Performance Of Solid Oxide Fuel Cells Research Articles

Valence Variability Induced in SrMoO₃ Perovskite by Mn Doping: Evaluation of a New Family of Anodes for Solid-Oxide Fuel Cells

We report on a series of SrMo1−xMnxO3−δ perovskite oxides designed as potential anode materials for solid oxide fuel cells (SOFCs). These materials were synthesized using a citrate method, yielding scheelite-type precursors with nominal SrMo1−xMnxO4 compositions, which were further reduced to obtain the active perovskite oxides. Their structural evolution was examined through X-ray diffraction (XRD) and neutron powder diffraction (NPD). These techniques provided insights into the crystallographic changes upon Mn doping, revealing key factors influencing ionic conductivity. Whereas the oxidized scheelite precursors are tetragonal, space group I41/a, the reduced perovskite specimens are cubic, space group Pm-3m, and show the conspicuous absence of oxygen vacancies, even at the highest temperature of 800 °C. The transport properties were analyzed through electrical conductivity measurements, exhibiting a metallic-like behavior. Thermogravimetric analysis (TGA) and dilatometry give insights into the thermal stability and expansion behavior, essential for SOFC operation. Test single SOFCs were built in an electrolyte-supported configuration, on LSGM pellets of 300 μm thickness, assessing the performance of the title materials as anodes. This work emphasizes the critical relationship between the crystal structure and its electrochemical behavior, providing a deeper understanding of how doping strategies can optimize fuel cell performance.

Effect of Low-temperature Pre-calcination on Bilayer Electrolyte Solid Oxide Fuel Cell Performance using Hydrothermally Grown Thin-film Gadolinium-doped Ceria

Effect of Low-temperature Pre-calcination on Bilayer Electrolyte Solid Oxide Fuel Cell Performance using Hydrothermally Grown Thin-film Gadolinium-doped Ceria

Thermodynamic Models of Solid Oxide Fuel Cells (SOFCs): A Review

In the delicate context of climate change and global warming, new technologies are being investigated in order to reduce pollution. The SOFC stands out as one of the most promising fuel cell technologies for directly converting chemical energy into electrical energy, with the added benefit of potential integration into co-generation systems due to its high-temperature waste heat. They also offer multi-fuel flexibility, being able to operate on hydrogen, carbon monoxide, methane, and more. Additionally, they could contribute to carbon sequestration efforts and, when paired with a GT, achieve the highest efficiency in electricity generation for power plants. However, their development is still challenged by issues related to high-temperature materials, the design of cost-effective materials and manufacturing processes, and the optimization of efficient plant designs. To better understand SOFC operation, numerous mathematical models have been developed to solve transport equations coupled with electrochemical processes for three primary configurations: tubular, planar, and monolithic. These models capture reaction kinetics, including internal reforming chemistry. Recent advancements in modeling have significantly improved the design and performance of SOFCs, leading to a sharp rise in research contributions. This paper aims to provide a comprehensive review of the current state of SOFC modeling, highlighting key challenges that remain unresolved for further investigation by researchers.

An entropy analysis model and irreversibility assessment of solid oxide fuel cells based on the Gibbs relation of charged particles

Energy conversion is the main purpose of various fuel cells, but the irreversibility of thermodynamic processes – including electrochemical reactions and heat and mass transfer in fuel cells – lead to a decrease in energy efficiency. In this paper, we develop a systemic theoretical model to evaluate the irreversibility of solid oxide fuel cells (SOFCs). By combining the conservation equations for energy, mass, and momentum with the Gibbs relation for charged particles, we establish the energy-balance equation for SOFCs and derive the entropy generation rates (EGRs) associated with electrochemical reactions and charged particle transfer processes. We solve the coupling multiphysics model in a three-dimensional computational unit of a SOFC, and calculate the EGRs and entropy flux rate based on the proposed thermodynamic model and the numerical results. We analyse the conversion and transfer mechanisms of energy based on the distributions of different local EGRs and the entropy flux rate, and the influence of various thermodynamic processes, such as mass transfer, heat transfer, and flow, on the overall operation of SOFCs. The results show that the EGR due to electrochemical reactions in the SOFC is the largest and is mainly due to activation and concentration polarisation. Complex heat and mass transfer processes occur in the corner region formed at the intersection of the channel, the current junction, and the electrode, leading to a higher localised EGR. We also evaluate the effects of variations in the anode gas mass flow rate, the oxygen fraction, and the channel length on thermodynamic efficiency. This study contributes to the understanding of the complex mechanisms of irreversible losses in SOFCs and provides guidance for further improving the thermodynamic efficiency of SOFCs.

