In-situ strategy to suppress chromium poisoning on La0.6Sr0.4Co0.2Fe0.8O3-δ cathodes of solid oxide fuel cells

The surface segregation of strontium in the La_0.6Sr_0.4Co_0.8Fe_0.2O_3-δ (LSCF) electrode interacts with volatile contaminants such as chromium in the solid oxide fuel cell (SOFC) interconnect, causing deterioration in cell performance. A simple in-situ reaction strategy has been exploited to synergistically improve oxygen reduction reaction (ORR) activity in air and anti-chromium stability of LSCF electrode via infiltration and calcination of nickel nitrate and ferrite nitrate (NF) precursor on the LSCF backbone. The chemical compatibility, electrochemical performance, interfacial element distribution and stability in chromium-containing atmosphere of the as-prepared hybrid electrodes were systematically investigated. At a calcination temperature of 1100 °C, Sr(Co,Ni)O_3-δ layer was formed owing to Co diffusion and Sr precipitation from LSCF and the reaction with Ni atoms at the surface of LSCF. This will promote anti-chromium ability for the hybrid LSCF@NF cathode material. After the symmetrical cells were operated at 750 °C for 400 h under Cr contamination, the polarization resistance of LSCF@NF was only half of that of blank LSCF electrode with much less Cr species. This strategy via in-situ reaction may be extended to other high temperature energy conversion systems such as anti-sulfur and anti-carbon deposition of SOFC anodes and CO₂ resistance of cathodes.     

Performance of Pd-impregnated Sr1.9FeNb0.9Mo0.1O6-δ double perovskites as symmetrical electrodes for direct hydrocarbon solid oxide fuel cells

Symmetrical solid oxide fuel cell (SSOFC) is one of efficient ways to simplify preparation process, reduce manufacturing cost, and improve redox stability and reliability. Here, we report the performance of Sr-deficient Sr_1.9FeNb_0.9Mo_0.1O_6-δ (SFNM) double perovskites as symmetrical electrodes for direct-hydrocarbon solid oxide fuel cells and significant improvement of electrochemical performance. The SFNM exhibits good structural stability, suitable thermal expansion coefficient and highly chemical compatibility with Sm_0.2Ce_0.8O_1.9 (SDC) and La_0.9Sr_0.1Ga_0.8Mg_0.2O_3–δ (LSGM) electrolytes in both air and 5% H₂/Ar atmospheres. The area specific resistance of SFNM electrode is decreased by 3.6 and 8.4 times at 800 °C in air and H₂, respectively, as compared to the pristine Sr₂FeNbO_6-δ electrode. The electrochemical performance is further improved by introducing a small amount of Pd to form Pd-impregnated SFNM composite electrode (Pd-SFNM). The SSOFCs with Pd-SFNM after two-time impregnation treatments as the electrodes achieve impressive electrochemical performances in different fuels. The Pd-SFNM symmetrical electrode reveals good electrochemical stability operating on CH₄–CO₂ mixed gas.     

Cobalt-free perovskite SrTa0.1Mo0.1Fe0.8O3-δ as cathode for intermediate-temperature solid oxide fuel cells

Ta⁵⁺ and Mo⁶⁺ substituted SrFeO_3-δ perovskites were researched as cathodes of intermediate-temperature solid oxide fuel cells (IT-SOFCs). The samples were synthesized with three components, e.g. mono-doped SrTa_0.2Fe_0.8O_3-δ, SrMo_0.2Fe_0.8O_3-δ and co-doped SrTa_0.1Mo_0.1Fe_0.8O_3-δ. Their phase structure, thermal stability, electrical conductivity and electrochemical catalytic property were researched comparatively. Ta⁵⁺ and Mo⁶⁺ co-doped SrTa_0.1Mo_0.1Fe_0.8O_3-δ possesses better electrochemical catalytic activity than that of the mono-doped SrFeO_3-δ. The performance difference between the mono-doped and co-doped SrFeO_3-δ has a close relation with the different contents of oxygen vacancy in the materials. The synergistic effect derived from Ta⁵⁺ and Mo⁶⁺ co-doping enhances the amount of oxygen vacancies in material, thus resulting in its better electrochemical property. The cells with SrTa_0.1Mo_0.1Fe_0.8O_3-δ as cathode deliver a R_p of 0.085 Ω·cm² and an output of 931 mW·cm^-2 at 800 °C.     

