Electrodes For Solid Oxide Research Articles

Evaluation and Upscaling of Impregnated La0.20Sr0.25Ca0.45TiO3 Fuel Electrodes for Solid Oxide Electrolysis Cells

Recent research into Rh and Ce0.80Gd0.20O1.90-impregnated La0.20Sr0.25Ca0.45TiO3 fuel electrodes for solid oxide fuel cells has demonstrated the high-stability of these material sets to a variety of harsh operating conditions at small scales (1 cm2 active area button cells), as well as commercial scales (100 cm2 cells) in short stacks (5 cells) and full micro-combined heat and power systems (60 cells). In this work, the authors present a comprehensive evaluation of the ability of these novel titanate-based materials to function as fuel electrodes in solid oxide electrolysis cells (SOECs). Short-term and durability testing of button cell scale SOECs highlighted the limited stability of lanthanum strontium manganite-based air electrodes, under CO2 and steam electrolysis conditions, with lanthanum strontium cobaltite ferrite-based air electrodes offering improved degradation characteristics. Upscaling of this optimized cell chemistry to a 16 cm2 active area SOEC and testing under CO2, CO2/H2O and H2O electrolysis conditions demonstrated encouraging performance over a period of ∼600 h, with stable co-electrolysis performance at ∼−7.5 A at 1.47 V for the first 100 h.

Improving the stability of La0.6Sr0.4Co0.2Fe0.8O3-δ electrode for solid oxide fuel cells by introducing sintering inhibitors

In this study, nano-sized Al2O3 and Gd0.1Ce0.9O1.95 (GDC) particles are added to La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) cathode material as sintering inhibitors for solid oxide fuel cells (SOFC) to improve the stability of the cell performance. Studies reveal that as the amount of the inhibitors increases, the sintering activation energy of the composite LSCF sample increases, resulting in retarded sintering kinetics indicated by the suppressed grain size of the sintered composite LSCF cathode. Long-term durability tests show that due to the enhanced stability of the microstructure of the composite LSCF cathode, the composite cathode exhibits improved performance stability. Furthermore, both the Al2O3 and GDC additions can improve the hardness and elastic modulus of the cathode, while the electrical conductivity of both cathodes exceed 100 S/cm and can still meet the requirements for the SOFC in the operation temperature range of 600–800 °C. In light of the boosted electrochemical durability of the Al2O3-added LSCF cathode and much lower cost of Al2O3 compared to the rare-earth element based GDC materials, LSCF cathode with a proper amount of the nano-sized Al2O3 inhibitors is a good solution to enhance the mechanical property, electrochemical durability of LSCF cathode for the SOFCs at low cost.

Correction: Optimization of misfit calcium cobaltite oxygen electrodes for solid oxide fuel cells through electrospinning processing

Correction for ‘Optimization of misfit calcium cobaltite oxygen electrodes for solid oxide fuel cells through electrospinning processing’ by Allan J. M. Araújo et al., J. Mater. Chem. A, 2024, https://doi.org/10.1039/D4TA04085F.

Optimization of misfit calcium cobaltite oxygen electrodes for solid oxide fuel cells through electrospinning processing

The calcium cobaltite (CCO) electrode processed by electrospinning (ES) benefits from reduced grain size and increased grain-to-grain contact, decreasing the total polarization resistance, compared to that produced by Solid State Reaction (SSR).