Analysis of a fitting model based on polarization characteristics of solid oxide fuel cells

Reliability and long life are the keys to the large-scale commercialization of solid oxide fuel cells (SOFCs), so many studies have focused on how to diagnose SOFC degradation mechanisms. Electrochemical tests have been widely used to study SOFC degradation. The SOFC overpotential can be obtained by measuring the current-voltage (I–V) curves, but these measurements do not show the cause of the SOFC performance attenuation. Electrochemical impedance spectroscopy (EIS) measurements can measure various types of SOFC impedances, but this method is difficult to apply to the high-power stack due to the limited output power of the electrochemical workstation. This paper presents a resistance fitting model based on the I-V measurements for large SOFCs that can determine various electrochemical parameters and resistances by fitting the voltages for different regions of the current densities. The model accuracy is verified by EIS measurements at various current densities with the mean absolute percentage error for each type of resistance given by the fitting model being within 10 % of the EIS measurements which shows that the model can accurately identify the SOFC degradation mechanisms.

Numerical investigation of micro solid oxide fuel cell performance in combination with artificial intelligence approach.

The current study presents a multiphysics numerical model for a micro-planar proton-conducting solid oxide fuel cell (H-SOFC). The numerical model considered an anode-supported H-SOFC with direct internal reforming (DIR) of methane. The model solves coupled nonlinear equations, including continuity, momentum, mass transfer, chemical and electrochemical reactions, and energy equations. Furthermore, The numerical model results are used in artificial intelligence (AI) models, the K-nearest neighbour (KNN) and, artificial neural network (ANN), to predict the current density and power density of the H-SOFC. The results show that increasing the air-to-fuel (A/F) ratio decreases the current density and overall cell power. In particular, improvements in power and current density observed in H-SOFC when the A/F ratio is set to 0.5, resulting in a respective increase of 2% and 7% compared to the initial state at A/F=1. With an error rate of less than 1% and an R-score of around 99%, the ANN model shows good agreement with the numerical results.

Physics-based and data-driven modelling and simulation of Solid Oxide Fuel Cells

This paper presents a comprehensive approach to multiscale and multiphysics modelling of Solid Oxide Fuel Cells (SOFCs) by combining physics-based simulations with data-driven techniques. The modelling approach is tailored to specific end-use scenarios, ensuring that parameter selection aligns with operational requirements for accurate and efficient SOFC design. The study begins by constructing Representative Volume Elements (RVEs) from reconstructed microstructures, applying first-order homogenisation to upscale material properties, which are then incorporated into a macroscopic SOFC model. A major contribution is the structured model definition based on physical process entities, using a graphical representation of model topology. This approach simplifies complex system interactions by representing capacities (such as reservoirs, distributed systems, and interfaces) and transport processes (e.g., diffusion, convection, thermal diffusion), thereby enhancing clarity and improving the accuracy of SOFC performance simulations.A machine learning framework complements the physics-based modelling by training Artificial Neural Networks (ANNs) on simulation-generated datasets, delivering fast and reliable performance predictions. The study compares two optimisation techniques — Levenberg–Marquardt (LM) and Adam optimiser — demonstrating that LM is more effective for sparse datasets and smaller networks, whereas Adam performs better with large datasets and higher learning capacities. This hybrid modelling approach not only boosts predictive accuracy for SOFC performance but also lowers computational costs. By integrating physics-based simulations, machine learning, and a knowledge-driven simulation platform, this work advances SOFC design and optimisation, contributing to more efficient and cost-effective clean energy solutions.Additionally, the paper introduces a knowledge-driven simulation platform to enhance data management and integrate multiscale, multiphysics models. The platform leverages structured data models and ontological mappings to improve semantic interoperability, allowing for dataset reuse and validation across different simulation stages. This ensures a robust, reusable, and well-organised workflow, facilitating large-scale simulations and improving overall modelling accuracy.