A promising Bi-doped La0.8Sr0.2Ni0.2Fe0.8O3-δ oxygen electrode for reversible solid oxide cells

Reversible solid oxide cells (RSOCs) are clean and effective electrochemical conversion devices that require highly active electrodes and stable electrochemical performance for the practical application. Herein, we investigate a series of La_0.8-xBi_xSr_0.2Ni_0.2Fe_0.8O_3-δ (LBSNF-x, x = 0.0, 0.05, 0.1, 0.15) oxides as the potential oxygen electrode material for RSOCs. The properties of electrical conductivity, thermal expansion coefficient, and chemical compatibility with the Ce_0.9Gd_0.1O_1.95 (GDC) barrier layer of LBSNF-x oxides are evaluated. When LBSNF-0.1 and GDC forms a composite oxygen electrode with the ratio of 7:3, it shows the lowest polarization resistance with fastest oxygen reduction reaction activity in the symmetrical cell test. Then the cell with the configuration of Ni-YSZ/YSZ/GDC/LBSNF-0.1-GDC was prepared and evaluated both in fuel cell (FC) and electrolysis cell (EC) mode. The maximum power density of 824 mW cm⁻² is obtained at 800 °C in FC mode, and current density of 1.20 A cm⁻² is achieved under 50% steam content at 1.3 V in EC mode. Additionally, the cell exhibits good stability both in FC and EC mode after 80 h test at 700 °C. The results of this work provide a strong support for application of the LBSNF-0.1-GDC oxygen electrode for reversible solid oxide cells.     

Ni-doped Ba0.9Zr0.8Y0.2O3-δ as a methane dry reforming catalyst for direct CH4–CO2 solid oxide fuel cells

Fuel flexibility is one of the significant advantages of solid oxide fuel cells (SOFCs). The utilization of methane in SOFCs can not only reduce fuel costs, but also greatly expand its application scenarios, which is of great significance to the commercial development of SOFCs. However, when methane is directly used, Ni-based cermet anode suffers from coking, which seriously affects the durability of the cell. To alleviate the coking issue, a reforming layer outside the Ni-based anode-supporter was proposed in this study, and Ba_0.9(Zr_0.8Y_0.2)_1-xNi_xO_3-δ (BZYNi_x, x = 0.05, 0.1, 0.15 and 0.2) was used as reforming layer material. Among BZYNi_x catalysts, BZYNi_0.2 exhibited excellent catalytic activity toward dry reforming of methane, and methane conversion was as high as 85% at 750 °C. The excellent catalytic durability and coking-resistance of BZYNi_0.2 were also confirmed. When BZYNi_0.2 reforming layer was applied, the single cell fueled with CH₄–CO₂ fuel showed significantly improved electrochemical performance, durability and coking-resistance. The utilization of BZYNi_0.2 reforming layer provides guidance for solving the coking issue of SOFC cermet anodes when fueled with hydrocarbon.     

A highly stable of tungsten doped Pr0.6Sr0.4Fe0.9W0.1O3-δ electrode for symmetric solid oxide fuel cells

