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.     

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.     

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.     

Highly stable La0.5Sr0.5Fe0.9Mo0.1O3-δ electrode for reversible symmetric solid oxide cells

Reversible solid oxide cells (RSOCs) using identical material as both fuel electrode and air electrode have received extensive attentions due to their simplified fabrication process, increased compatibility between electrolyte and electrode. In this work, Molybdenum doped La_0.5Sr_0.5Fe_0.9Mo_0.1O_3-δ (LSFMo) symmetric electrode based on RSOCs is firstly designed and synthesized via sol-gel method. The effect of Molybdenum substitution at Fe-site on crystal structure, chemical stability, conductivity and electrochemical performance of La_0.5Sr_0.5FeO_3-δ oxide is thoroughly investigated. The structural stability of La_0.5Sr_0.5FeO_3-δ (LSF) in reducing condition is significantly enhanced after the incorporation of Mo^5+/6+ and the conductivity in 5% H₂ for LSFMo is ~7 times higher than that of undoped LSF. In addition, the polarization resistance value at 850 °C based on LSFMo/LSGM/LSFMo is 0.08 and 0.09 Ω cm² in air and wet H₂, respectively. At 850 °C and 20%H₂O–H₂, a peak power density of 640 mW cm⁻² is obtained in fuel cell mode, while a current density of −1000 mA cm⁻² is attained at 1.3 V in electrolysis mode. Finally, the symmetric cell exhibits an excellent cycling reversible operation in both SOFCs mode and SOECs mode without detectable degradation.     

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.     

Study on durability of novel core-shell-structured La0.8Sr0.2Co0.2Fe0.8O3-δ@Gd0.2Ce0.8O1.9 composite materials for solid oxide fuel cell cathodes

Core-shell-structured La_0.8Sr_0.2Co_0.2Fe_0.8O_3-δ@Gd_0.2Ce_0.8O_1.9 (LSCF@GDC) composite materials are synthesized and sintered as the SOFC cathodes by screen-printing method. The durability of core-shell-structured LSCF@GDC composite cathodes are evaluated through constant current polarizations (CCP) process at 750 °C and the results indicate that the core-shell-structured LSCF@GDC composite cathode (nanorod, 0.6) possesses an excellent long-term stability. In addition, molecular dynamics (MD) model is developed and applied to simulate the interaction between LSCF and GDC particles. According to the simulation results, compressive stress is generated at the cathode-electrolyte interface by the coated GDC layer. Combining with the X-ray diffraction (XRD) refinement results, it's revealed that the lattice strains are introduced in LSCF lattices because of the compressive stress. Furthermore, XPS results show that the core-shell-structured LSCF@GDC composite cathode (nanorod, 0.6) possess a better inhibition ability for Sr surface segregation. This study provides a possible way to suppress Sr surface segregation.     

A La0.8Sr0.2MnO3/La0.6Sr0.4Co0.2Fe0.8O3−δ core–shell structured cathode by a rapid sintering process for solid oxide fuel cells

A La_0.8Sr_0.2MnO₃ (LSM)/La_0.6Sr_0.4Co_0.2Fe_0.8O_3?δ (LSCF) core–shell structured composite cathode of solid oxide fuel cells (SOFCs) has been fabricated by wet infiltration followed by a rapid sintering (RS) process. The RS is carried out by placing LSCF infiltrated LSM electrodes directly into a preheated furnace at 800 °C for 10 min and cooling down very quickly. The heating and cooling step takes about 20 s, substantially shorter than 10 h in the case of conventional sintering (CS) process. The results indicate the formation of a continuous and almost non-porous LSCF thin film on the LSM scaffold, forming a LSCF/LSM core–shell structure. Such RS-formed infiltrated LSCF–LSM cathodes show an electrode polarization resistance of 2.1 Ω cm² at 700 °C, substantially smaller than 88.2 Ω cm² of pristine LSM electrode. The core–shell structured LSCF–LSM electrodes also show good operating stability at 700 °C and 600 °C over 24–40 h.     