Multi-objective optimization and dynamic characteristic analysis of solid oxide fuel cell - Supercritical carbon dioxide brayton cycle hybrid system

Solid oxide fuel cells (SOFCs) are widely used in distributed power generation systems due to their high energy conversion efficiency, low emissions. Therefore, investigating the dynamic characteristics of fuel cell integration systems is significant for ensuring the efficient and stable operation of SOFC integrated systems. In this study, an SOFC integrated system with a supercritical CO2 Brayton cycle as the bottoming cycle is proposed. A dynamic model is established to investigate the dynamic characteristics of this system under optimal operating conditions. This integrated system is optimized from the perspectives of two objectives: energy conversion efficiency and operational cost. Using the Pareto frontier, the optimal solutions are a system electrical efficiency of 61.21 % and a total cost rate of 4583.8 $/hour. These optimized results are used as steady-state design points for the integrated system. At the steady-state design point, flow and voltage perturbation simulation experiments are conducted on the integrated system to analyze the dynamic characteristics of key system parameters. This study provides a theoretical foundation for the control structure design of SOFC integrated systems.

Surface Ionic Conduction of Ce0.8Gd0.2O2-Δ Multilayer Thin Films with Large Amount of Oxygen Vacancies

Gd-doped CeO2 (GDC) with high chemical stability is a good electrolyte material with high oxygen ion conduction above 600°C and surface proton conduction below 100°C in thin film form [1]. In particular, Ni-GDC cermet material is well known as anode electrode of solid oxide fuel cell (SOFC) operating at medium temperature region. Ni is suitable for the anode as it has the characteristics of being inexpensive and having high catalytic activity, which enhances the hydrogen oxidation reaction. Ni is characterized by its low cost, high catalytic activity, and enhanced hydrogen oxidation reaction. Mixtures of electronic conductors such as Ni and ionic conductors such as Yttria-stabilized zirconia (YSZ) and GDC are often used as anode materials because they expand the three-phase interface [2].Based on these backgrounds, we have attempted to realize high conductivity in GDC (Ce0.90Gd0.10O2-δ) thin films, which contain a large amount of oxygen vacancies and lattice distortion. if the GDC films show high ionic conductivity above σ T~10-1Scm-1K, the performance of SOFCs and EDLTs will be dramatically improved. performance of SOFC and EDLT will be dramatically improved. To realize this goal, thin films were prepared by sputtering method, the relationship between surface defect structure and ionic conductivity was investigated in detail, and electrodes were fabricated on the thin films with Pt and Ni thin films.Based on these backgrounds, in this study, we tried to realize high conductivity by fabricating electrodes with Ni thin films on GDC (Ce0.90Gd0.10O2- δ) with large amount of oxygen vacancies and lattice distortion. If the GDC thin films show high ionic conductivity above σ T~10-1Scm-1K, the performance of SOFCs and EDLTs will improve dramatically. In order to realize this purpose, we fabricated thin films by the sputtering method and studied in detail the relationship between the surface defect structure and ionic conductivity.The GDC thin films were prepared on Al2O3 (0001) substrates by RF magnetron sputtering using ceramic targets. The target size had a diameter of 47 mm and thickness of 3 mm. The RF power of the ceramic target was fixed at 30 W. The flow rate of Ar gas controlled by a mass-flow controller was kept at approximately 2.81 ccm. The pressure of Ar gas was fixed at 3.5 × 10−3 Torr during the deposition. The film thicknesses ~30 and ~110 nm to probe the changes in the lattice constant and the conductivity. The electrode film was fabricated on the GDC thin film using a similar method with Pt and Ni metal targets. Electrical conductivity was measured by the AC impedance method. The measurement range was 600 °C to 20 °C. The result when only Ar was filled at the time of measurement is called As-deposited, and the result when a 4:1 mixture of Ar and gases was filled at the time of measurement is called -annealed.Arrhenius plots at low temperatures below 100 °C are shown in Fig. The thin films with Pt electrode are designated as Pt-GDC and those with Ni electrode as Ni-GDC. The PES spectra show that the OH- peak appears after Wet annealing. Therefore, it can be said that surface proton conduction by the Grotthuss mechanism is taking place [3]. In comparison for Pt-GDC, the O2 annealed condition resulted in higher conductivity than the As-deposited condition. This is thought to be due to the reduction of oxygen defects in the thin film by O2 annealing and the dominance of proton conduction. Ni-GDC resulted in lower conductivity than Pt-GDC under the two conditions. For Ni-GDC, there are reports that the peak power density varied with the voltage at the time of deposition [4], that ohmic resistance decreased by moderately thickening the anode and that the power density was highest at 800 nm thickness [4], and that the oxygen reduction reaction at the cathode was promoted by the grain boundaries and lattice defects report [5] that grain boundaries and lattice defects promote the oxygen reduction reaction at the cathode.Reference[1] M, Shirpor et al. Phys. Chem. Chem. Phys., 13 (2011) 937-940.[2] I.D. Unachukwu et al. Journal of Power Sources 556 (2023) 232436[3] D. Nishioka et al, Nanoscale Res. Lett. 15 (2020) 42-49[4] S, Ryu et al. ACS Appl. Mater. Interfaces 2023, 15, 11845−11852[5] Y, Li et, al, Scientific Reports 6, 22369 (2016) Figure 1

