Performance Of Solid Oxide Fuel Cells Research Articles

Numerical study on the impact of carbon deposition on methane/steam mass transport in solid oxide fuel cell porous anode using lattice Boltzmann modeling

Solid Oxide Fuel Cell (SOFC) is an energy conversion device with high efficiency and cleanliness. However, anode carbon deposition severely affects SOFC performance during reforming with hydrocarbon fuels. In this paper, numerical simulations based on the Lattice Boltzmann (LB) method are used to construct the porous anode structure after carbon deposition by means of the binary dilation method, and the effects of different carbon deposition behaviors on the methane/steam flow behaviors and mass transport in the porous medium of SOFC anode are investigated. The results show that anode carbon deposition decreases the methane/steam mass transfer efficiency, and as the degree of carbon deposition increases, dead pores are formed and gas passage is impeded. This paper investigates the effect of different degrees of carbon deposition behavior on anode gas transport, which can further understand the importance of carbon removal in SOFC anode during the methane reforming reaction.

Evaluation of Water-Cooling Effect in Hydrogen-Fed SOFC for High-Efficiency Combined System Design

Abstract If pure hydrogen is used as a fuel in high-temperature fuel cells, waste heat must be removed by air cooling, which requires increased power consumption for supplying excess air. This study presents a hydrogen-fed solid oxide fuel cell (SOFC) that uses water instead of air for stack cooling and improved system performance. A novel SOFC system with energy cascade utilization is also proposed using cooling water as the working fluid for a steam turbine. Water cooling for the SOFC stack cooling reduced the stack power and efficiency but significantly reduced the power consumption for supplying excess air by more than 60%. Under ambient SOFC operating pressure, the net power and efficiency of the proposed system were increased by 25.6% and 12.2%p compared to the air-cooled system, respectively. At an SOFC operating pressure of 1000 kPa, the proposed hybrid system with energy cascade utilization achieved improvements of 10.2% in net power and 7.5%p in net efficiency, leading to efficiency higher than 73%. This study is significant in that it proposes a novel high-efficiency SOFC system with energy cascade utilization by using two-phase water as a cooling medium and working fluid of steam turbine.

Solid Oxide Fuel Cell Anode Porosity and Tortuosity Effect on the Exergy Efficiency

Improving the efficiency of solid oxide fuel cells (SOFCs) is critical for advancing clean energy solutions on a global scale. One major challenge in enhancing SOFC efficiency is reducing anode diffusion polarization, which can significantly hinder performance. This study addresses this issue by investigating the effects of anode tortuosity and porosity on the exergy efficiency of SOFCs. The novelty of this research lies in its comprehensive numerical model, which uniquely incorporates detailed material properties and their impact on SOFC performance—specifically focusing on anode tortuosity and porosity. Using advanced Multiphysics software, we developed a model that solves mass, electron transfer, and energy equations discretized via the finite differences method. The study meticulously examines how variations in these parameters influence SOFC efficiency, providing new insights into optimal anode design. Our methodology involves simulating different anode configurations to pinpoint the key parameters that affect exergy efficiency, thereby minimizing the experimental costs and time associated with traditional approaches. The quantitative results of this study are significant. We found that an anode tortuosity of 5.5 and a porosity range of 0.05–0.1 optimize exergy efficiency, achieving a 15% improvement compared to conventional designs. Additionally, a mean pore radius between 15 and 20 µm was identified as optimal for enhancing cell voltage. These findings elucidate the critical relationship between anode material properties and SOFC performance, offering a practical pathway to improving efficiency. This research provides a novel numerical approach to understanding and optimizing anode characteristics in SOFCs. By highlighting the importance of specific material properties, such as tortuosity and porosity, and demonstrating their impact on exergy efficiency, this study offers valuable guidance for future SOFC design and development.