In this work, a single perovskite Pr_0.6Sr_0.4Fe_0.9W_0.1O_3-δ (PSFW) for the electrode of SSOFCs is designed and successfully synthesized. The PSFW exhibits excellent structure stability in both reducing and oxidizing atmospheres and thermal compatibility with La_0.8Sr_0.2Ga_0.8Mg_0.2O_3-δ (LSGM) electrolyte. The area specific polarization resistances (ASRs) of PSFW under oxidizing and reducing atmospheres are only 0.086 and 0.215 Ω cm² at 800 °C, respectively. The symmetric electrode shows excellent electro-catalytic activity toward oxygen reduction reaction (ORR) and hydrogen oxidation reaction (HOR) and the corresponding impedance spectra under different hydrogen and oxygen partial pressures are further explored by distribution of relaxation times (DRT), which reveals that rate-limiting steps of HOR and ORR are the hydrogen adsorption/diffusion and oxygen diffusion, respectively. A LSGM electrolyte-supported cell with PSFW as symmetric electrodes displays the outstanding power density, considerable stability and reversibility, proving that the PSFW is a promising electrode material for symmetric solid oxide fuel cells.     

High-performance La0.5(Ba0.75Ca0.25)0.5Co0.8Fe0.2O3-δ cathode for proton-conducting solid oxide fuel cells

La_0.5(Ba_0.75Ca_0.25)_0.5Co_0.8Fe_0.2O_3-δ, a simple perovskite cathode material with high electrical conductivity (940 S cm^?1 at 600 °C) and impressive surface catalytic activity, was prepared and used in proton-conducting solid oxide fuel cells. As its thermal expansion coefficient is higher than that of the electrolyte material BaZr_0.1Ce_0.7Y_0.1Yb_0.1O_3-δ, they were combined and used as a composite cathode. The crystal structure, chemical compatibility, electrical conductivity, cell performance, and the oxygen reduction reaction of the cathode material were explored, and we found that the single fuel cell developed with the composite cathode achieved excellent electrochemical performance, with both a low polarization resistance and high peak power density (0.044 Ω cm² and 1102 mW cm^?2 at 750 °C, respectively). Outstanding stability was also achieved, as indicated by a long-term 100-h test. Additionally, the rate-limiting steps of the oxygen reduction reaction were the oxygen adsorption, dissociation, and diffusion processes.     

Robust Ni-doped Ruddlesden-popper (La,Sr)Fe1-xNixO4+δ oxide as solid oxide cells fuel electrode for CO2 electrolysis

Ruddlesden-popper (La, Sr)FeO_4+δ perovskite oxide with excellent redox stability shows insufficient electrochemical catalytic activity for CO₂ reduction because of low conductivity and oxygen vacancy concentration. In this work, Ni modified (La, Sr)Fe_1-xNi_xO_4+δ cathode was developed to improve the conductivity and catalytic activity for CO₂ electrolysis. The introduction of the Ni element significantly increases the conductivity of (La, Sr)FeO_4+δ perovskite oxide in both air and 50%CO₂/CO due to the increasing charge carrier's concentration. Furthermore, the symmetric cell with (La, Sr)Fe_0·9Ni_0·1O_4+δ (RPLSFNi0.1) electrode exhibits the lowest polarization resistance in 50%CO₂/CO, suggesting that the RPLSFNi0.1 electrode has the best catalytic activity for CO₂ electrolysis. Moreover, the addition of Sm_0.2Ce_0·8O_2-δ (SDC) in RPLSFNi0.1 electrode further enhances the electrochemical performance, and the current density of ?1170 mA cm^?2 is obtained at 850 °C and 1.5 V. In addition, the electrolysis cell exhibits excellent reversible cycling operating stability between 0.6 V at fuel cell mode and 1.2 V at electrolysis mode, indicating that RPLSFNi0.1 is a robust cathode material for solid oxide cells (SOCs) fuel electrode.     

