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In this work, the performance of solid oxide fuel cells is improved by physically mixing Ce0.9Gd0.1O1.95 (GDC) in La0.6Sr0.4CoO3–δ (LSC) cathode. The grain size and chemical compatibility of the powder were analyzed using X‐ray diffraction. Scanning electron microscopy was used to observe the microstructure of powder and cells. The thermal expansion coefficients (TECs) of LSC–GDC powder with different mass ratios were tested (LSC:GDC = 10:0, 9:1, 8:2, 7:3, 6:4, and 5:5) and LSC–GDC (5:5) showed the minimal TEC (1.34 × 10−5 K−1 at 650°C). The cathodes with different mass ratios are prepared by screen printing. The symmetrical cell with LSC–GDC (5:5) had the smallest cathode polarization resistance (0.0801 Ω cm2 at 650°C) and the lowest activation energy (1.12 eV). The button cell with LSC–GDC (5:5) exhibited the maximum power density (513 mW cm−2 at 650°C) and could be discharged for 550 h without significant degradation. The LSC–GDC (5:5) cathode was applied to a flat‐tube solid oxide fuel cell and achieved a high power density of 552 mW cm−2 at 0.8 V. The results show that the LSC–GDC (5:5) has a bright future in commercialization. [ABSTRACT FROM AUTHOR]

Protonic ceramic fuel cells (PCFCs) using BaZr0.8−xCexY0.2O3−δ (BZCY) as electrolyte materials have attracted widespread attention because of their high performance at reduced temperature. However, there are few systematic studies on both the performance and stability of BZCY materials. In this paper, we report our work on the electrochemical performance and chemical stability of BaZr0.8−xCexY0.2O3−δ (x = 0, 0.1, 0.3, 0.5, and 0.7) series. The results show that electronic hole conductivity decreases with increasing Ce4+ content, especially at high temperature. In addition, H2 atmosphere reduces the conductive activation energy of BZCY. On the contrary, air atmosphere causes serious electronic leakage. These effects are also reflected in the operation of PCFCs, that is, the higher the Ce4+ content, the higher the open‐circuit voltage and output power density. However, low Ce4+ content may stabilize the materials in CO2 atmosphere. At 700°C, an anode‐supported PCFC based on BaZr0.1Ce0.7Y0.2O3−δ electrolyte, using humid H2 fuel, gives a peak power density of 1.0 W cm−2. At 600°C, BaZr0.8Y0.2O3−δ and BaZr0.7Ce0.1Y0.2O3−δ show a good stability in CO2‐containing atmosphere. [ABSTRACT FROM AUTHOR]

Protonic ceramic fuel cells (PCFCs) show great potential in terms of lowering the operation temperature and overall cost of solid oxide fuel cells based on the high ionic conductivity and low activation energy of proton-conducting electrolytes in intermediate or low temperature environments. However, a significant reduction in anode activity with decreasing temperature hinders the broad application of PCFCs. In this study, a novel anode material Ni–Ba 0.96 (Ce 0.66 Zr 0.1 Y 0.2 Ni 0.04)O 3-δ (Ni-BCZNY) with in-situ exsolved Ni nanoparticles is developed. This material exhibits extremely high activity in PCFCs in intermediate and low temperatures. A cell fabricated with this anode material achieves a power density of 912 mW cm−2 and polarization resistance of 0.04 Ω cm2 in wet H 2 /air at 700 °C. Additionally, the microstructure, electrochemical performance, electrochemical impedance, and electrode processes of a Ni-BCZNY cell are analyzed in detail. The results indicate that performance enhancements can be attributed to the Ni nanoparticle exsolution promoting charge transfer and hydrogen dissociative adsorption. [ABSTRACT FROM AUTHOR]