Boosting the electrochemical performance of oxygen electrodes via the formation of LSCF-BaCe0.9–xMoxY0.1O3–δ triple conducting composite for solid oxide fuel cells: Part II

This research is the continuation of our previous work, in which we introduced novel proton-conducting electrolytes BaCe0.9–xMoxY0.1O3–δ (BCMxY; x = 0.025, 0.05). In this study, we explore the potential of the proton-conducting BCM0.025Y electrolyte by creating a composite with La0.6Sr0.4Co0.2Fe0.8O3–δ (LSCF) to form triple conducting electrodes for solid oxide fuel cells (SOFC). The formation of the LSCF-BCM0.025Y composite enhances both the three-phase reaction interface length and the concentration of oxygen vacancies, contributing to improved dissociation rates and enhanced oxygen adsorption. The desired characteristics, including density, structure, composition, electrochemical performance, and thermal stability, have been confirmed through a comprehensive set of analyses including scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), Fourier-transform infrared spectroscopy (FTIR), electrochemical impedance spectroscopy (EIS), and thermogravimetric analysis (TGA) coupled with differential scanning calorimetry (DSC), respectively. The cell configuration of Ni-YSZ | BCZY | LSCF-BCM0.025Y exhibited a remarkable maximum power density (MPD) of 418.7 mW cm−2, which is approximately 29 % higher than that achieved with a typical LSCF cathode (325.6 mW cm−2) at an operating temperature of 600 °C. The outstanding performance and enduring stability of the LSCF-BCM0.025Y composite over a 500 h period demonstrate its potential as a promising cathode material for intermediate-temperature SOFCs.

Simultaneous Performance and Stability Enhancement in Intermediate Temperature Solid Oxide Fuel Cells by Powder-Atomic Layer Deposited LSCF@ZrO2 Cathodes.

Employing porous structures is essential in high-performance electrochemical energy devices. However, obtaining uniform functional coatings on high-tortuosity structures can be challenging, even with specialized processes such as atomic layer deposition (ALD). Herein, a novel method for achieving a porous composite electrode for solid oxide fuel cells by coating La0.6 Sr0.4 Co0.2 Fe0.8 O3 -δ (LSCF) powders with ZrO2 using a powder ALD process is presented. Unlike conventional ALD, powder ALD can be used to fabricate extremely uniform coatings on porous electrodes with a thickness of tens of micrometers. The powder ALD ZrO2 coating is found to effectively suppress chemical degradation of the LSCF electrodes. The cell with the powder ALD coated cathode shows a 2.2 times higher maximum power density and 60% lower thermal degradation in activation resistance than the bare LSCF cathode cell at 700-750 °C. The result demonstrated in this study is expected to have significant implications for high-performance and durable electrodes in energy conversion/storage devices.

(Digital Presentation) Ni-Doped PrBaFe2O5+ δ As Symmetrical Electrode for Solid Oxide Cells