Influence of Local Environment Under Polarization on Wettability of Ni/YSZ Interface

In solid oxide fuel cells (SOFCs) and solid oxide electrolysis cells (SOECs), degradation of hydrogen electrode during long–term operation is one of the issues to be solved. Migration and aggregation of Ni particles are major factors of this degradation, and especially after steam electrolysis operation, intense Ni migration has been observed at the hydrogen electrode/electrolyte interface [1]. This phenomenon is assumed to be related to the change in wettability of the Ni/electrolyte interface under polarization [2]. A quantitative measurement of interface wettability is the concept of contact angle. It is known that the contact angle is determined by the balance between the surface tension of contacting materials and the interfacial tension. Contact angle analysis is usually used for liquid–solid interfaces, but it has also been suggested to be useful for the characterization of solid metal–oxide interfaces [3]. Therefore, the aim of this study was to directly measure the contact angle between Ni and YSZ electrolyte under various conditions in order to quantify the changes in wettability at the interface.Ni thin film electrodes were prepared by sputtering Ni on YSZ electrolyte. Using this model electrode, electrochemical measurements were performed under open circuit holding or a potentiostatic operation (SOFC operation or SOEC operation) at high temperatures. Subsequently, postmorterm analysis of the samples was performed using a Focused Ion Beam–Scanning Electron Microscope (FIB–SEM). Using the cross–sectional SEM images of the model electrode, the contact angle was calculated by distinguishing the three phases of Ni, YSZ, and pores based on the difference in contrast of each phase. The analysis revealed that the wettability of the Ni/YSZ electrolyte interface changed depending on the operation mode. Specifically, the contact angle after SOEC operation increased compared to values after open circuit holding or SOFC operation. This phenomenon is thought to be related to changes in oxygen potential.AcknowledgementsThis paper is based on results obtained from a project, JPNP20003, commissioned by the New Energy and Industrial Technology Development Organization (NEDO).

Simulation of Stack-Integrated Autothermal Reformer and Solid Oxide Fuel Cells for Operation in Aircraft Engines