Design of an integrated system that combines the steam gasification of plastic waste and a solid oxide fuel cell for sustainable power generation

As part of sustainable development efforts, this study presents an innovative integrated system that combines the steam gasification of plastic waste with solid oxide fuel cells (SOFCs) to produce electricity. The proposed system is designed using Aspen Plus v10® with two primary units. The first, a steam gasification system to produce H2 from the steam gasification of plastic waste. The second is a H2 driven SOFC system that generates electricity and is developed using Python. The study evaluates the combined system output in terms of power, current and voltage based on variation of temperature, steam/feed ratio (0.5–2), and CaO/feed ratio (0–1.5) of the gasifier. The study observes a decrease in the voltage (0.864 to 0.859 V) and power (0.852 to 0.845 W) with increasing gasification temperature (923–1173 K). Conversely, a rise in the steam/feed ratio inversely impacts the SOFC output, which is attributed to a decline in the H2 flowrate. Optimal conditions are met at gasifier temperature of 973 K, steam/feed ratio of 1.5, and CaO/feed ratio of 1. Moreover, using H2 flow rates to assess SOFC performance reveal increasing activation and ohmic losses (0.04 to 0.09 V and 0 to 0.28 V) with a temperature increase (973–1473 K), while concentration losses decreased (0–0.10 V). Nernst voltage and SOFC output voltage also decreased (1.1 to 0.52 V and 1.1 to 0.78 V) as SOFC temperature increases. Power output increased (0.0 to 1.57 W) with temperature, and the current–voltage relationship demonstrated reduced voltage (1.1 to 0.53 V) as the current is increased (0.0 to 2.8 A). This study provides an in-depth exploration into the development, modelling, and performance of both units, emphasizing their synergistic potential in the realm of sustainable electricity generation.

Bismuth-oxide nanoparticles: study in a beam and as deposited.

Bi2O3 is a promising material for solid-oxide fuel cells (SOFC) due to the high ionic conductivity of some phases. The largest value is reached for its δ-phase, but it is normally stable at temperatures too high for SOFC operation, while nanostructured oxide is believed to have more suitable stabilization temperature. However, to manufacture such a material with a controlled chemical composition is a challenging task. In this work, we investigated the fabrication of nanostructured Bi2O3 films formed by deposition of free Bi-oxide nanoparticles created in situ. The particle-production method was based on reactive sputtering and vapour aggregation. Depending on the fabrication conditions, the nanoparticles contained either a combination of Bi-metal and Bi-oxide, or only Bi-oxide. Prior to deposition, the free particles were probed in the beam - by synchrotron-based photoelectron spectroscopy (PES), which allowed assessing their composition "on the-fly". The nanoparticle films obtained after deposition were studied by PES, scanning electron microscopy, transmission electron microscopy, and electron diffraction. The films' chemical composition, grain dimensions, and crystal structure were probed. Our analysis suggests that our method produced Bi-oxide films in more than one polymorph of Bi2O3.

Penjanaan Kuasa yang Bersih: Kajian Mendalam Penilaian Kitaran Hayat bagi Sel Bahan Api Oksida Pepejal

Nowadays, there is a growing emphasis on creating alternative power generation methods to replace outdated technologies like coal-fired power and hydroelectric plants. One promising solution is the Solid Oxide Fuel Cell (SOFC), which offers high energy efficiency, low carbon emissions, and cost-effectiveness. This study presents a focused examination of the Life Cycle Assessment (LCA) of SOFCs, with the objective of reducing dependence on nonrenewable energy sources. The review encompasses a review of published articles between years 2016 to 2023 and an analysis of research gaps in SOFCs' environmental performance. A systematic literature review underpins this investigation, where several publication selection criteria were considered including plants that can produce hydrocarbon such as biogas and biomass, utilization of LCA software as a method of assessment and incorporation of the life cycle impact assessment in the articles. The results suggest that using SOFC powered by biogas as a stationary power generator is a viable option. This is supported by recent LCA studies demonstrating that SOFCs using biogas have a reduced impact on climate change compared to other fuels. Implementing SOFCs holds great potential for a cleaner energy future, aligning with society's goals for sustainable power production. For a more precise comparison of results, future LCA studies should adopt a multi-criteria environmental impact analysis using a consistent functional unit across different SOFC operations.

Robust Pr6O11 infiltration for La0.6Sr0.4Co0.2Fe0.8O3-δ cathode performance enhancement on electrolyte supported solid oxide fuel cells

In this study, the infiltration of a novel electrocatalyst, Praseodymium oxide (Pr6O11), has successfully enhanced solid oxide fuel cell (SOFC) performance via simple infiltration method. Pristine Lanthanum strontium cobalt ferrite (LSCF) screen printed on a electrolyte supported SOFC button cell showed peak power density of 0.086 W/cm2 at 800 °C, infiltrating 0.1 mol/L of Pr6O11 precursor into the LSCF cathode increased performance by 16.3 % by recording a 0.100 W/cm2 peak power density and infiltrating higher concentration of 1 mol/L Pr6O11 precursor further increased power density to 0.118 W/cm2, a 37.2 % improvement. Although increasing temperature lowered the effectiveness of the electrocatalyst, 1 mol/L Pr6O11 precursor infiltrated LSCF still showed the highest peak power density overall with 0.237 W/cm2 at 900 °C, a 13.9 % increase from pristine LSCF's 0.208 W/cm2 at the same temperature. The results confirm that increasing Pr6O11 precursor concentration in infiltration solution is an effective way for improving SOFC performance.