The development of new redox stable electrode materials for Solid Oxide Cells (SOFs) have attracted great attention in recent years, since finding suitable compositions to operate efficiently in both fuel cell and electrolyzer modes is crucial for their wide commercialization [1]. For this reason, research on new doping strategies [2] and advanced deposition techniques [3] for symmetrical electrode materials have significantly increased with the aim of simplifying cell fabrication and extending cell durability. In this sense, double perovskites are gaining great interest due to their excellent electrical properties and high redox and long-term stability in different atmospheres [4].In this study, the double-perovskite (PrBa)0.95Fe2O5+δ (PBF) is proposed as symmetrical electrode for SOCs [5]. Two different strategies are implemented: on the one hand, Ni-doping in order to improve the electrical properties under reducing atmosphere and, on the other hand, the preparation of nanostructured electrodes in one-step by spray-pyrolysis deposition. A thorough characterization of the material is performed regarding its crystal structure, microstructure and electrochemical properties in both oxidizing and reducing atmospheres.With that purpose, PBF and (PrBa)0.95Fe2-xNixO5+ δ (PBFNx) powders are prepared by the freeze-drying precursor method. XRD patterns show the formation of a single perovskite-type phase in both air and H2 atmospheres, without the presence of any secondary phases. As for conductivity tests, they reveal increased values for the Ni-doped material over the pristine PBF material in air and 5% H2 at 600 ºC. These materials were thereafter screen-printed onto La0.9Sr0.1Ga0.8Mg0.2O2.85 (LSGM) electrolyte and calcined at 1100 ºC for 1h to ensure adequate adhesion to the electrolyte.Alternatively, spray-pyrolysis deposition method is employed to infiltrate PBFNx, with a 0.02 M precursor solution of the corresponding nitrate salts, into a porous Ce0.9Gd0.1O1.95 (CGO) layer previously fixed onto LSGM electrolyte (PBFNx-CGO). SEM images reveal that the screen-printed PBFNx has a thickness of 30 µm and a particle size of around 1 µm, while the same composition deposited by spray-pyrolysis shows a nanometric particle size and it is well-infiltrated in the 10 µm-thick CGO layer (Figure 1a). These electrode microstructures are maintained after ongoing a reduction process, where exsolved Ni particles are observed on the surface.The impedance spectra show lower polarization resistance (Rp) values for PBFNx with respect to PBF, i.e. 0.47 and 0.62 Ω cm2 at 650 ºC in air, respectively. But most significantly, further Rp reduction is observed for PBFNx-CGO prepared by spray-pyrolysis, values as low as 0.17 Ω cm2 at 650 ºC in air (Figure 1b). In reducing atmosphere, the PBFNx-CGO electrode also has lower Rp values (0.23 Ω cm2 at 650 ºC) when compared to the pristine PBF (0.52 Ω cm2 at 650 ºC).All in all, the nanostructured Ni-doped PBF electrodes exhibit high redox stability and low polarization resistance values under both oxidizing and reducing atmospheres, demonstrating their potential application as symmetrical electrodes for SOCs. These findings show that the optimization of the electrode composition but mostly its microstructure is key when developing new electrode materials for solid oxide cells.This research is supported by Ministerio de Ciencia, Innovación y Universidades through the RTI2018-093735-B-I00 and UMA18-FEDERJA-033 projects (Spain), and the University of Malaga through the B1-2021_03 project.[1] J. Zamudio-García, L. Caizán-Juanarena, J.M. Porras-Vázquez, E.R. Losilla, D. Marrero-López, A review on recent advances and trends in symmetrical electrodes for solid oxide cells, J. Power Sources. 520 (2022). https://doi.org/10.1016/j.jpowsour.2021.230852.[2] T. Su, Y. Li, Y. Yang, Z. Xu, N. Shi, Y. Wan, Y. Xie, D. Huan, S. Xue, C. Xia, Effect of tungsten doping on strontium ferrite electrode for symmetrical solid oxide electrochemical cell, Int. J. Hydrogen Energy. 45 (2020) 23401–23410.[3] Y. Kwon, S. Kang, J. Bae, Development of a PrBaMn2O5+δ-La0.8Sr0.2Ga0.85Mg0.15O3-δ composite electrode by scaffold infiltration for reversible solid oxide fuel cell applications, Int. J. Hydrogen Energy. 45 (2019) 1748–1758.[4] B. Zhang, Y. Wan, Z. Hua, K. Tang, C. Xia, Tungsten-Doped PrBaFe2O5+δ Double Perovskite as a High-Performance Electrode Material for Symmetrical Solid Oxide Fuel Cells, ACS Appl. Energy Mater. 4 (2021) 8401–8409.[5] D. Kim, S.J. Son, M. Kim, H.J. Park, J.H. Joo, PrBaFe2O5+δ promising electrode for redox-stable symmetrical proton-conducting solid oxide fuel cells, J. Eur. Ceram. Soc. 41 (2021) 5939–5946. Figure 1. a) PBFNx-CGO electrode deposited by spray-pyrolysis onto LSGM electrolyte: (i) Low magnification image of the electrode and electrolyte; (ii) Zoomed image of the pure PBFN top layer and the PBFNx layer infiltrated in CGO; and (iii) Zoomed image of PBFNx particles infiltrated on CGO scaffold. b) Polarization resistance (Rp) in air of PBF, PBFNx and PBFNx-CGO electrodes as a function of temperature (450-800 ºC). Figure 1