Pr0.5Ba0.5Co0.7Fe0.25Nb0.05O3-δ as air electrode for solid oxide steam electrolysis cells

Pr_0.5Ba_0.5Co_0.7Fe_0.25Nb_0.05O_3-δ (PBCFN) is synthesized and evaluated as air electrode for solid oxide steam electrolysis cells (SOECs). X-ray diffraction and TEM analysis show that PBCFN has a pure tetragonal perovskite structure with a lattice fringe spacing of 0.39 nm for the (110) planes. When the applied voltage is set at 1.3 V, a relatively high electrolysis current density of 470 mA cm² at 800 °C is achieved for electrolyte-supported electrolysis cells with the cell configuration of Sr₂Fe_1.5Mo_0.5O₆ (SFM)–Sm_0.2Ce_0.8O₂ (SDC)/La_0.8Sr_0.2Ga_0.87Mg_0.13O₃ (LSGM)/SDC–PBCFN. In addition, there is no obvious performance degradation during the short-term stability test of the above cells at a constant electrolysis voltage of 1.3 V, indicating that PBCFN is a promising air electrode for SOECs.     

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.     

Ba0.5Sr0.5Fe0.8Sb0.2O3-δ- Sm0.2Ce0.8O2-δ bulk heterostructure composite: A cobalt free Oxygen Reduction Electrocatalyst for low-temperature SOFCs

Low-temperature operated ceramic fuel cells (LT-CFCs 350° to 550 °C) hold a great promise than high-temperature solid oxide fuel cells (HT-SOFCs ≥ 800 °C) for numerous large-scale real-application. If a suitable cathode should be developed to overcome the sluggish oxygen reduction activity at low temperatures, the low-temperature operation of ceramic fuel cells could be possible. In this study, we have developed a cobalt-free Ba_0.5Sr_0.5Fe_0.8Sb_0.2O_3-δ- Sm_0.2Ce_0.8O_2-δ (BSFSb- SDC) a bulk heterostructure composite for efficient ORR electrocatalyst for LT-SOFC cathode. The established BSFSb-SDC bulk heterostructure composite exhibits large lattice parameters, very low-area-specific resistance, and high oxygen reduction reaction (ORR) activity at low operating temperatures. The prepared fuel cell device has demonstrated high-power densities of 890 mW-cm-² at 550 °C for button-sized SOFC on H₂ and even possible operation at 400 °C. It is also found that BSFSb-SDC effectively facilitates small polaron hopping of valence electrons and diffusion of oxygen ions. Various spectroscopic measurements such as X-ray photoelectron, UV–visible, Raman, and Density Functional Theory (DFT) calculations were employed to understand the improved ORR electrocatalyst function of BSFSb-SDC bulk heterostructure composite SOFC cathode. The results can further help to develop functional cobalt-free electro-catalysts for LT-SOFCs and other related applications.     

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.     

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.     

Kinetics of oxygen reaction in porous La0.6Sr0.4Co0.2Fe0.8O3–δ-Ce0.8Gd0.2O1.9 composite electrodes for solid oxide cells

Kinetics of oxygen reaction in porous La_0.6Sr_0.4Co_0.2Fe_0.8O_3–δ (LSCF) and La_0.6Sr_0.4Co_0.2Fe_0.8O_3–δ-Ce_0.8Gd_0.2O_1.9 (LSCF-GDC) electrodes are systematically studied. Normally, there are two pathways of oxygen reaction in porous LSCF: in reaction region with oxygen exchanging at electrode/air interface, and around electrode/electrolyte interface with oxygen exchanging at electrode/electrolyte/air triple-phase boundary (TPB). GDC in porous LSCF-GDC accelerates oxygen transport and oxygen gas diffusion during oxygen reaction. In addition, because the formation of LSCF/GDC interface increases the length of TPB and affects the geometry of reaction region, oxygen reaction in LSCF-GDC tends to proceed in the TPB pathway. The performance and oxygen reactions of LSCF-GDC are evaluated at 650 °C and 850 °C. Oxygen reaction in LSCF-GDC is suppressed by CO₂, but increasing GDC content is able to improve the CO₂ tolerance of electrode. Though the performance reduction by H₂O is unobvious, H₂O can aggravate CO₂ degradation at low temperature.     

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.     