Renewable liquified natural gas provides a potential sustainable aviation fuel, but with a volumetric energy density around 70% of conventional jet fuel. As such, alternative aircraft power plants such as hybrid gas turbine (GT) / solid oxide fuel cells (SOFCs) have been proposed to increase fuel conversion efficiency and support hybrid electric propulsion concepts. To enable reliable SOFC operation within aircraft gas turbine flow paths, stack architectures must be identified that sustain very high-power densities with direct inline air feeds from the gas turbine compressor outlet. Typical aircraft compressor outlet temperatures are below SOFC operating temperatures but high enough to light-off a catalytic autothermal reformer (ATR). The ATR combined with an air heat exchanger (HX) can preheat anode and cathode streams to desirable inlet temperatures above 500 °C for intermediate-temperature SOFCs that utilize gadolinia-doped ceria (GDC) electrolytes or thin-film, yttria-stabilized zirconia (YSZ) electrolytes. By packaging the inline ATR/HX within the SOFC stack and mixing partial anode exhaust recycle and bleed air with the ATR fuel stream, a volumetrically efficient inline stack architecture is being designed for demonstration at conditions simulating an aircraft gas-turbine compressor outlet. The combination of the ATR/HX and the high-power-density SOFC imposes significant temperature gradients within the stack that can impact performance. To assess suitable operating conditions and preferred designs for the ATR/HX/SOFC operating on renewable natural gas, a 3-D multi-physics CFD model has been developed. Simulation results for SOFCs with thin-film YSZ or GDC electrolytes show the challenge maintaining high-power densities while maintaining the full stack within expected temperature limits for expected cell materials.The ATR/HX/SOFC stack design includes the upstream ATR/HX, 3.6 cm in length. The ATR flow path is filled by a porous mesh with a washcoat-supported Pt catalyst for light off of CH4/bleed air/H2O inlet mixtures. The air-side flow paths in the ATR/HX are etched parallel channels that extract heat from the exothermic ATR reactions. The ATR/HX outlets feed the SOFC anode and cathode flow paths respectively. For this study, the SOFC membrane electrode assembly (MEA) 10 cm in length, consists of a porous Ni-YSZ anode-support (400 mm thick), dense YSZ or GDC electrolytes (≤ 20 mm thick), and a perovskite-YSZ composite cathode (35 mm thick). The anode flow passages over the support involve a high-porosity mesh that enables current collection. The cathode flow channels are etched ribs that enable high air flow rates to support high power density with adequate SOFC stack cooling. The ATR/HX/SOFC design has been incorporated into an ANSYS Fluent model to explore how integration of the ATR/HX in the stack can enable high-power performance of the SOFC while supporting light-off of the ATR fuel stream at aircraft compressor outlet conditions. The ANSYS Fluent model uses customized user-defined functions to handle the heterogeneous catalytic CH4oxidation surface chemistry for the ATR (supported Pt catalyst [1]) and for internal CH4 reforming in the Ni/cermet anode support in the SOFC [2]. The model simulates non-isothermal operation of a single ATR/HX/SOFC cell, representative of a full stack, at various inlet flow temperatures, pressures, flow rates, and fuel stream compositions, which are set by anode exhaust recycle fraction.CFD model results for thin-film YSZ-electrolyte MEAs illustrate a strong dependence of SOFC power density on the anode recycle fraction and cathode bleed air splits into the ATR fuel stream. For a 400 °C air inlet, the short ATR/HX is capable of achieving near-equilibrium CH4 conversion to an H2-rich reformate while preheating the cathode inlet up to 500 °C. Simulations over a range of anode recycle fractions show that lower recycle fractions increase ATR outlet temperatures and H2 mole fractions with SOFC power densities reaching 2.0 W cm-2, but at the risk of excessive anode temperatures and large temperature gradients across the length of the MEA. Increased cathode excess air ratios can lower the temperatures at the expense of stack power density. Higher anode recycle fractions decrease the temperature rise across the length of the MEA, but also at the expense power density. Further studies with GDC electrolytes based on recent GDC SOFC model developments [3] will explore how high-power densities of GDC can be supported within its operating temperature constraints.

Micro-Scale Thermal Partial Oxidation Reforming of Liquid Fuels and Solid Oxide Fuel Cell Performance and Stability Analysis

Thermal partial oxidation of hydrocarbons to hydrogen and carbon monoxide (i.e., synthesis gas) is limited for conventional scale reactors due to soot formation under higher fuel/air equivalence ratios. Recent research into micro-scale (<4 mm diameter) thermal partial oxidation reactors with a controlled temperature of 800-900 °C has shown promise for conversion to synthesis gas without soot formation. Direct integration of Solid Oxide Fuel Cells (SOFCs) with these micro-scale thermal partial oxidation reactors has been proposed for portable power generation systems. In this work, the micro-scale thermal partial oxidation of methanol/air is investigated at fuel/air equivalence ratios from 1-5 and at a temperature of 800 °C. High conversion rates to synthesis gas are measured with a gas chromatograph for equivalence ratios between 1.5 and 3, with the concentration of hydrogen exceeding 10% and approaching chemical equilibrium predictions. A micro-tubular SOFC is integrated with the micro-scale thermal partial oxidation reformer to electrochemically oxidize the synthesis gas while generating power. SOFC polarization losses are investigated at different equivalence ratios and temperatures of the reformer with results indicating the mass transport losses decrease significantly as the equivalence ratio increases. Peak power densities occur when the synthesis gas concentration is maximized. Short term testing of the SOFC is stable no carbon deposition on the Ni-YSZ anode.