Boosting the Stability and Performance of SOFCs: A New Approach to Oxygen Storage Capacity Using Lanthanum-Doped Ceria Interlayer Technology

Being carbon neutral is one of the world's most important objectives. More than 65 percent of the countries that emit harmful greenhouse gases have committed to achieving net-zero emissions by the middle of the century.[1] There are numerous essential ways to gather energy for worldwide missions, including fuel cells, solar power, wind power, etc. The growing marketplace of fuel cells is following the trend of green-energy demand. Solid oxide fuel cells (SOFCs) are gaining popularity in the next-generation energy industry due to their high energy conversion efficiency, fuel flexibility, and low emissions.[2]The main challenges for the commercialization of SOCs that need to address are high performance, long-term durability, and effective cost. Stabilized zirconia such as Yttria-stabilized zirconia (YSZ) and Scandia-stabilized zirconia (ScSZ) is commonly used as a self-standing electrolyte support. The inability of zirconia-based electrolytes to react with Sr-rich cathode materials like LSC, LSCF, BSCF, etc. Therefore, the electrodes and the zirconia-based electrolyte must have the best-interlayered buffer structure. Optimizing interlayer microstructures to make them more effective at high-performance ESCs is of great interest. Several Rare-earth doped ceria (RDC) materials, including (Gd, Ce)O2, (Sm, Ce)O2, and (La, Ce)O2, have been used as efficient interlayers to lessen reactivity and preserve ionic conductivity in the interface. However, the difference in the thermal expansion coefficient (TEC) between the GDC and the YSZ poses a significant problem for starting and halting SOCs. In the present work, we focus on the commercial lanthanum-doped ceria (Ce0.6La0.4O1.8 - LDC) as a buffer layer between the YSZ electrolyte and the LSCF cathode because of its higher oxygen storage capacitance. The reactivity of the YSZ/GDC composite was higher than that of the YSZ/LDC composite. And the total conductivity of the LDC/YSZ composite is higher than GDC/YSZ composite even though LDC has lower conductivity than GDC. Moreover, the mismatching of TEC was reduced by replacing the GDC with the LDC bilayer.Consequently, the maximum power density for the electrolyte-supported cell SOFC with LDC interlayer was ~0.55 W.cm−2 at 1073 K. A variety of additives (Co, Mn, and Cu) was added to the LDC buffer layer to examine the sintering properties. The addition of copper not only obtained the highest microstructural density but also improve mechanical stability under cost-effective processes.

