_xO_3−δ (x ≥ 0.05) symmetrical cells reveal polarization resistances below 0.09 Ω cm² at 750 °C which are much smaller than that displayed by the pristine SrCoO_3−δ sample. The composition with x = 0.05 shows the lowest ASR values ranging from 0.009 to 0.23 Ω cm² in the 900-600 °C temperature interval with an activation energy of 0.82 eV.     

SrCo1−yTiyO3−δ as potential cathode materials for intermediate-temperature solid oxide fuel cells

The perovskites SrCo_1−yTi_yO_3−δ (SCTy, y = 0.00-0.20) are synthesized and assessed as potential cathode materials for intermediate-temperature solid oxide fuel cells (IT-SOFCs) based on the La_0.9Sr_0.1Ga_0.8Mg_0.2O_3−δ (LSGM) electrolyte. SCTy composites with y ≥ 0.05 adopt a cubic perovskite structure with thermal stability between 30 °C and 1000 °C in air. Substitution of Ti significantly enhances the electrical conductivity of the SCTy composites relative to the undoped SrCoO_3−δ. The highest electrical conductivity of the sample with y = 0.05 varied from 430 S cm⁻¹ to 160 S cm⁻¹ between 300 °C to 800 °C in air. The area-specific resistances of the SCTy cathodes on the LSGM electrolyte gradually increase from 0.084 Ω cm² at y = 0.05 to 0.091 Ω cm² at y = 0.20 with increasing Ti content at 750 °C. Single-cells that used SCTy cathodes with y = 0.05, 0.10, 0.15, and 0.20 on a 300 μm-thick LSGM electrolyte achieve peak power densities of 793, 608, 525, and 425 mW cm⁻² at 800 °C, respectively. These novel SCTy cubic perovskites demonstrate considerable potential for application in IT-SOFC cathodes.     

Preparation and properties of BaxSr1−xCoyFe1−yO3−δ cathode material for intermediate temperature solid oxide fuel cells

Ba_xSr_1−xCo_yFe_1−yO_3−δ (BSCF) materials with perovskite structure were synthesized via solid-state reaction. Their structural characteristics, electrical-conduction behavior and cathode performance were investigated. Compared to A-site elements, B-site elements show a wide solid-solution range in BSCF. The electrical-conduction behavior of BSCF obeys the small polaron-hopping mechanism. An increase of Ba or Co content in the BSCF samples results in a decrease of electrical conductivity, which is mainly attributable to the preferential existence of B³⁺ rather than B⁴⁺ in Ba- or Co-rich samples. At the same time, this leads to increases in the lattice parameter a and the number of oxygen vacancies. BSCF samples with high Ba content show a high structural stability (high oxygen-loss temperature). Ba_0.6Sr_0.4Co_0.8Fe_0.2O_3−δ and Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3−δ materials present good thermal-cycling stability of the electrical conductivity. Compared with Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3−δ, Ba_0.6Sr_0.4Co_0.8Fe_0.2O_3−δ exhibits a better cathode performance in a Ce_0.8Gd_0.2O_2−δ (GDC)-supported half cell. The cell performance can be improved by introducing a certain amount of GDC electrolyte into the BSCF cathode material.     

Performance of solid oxide electrolysis cells based on composite La0.8Sr0.2MnO3−δ – yttria stabilized zirconia and Ba0.5Sr0.5Co0.8Fe0.2O3−δ oxygen electrodes

The electrochemical performance of solid oxide electrolysis cells (SOECs) having barium strontium cobalt ferrite (Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3−δ) and composite lanthanum strontium manganite–yttria stabilized zirconia (La_0.8Sr_0.2MnO_3−δ–YSZ) oxygen electrodes has been studied over a range of operating conditions. Increasing the operating temperature (973 K to 1173 K) significantly increased electrochemical performance and hydrogen generation efficiency for both systems. The presence of water in the hydrogen electrode was found to have a marked positive effect on the EIS response of solid oxide cell (SOC) under open circuit voltage (OCV). The difference in operation between electrolytic and galvanic modes was investigated. Cells having BSCF oxygen electrodes (Ni–YSZ/YSZ/BSCF) showed greater performance than LSM-YSZ-based cells (Ni–YSZ/YSZ/LSM-YSZ) over the range of temperatures, in both galvanic and electrolytic regimes of operation. The area specific resistance (ASR) of the LSM-YSZ-based cells remained unchanged when transitioning between electrolyser and fuel cell modes; however, the BSCF cells exhibited an overall increase in cell ASR of ∼2.5 times when entering electrolysis mode.     

Electrode redox properties of Ba1−xLaxFeO3−δ as cobalt free cathode materials for intermediate-temperature SOFCs