Perovskite Anode for SOFCs Running on Dry Reforming of CH4

Dry reforming of biogas, which contains methane and carbon dioxide, for use as fuel in Solid Oxide Fuel Cells (SOFCs) can achieve superior efficiency and carbon neutrality compared to conventional steam reforming. In this study, we investigated Sr1-xLaxTi1-yRuyO3 (SLTRO) perovskite cathode materials for SOFCs with high electrical conductivity and excellent catalytic activity for dry reforming. La+3 doping on the Sr+2 site of the basic SrTiO3 (STO) perovskite material enhanced electronic conductivity, while simultaneous exsolution of Ru+4 doped on the Ti+4 site at high temperatures facilitated the formation of numerous Ru nanoparticles on the surface. The SLTRO cathode material with exsolved Ru nanoparticles exhibited high catalytic activity for dry reforming, with methane conversion rates of 85% and carbon dioxide conversion rates of 83% at the SOFC operating temperature of 700°C. Notably, it maintained a degradation rate of less than 1%/1000 hours without carbon deposition during dry reforming operation at 700°C for over 1000 hours. Additionally, we will report the electrochemical properties and performance of SOFC cells equipped with SLTRO cathodes. Figure 1

Effect of Y Doping on Proton Conductivity of BaCo0.4Fe0.4Zr0.2-XYxO3-Δ (BCFZY) Proton Ceramic Fuel Cell (PCFC) Cathodes

Solid oxide fuel cells (SOFCs) are recognized as highly efficient renewable energy devices. However, their high operating temperatures (800–1000°C) present severe challenges, including material degradation and reduced energy conversion efficiency. Protonic ceramic fuel cells (PCFCs) have been developed to address these issues by operating at lower temperatures (400–700°C). PCFCs utilize proton conduction in oxide, which has a lower migration barrier than the oxygen ion conduction in SOFCs, making them promising for high performance at reduced temperatures. Nevertheless, current PCFC performance still falls short of SOFC performance, primarily due to sluggish oxygen reduction reaction (ORR) kinetics at the cathode perovskite materials. Enhancing the reaction kinetics necessitates the development of a cathode with high proton conductivity, which can broaden the reaction area within the cathode material. Doping with yttrium (Y) in perovskite material has been a potential solution for enhancing proton conductivity in cathode materials. Y doping in BaZrO3-based electrolytes has successfully led to the development of fast proton-conducting electrolytes for PCFCs. Y doping has also been introduced to the cathode perovskite material, BaCo0.4Fe0.4Zr0.1Y0.1O3-δ (BCFZY), by substituting Y for Zr atoms in BaCo0.4Fe0.4Zr0.2O3-δ (BCFZ) materials. BCFZY has shown potential as a cathode material aiming for high proton conductivity. It demonstrates superior performance in reducing oxygen while concurrently conducting electrons, oxygen ions, and protons. However, the exact effects of Y doping on BCFZY performance are not fully understood, even though research has indicated that the amount of Y doping in BCFZY significantly influences cell performance, including proton conductivity and area-specific resistance (ASR). In this study, we examined the effect of Y doping on the proton conductivity of BCFZY material. The critical question is whether Y doping affects proton diffusion or proton concentration, the main components of proton conductivity. To analyze proton diffusion, we employed density functional theory (DFT) to investigate the impact of Y doping on the proton self-diffusion coefficient. For proton concentration, we applied thermodynamics and defect models to assess the effects of Y doping. Finally, we validated and refined our findings using proton conductivity data from our experimental collaborators, Duffy et al. Our results indicate that Y doping in the BCFZY system slightly impacts proton diffusion, alters the proton uptake mechanism, and can significantly increase hydrogen concentration. This study provides insights for designing high-performance BCFZY materials or perovskite materials for PCFCs that contain redox-inactive acceptor dopants like Y.