Nickel agglomeration poses a noteworthy impediment to the commercialization of SOFCs. A comprehensive coupled degradation model is established, encompassing a Ni-particle coarsening model, microstructural parameters, effective mesoscopic parameters, and various transport processes (mass/momentum/heat/charge/multi-species transports), and chemical/electrochemical reactions. The initial anode microstructural parameters are optimized by the comprehensive model and response surface method (RSM). Single-factor analysis shows that within the initial Ni-particle diameter (d Ni (t = 0) ) range of 0.6–0.9 μm, a particle size ratio (R) of 1.0–1.5 between YSZ-particle and Ni-particle, and a solid-phase volume fraction of Ni-particle (ψ Ni) ranging from 0.35 to 0.55, SOFC demonstrates high power density and a reduced degradation rate. Using the single-factor results, RSM is employed for -anode microstructure optimization, specifying: d Ni (t = 0) = 0.7 μm, R = 1.0, and ψ Ni = 0.49. Correspondingly, the average power density at 0.6 V ( P D ‾ 0.6 V ) reaches 2828.5 W/m2, with a degradation rate (V de) off 0.441 %/1000 h. In comparison to original microstructure parameters (d Ni (t = 0) = 0.6 μm, R = 1.0, ψ Ni = 0.4), the optimal SOFC exhibits a remarkable enhancement in electrical performance and durability, with an 11.9 % increase in P D ‾ 0.6 V and a 69 % reduction in V de. The integration of the comprehensive model and RSM presents a promising strategy for predicting performance, refining operation condition, and optimizing electrode microstructure for long-term operating SOFC. [Display omitted] • A comprehensive multiscale-multifield fully coupled degradation model is developed. • Particle size and composition evolution of Ni-YSZ anode are quantitatively studied. • Effective mesoscopic parameters of anode are studied. • Initial anode microstructure is optimized by the model and response surface method. • Power density is increases by 11.9 % and degradation rate is decreases by 69 %. [ABSTRACT FROM AUTHOR]

This study presents a novel interconnector design, termed groove and rib-finned interconnector, to improve the performance of the planar solid oxide fuel cell (SOFC). We have conducted a detailed comparative study on the flow characteristics and electrical performance of conventional straight channel interconnectors and novel interconnectors through a three-dimensional model. Compared with the conventional straight channel interconnector, the result shows that the novel interconnector can provide higher fuel utilization, and the output power density at a low fuel flow is still higher than that of the conventional design at a high fuel flow. The novel interconnector increases the velocity and vorticity of the reactant gas, and promotes gas disturbance, and enhances the mass transport in the electrode. The novel interconnector eliminates the oxygen-free zone of the cathode under the rib and provides sufficient oxygen with uniform concentration distribution for the electrochemical reaction. Therefore, the novel interconnector significantly reduces the activation and concentration overpotentials and improves the electrical performance of the SOFC stack. • Novel interconnector improves the gas velocity and vorticity. • Novel interconnector eliminates oxygen-free zone and provides sufficient oxygen. • Novel interconnector reduces the activation and concentration overpotentials. [ABSTRACT FROM AUTHOR]

This study designed a novel interconnector, known as the dual-channel interconnector (DCI), for the anode-supported planar solid oxide fuel cell (SOFC). The DCI have two independent flow channels and allow multiple gases to enter SOFC simultaneously without interference. The DCI has half the height of a conventional interconnector. The electrochemical reaction of carbon monoxide and hydrogen as well as the methane steam reforming reaction, water gas shift reaction and dry reforming reaction of methane were coupled in the mathematical models. Results show that the peak power densities of the DCI-SOFC increased by 21.7% and 11.3% compared to the SCI–SOFC for wet hydrogen and 30% reformed methane when both channels are utilized together. The DCI-SOFC exhibits similar electrical performance in any single-channel operation, accompanied by a 30% decrease in peak power density. The DCI-SOFC can significantly reduce the activation overpotential and concentration overpotential, while slightly increase the contact overpotential. The DCI eliminates the oxygen-free zone under the ribs and enhances the mass transfer inside the electrodes. The temperature inside of the DCI-SOFCs are strongly correlated with the gas composition and the flow direction. Overall, the DCI for SOFC is a promising design. • Novel interconnectors have two independent flow channels. • Novel interconnectors improve the SOFC electrical performance. • Novel interconnectors eliminates the oxygen-free zone under the ribs. • Novel interconnectors reduce activation and concentration overpotentials. • Novel interconnectors increase the direct contact area between gas and electrode. [ABSTRACT FROM AUTHOR]

Reliability and durability are two major problems restricting for Solid oxide fuel cells (SOFCs) industrial applications. To ensure the long-term stability, understood the internal operation mechanism of SOFC was necessary. The polarization curve combined with the distribution of relaxation times (DRT) method to analyze the electrochemical impedance spectroscopy (EIS) was used to identify the SOFCs modulation and degradation effect through the excitation frequency. Dynamic evolution of carbon deposition process and specific time constants were determined employing EIS and DRT. Special attention was paid to the dependency between the complex reaction processes that occur during the different operation of SOFC. The corresponding frequencies of concentration and activation polarization resistances in EIS were investigated under various gas compositions. The high concentration polarization resistance caused by the addition of nitrogen and hydrogen starvation was the key limiting factor for high cell power density. The total polarization resistance increased from 1.50 Ω/cm2 to 5.26 Ω/cm2 when the H 2 :N 2 ratio decreased from 1:0 to 1:5. The anode did not deteriorate due to the poisoning of Ni particles in a short-term tested under 0.5 A/cm2 current density when the fuel was methane. • Modulation and degradation evaluation for SOFCs. • Detailed electrochemical investigation of anode-supported button SOFCs. • The addition of nitrogen significant increase the concentration polarization resistance. • The influence of fuel composition on the electrical performance of SOFCs. • Dynamic evolution of carbon deposition was observed by means of EIS and DRT. [ABSTRACT FROM AUTHOR]