Effects of Current Collector on Internal Visualization of Solid Oxide Cells

Introduction Visualization of spatial distribution in solid oxide fuel cells (SOFCs) operating under high temperature is difficult to use various measurement equipment and sensors due to their recommended operating temperature. Therefore, it is difficult to reveal the distributions of gas species and reactions in the cell, as well as the loading current, using only electrochemical measurement methods. Simulation technology can be used to visualize various distributions in the cell and predict cell performance. While many simulation studies have revealed various spatial distributions in the SOFCs such as current density, they have also indicated that it is essential to accurately reflect the cell shape and multiphysics to simulate the cell performance1, 2.In our previous study, simulation and experimental thermal imaging combined temperature visualization method was developed. It was suggested that the temperature distribution under actual operating conditions is affected by Joule heating due to loading current distribution depending on the current collector geometry. Therefore, in order to evaluate the influence of the collector shape on the spatial temperature distribution, the influences of Joule heating and the collector geometry on the temperature distribution are evaluated. Then, we also analyze the influence of the current collector on the SOFC performance and propose a current collection method suitable for visualizing the reaction in an SOFC. Simulation Method In this study, the calculation was performed using a three-dimensional model that simulates the actual cell geometry used in the experiments. The simulated 3-D model was based on an electrolyte-supported plate cell with Scandia-stabilized Zirconia (ScSZ, 5 cm × 5 cm in size) as the support, LSM ((La0.8Sr0.2)0.98MnO3) and LSM-ScSZ composite material for the air electrode, and Ni-ScSZ cermet for the fuel electrode, respectively. The electrode area was 4 cm × 4 cm (16 cm2), and a platinum mesh and wire were used as a current collector. A schematic diagram of one of these examples is shown in Fig. 1. COMSOL Multiphysics (Ver. 6.0) was used as the 3-D simulation software to calculate the I-V characteristics and cell temperature distribution.The cell operating conditions were set to 800 ℃ for the operating temperature, 100 ml min-1 of 3 % humidified hydrogen as the incoming fuel, and the air electrode side opened to the atmosphere. I-V characteristics and cell temperature distributions were calculated under current density loading conditions ranging from 0.01 A cm-2 to 0.15 A cm-2. Based on each result, the relationship between current density and cell temperature distribution was evaluated. Results and Discussion As a result of numerical analysis and experiments focusing on the effect of the current collector shape, it was confirmed that the influence of the current collector shape appeared significantly in the cell temperature distribution as shown in Fig. 2. In addition, it was found that the visualization of the spatial distribution may be difficult because the effect of the heat generated by the Pt wire used as the current collector appears in the results of the temperature distribution on the surface. Based on these findings, we improved the current collector shape. Although the effect of the improvement on the Joule heating at Pt wire appeared in the temperature distribution result, the temperature distribution change was confirmed due to the loading current flow pattern, which depends on the shape of the current collector. The simulation results of the further improved collector shape showed that the temperature distribution change depending on the collector shape became smaller, suggesting that this collector shape is promising as a current collecting method suitable for visualizing the cell inside. In this presentation, we report the simulation results and discussion on the changes in current density distribution, gas distribution, and I-V characteristics, in addition to the changes in temperature distribution. References (1) M. Andersson, H. Paradis, J. Yuan, and B. Sundén, Electrochimica Acta, 109, 881 (2013).(2) A. Li, C. Song, and Z. Lin, Applied Energy, 190, 1234 (2017). Figure 1

(Invited) Boosting Solid Oxide Fuel Cell Performance through the Effect of of Interstitial Oxide Ion Supplying of Oxygen Storage Capacitance Materials at Cathodic Functional Layer

Chemical compatibility between the hierachical interface components in solid oxide fuel cells (SOFCs) is an emerging critical issues that significantly impact the durability of SOFCs. However, there are several challenging issues to be solved: cost-effective manufacturing configuration, lowering the operating temperature, and durability. The creation of novel materials or long-lasting electrode/electrolyte interfaces that permit high activity (oxygen reduction or fuel oxidation) while maintaining long-term stability is one of the major barriers to the commercialization of the SOFC Rare-earth doped ceria (REDC) is commonly used to enhance durability and activity in solid oxide cells (SOCs) engineering, with Gd-doped ceria (GDC) being a popular choice for interlayer and additives in solid oxide fuel cells (SOFCs). However, the Ce diffusion into the lattice of ZrO2of YSZ-based electrolyte as a solid solution at high-temperature manufacturing still is remained to be solved. In this study, we conducted La-doped CeO2 (LDC), whose Ce-sites are highly occupied with La to avoid a solid solution of Ce-Zr, as a functionalized interlayer between YSZ-based electrolyte and cathode. When LDC (La-doped CeO2, LDC, Ce0.6La0.4O2−δ) or Bi doped Cerium Oxide buffer layer was optimized at lowering sintering temperature to prevent a La2Zr2O7 impurity reaction, the improved electrochemical performance was achieved at the maximum power density (MPD) of ~1.43 W cm-2 at 800 oC. The high substitution of La3+ into the ceria lattice improves the oxygen non-stoichiometry of LDC, leading to improve the oxide ion supplying of the cathode side during the high current operation. Consequently, we firstly propose that the larger oxygen storage or supplying capacitance (OSC) effect of the interdiffusion layer composition (La, Zr, Ce, Y)O2 in La-doped CeO2 (LDC) is responsible for the positive enhancement of the oxygen reduction reaction (ORR) at high current ranges through interstitial oxygen supply at the cathode/electrolyte interface rather than (Gd, Zr, Ce, Y)O2 in GDC. The OSC of the LDC is higher than that of the GDC, and it effectively enhances the electrochemical performance of the cathode interface in the SOFCs because it may be affected by the high oxygen carrier concentration of the LDC, the higher oxygen releasing, and storage capacitance. This revealed that the effect of oxygen releasing, and storage capacity of the buffer layer might be the cause of improved performance. Consequently, the cell containing the high OSC buffer layer fabricated at 1250 oC to avoid interfacial insulating layers, such as La2Zr2O7 impurities, successfully displayed a dramatically high-power density value. Figure 1

