A conceptual design of a commercial 154-passenger electric aircraft was investigated, focusing on renewable fuels to supply efficient, high-temperature, solid oxide fuel cells (SOFCs). Hybrid SOFCs were integrated with turbine-electric propulsion and batteries to power the aircraft, with the goal of addressing the current range limitations of electric aviation. The concept matched the range and the comparable payload capabilities of a B737-800 while using two-thirds less fuel on a 3000-mile mission. The aircraft featured a NASA/Boeing truss-braced wing design, selected for its high-wing configuration, a 10% improvement in aerodynamic efficiency, and compatibility with open fans that offered 13% higher propulsive efficiency. Renewable liquid natural gas (LNG) fuel was chosen for its ease of fuel reformation, potentially higher availability, and lower cost than sustainable aviation fuel. Additionally, LNG is safer and easier to use than LH2 or ammonia fuels and will enable safe, wing-mounted fuel tanks. Although many of these technologies can likely be implemented before aviation SOFCs fully mature, they will further reduce operating costs while utilizing a smaller volume of carbon-neutral fuel. This configuration also has the potential to capture and divert exhaust water vapor, reducing the formation of persistent contrails that are believed to nearly double the environmental impact of traditional aircraft.

An alternating constant-current (CC)/constant-voltage (CV) discharge for the optimal operation mode of solid oxide fuel cells (SOFCs) inside stack is carried out, and the degradation of SOFCs is discussed. The SOFCs are operated alternately in CC/CV mode for 985 h at 750 degrees C. The results show that the degradation rate of SOFCs first decreases and then increases in the CC/CV alternating operation mode. And the lowest degradation rate is 3.64%/100 h in the CV operation mode at similar to 0.85 V, which is about one order of magnitude higher than the average degradation rate (0.36%/100 h) in the corresponding CC operation mode. The EIS analysis indicates that the ohmic resistance increases and the polarization resistance decreases after the CV operation mode, while the impedance change after CC discharge shows the opposite trend. (c) 2023 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

In this work, the anti-poisoning performance of flat-tube solid oxide fuel cells (FT-SOFCs) is investigated in high concentrations of H2S. The degradation rate of the cell is 0.52%/ h, 0.27%/ h and 0.305%/ h at 750 degrees C, when the concentration of H2S is 161 ppm, 182 similar to 222 ppm and 226 ppm, respectively, and the performance can be restored by humidification of H2. The resistance to sulfur poisoning breaks through the limitation, proving the stability advantage of the flat-tube structure. Through energy dispersive spectrometer (EDS) and Raman spectrum analysis, it is found that the cell performance degradation under high concentration of H2S is mainly caused by the loss of metallic nickel caused by the migration and decomposition of nickel-sulfur compounds, which will reduce the active sites of H2 participating in the anode reaction. This study provides a reference for the application of flat-tube structure cells under high concentrations of H2S.(c) 2023 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

With countless global industries pledging and pursuing decarbonization targets set for the 2030 – 2050 timeframe, the aerospace industry faces many key challenges including reduction of greenhouse gas emissions, contrail abatement, and development/adoption of technologies with higher Fuel-to-Electricity (FTE) conversion efficiencies. One such technology identified as a potential fit for commercial aircraft is the solid oxide fuel cell and gas turbine (SOFC-GT) hybrid power system. Progress in system-level SOFC-GT modeling is critical to produce higher fidelity feasibility studies used to influence SOFC design and performance targets of the future. In this study, the first ProMax 5.0-based SOFC-GT model was developed, validated, and optimized. The impact of process configuration, balance-of-plant, and operating conditions were investigated. An optimal process design comprising 8 SOFC stacks and 7 Energy Storage and Power Generation (ESPG) modules with a total power output of > 7.0-MW and FTE conversion efficiencies of 73 – 76% is reported. Additionally, preliminary airplane architecture with the 7 onboard ESPG modules is presented to show the feasibility of future, hybrid electric airplane design.

The coupling of CO2 electrolysis and renewable energy storage is of great significance, especially to CO2 capture and utilization. In this work, the factors influencing the performance and degradation of flat-tube solid oxide electrolytic cell stack (SOEC stack) for CO2/H2O co-electrolysis under an intermittent pulsed current are investigated by inserting a voltage lead inside the SOEC stack to monitor the variations in the cell and stack voltages during the electrolysis process. The results show that after 64 pulsed electrolysis cycles (900 h), the average voltage degradation rate is about 0.018%/cycle at 50-250 mA/cm2, and the useful life is expected to reach more than 1100 cycles (10,000 h). The microstructural analysis shows that a SrCrO4 barrier layer is formed on the contact surface between the metal interconnect and the current collecting layer of the cell, which in-creases the interface resistance of the metal interconnect and the cell, resulting in the degradation of the elec-trolytic performance. This study provides useful information for improving the stability of the SOEC stack for CO2/H2O co-electrolysis.