Cobalt-free perovskite oxides Ba_1−xLa_xFeO_3−δ (x = 0.1–0.4) were synthesized by glycine-nitrate combustion method and investigated as a candidate cathode material for intermediate temperature solid oxide fuel cells (IT-SOFCs). Cubic perovskite structure was obtained when 10–20 mol% La was substituted at Ba-site in Ba_1−xLa_xFeO_3−δ, and the crystal structure was transformed from cubic structure into orthorhombic one at x ≥ 0.2 with an addition of lanthanum doping. The thermal expansion coefficients of Ba_1−xLa_xFeO_3−δ oxides decreased gradually with La content due to increasing electrostatic attraction forces. A gradual increase existed in electrical conductivity tendency with La content due to disproportionation of Fe³⁺ and the larger extent of electron clouds. The electrode redox performance was investigated by electrochemical impedance spectroscopy. Among Ba_1−xLa_xFeO_3−δ series oxides, Ba_0.9La_0.1FeO_3−δ exhibited the best electrochemical performance. The area specific resistance (ASR) of Ba_0.9La_0.1FeO_3−δ was 0.079 Ω cm², 0.37 Ω cm², and 2.15 Ω cm² at 800, 700 and 600 °C under open circuit potential. To investigate electrochemical performances after cathodic polarization, bias potentials were employed on Ba_1−xLa_xFeO_3−δ cathode at 650–800 °C. The results demonstrated the potential applications for Ba_0.9La_0.1FeO_3−δ as cathode materials for IT-SOFCs as a tradeoff between electrochemical and thermal expansion performance.     

Investigation on thermal, electrical, and electrochemical properties of scandium-doped Pr0.6Sr0.4(Co0.2Fe0.8)(1−x)ScxO3−δ as cathode for IT-SOFC

A systematic study and evaluation were performed on the effect of scandium doping at the B site of Pr_0.6Sr_0.4Co_0.2Fe_0.8O_3−δ (PSCF) on key material properties as cathode for intermediate temperature solid oxide fuel cells (IT-SOFC). The doped products Pr_0.6Sr_0.4(Co_0.2Fe_0.8)_(1−x)Sc_xO_3−δ (PSCFS_x, x=0.0-0.2) retained perovskite structure confirmed by X-ray diffraction, and their particles were smaller than the non-doped materials as evidenced by TEM. The electrical conductivity (EC) of PSCFS_x decreased with increasing Sc³⁺ content, but EC values were still larger than 100 S cm⁻¹ in temperature range of 300-800 °C as x ≤ 0.1. The thermal expansion coefficients (TEC) of PSCFS_x were observed to generally decrease with increasing x especially at lower temperature range of 50-600 °C. In addition, the AC impedance revealed better electrochemical performance of PSCFS_x cathode as x ≤ 0.1 than that of the undoped sample PSCF. Therefore, PSCFS_x (x ≤ 0.1) shows some potential as cathode electrode for IT-SOFC. The function of Sc³⁺ dopant was tentatively elucidated and discussed.     

The synthesis and characterization of the Sm0.5Sr0.5Co1−xCuxO3−δ cathode by the glycine-nitrate process

In this study, a new oxygen-deficient cathode material, Sm_0.5Sr_0.5Co_1−xCu_xO_3−δ (SSCCu) was developed. It is expected to enhance the efficiency of intermediate-temperature solid oxide fuel cells (IT-SOFCs). The structure, conductivity and electrochemical performance of SSCCu were examined as a function of copper content. The structure of Sm_0.5Sr_0.5Co_0.9Cu_0.1O_3−δ and Sm_0.5Sr_0.5Co_0.8Cu_0.2O_3−δ samples was a single orthorhombic perovskite phase. Second phase SrCoO_2.8, however, formed in the Sm_0.5Sr_0.5Co_0.7Cu_0.3O_3−δ and Sm_0.5Sr_0.5Co_0.6Cu_0.4O_3−δ samples. The conductivity of the Sm_0.5Sr_0.5Co_0.7Cu_0.3O_3−δ cathode was higher than that of other samples. However, the Sm_0.5Sr_0.5Co_0.8Cu_0.2O_3−δ electrode exhibited the lowest overpotential of 25 mV at 400 mA cm⁻² and the lowest area special resistance of 0.2 Ω cm² at 700 °C.     

Structural and electrochemical characterisation of Pr0.7Ca0.3Cr1−yMnyO3−δ as symmetrical solid oxide fuel cell electrodes

A series of compounds with composition Pr_0.7Ca_0.3Cr_1−yMn_yO_3−δ (y = 0.2, 0.4, 0.6, 0.8) were prepared from an alternative freeze-drying precursor method to obtain polycrystalline powders at relatively low temperature. These perovskite-type materials were tested simultaneously as both anode and cathode in a symmetrical SOFC. The effect of the ratio Mn/Cr on the structure, microstructure and electrochemical properties was studied. The performance is rather modest at low temperature and only interesting values were obtained at high temperatures. An assembled symmetrical SOFC rendered performances of 250 and 160 mW cm⁻², at 950 °C, under humidified H₂ and CH₄ respectively.     

Sr0.92Y0.08TiO3−δ/Sm0.2Ce0.8O2−δ anode for solid oxide fuel cells running on methane

Yttria-doped strontium titanium oxide (Sr_0.92Y_0.08TiO_3−δ; SYT) was investigated as an alternative anode material for solid oxide fuel cells (SOFCs). The SYT synthesized by the Pechini method exhibits excellent phase stability during the cell fabrication processes and SOFC operation and good electrical conductivity (about 0.85 S/cm, porosity 30%) in reducing atmosphere. The performance of SYT anode is characterized by slow electrochemical reactions except for the gas-phase diffusion reactions. The cell performance with the SYT anode running on methane fuel was improved about 5 times by SDC film coating, which increased the number of reaction sites and also accelerated electrochemical reaction kinetics of the anode. In addition, the SDC-coated SYT anode cell was stably operated for 900 h with methane. These results show that the SDC-coated SYT anode can be a promising anode material for high temperature SOFCs running directly on hydrocarbon fuels.