(Digital Presentation) Efficient Mixed Ionic Electronic Conductor (MIECs) for Conventional SOFC

A new kind of composite material has been developed to use for electrochemical conversion in solid oxide fuel cells (SOFCs) and semi-ionic fuel cells (SIFCs). The developed composite material based on Ni0.1Cu0.1Ce0.8, NiCuCeO with different ratios exhibited the exceptional properties of MIECs. Here the material 8NC2C employed in SOFC showed good electronic, ionic conductivity and total conductivity 1.480, 0.098 and 1.578 S/cm respectively. However, by comparison material composition 8NC2C rendered the open circuit voltage (OCV) 1.097 V and fuel cell performance 765.099mW/cm2at 550°C for SOFC and reasonably good value of good fuel cell performance of 678.659 mW/cm2 at 550°C was observed by SIFC 4NC6C composition. The comparative study showed that total conductivity, fuel cell performance and polarization resistance of SOFC exhibited better results than SIFC nevertheless 4NC6C composition polarization resistance Rp was lower in SIFC over SOFC which establish the SIFC as a good candidate for fuel cell application.

Novel Perovskite Structured Nd0.5Ba0.5Co1/3Ni1/3Mn1/3O3-δ as Highly Efficient Catalyst for Oxygen Electrode in Solid Oxide Electrochemical Cells.

Developing catalytic materials with highly efficient oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is essential for lower-temperature solid oxide fuel cell (SOFC) and electrolysis cell (SOEC) technologies. In this work, a novel triple perovskite material, Nd0.5Ba0.5Co1/3Ni1/3Mn1/3O3-δ, has been developed and employed as a catalyst for both ORR and OER in SOFC and SOEC operations at relatively lower temperatures, showing a low polarization resistance of 0.327 Ω cm2, high-power output of SOFC up to 773 mW cm-2 at 650 °C, and a high current density of 1.57 A cm-2 from SOEC operation at 1.5 V at 600 °C. The relaxation time distribution reveals that Nd0.5Ba0.5Co1/3Ni1/3Mn1/3O3-δ could maintain a slow polarization process at the relatively low operating temperature, offering a significant antipolarization advantage over other perovskite electrode materials. The Nd0.5Ba0.5Co1/3Ni1/3Mn1/3O3-δ electrode provides a low energy barrier of about 0.36 eV in oxygen ion mobility, which is beneficent for oxygen reduction/evolution reaction processes.

Enhanced stability and electrochemical investigations of Ni/ZSM-5 catalyst layer on nickel-based anodes for ammonia-fed solid oxide fuel cells

Ammonia-fed solid oxide fuel cell (SOFC) is a promising clean energy technique with distinctive advantages of zero-carbon emission, easy storage, and high efficiency. However, the typical nickel anode for SOFC is susceptible to structural change and performance degradation under an ammonia environment, particularly at reduced operating temperatures. In addition, obtaining a deep understanding of the individual electrode processes is demanded for the rational design and optimization of NH3–SOFCs. This work enhances the cell performance and durability of ammonia-fed SOFCs by utilizing a cost-effective ammonia decomposition catalyst (Ni/Na-ZSM). The electrode processes are investigated quantitively using distributed relaxation time (DRT) and equivalent circuit model (ECM) analysis. Accelerated degradation tests are conducted for the NH3-based SOFC cells by thermal cycling at operational temperatures of 700 °C-650 °C. Compared to the conventional cell, the cell with the Ni/Na-ZSM catalyst exhibits improved cell performance and five times less decay. In situ measurements and impedance analysis combined with microstructural characterization reveal that the durability enhancement is probably ascribed to protecting the structure of the three-phase boundaries (TPBs), which maintains a stable resistance of the TPB charge transfer processes during the temperature cycling.