This paper reviews the design and operation of the high temperature solid oxide fuel cells based on yttria-stabilized zirconia electrolyte. The functional requirements of the various cell components are presented; and the materials and fabrication processes used for different cell components are described. Finally, the recent progress made toward commercialization of these cells for clean and efficient power generation is discussed.

Dry reforming of liquid alcohols coupled with solid oxide fuel cells (SOFCs) is a promising approach for clean and efficient energy conversion. Herein, the feasibility of power generation from flat-tube SOFCs with direct internal dry reforming of methanol has been studied. The effects of CO2/MeOH ratio, temperature, and current density on cell performance and long-term durability were investigated. Higher CO2/MeOH ratios reduced the power density, but suppressed carbon deposition and enhanced long-term durability. A cell was operated stably over 500 h with a constant current density of 200 mA/cm2 under CO2/MeOH =1 and 2 at 750 degrees C. In addition to stable power generation, simultaneous syngas production and reduction in CO2 emissions were achieved. Density functional theory (DFT) calculations elucidated the possible pathways for methanol dry reforming and mechanism of carbon removal. Our experimental and simulation results provide insights into the direct utilization of methanol in SOFCs using dry reforming.

A novel (SmBa)(0.9)Mn1.8Co0.2O5+delta (SBMCo) electrode is elaborately designed for symmetrical solid oxide fuel cells (SSOFCs). In operating conditions, the SBMCo material is codecorated with exsolved metallic cobalt for the anode and cobalt oxide for the cathode. The electrochemical impedance spectroscopy (EIS) results combined with distribution of relaxation times (DRT) analysis reveal that the rate-limiting step for hydrogen oxidation at the anode is the adsorbed hydrogen dissociation process, while for the oxygen reduction at the cathode, it is the charge transfer process. The exsolved nanoparticles on the SBMCo backbone of Co and Co3O4 significantly promote the corresponding rate-limiting steps and enable the decorated electrodes to exhibit remarkable catalytic activity toward hydrogen oxidation and oxygen reduction, respectively. When fueled with humidified hydrogen, the constructed symmetrical cell based on the designed SBMCo electrodes with the 300 mu m La0.8Sr0.2Ga0.8Mg0.2O3-delta (LSGM) electrolyte-supported configuration delivers an attractive maximum power density of 712 mW cm(-2) at 900 degrees C. The results demonstrate that the elaborate design of the codecorated anode and cathode from a single parent compound is a promising route for the development of candidate electrodes for SSOFCs.

Algae have emerged as a promising sustainable energy source; how-ever, efficient methods for generating electricity from algae are still lacking. In this study, power generation using large-scale flat-tube solid oxide fuel cells fueled with biosyngas from microwave -enhanced pyrolysis of algae is demonstrated. The power density of a cell fueled with biosyngas from laminaria is 379.8 mW/cm2 un-der 0.8 V at 750 & DEG;C, which is approximately 91.7% of the density of a cell fueled with pure hydrogen. Fueled with dry syngas (laminaria), the cell fails within 3 h because of carbon deposition. Adding 5 vol % H2O to syngas (laminaria) inhibits carbon deposition and enables 800 h of galvanostatic operation without degradation under 200 mA/cm2 at 750 & DEG;C. A 100-cycle pulsed operation of the cell with syn-gas (laminaria, 5 vol % H2O) under different loads, simulating prac-tical scenarios with variable energy demands, is obtained. Based on the simulation results, the temperature fluctuations within the cell under different current densities are analyzed. Overall, this work ad-vances practical efforts to improve solid oxide fuel cells for bio-syngas consumption.

Deformation of the interconnect in a solid oxide fuel cell (SOFC) stack affects the internal thermal stresses of the cell at high temperatures. In this study, the effect of the interconnect deformation on the cell temperature and thermal stress at different operating voltages was simulated based on the thermal-chemical-electrical-mechanical multiphysics coupling theory. The results show that when the operating voltage of the cell is above 0.85 V, the interconnect mainly generates a compressive strain. When the operating voltage is below 0.85 V, the interconnect produces tensile strain, which increases with decreasing voltage. Interconnect deformation significantly increases the thermal stress of the cells within the stack, but effectively improves the uniform distribution of thermal stress. The coupling effect of interconnect deformation on cell thermal stress within the stack varies at different operating voltages.