Progress of Solid Oxide Electrolysis and Fuel Cells for Hydrogen Generation, Power Generation, Grid Stabilization, and Power-to-X Applications

Over the past 25+ years, Nexceris has been developing solid oxide cell (SOC) technology for power generation, energy storage and hydrogen production applications. Nexceris is vertically integrated SOC technology provider that develops and manufactures solid oxide electrode materials, interconnect coatings, planar electrolyte supported cells, and solid oxide stacks. Nexceris stacks are designed for low-cost manufacture and pressurized operation, and stacks have large repeat unit area for efficient packaging into megawatt-scale systems. Nexceris’ stacks are being tested in fuel cell, electrolysis, and reversible modes, with a focus on optimizing performance, efficiency, and durability. Current work at Nexceris includes long-term electrolysis stack durability testing, breadboard system testing of reversible SOC stacks, third-party stack validation testing, and SOC system design and demonstration testing. Nexceris also is exploring solid oxide co-electrolysis for converting steam and CO2 to syngas and the conversion of this syngas to fuels and chemicals. This presentation will provide an update on Nexceris’ solid oxide cell technology development and commercialization activities.

Kinetic Monte Carlo (KMC) simulation of sintering of nickel oxide-yttria stabilized zirconia composites: Model, parameter calibration and validation

This study proposes a kinetic Monte Carlo (KMC) model for the sintering of two-phase composites using nickel oxide-yttria stabilized zirconia (NiO-YSZ) as a case study. An artificial neural network (ANN) assisted method is used to calibrate the KMC model parameters by comparing the simulated microstructures and the real microstructure reconstructed by focused ion beam scanning electron microscopy (FIB-SEM). It is demonstrated that the ANN calibrated KMC model can predict quantitatively the microstructure evolution of NiO-YSZ composite. The microstructural parameters such as volume fraction, specific surface area, and triple-phase boundary length density of sintered NiO-YSZ are well predicted within acceptable errors. The proposed framework can be adapted for the simulation of the microstructure evolution of any other composite electrodes for solid oxide fuel cells and other composites fabricated by sintering.

Evaluation and Upscaling of Impregnated La0.20Sr0.25Ca0.45TiO3 Fuel Electrodes for Solid Oxide Electrolysis Cells Under H2O, CO2 and Co-Electrolysis Conditions

Recent research into Rh and Ce0.80Gd0.20O1.90-impregnated La0.20Sr0.25Ca0.45TiO3 fuel electrodes for solid oxide fuel cells has demonstrated the high-stability of these material sets to a variety of harsh operating conditions at small scales (button cells with 1 cm2 active area), as well as full commercial scales (100 cm2 cells) in short stacks (5 cells) and full micro-combined heat and power systems (60 cells). In this work, the authors present a comprehensive evaluation of the ability of these novel titanate-based materials to function as fuel electrodes in solid oxide electrolysis cells (SOECs). Short-term and durability testing of button cell scale SOECs, under CO2 and steam electrolysis conditions, highlighted the limited stability of lanthanum strontium manganite-based air electrodes with lanthanum strontium cobaltite ferrite-based air electrodes offering improved degradation. Upscaling of this optimized cell chemistry to a 16 cm2 active area SOEC and testing under CO2, CO2/steam and steam electrolysis conditions demonstrated encouraging performance over a period of ~600 hours.