Investigation of structural and electrical properties of electrolyte LaGaO3 for solid oxide fuel cell.

Electrochemical devices such as solid oxide fuel cells (SOFCs) allow the direct transformation of fuel's chemical energy into electrical power. Even though YSZ electrolyte-based conventional SOFCs are widely used in both laboratories and on a commercial scale, developing alternative ion-conducting electrolytes is crucial for enhancing SOFC performance at lower operating temperatures. In this work, we conducted a thorough computational analysis on the characteristics of Sr- and Mg-doped superior oxide ion conductors. We have used the DFT technique to examine the system's electrical and structural characteristics and the impact of doping. The GII value and LaGaO3 formation energy are used to investigate thermodynamical and structural stability, respectively. Theoretical investigations are validated against data to ensure the accuracy of the computational model. The research shows that the properties of Sr- and Mg-doped LaGaO3 have changed in a desirable way. This DFT study sheds light on the underlying mechanisms that affect the structural and electronic properties of LaGaO3 electrolytes and offers a thorough investigation of the synergistic effects of strontium and magnesium co-doping. The knowledge acquired is critical for the logical design and development of more stable and efficient solid oxide fuel cells.

One-pot fabrication of high-entropy heterostructure cathode materials with excellent anti-poisoning properties in solid oxide fuel cells

Degradation of cathode performance in solid oxide fuel cells (SOFCs), which is poisoned by atmospheric CO2 and volatilized Cr from steel connecting plates, is a key factor limiting the long-term stable operation. In this work, high entropy heterostructure La0.5Ba0.5Fe0.2Co0.2Ni0.2Cu0.2Mn0.2O3-δ@Ba2CuO3 (HE-LBF@BCO) is designed and prepared by the one-pot method to improve the anti-poisoning ability of the electrode against CO2 and Cr. Meanwhile, the Ba2CuO3 (BCO) heterostructure formed by self-assembly using atomic size effect improves the electrochemical performance. The peak power density with HE-LBF@BCO cathode reaches 789 mW cm−2 at 800 °C with the polarization impedance of 0.34 Ω cm2. To further extend the three-phase interface and enhance oxygen catalytic activity, for HE-LBF@BCO-Gd0.1Ce0.9O2-δ(GDC) composite cathode, the peak power density reaches 789 mW cm−2 and the polarization impedance decreases to 0.16 Ω cm2 at 800 °C, exhibiting a brilliant application potential of the high entropy cathode. More importantly, HE-LBF@BCO-GDC shows an outstanding stability both in CO2 and Cr-containing atmosphere. After testing in Cr-containing atmosphere at 0.8V, the current density of the single cell with HE-LBF@BCO-GDC cathode decreases from 250.86 to 208.64 mA cm−2 at 700 °C. The results confirm the design of high-entropy heterojunction electrode materials provides a new strategy to address the enhancement of SOFC performance.

Materials selection of non-metallic glasses for planar solid-oxide fuel cell sealants

Solid Oxide Fuel Cells (SOFCs) are emerging as promising solutions for advancing sustainable energy systems, mainly due to their high efficiency and fuel flexibility. The performance of planar SOFCs, distinguished by their high power density, significantly relies on the effectiveness of their seal components. This study applies the Ashby method to systematically identify seal materials that can endure the demanding conditions of SOFC operations, specifically with the target operating temperature of 800 °C, aimed at mitigating operational challenges while maintaining efficiency. We screened potential glass sealants based on their thermal, mechanical, and electrical properties using the SciGlass database and a compiled dataset with 38 new compositions from the last four years. Machine learning models helped predict missing data to refine our selection process. We identified nineteen exceptional glass candidates, including four defining the Pareto front, primarily composed of aluminosilicates and borosilicates enriched with BaO, CaO and SrO, with minor additions of MgO, ZrO, and La2O3. This study offers a valuable resource for researchers and engineers focused on developing high-performance SOFCs, presenting promising non-metallic glass candidates suited for sealant applications at operating temperatures of 800 °C.