Electrochemical performance of La0.65Sr0.35MnO3 oxygen electrode with alternately infiltrated Sm0.5Sr0.5CoO3-δ and Sm0.2Ce0.8O1.9 nanoparticles for reversible solid oxide cells

La_1-xSr_xMnO₃ is a well-known oxygen electrode for reversible solid oxide cells (RSOCs). However, its poor ionic conductivity limits its performance in redox reaction. In this study, we selected Sm_0.5Sr_0.5CoO_3-δ (SSC) as catalyst and Sm_0.2Ce_0.8O_1.9 (SDC) as ionic conductor and sintering inhibitor to co-modify the La_0.65Sr_0.35MnO₃ (LSM) oxygen electrode through an alternate infiltration method. The infiltration sequence of SSC and SDC showed an influence on the morphology and performance of LSM oxygen electrode, and the influence was gradually weakened with the increasing infiltration time. The polarization resistance of the alternately infiltrated LSM-SSC/SDC electrode was 0.08 Ω cm² at 800 °C in air, which was 3.36% of the LSM electrode (2.38 Ω cm²). The Ni-YSZ/YSZ/LSM-SSC/SDC single cell attained a maximum power density of 1205 mW cm^?2 in SOFC mode at 800 °C, which was 8.73 times more than the cell with LSM electrode. The current density achieved 1620 mA .cm^?2 under 1.5 V at 800 °C in SOEC mode and the H₂ generation rate was 3.47 times of the LSM oxygen electrode.     

High-performance oxygen electrode Ce0.9Co0.1O2-δ-LSM-YSZ for hydrogen production by solid oxide electrolysis cells

Hydrogen production via solid oxide electrolysis cell (SOEC) is world widely concerned with the new energy revolution. The SOEC performance must be enhanced for the practical application. In this study we report a high-performance Ce_0.9Co_0.1O_2-δ-LSM-YSZ (CC-LSM-YSZ) oxygen electrode, in which Ce_0.9Co_0.1O_2-δ nanoparticles are loaded on LSM-YSZ scaffold and characterized by XRD, SEM, O₂-TPD and H₂-TPR. Under 50% absolute humidity (A.H), the cell with 1CC-LSM-YSZ, 2CC-LSM-YSZ, 3CC-LSM-YSZ and 4CC-LSM-YSZ oxygen electrode delivers a current density of 0.63, 0.94, 1.14 and 1.26A cm^?2 at 1.3 V, which is 1.7, 2.5, 3.0 and 3.3 times higher than the blank LSM-YSZ cell, respectively. The hydrogen generation rate of the 4CC-LSM-YSZ cell is as high as 873 m L cm^?2 h^?1 under 70% A.H. The DRT results demonstrate the accelerated charge transfer reaction on LSM-YSZ-Ce_0.9Co_0.1O_2-δ oxygen electrode. LSM-YSZ-Ce_0.9Co_0.1O_2-δ has the potential for the application of oxygen electrode in SOEC technology.     

Electrochemical performance of Sr1.9La0.1Fe1.5Mo0.5O6-δ symmetric electrode for solid oxide fuel cells with carbon-based fuels

La-doped Sr_2-xLa_xFe_1.5Mo_0.5O_6-δ perovskite oxides are synthesized and used as a symmetric electrode to evaluate the effect of La on the crystal structure, conductivity, and catalytic activity for O₂ reduction and H₂ oxidation reaction. The electronic doping effect dominates the oversize effect in Sr_2-xLa_xFe_1.5Mo_0.5O_6-δ oxide, resulting in unit cell volume expansion and decreased conductivity in air. In addition, the introduction of La increases the chemical structural stability of Sr₂Fe_1.5Mo_0.5O_6-δ in reducing condition due to the higher La–O bond compared with Sr–O bond, leading to high catalytic activity for the H₂ oxidation reaction. At 800 °C, the R_p values of Sr_1.9La_0.1Fe_1.5Mo_0.5O_6-δ symmetric cell in air and wet H₂ are as low as 0.075 and 0.21 Ω cm², respectively. Moreover, the peak power densities of 769, 561, 439, and 653 mW cm^?2 at 850 °C are obtained when wet H₂, CO, CH_4, and C₃H₈ are used as fuels on Sr_1.9La_0.1Fe_1.5Mo_0.5O_6-δ/LSGM/Sr_1.9La_0.1Fe_1.5Mo_0.5O_6-δ cell. The symmetric cell also shows excellent stability (>100 h) in wet H₂/air, implying Sr_1.9La_0.1Fe_1.5Mo_0.5O_6-δ oxide is a promising symmetric electrode material.     

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 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.     

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.