With the explosive growth of intermittent renewable energy power and the global concerns on carbon neutralization, whether the carbon oxide (CO2) could be utilized as a medium for high security and long-term power storage was attached a great attention. Reversible solid oxide cells (RSOCs) are promising for storage of renewable energy because of their highly efficient gas-to-power and power-to-gas conversion processes. RSOCs were used in this work for efficient CO2 utilization under three operating conditions: CO2 electrolysis under constant current, CO2 electrolysis under pulsed current, and reversible operation with CO/CO2 fuel. By analyzing the efficiency and durability of RSOCs in these three conditions and comparing them with those of other electrochemical energy storage methods, the advantages and the development prospects of RSOCs for energy storage and carbon neutralization are discussed, which provide a reference for large-scale long-term energy storage utilizing CO2 in SOCs.

The conventional Ni-Y0.16Zr0.84O1.92 anode in solid oxide fuel cells fueled with hydrocarbon fuels is prone to suffer from carbon deposition. In this work, we employed an in-situ solvothermal method to decorate the Ni-Y0.16Zr0.84O1.92 anode with Gd0.1Ce0.9O1.95-delta nanoparticles to improve its resistance to carbon deposition and thus improve the electrochemical performance of the cell. This method generates small Gd0.1Ce0.9O1.95-delta particles and at the same time does not block the gas diffusion channels. The Gd0.1Ce0.9O1.95-delta-decorated anode showed enhanced long-term stability in methane with no significant performance degradation after 700 at 750 degrees C, whereas an untreated Ni-Y0.16Zr0.84O1.92 anode only worked for less than 8 h under the same conditions. The addition of Gd0.1Ce0.9O1.95-delta nanoparticles was found to enhance internal reforming reactions of methane by the distribution of relaxation times technique. This work demonstrated that in-situ solvothermal modification strategy can provide anodes with excellent carbon deposition resistance.

In this study, electrolysis of seawater in flat-tube nickel-yttria-stabilized zirconia (Ni-YSZ) electrode-supported solid oxide electrolysis cells (SOECs) were modeled and the effects of variations in electrical conductivity and microstructure of Ni-YSZ electrode support were investigated. When the current density was greater than 700 mA & BULL;cm-2, the conductivity of the electrode support decreased slightly with an increase in current density at 800 & DEG;C in hydrogen reduction environment; the conductivity of the electrode support decreased with an increase in the current density when the current density was greater than 400 mA & BULL;cm-2 at 800 & DEG;C in the seawater electrolysis environment. During long-term durability experiment of seawater electrolysis, the degradation rates in area specific resistance (ASR) were 0.096 mU & BULL;cm2/100 h and 0.207 mU & BULL;cm2/100 h with a current density of 300 mA & BULL;cm-2 (i.e., & LE;400 mA & BULL;cm-2) and 1000 mA & BULL;cm-2 (i.e., & GE;400 mA & BULL;cm-2), respectively. Besides, the various ions commonly present in seawater did not contaminate the Ni-YSZ support during the long-term durability test. The degradation mechanism of seawater electrolysis in flat-tube SOECs is discussed and clarified.& COPY; 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

In this work, the nano-structured Sm0.5Sr0.5CoO3-$ (SSC) was infiltrated into La0.6Sr0.4-Co0.2Fe0.8O3-$-Gd0.1Ce0.9O2-$ (LSCF-GDC) electrode of a large-area flat-tube solid oxide cell for hydrogen production. The electrolysis current density under 76% H2O-24% H2 increased only approximately 3% at about the thermal neutral voltage (1.29 V) and 750 & DEG;C, but the electrolysis durability with 76% H2O-24% H2 and 500 mA cm-2 improved significantly by more than 90%, with the degradation rate being approximately 1/10th of that of the non infiltrated cell. This work indicates that SSC infiltration of the air electrode could suppress Sr segregation in LSCF, thus greatly enhancing the cell durability. The study provides a reference for large-scale hydrogen production of high durability SOECs by designing nanostructured electrodes via infiltration.& COPY; 2023 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