High-performance NdSrCo2O5+δ–Ce0.8Gd0.2O2-δ composite cathodes for electrolyte-supported microtubular solid oxide fuel cells

NdSrCo₂O_5+δ (NSCO) is a perovskite with an electrical conductivity of 1551.3 S cm⁻¹ at 500 °C and 921.7 S cm⁻¹ at 800 °C and has a metal-like temperature dependence. This perovskite is used as the cathode material for Ce_0.8Gd_0.2O_2-δ (GDC)-supported microtubular solid oxide fuel cells (MT-SOFCs). The MT-SOFCs fabricated in this study consist of a bilayer anode, comprising a NiO–GDC composite layer and a NiO layer, and a NSCO–GDC composite cathode. Three cell designs with different outer tube diameters, GDC thicknesses, and NSCO/GDC ratios are designed. The MT-SOFC with an outer tube diameter of 1.86 mm, an electrolyte thickness of 180 μm, and a 5NSCO–5GDC composite cathode presents the best performance. The flexural strength of the aforementioned cell is 177 MPa, which is sufficient to confer mechanical integrity to the cell. Moreover, the ohmic and polarization resistance values of the cell are 0.22 and 0.09 Ω cm² at 700 °C, respectively, and 0.15 and 0.03 Ω cm² at 800 °C, respectively. These results indicate that the NSCO-GDC composite exhibits high electrochemical activity. The maximum power densities of the cell at 700 and 800 °C are 0.46 and 0.67 W cm⁻², respectively, exceeding those of existing electrolyte-supported MT-SOFCs with similar electrolyte thicknesses.     

Electrochemical and thermal properties of SmBa0.5Sr0.5Co2O5+δ cathode impregnated with Ce0.8Sm0.2O1.9 nanoparticles for intermediate-temperature solid oxide fuel cells

SmBa_0.5Sr_0.5Co₂O_5+δ (SBSC55) impregnated with nano-sized Ce_0.8Sm_0.2O_1.9 (SDC) powder has been investigated as a candidate cathode for intermediate-temperature solid oxide fuel cells (IT-SOFCs). The cathode chemical compatibility with electrolyte, thermal expansion behavior, and electrochemical performance are investigated. For compatibility, a good chemical compatibility between SBSC55 and SDC electrolyte is still kept at 1100 °C in air. For thermal dilation curve, it could be divided into two regions, one is the low temperature region (100–265 °C); the other is the high temperature region (265–850 °C). In the low temperature region (100–265 °C), a TEC value is about 17.0 × 10^?6 K^?1 and an increase in slope in the higher temperatures region (265–800 °C), in which a TEC value is around 21.1 × 10^?6 K^?1. There is an inflection region ranged from 225 to 330 °C in the curve of d(δL/L)/dT vs. temperature. The peak inflection point located about 265 °C is associated to the initial temperature for the loss of lattice oxygen and the formation of oxygen vacancies. For electrochemical properties, the polarization resistances (R_p) significantly reduced from 4.17 Ω cm² of pure SBSC55 to 1.28 Ω cm² of 0.65 mg cm^?2 of SDC-impregnated SBSC55 at 600 °C. The single cell performance of SBSC55∣SDC∣Ni-SDC loaded with 0.65 mg cm^?2 SDC exhibited the optimum power density of 823 mW cm^?2 at operating temperature of 800 °C. Based on above-mentioned properties, SBSC55 impregnated with an appropriate SDC is a potential cathode for IT-SOFCs.     

Ni-doped A-site-deficient La0.7Sr0.3Cr0.5Mn0.5O3-δ perovskite as anode of direct carbon solid oxide fuel cells

A Ni-doped A-site-deficient La_0.7Sr_0.3Cr_0.5Mn_0.5O_3-δ perovskite (N-LSCM) was synthesized and systematically characterized towards the application as the anode electrode for direct carbon solid oxide fuel cells (DC-SOFCs). The microstructure and electrochemical properties of N-LSCM under the operation conditions of DC-SOFCs have been evaluated. An in-situ exsolution of Ni nanoparticles on the N-LSCM perovskite matrix is found, revealing a maximum power density of 153 mW cm⁻² for the corresponding DC-SOFC at 850 °C, compared to 114 mW cm⁻² of the cell with stoichiometric LSCM. The introduction of Ni nanoparticles exsolution and A-site deficient is believed to boost the formation of highly mobile oxygen vacancies and electrochemical catalytic activity, and further improves the output performance of the DC-SOFC. It thus promises as a suitable anode candidate for DC-SOFCs with whole-solid-state configuration.     