Presentation and Performance of a Planar Solid Oxide Fuel Cell with Chaotic Gas Channels

Flow condition in gas channels determines the distribution and diffusion of reactants, governing electrochemical reactions in the solid oxide fuel cell (SOFC). It is found that the magnitude and direction of fluid velocity change with the geometric position in the channel, which leads to larger secondary flow velocity components and enhances mass transfer between fluids. Laser Doppler velocimetry experiment is conducted to verify the accuracy of numerical results of fluid flow in chaotic flow channels. Herein, a 3D numerical model with coupled multiphysics fields is built to evaluate fluid flow in channels and SOFC performance. The distribution characteristics of reactants in chaotic flow channel and the characteristics of temperature distribution, current density and power density in SOFCs caused by structures of straight and chaotic flow channels are analyzed and discussed. Compared with conventional straight flow channel SOFCs, the average current density of SOFC with chaotic flow channel is improved and the power density is increased by 9.7%. The reactant homogeneity in the electrode is also improved, which reduces the concentration polarization loss of SOFC.

Conception and thermo-economic performance investigation of a novel solid oxide fuel cell/ gas turbine/Kalina cycle cascade system using ammonia-water as fuel

In order to develop a zero-carbon, high-efficiency and low-cost energy system, the conception of an innovative ammonia-water fueled solid oxide fuel cell (SOFC) - gas turbine (GT) - Kalina cycle (KC) cascade power system is proposed. The performance superiority of novel cascade system is verified by comparing with SOFC system using anode off-gas recycle (AOR). The influence of system key operation parameters including fuel ammonia mass fraction on novel system total energy efficiency and levelized cost of electricity (LCOE) is revealed. The rapid prediction and multi-objective optimization of novel system thermo-economic performance are conducted based on artificial neural network - multi-objective Harris hawks optimizer (ANN-MHHO). The results show that the total energy efficiency and LCOE of novel ammonia-water fed SOFC-GT-KC system are 12.92% higher and 8.91% lower than the SOFC system using AOR under preliminary condition, respectively. Parametric analysis reveals that fuel ammonia mass fraction presents a more significant effect on novel system thermo-economic performance than cell stack fuel utilization ratio. A high cell stack fuel utilization ratio of more than 0.64 is not conducive to improving novel system economic performance. The novel system LCOE reaches the minimum of 0.13807 $/kWh at SOFC operation pressure of 9.5 bar. The multi-objective optimization results demonstrate that the novel system total energy efficiency is increased by 1.14% and LCOE is reduced by 1.23% under optimal condition compared with preliminary condition. The novel system LCOE is more sensitive to ammonia price than interest rate.

Power generation via solid oxide fuel cell using ex-reformed oxygen-containing low-concentration methane

Solid oxide fuel cells (SOFCs) using oxygen-containing low concentration coal mine methane (O-LCM, CH4<30 %) for power generation are an attractive way to cleanly and efficiently convert abundant O-LCM resources into clean energy. However, direct use of O-LCM for power generation leads to low internal reforming performance and anode coking problems. Therefore, in this study, simulated O-LCM (30 vol% CH4-70 vol% air) was used as fuel and Ni–BaO–CeO2 (NBC) and Ni–BaO-(Ce,Zr)O2 (NBCZ) catalysts were prepared to improve the electrochemical performance and carbon deposition resistance of SOFCs. The composite catalyst containing nanoscale Ni and (Ce,Zr)O2 solid solution with abundant oxygen vacancies are favorable for the enhancement of CH4 reforming and the elimination of carbon deposit. The results show that the NBCZ-modified SOFCs using O-LCM exhibits the much better electrochemical performance, resistance to carbon deposits and discharging stability than the NBC-modified SOFCs. The research provides a strategy for the utilization of O-LCM for power generation via SOFCs.

Optimizing fuel transport and distribution in gradient channel anode of solid oxide fuel cell

Precise geometrical adjustment of an anode is crucial for optimizing the performance of solid oxide fuel cell (SOFC). Fuel gas components of SOFC, including H2, CH4, CO, CO2 and H2O, are complex in composition but play a significant role in determining the efficiency of SOFC. This study examines the fuel transport and distribution and the resultant SOFC performance by constructing various gradient channel anode (GCA) structures. The findings show that compared to the traditional un-gradient channel anode (un-GCA) cell, the GCA cell results in more uniform gas distribution and better diffusion of fuel gases, particularly H2, CH4 and H2O. Because of the improved gas diffusion in the anode electrode, the GCA (12 μm) cell exhibits a 2.34 % improvement in power density compared to the un-GCA cell at 800 °C and 0.6 V. Additionally, after increasing the mole fractions of H2 and CH4 in the fuel gas, the power density of the GCA (12 μm) cell is improved by 2.42 % compared with that of the un-GCA cell under the same condition. This study provides clear evidence that incorporating the gradient channel structure in the anode can effectively enhance gas transport, minimize localized gas aggregation and eventually improve the performance of SOFC.