The performance stability of solid oxide fuel cells (SOFCs) under thermal and redox cycles is vital for large-scale applications. In this work, we investigated the effects of thermal and redox cycles on cell performances of flat-tube Ni/yttria-stabilized zirconia (Ni/YSZ) anodesupported SOFCs. Cell performance was considerably affected by the duration of oxidation during redox cycles and the heating rate during the thermal cycles. The cell tolerated 20 short-term redox cycles (5 min oxidation) without significant performance degradation. Besides, the cell exhibited superior stability during 8 thermal cycles with a slow heating rate (4 & DEG;C min-1) to that with a fast heating rate (8 & DEG;C min-1). These results reflected that the thick anode support (2.7 mm) offered strong resistance to the shocks caused by redox and thermal cycling. Moreover, the morphological changes of the Ni phase during the redox and thermal cycling were investigated using Ni-film anode cells. Agglomeration of Ni particles and dissociation between the Ni film and the YSZ substrate were confirmed after 5 redox cycles, whereas no significant changes in Ni film emerged after 8 thermal cycles. & COPY; 2023 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Conversion of renewable energy sources like bioethanol to electricity using solid oxide fuel cells (SOFCs) is promising to reduce the consumption of fossil fuels and to mitigate global warming. However, direct ethanol-fed SOFCs are susceptible to carbon deposition on Ni- based anode. In this study, the power generation from and degradation mechanism of large-scale flat-tube SOFCs by direct internal reforming of ethanol are investigated. The steam/carbon (S/C) ratio causes minor influence on the cell performance but considerably affects the long-term durability. Elevating temperature improves ethanol conversion rate and cell performance. Ethanol is efficiently reformed by the thick anode support and long anode channels, with low selectivity for CH4 and C2H4. Stable power generation with current density of 200 mA/cm2 is obtained over 300 h under S/C=2 and 3 at 800 & DEG;C. Due to the high operating temperature and complex cell structure, the in-situ measurements of the temperature and gas compositions within the cell, related to carbon deposition, are difficult. The distributions of the gas compositions and temperature within the cell before and after the durability test are clarified by simulation. Simulation results reveal that, in addition to CH4 and C2H4, the cold zone near inlet contributes to carbon formation.& COPY; 2023 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

CO2 electrolysis with solid oxide electrolytic cells(SOECs)using intermittently available renewable energy has potential applications for carbon neutrality and energy storage.In this study,a pulsed current strategy is used to replicate intermittent energy availability,and the stability and conversion rate of the cyclic operation by a large-scale flat-tube SOEC are studied.One hundred cycles under pulsed current ranging from-100 to-300 mA/cm2 with a total operating time of about 800 h were carried out.The results show that after 100 cycles,the cell voltage attenuates by 0.041％/cycle in the high current stage of-300 mA/cm2,indicating that the lifetime of the cell can reach up to about 500 cycles.The total CO2 conversion rate reached 52％,which is close to the theoretical value of 54.3％at-300 mA/cm2,and the calculated efficiency approached 98.2％,assuming heat recycling.This study illustrates the significant advantages of SOEC in efficient electrochemical energy conversion,carbon emission mitigation,and seasonal energy storage.

Conversion of renewable energy sources like bioethanol to electricity using solid oxide fuel cells (SOFCs) is promising to reduce the consumption of fossil fuels and to mitigate global warming. However, direct ethanol-fed SOFC is susceptible to carbon deposition on Ni-based anode. In this study, we investigated the power generation from and degradation mechanism of flat-tube SOFCs with an active cathode area of 60 cm 2 by direct internal reforming of ethanol. The effects of steam/carbon ratio (S/C), temperature, and current density on the performance and long-term durability of the cells were studied. It was found that S/C ratio caused minor influence on the cell performance but considerably affected the long-term durability, and elevating temperature improved the ethanol conversion rate and cell performance. The results indicated that ethanol was efficiently reformed by the thick anode support and long anode channels, with low selectivity for CH 4 and C 2 H 4 which were the main precursors of carbon deposition. Stable power generation with a constant current of 200 mA/cm 2 was obtained over 300 h under S/C = 2 and 3 at 800°C. Carbon deposition was confirmed via Raman spectroscopy and scanning electron microscopy (SEM) to propagate along the anode channels and in the thickness direction of anode support, and higher S/C ratios inhibited the accumulation of carbon. Simulation results reveal that, in addition to CH 4 and C 2 H 4 , the cold zone near the inlet contributes to carbon formation. This work provides insight into the mechanism of ethanol conversion within flat-tube SOFCs.

In-situ characterization of solid oxide fuel cells (SOFCs) under operating conditions is of great significance to mechanism studies on performance or long-term stability. In this study, real-time visualization of the twodimensional gas distribution inside a large flat-tube SOFC is realized by built-in gas sampling tubes combined with external gas chromatography, validated by simulating calculation. The gas composition inside anode of the cell fueled with CH4/CO2 is in-situ monitored during a 1000-h discharge test. Decrease in catalytic activity for methane dry reforming during the long-term test differs at different region of the cell, and is related with local carbon deposition and sintering of Ni particles. Based on these experimental results, the mechanism of cell performance degradation of the large flat-tube SOFCs under methane dry reforming conditions is discussed.