• Novel interconnector replaces straight channel to improve SOFC performance. • Novel interconnector enhances disturbance and improves the gas velocity and vorticity. • Novel interconnector eliminates the limitation of ribs on gas diffusion. • Novel interconnector shortens the charge transfer path in SOFC. • Novel interconnector reduces activation, concentration, and contact overpotentials. This study proposes a novel interconnector, termed beam and slot interconnector (BSI), for the anode-supported planar solid oxide fuel cell (SOFC). A detailed comparative investigation is conducted on various transport characteristics and electrical performance of the SOFC stacks with conventional straight channel interconnectors (SCIs) or with novel interconnectors. Results show that the peak power density of a SOFC stack with BSIs is 24.8% higher than it with SCIs at 700 °C and a fuel–air flow rate of 16–40 Nml/(min·cm2). Moreover, BSI can reduce the fuel–air feeding and enhance the fuel–air utilization while maintaining high output power density. Compared with SCI, BSI promotes the gas disturbance, significantly increases the gas velocity and vorticity, and leads the gas to flow in the direction perpendicular to the channel. BSI eliminates the limitation of SCIs on gas diffusion in the electrode and transfers sufficient reactant gas into the electrode function layers for electrochemical reactions. BSI shortens the charge transfer path in SOFC and almost avoids the adverse effects of the electrode-interconnector contact resistance. Compared with the conventional SOFC stack, the novel SOFC stack with BSIs significantly reduces various overpotentials. At 700 °C and 0.5 A/cm2, the activation, concentration, and contact overpotentials are reduced by 8.5%, 47.4%, and 96.4% respectively, and the total overpotential finally drops by 20.0%. Overall, the electrical performance of the SOFC stack with novel interconnectors significantly exceeds the one with conventional interconnectors under the same operating conditions. [ABSTRACT FROM AUTHOR]

[Display omitted] • A modified Ni-particle coarsening model for predicting the degradation of SOFC. • Evolution of microstructure parameters over time is quantified. • A fully-coupled model is developed for long-term DIR-SOFC. • Optimal operating conditions for improved performance and stability. Long-term stability and durability of solid oxide fuel cell (SOFC) are the major challenges for fuel flexibility and commercialization. In this study, a fully coupled multi-field model is developed by coupling a modified Ni-particle coarsening model and a microstructure model for predicting the performance degradation of methane direct reforming (DIR) SOFC due to Ni-particle coarsening. The effect of Ni-particle coarsening on percolation probability of Ni-particle, effective TPB area, effective electron-conductivity, maximum power density, and the degradation rate of DIR-SOFC are quantitatively investigated under different operating conditions. The results indicate that to enhance the electrical performance and to reduce the degradation rate, the optima of the operating conditions and anode microstructure for the long-term DIR-SOFC are as follows: 750 °C for the cell operating temperature, 1.0 for anode inlet steam to carbon ratio (S/C), 0.3 A/cm2 for the operating current density, and corresponding to Ni-particle with an initial diameter of 0.6 μm, the optimal YSZ-particle diameter is 1.0 μm. [ABSTRACT FROM AUTHOR]

• Tubular PCFC with effective area of 2.3 cm2 is fabricated by dip-coating technique. • It shows high performance at reduced temperature, giving 465 mW cm−2 at 600 °C. • The cell outputs 118 mW cm−2 at 450 °C and reveals detectable power at 200 °C, 3 mW. • Cell stability is tested for 30 h, at a constant voltage of 0.7 V under 600 °C. • Performance declines first and then tend to be stable during stability test. An anode-supported tubular protonic ceramic fuel cell with BaCe 0.7 Zr 0.1 Y 0.2 O 3-δ electrolyte is fabricated using dip-coating technique. Electrochemical performances of the cell are tested at temperatures from 600 to 200 °C, utilizing humidified H 2 (3 vol% H 2 O) as fuel and ambient air as oxidant. With an effective area of 2.3 cm2, the cell yields a peak power density of 465 mW cm−2 at 600 °C and 118 mW cm−2 at 450 °C. Even when the temperature is as low as 200 °C, there is still an output power of 3 mW. Stability of the cell under 600 °C is tested by operating the cell at a constant voltage of 0.7 V. The test lasts for 30 h during which the operating power density decreases rapidly in the first 10 h, then tend to be stable at 300 mW cm−2. [ABSTRACT FROM AUTHOR]