Preparation of bulk-like La0.8Sr0.2Ga0.8Mg0.2O3-δ coatings for porous metal-supported solid oxide fuel cells via plasma spraying at increased particle temperatures

While porous metal-supported solid fuel oxide cells (PMS-SOFCs) have the potential to decrease the cost and increase the start-up speed of power units, the available fabrication processes remain too cumbersome for industrial production. In this study, we prepared bulk-like strontium and magnesium-doped lanthanum gallate (LSGM) coatings using atmospheric plasma spraying (APS) at an increased particle temperature. The large equiaxed grains inside the coatings indicated the epitaxial growth of the splat interfaces and improvement in the coating quality. With increased particle temperature, the conductivity of dense LSGM coatings directly deposited by APS was comparable to that of the bulk material, and cell performance was also significantly enhanced. The maximum power density of the PMS-SOFC at 700 °C was 831 mW cm⁻² and 596 mW cm⁻² when high and low particle temperatures were used, respectively. These results indicated that the quality of the coating was improved by increasing the in-flight particle temperature.     

Modified La0.6Sr0.4Co0.2Fe0.8O3-δ cathodes with the infiltration of Er0.4Bi1.6O3 for intermediate-temperature solid oxide fuel cells

Aiming to lower the activation energy and expedite the oxygen reduction reaction (ORR) process of La_0.6Sr_0.4Co_0.2Fe_0.8O_3-δ (LSCF) cathodes for application in intermediate-temperature solid oxide fuel cells (IT-SOFCs), Er_0.4Bi_1.6O₃ (ESB) modified LSCF was prepared by infiltrating using organic solvents. The infiltration of ESB dramatically reduces the polarization resistances of LSCF cathodes (from 0.27 to 0.11 Ω cm² at 700 °C, from 0.58 to 0.25 Ω cm² at 650 °C), and lowers their activation energy (from 100.28 to 97.15 kJ mol^?1). Also, ESB makes the rate-limiting step of LSCF cathodes at high frequency change from the charge transfer process on the cathode to the adsorption and diffusion of oxygen on cathode surface. The single cell with ESB infiltrated LSCF cathodes shows a peak power density of 469 mW cm^?2 at 700 °C using humid hydrogen and air as fuels and oxidants, respectively, as well as a good short-term stability for 50 h.     

A highly stable cobalt-free LaBa0.5Sr0.5Fe2O6-δ oxide as a high performance cathode material for solid oxide fuel cells

The expedition of cathode materials with high stability, superior catalytic activity and better electrochemical performance is critical for realizing the commercial application of solid oxide fuel cells. Herein, we report a cobalt-free LaBa_0.5Sr_0.5Fe₂O_6-δ oxide as the cathode material and systematically evaluate its physical and electrochemical properties. The research results indicate that this material exhibits the perovskite-typed structure and possesses a good high-temperature chemical compatibility and interface stability with the Ce_0.8Sm_0.2O_1.9 electrolyte. At 750 °C, the LaBa_0.5Sr_0.5Fe₂O_6-δ cathode shows the lowest polarization resistance and the maximum power density with the values of 0.152 Ω cm² and 370 mWcm⁻², respectively. Furthermore, there is almost no significant change in the polarization resistance and output power density during the 100 h stability test. The oxygen partial pressure dependence studies indicate that the determining steps are the transfer process of oxygen ions from the cathode to the electrolyte, the charge-transfer process and the adsorption process of oxygen molecules on the electrode surface. The preliminary results suggest that the LaBa_0.5Sr_0.5Fe₂O_6-δ oxide is expected to be a promising cathode material for solid oxide fuel cells.     