Optimizing infiltration parameters of nanostructured anode electrode in solid oxide fuel cells

This study focuses on the development and optimization of nanostructured anode electrodes for solid oxide fuel cells (SOFCs) by infiltration method. Ni (nickel) catalyst in the form of a nickel nitrate solution is infiltrated into porous YSZ (yttria stabilized zirconia) backbone fabricated by tape casting. Numerous electrolyte-supported cells are fabricated to investigate the effects of several significant infiltration fabrication parameters such as catalyst loading and infiltration sintering temperature. Conventional cell with screen printed Ni-YSZ anode is also fabricated for comparison. Electrochemical performances and microstructural properties of the cells are examined and evaluated. The best peak performance of 0.398 W/cm2 at 800 °C is obtained from the cell, which is infiltrated 9 times with 2 M solution followed by firing at 800 °C. The conventional cell, on the hand, exhibits only 0.174 W/cm2 under the same testing conditions in spite of the relatively higher Ni catalyst content in the anode. Furthermore, the optimized cell produces 0.169 W/cm2 maximum power density at 700 °C. The overall results reveal that nickel catalyst infiltration is a very effective method to improve the cell performance by providing increased number of electrochemical reaction zones within the anode electrode due to nanostructured nickel catalyst formed around the main YSZ phase.

Advanced electrocatalytic activity of praseodymium-deficient copper-based oxygen electrodes for solid oxide fuel cells

Herein praseodymium-deficient Pr1.90−xCe0.1CuO4 oxides are evaluated as potential oxygen electrodes for solid oxide fuel cells (SOFCs). Introducing Pr-deficiency promotes the oxygen vacancy concentration, further improving electrocatalytic activity of the Pr1.90−xCe0.1CuO4 electrodes towards oxygen reduction reaction (ORR). The Pr1.75Ce0·.1CuO4 (P1·75CC) component exhibits outstanding electrode performance, as supported by a polarization resistance as low as 0.025 Ω cm2 and high peak power density of the single cell (1.11 W cm−2) at 700 °C. In addition, the rate-limiting steps for ORR kinetics are determined to be the charge transfer reaction and oxygen adsorption/diffusion process on the electrode surface. This work highlights an effective way for developing the cathode candidates with high electrocatalytic activity and superior stability.

Unveiling positive impacts of fluorine anion doping on extraordinary catalytic activity of bifunctional-layered double perovskite electrodes for solid oxide fuel cells and electrolysis cells

To address the impacts of anion doping, F-doped layered double perovskites (Pr1.1Ba0.9Co2O5+δFx) have been synthesized, demonstrating bifunctional activity in both solid oxide fuel cell and solid oxide electrolysis cell models. The F doping induces increased oxygen vacancy concentration and enhanced electrical conductivity. Combined with spherical aberration-corrected transmission electron microscopy and X-ray photoelectron spectroscopy analyses, the F− anions are successfully introduced into the host lattice, promoting the oxygen surface exchange/diffusion rates. From the density functional theory calculations, the covalence between Co 3d and O 2p-orbital is enlarged in the F-doped model, and both oxygen reduction reaction and oxygen evolution reaction activities are improved. The area-specific resistance of the Pr1.1Ba0.9Co2O5+δF0.1 (P1.1BCOF0.1) electrode is as low as 0.033 Ω/cm2 at 700 °C. The P1.1BCOF0.1 cathode-based fuel cell delivers a peak power density of 1102 mW/cm2, along with an excellent operating stability at 700 °C. Moreover, the current density of 1335 mA/cm2 is achieved in the P1.1BCOF0.1 anode-based electrolysis cell at 1.8 V toward CO2 reduction reaction at 750 °C. These results here highlight the performance origin and bifunctional activity of fluorine-doped perovskite materials, which may help us rationally design the oxide catalysts.

Advanced electrochemical activity and CO2 tolerance of iron-based cathode electrocatalyst for solid oxide fuel cells

Here, we report the Sr0.5Bi0.4Ca0.1FeO3−δ (SBCF) and Sr0.5Bi0.5FeO3−δ (SBF) oxides, which are regarded as the oxygen electrodes for solid oxide fuel cells (SOFCs). The Ca2+ cations that doped into SBF substitutes the Bi3+ site, which can increase the oxygen vacancy concentration, promote the oxygen transport kinetics, enhance the electrical conductivity, and improve the electrochemical activity. Impedance result shows that SBCF possesses a lower polarization resistance of 0.13 Ω cm2 at 700 °C. Additionally, SBCF performs well in single cells, achieving a peak power density of 0.83 W cm−2 at 650 °C and a superior durability for ∼ 100 h. When SBCF electrode is exposed to a CO2-containing atmosphere, no carbonate species are formed on SBCF cathode, indicating that SBCF has a good CO2 tolerance. The high activity and good chemical stability make SBCF a potential electrode for SOFCs.