Characterization of Oxygen Diffusion and Catalytic Behavior of Composite Materials in Solid Oxide Fuel Cells Using the Non-destructive Adler-Lane-Steele Method

Solid oxide fuel cells (SOFCs) are technologically interesting because they provide high-efficiency energy conversion via an electrochemical reaction within the cells. To bring SOFC to market, researchers must develop highly electroactive, low-cost devices that are chemically stable in both high (800 – 1000 °C) and low (600 – 800 °C) temperatures, as well as optimize oxygen reduction in electrodes. The electrochemical performance of SOFC is highly dependent on the catalytic activity (or catalyst behaviours) of the electrode materials involved in the oxygen reduction reaction due to the slower oxygen reduction kinetics at lower temperatures. Understanding the fundamental properties of oxygen self-diffusion in solid-state ionic systems is critical for developing nextgeneration electrolyte and electrode material compositions and microstructures that enable SOFCs to operate at lower temperatures more effectively, durably, and affordably. To date, the most common method for evaluating electrocatalytic performance is electrochemical impedance spectroscopy (EIS), which causes sample damage due to its set-up procedure. As a result, modelling approaches have been used to better understand the reaction mechanism, oxygen diffusion coefficient, and kinetics of SOFC electrode reactions, including the mixed ionic electronic conductor (MIEC)-based electrode. Several models have recently been developed to represent the reaction mechanisms of SOFCs, with Adler-Lane-Steele (ASL) mathematical theory believed to be suitable for predicting oxygen gas diffusion through the pores of the MIEC-based materials. Hence, the aim of this paper is to validate the area-specific resistance of composite electrodes using the ASL modeling technique rather than the standard EIS analysis. The findings are significant in contributing to the development of a new non-destructive method for analyzing the catalytic behavior of SOFC components.

Influence of Mg2+ doping on the oxide ion conductivity of layered ferroelectric SrBi2Ta2O9

Layered perovskites structures are an interesting candidate to explore as a potential electrolyte materials for Solid oxide fuel cell (SOFC) applications. However, achieving a high ionic conductivity (∼0.01 S cm⁻1 below 650 °C) remains a significant challenge to lowering the SOFC operating temperatures. SrBi2Ta2O9 (SBT), an Aurivillius-based layered perovskite, is a well-known ferroelectric material with TC of 320 °C. Site exchange and Bi volatility related defects lead to ionic conductivity in SBT above 700 °C. Here, we aim to control the defect chemistry by doping to promote the oxygen vacancies. We show that Mg doping at the Ta-site in the perovskite block results in 4-fold increase in the bulk conductivity of SBT 3.65 × 10−4 S cm−1 and improvement in the ionic transport number from 0.26 to 0.71. The study provides an opportunity to design new oxide ion conductors in layered ferroelectric oxides.

Cathode-supported SOFCs enabling redox cycling and coking recovery in hydrocarbon fuel utilization

Although cathode-supported solid oxide fuel cells (SOFCs), characterized by significantly thinner anode layers than anode-supported SOFCs, are known to have unique advantages in ensuring stability and reliability against redox operating conditions and carbon deposition, they have received relatively less attention due to their lower performance. Furthermore, there is a lack of in-depth theoretical and experimental studies on their outstanding redox cycle characteristics than the anode-supported cells. Here, applying a sintering aid to the electrolyte considerably reduces the sintering temperature of the electrolyte, with the shrinkage and microstructure of the cathode effectively controlled to lower the diffusion resistance. Consequently, the operating temperature was lowered by more than 100 °C compared to previously reported cathode-supported SOFCs; moreover, at 650 °C, a maximum power density more than twice that reported in previous reports. The redox stability of the cathode-supported cells was demonstrated experimentally and theoretically through a redox cycling test and a 3-D finite element method-based SOFC structure model. Moreover, the outstanding redox cycle property of cathode-supported cells has been experimentally demonstrated for the first time to have the potential to mitigate carbon deposition that occurs when utilizing methane fuel. Hence, this study presents new insights for achieving stable and reliable SOFC operation.