Electrochemical properties of Sr2.7-xCaxLn0.3Fe2-yCoyO7-δ cathode for intermediate-temperature solid oxide fuel cells

The influence of Ca and Co doping in the Ruddlesden ‒ Popper series of oxide Sr_2.7-xCa_xLn_0.3Fe_2-yCo_yO_7-δ with x = 0 and 0.3, y = 0 and 0.6, and Ln = La and Nd on the electrical and thermal properties, catalytic activity for the oxygen reduction reaction (ORR) in solid oxide fuel cells (SOFC), and phase stability has been investigated. The Co-substituted samples display an increase in oxygen vacancies, electrical conductivity, thermal expansion coefficient, and electrocatalytic activity for both Ln = La and Nd. Although Ca doping in the Sr site slightly reduces the oxygen loss and thermal expansion coefficient, the symmetric cell performance is improved for both lanthanides at high temperatures. Among the cathode materials in this study, the highest catalytic activity for the ORR is achieved with Sr_2.7Ca_0.3Nd_0.3Fe_1.4Co_0.6O_7-δ + Gd_0.2Ce_0.8O_1.9 (GDC) composite cathode with an area specific resistance of 0.034 Ω cm² at 800 °C. Long-term thermal stability test shows that no impurity forms when Sr_2.7-xCa_xLn_0.3Fe_2-yCo_yO_7-δ oxides were heated at 800 °C for 150 h in air.     

Cr deposition and poisoning on SrCo0.9Ta0.1O3-δ cathode of solid oxide fuel cells

Perovskite type SrCo_0.9Ta_0.1O_3-δ (SCT10) is a promising cathode for solid oxide fuel cell (SOFC), but its stability towards Cr impurities is not yet exploited. Herein, the Cr deposition on the electrochemical performance of SCT10 cathodes is evaluated at 700 °C with a cathodic constant current density of 200 mA cm^?2. Both polarization and impedance results reveal that Cr impurities lead to serious performance degradation, especially in wet condition. Significant morphology damages occur after Cr exposure and the formation of SrCrO₄ and Co₃O₄ secondary phases on the cathode surface are determined, which greatly deteriorates the oxygen reduction kinetics and thereby the cathode activity. Our study highlights that surface Sr segregation plays a vital role for Cr deposition and special attention should be paid for the practical applications in SOFC.     

Zr doped BaFeO3-δ as a robust electrode for symmetrical solid oxide fuel cells

A BaFe_0.9Zr_0.1O_3-δ (BFZ) is successfully synthesized and its characteristics are investigated. The oxide exhibits high stability and a cubic perovskite structure in a reducing atmosphere. A La_0.9Sr_0.1Ga_0.8Mg_0.2O_3-δ (LSGM) supported symmetrical solid oxide fuel cell (SOFC) with BFZ electrode demonstrates a maximum power density of 1097 mW cm⁻² using humidified H₂ as the fuel and ambient air as the oxidant at 800 °C. And as low as 0.190 Ω cm² of polarization resistance of single cell is observed at 650 °C. Moreover, the electrode demonstrates high stability in 100 h test, as well as redox stability in both oxidizing and reducing atmospheres. The high electrochemical property and good stability suggest that the BFZ is promising candidate for symmetrical SOFC electrode.     

Sucrose-nitrate auto combustion synthesis of Ce0.85Ln0.10Sr0.05O2-δ (Ln = La and Gd) electrolytes for solid oxide fuel cells