Effect of calcium doping on the electrocatalytic activity of the Bi1-x Ca x FeO3-δ oxygen electrode for solid oxide fuel cells.

For solid oxide fuel cell (SOFC) applications, there remains a growing interest in developing efficient cathode catalysts. Herein, iron-based Ca-doped Bi1-x Ca x FeO3-δ (BCFx, x = 0.1, 0.2, and 0.3) oxides are evaluated as potential cathode materials for SOFCs. The phase structure, thermal expansion behavior, electrical conductivity, and electrocatalytic properties for the oxygen reduction reaction (ORR) of the BCFx cathodes are systematically characterized. Among all compositions, the Bi0.8Ca0.2FeO3-δ (BCF0.2) cathode exhibits the highest oxygen vacancy concentration and considerable electrocatalytic activity, demonstrating the lowest polarization resistance (0.11 Ω cm2) and largest exchange current density of 41.91 mA cm-2 at 700 °C. The BCF0.2 cathode-based single cell delivers excellent output performance, yielding a maximum power density of 760 mW cm-2 700 °C along with exceptional stability over a period of 60 h. This work highlights the Ca-doping strategy for enhancing electrocatalytic activity of the cathode electrocatalysts in SOFCs.

Atomic layer deposition for surface area determination of solid oxide electrodes

A method to measure the total surface area of porous electrodes is developed, leveraging the conformal atomic layer deposition of alumina over internal features, with example structures measured from the field of solid oxide electrochemical cells.

Preparation and characterization of highly active and stable NdBaCo0.8Fe0.8Ni0.4O5+δ oxygen electrode for solid oxide fuel cells

In order to develop high active and stable oxygen electrode for intermediate temperature solid oxide fuel cells (IT-SOFCs), NdBaCo0.8Fe0.8Ni0.4O5+δ (NBCFN) oxygen electrode was successfully prepared by sol-gel method. The NBCFN sample formed a double perovskite structure after calcination at 1100 °C for 10 h. The NBCFN electrode and La0.9Sr0.1Ga0.83Mg0.17O3-δ (LSGM) electrolyte has good chemical compatibility below 950 °C. Compared with NdBaCo2O5+δ, the average thermal expansion coefficient (TEC) of NBCFN sample was 17.2 × 10−6 K-1 at 30 °C - 850 °C in air and decreased by 30%. The conductivity of NBCFN sample exhibited p-type semiconductor conduction and reached 441.8 S cm−1 at 800 °C. The polarization impedance (RP) of NBCFN oxygen electrode on LSGM electrolyte reached 0.055 Ω cm2 at 700 °C. The charge transfer process of NBCFN oxygen electrode was mainly rate-limiting step. The RP of NBCFN oxygen electrode exhibited good stability in air during 200 h test. At 800 °C, the NBCFN oxygen electrode on 300μm-thick LSGM electrolyte reached 1042 mWcm−2 at fuel cell mode and current density was 0.9 A cm−2 at 1.3 V under the electrolysis cell mode, respectively. These results primarily indicated that NBCFN oxygen electrode had good electrochemical performance for IT-SOFCs.