Determination and validation of polarization losses parameters to predict current/voltage-characteristics for SOFC button cell

Solid Oxide Fuel Cell represents a valid and clean alternative to conventional combined heat and power systems. These devices can convert different kinds of fuels into electricity with high efficiencies (up to 75–80 %) and low CO2 or hazardous emissions. In order to understand and validate Solid Oxide Fuel Cell behavior at different operating conditions, investigations are currently focusing their attention on modeling. In this work, an experimental-based model to study the effect of different hydrogen and temperature conditions on both the polarization processes and its effect on Solid Oxide Fuel Cell performance is presented. Experimental parametric campaigns were carried out using a button anode supported Solid Oxide Fuel Cell with an active area of about 2 cm2. A practical zero-dimensional mathematical model based on low and high voltage approximations of the Butler-Volmer equations was used starting from an experimental current–voltage dataset to obtain polarization curve parameters representing different physical phenomena associated with the cell. To validate the obtained results and gain additional information, electrochemical impedance spectroscopy measurements and distribution of relaxation times analysis were performed both in open circuit voltage and underload at 0.5 A/cm2. Finally, from the fitted parameters, it was possible to derive dimensionless charge transfer coefficients related to the most probable reaction mechanisms occurring in the cell, equal to 2 for the anodic process and 3.5 for the cathodic process. Moreover, from the results the obtained exchange current densities range from 0.024 A/cm2 to 0.048 A/cm2 for O2 reduction and from 0.012 A/cm2 to 0.073 A/cm2 for H2 oxidation and subsequently, the activation energies equal to 100 kJ/mol and 66 kJ/mol for anodic and cathodic electrochemical processes, respectively.

Numerical performance analysis of the solid oxide fuel cell for aviation hybrid power system

A detailed three-dimensional model of solid oxide fuel cell (SOFC) is established to explore its performance under special requirements in the aviation SOFC - gas turbine hybrid system. In this context, the SOFC has the distinction of pressurization, lightweight and low pressure loss compared to its conventional independent application. Based on this, the SOFC performance is fully investigated in terms of different operating conditions and geometric dimensions, and in addition to typical electrochemical parameters, the power-to-weight ratio is also considered as evaluation indicator. The results indicate that high operating pressure is beneficial for improving SOFC electrochemical performance, but the performance enhancement becomes slow when pressure exceeds 0.5 MPa. The inlet velocities of fuel and air both affect fuel utilization and power density of SOFC. And the high air velocity is favorable to reduce the SOFC temperature and temperature gradient, but it also increases the pressure drop. Therefore, the air inlet velocity of 2 m/s-15 m/s is more suitable under comprehensive consideration. In addition, the optimal power density and power-to-weight ratio correspond to different rib widths, with the former having wider ribs and differing within 0.5 mm. And this characteristic is maintained at different pressure, contact resistance and interconnect density.

Exploring B-site high-entropy configuration of spinel oxides for improved cathode performance in solid oxide fuel cells

High-entropy engineering is an emerging strategy to enhance material properties beyond their individual components. In this study, we synthesized a high-entropy spinel oxide cathode material, Ni(Fe0.2Mn0.2Co0.2Cr0.2Ni0.2)2O4, for solid oxide fuel cells (SOFCs) using a solution combustion method. The material exhibits a spinel structure with diverse surface metal valence states and a high concentration of oxygen vacancies. Density functional theory calculations reveal the B-site high-entropy design can significantly improve the oxygen adsorption capability. Electrochemical tests demonstrate that Ni(Fe0.2Mn0.2Co0.2Cr0.2Ni0.2)2O4 has superior conductivity and oxygen reduction activity compared to binary spinel oxides. An anode-supported SOFC with Ni(Fe0.2Mn0.2Co0.2Cr0.2Ni0.2)2O4 cathode achieved a peak power density of 583 mW cm-2 at 800 °C. Impedance and relaxation time distribution (DRT) analyses indicate that the oxygen molecular dissociation and oxygen atom diffusion dominates the cathode polarization. This study demonstrates that high-entropy engineering of the B-site in spinel oxides is a promising strategy to optimize cathode performance for SOFCs.