Nanocrystalline powders of co-doped ceria oxides Ce_0.85La_0.10Sr_0.05O_2-δ (CLSO) and Ce_0.85Gda_0.10Sr_0.05O_2-δ (CGSO) have been synthesized by auto combustion method at 100°C using sucrose as fuel. Thermal analysis (TGA/DSC) of as-prepared powders indicated calcination above 400°C to remove organic residue. The average grain size of the pellets sintered at 1200°C for 4 hours is 436 and 683 nm for CLSO and CGSO, respectively. The electrical conductivity of the sintered samples was determined by impedance measurements in the temperature range 300°C to 600°C and the frequency range 20 Hz to 2 MHz. At 600°C, the total electrical conductivity (σ_t) of CGSO is 6.78 × 10⁻³ S cm⁻¹, 2.5 times higher than 2.72 × 10⁻³ S cm⁻¹ of CLSO. Further, it is found that the value of grain boundaries blocking factor (α_gb) of CGSO is 0.47 which is 30% lesser than 0.68 of CLSO at 600°C. The higher value of electrical conductivity of CGSO as compared to CLSO is attributed to the lesser blocking effect of grain boundaries, smaller lattice distortion and denser microstructure of CGSO as compared to CLSO. The electrical conductivity of synthesized samples has been compared with the electrical conductivity of similar compositions of co-doped CeO₂ oxides. Our study indicated that the sintering temperature, and hence, the morphology of sintered samples has a significant role in determining the electrical conductivity. The presence of oxygen vacancies in the synthesized samples is experimentally supported by using UV-visible spectroscopy, Raman spectroscopy, and thermal analysis techniques.     

High-performance anode-supported solid oxide fuel cells with co-fired Sm0.2Ce0.8O2-δ/La0.8Sr0.2Ga0.8Mg0.2O3−δ/Sm0.2Ce0.8O2-δ sandwiched electrolyte

In this study, intermediate-temperature solid oxide fuel cells (IT-SOFCs) with a nine-layer structure are constructed via a simple method based on the cost-effective tape casting-screen printing-co-firing process with the structure composed of a NiO-based four-layer anode, a Sm_0.2Ce_0·8O_2-δ(SDC)/La_0·8Sr_0.2Ga_0.8Mg_0·2O_3?δ (LSGM)/SDC tri-layer electrolyte, and an La_0·6Sr_0·4Co_0·2Fe_0·8O_3-δ (LSCF)-based bi-layer cathode. The resultant SDC (4.14 μm)/LSGM (1.47 μm)/SDC (4.14 μm) tri-layer electrolyte exhibits good continuity and a highly dense structure. The R_o and R_p values of the single cell are observed to be 0.15 and 0.08 Ω cm² at 800 °C, respectively, and the MPD of the cell is 1.08 Wcm-2. The high MPD of the cell appears to be associate with the significantly lower area-specific resistance and the reasonably high OCV. Compared to those with a similar electrolyte thickness reported in prior studies, the nine-layer anode-supported IT-SOFC with a tri-layer electrolyte developed by the study demonstrates superior cell properties.     

Processing and characterization of novel Ce0.8Sm0.1Bi0.1O2-δ-BaCe0.8Sm0.1Bi0.1O3-δ (BiSDC-BCSBi) composite electrolytes for intermediate-temperature solid oxide fuel cells

Ce_0.8Sm_0.1Bi_0.1O_2-δ-BaCe_0.8Sm_0.1Bi_0.1O_3-δ (BiSDC-BCSBi) composites are fabricated as novel electrolytes for intermediate-temperature solid oxide fuel cells (IT-SOFCs). Both dramatically enhanced sinterability and electrical performance are obtained due to the Bi doping. BiSDC-BCSBi composites are densified at as low as 1200 °C, allowing a decrease of 350 °C compared with Ce_0.8Sm_0.2O_2-δ-BaCe_0.8Sm_0.2O_3-δ (SDC-BCS) composites. The optimal electrical conductivity of BiSDC-BCSBi electrolytes measured at 600 °C in humid air reaches up to 27.97 mS cm^?1, almost 6 times higher than that of SDC-BCS electrolytes (3.91 mS cm^?1 in humid air), which is mainly attributed to their lower sintering temperature, more uniform microstructure, larger tensile strains, and higher concentrations of O–H groups and oxygen vacancies. The electrolyte-supported single cell with BiSDC-BCSBi electrolyte displays a peak power density of 397 mW cm^?2 at 600 °C using humid hydrogen as fuel and ambient air as oxidant. These results imply that BiSDC-BCSBi composites have a great application prospect for IT-SOFCs.