Further optimization of the properties of Pr0.6Sr0.4Fe0.9W0.1O3-δ by Cu-doping as symmetric electrodes for solid oxide fuel cells

Copper-doped Pr0.6Sr0.4Fe0.8Cu0.1W0.1O3-δ (PSFCuW) as a symmetric electrode material is investigated for La0.8Sr0.2Ga0.8Mg0.2O3-δ (LSGM)-based symmetric solid oxide fuel cells (SSOFCs). The effect of Cu-doping on stability and mechanism of hydrogen oxidation reaction (HOR) and oxygen reduction reaction (ORR) is investigated and analyzed. Fe partially replaced by Cu on the B-site could also keep the phase structure stable after treatment under reducing conditions and improve the electrical conductivity, which reaches 30.3 and 0.78-1 under oxidizing and reducing conditions at 800 oC, respectively. The distribution of relaxation times (DRT) indicates that the rate-limiting step processes under oxidation conditions are oxygen adsorption and diffusion, while hydrogen adsorption and charge transfer have important influences on the rate-limiting step under reduced atmospheres, respectively. Finally, the LSGM-supported SSOFC (PSFCuW|LSGM|PSFCuW) shows excellent stability and reversibility. These results imply that PSFCuW is an up-to-coming symmetric electrode material for application in SSOFCs.

CO2 Electroreduction to Fuels Using Solid Oxide Electrodes: Beyond Ni-YSZ

Ni-YSZ electrodes form the benchmark in Carbon Dioxide electroreduction to CO. Ni-YSZ due its popular use in Solid Oxide Fuel Cells forms the basis of various process steps. Unfortunately, this material remains active only if a certain amount of hydrogen is supplied along side CO2 to the inlet of the reaction. Consequently, the Ni-YSZ results in CO production via reverse water gas shift (RWGS) reaction when H2 is supplied at the inlet. The currents for the electrode originate from electrolysis of H2O which is formed as a result of reverse water has shift. We have quantified the amount of CO produced from RWGS vs direct CO2 electrolysis in such a system using online mass spectrometry (MS). Electrochemical impedance spectroscopy measurements where analysed using distribution of relaxation times analysis. Under low concentration of H2 the overall impedance is dominated by H2 mass transfer. Effects of concentration of various reactants were measured using online MS. The process of pretreatment of the electrodes and catalyst surface development during reaction were tracked using in situ Raman Spectroscopy and optical spectrocopy. Electrodes were structurally characterised using SEM, TEM, XPS and ICP-OES measurememts. Various new combination of mixed metal oxide electrodes Ni(M)-YSZ were tested and compared with the performance of pure Ni-YSZ. Ni-YSZ electrode when used under pure CO2 results in catastrophic failure of the electrode performance. We have investigated this failure using in situ Raman and Mass spectrometry. The mechanism of CO2 production in pure CO2 stream was found to be drastically different from when a small amount of H2 is used. Figure 1

Influences of equal A-site rare-deficiency or B-site high-valent metal doping on NdBaFe2O employed as the symmetrical electrode for solid oxide fuel cells

Symmetric solid oxide fuel cells (SSOFCs), which can effectively deal with the issue of anode carbon accumulation and sulfur poisoning while simplifying the preparation process, have received much attention. Fe-based compounds are commonly used as symmetric electrodes for SOFCs, due to their low cost and excellent stability. The effects of equivalent quantities of Nd-deficiency or Mo-doping on NdBaFe 2 O 5+δ (NBF) electrode materials for SOFCs are investigated in this work. Under hydrogen atmosphere, NBF has the highest electrical conductivity, while also containing the biggest amount of oxygen species both before and after reduction, showing outstanding electrocatalytic activity for both hydrogen oxidation reaction (HOR) and oxygen reduction reaction (ORR). A laboratory-scale YSZ electrolyte-supported cell with an NBF95 electrode is fabricated and obtains a maximum power density of 366.66 mW·cm -1 at 800 °C. The results show that either Nd-deficiency or Mo-doping can enhance the electrochemical performance of the NBF electrode, and the advantage of Nd-deficiency is more significant. • NBF95 and NBFM enhance electrochemical performance of NBF cathode. • NBF, NBF95, and NBFM remain phase stable at 800 °C under reducing atmosphere. • Compared with NBFM, NBF95 saves cost to a certain extent.