Solid Oxide Fuel Cells Research Articles

Density functional theory modeling of Pr and B-site promoters (Pd, Ti and Ru) doping effects on oxygen vacancy formation in perovskite Solid Oxide Fuel Cell Anodes

Density functional theory modeling of Pr and B-site promoters (Pd, Ti and Ru) doping effects on oxygen vacancy formation in perovskite Solid Oxide Fuel Cell Anodes

Review of Electrochemical Systems for Grid Scale Power Generation and Conversion: Low- and High-Temperature Fuel Cells and Electrolysis Processes

This review paper presents an overview of fuel cell electrochemical systems that can be used for clean large-scale power generation and energy storage as global energy concerns regarding emissions and greenhouse gases escalate. The fundamental thermochemical and operational principles of fuel cell power generation and electrolyzer technologies are discussed with a focus on high-temperature solid oxide fuel cells (SOFCs) and solid oxide electrolysis cells (SOECs) that are best suited for grid scale energy generation. SOFCs and SOECs share similar promising characteristics and have the potential to revolutionize energy conversion and storage due to improved energy efficiency and reduced carbon emissions. Electrochemical and thermodynamic foundations are presented while exploring energy conversion mechanisms, electric parameters, and efficiency in comparison with conventional power generation systems. Methods of converting hydrocarbon fuels to chemicals that can serve as fuel cell fuels are also presented. Key fuel cell challenges are also discussed, including degradation, thermal cycling, and long-term stability. The latest advancements, including in materials selection research, design, and manufacturing methods, are also presented, as they are essential for unlocking the full potential of these technologies and achieving a sustainable, near zero-emission energy future.

Densification of Plasma‐Sprayed ScSZ Enables High Performance of Intermediate Temperature Solid Oxide Fuel Cells With EWSB/ScSZ Bilayer Electrolyte

ABSTRACTThe stabilized Bi2O3 electrolyte bilayer solid oxide fuel cells (SOFCs) are known as promising intermediate temperature SOFCs. However, it is necessary to develop a cost‐effective method for manufacturing electrolyte bilayer SOFCs. In this study, atmospheric plasma spraying (APS) is employed to develop a facile method to deposit EWSB ((Bi2O3)0.705(Er2O3)0.245(WO3)0.05) and ScSZ ((Sc2O3)0.1(Zr2O3)0.9) electrolytes for assembling SOFCs with an EWSB/ScSZ bilayer structure. Results show that the maximum power density (MPD) of the electrolyte bilayer cell with 20 µm EWSB is increased by 52% compared with the monolayer ScSZ electrolyte cell at 750°C. The cell of electrolyte bilayer with a densified ScSZ presents open circuit voltage of ∼1 V and a remarkable performance enhancement with the MPDs of 1110 mW cm−2 at 750°C and 581 mW cm−2 at 650°C, being increased by 57% at 650°C compared with electrolyte bilayer cell with the as‐sprayed ScSZ electrolyte. The dense ScSZ electrolyte effectively ensures the superior electrochemical performance and stability of EWSB at the interface between electrolytes of EWSB/ScSZ bilayer cell.

Oxygen Reduction Activity Enhancement of Solid Oxide Fuel Cell Cathode via a Tiny Amount of Ni Doping

AbstractThe predictable consequences of pollution and global warming force the attention to focus on clean and sustainable energy devices like solid oxide fuel cells (SOFCs). One crucial component of SOFCs is the advanced cathode material with excellent oxygen reduction reaction (ORR) activity and outstanding operating stability. Herein, a novel Ni‐doped cathode material with a detailed composition of Pr0.5Ba0.4Ca0.1Co1‐xNixO3‐δ (PBCCNix, x = 0, 0.0125, 0.025) is successfully synthesized and evaluated. The unconventionally low Ni doping amount optimizes the oxygen defects on PBCCNi0.0125, enhancing the oxygen surface absorption and ORR activity. Among the cathodes investigated in this study, PBCCNi0.0125 exhibits the best catalytic ORR activity, showing a low area‐specific resistance of 0.0152 Ω cm−2 at 800 °C. Ultimately, a single cell with PBCCN0.0125 shows a peak power density of 1.72 W cm−2, compared to that of 1.29 W cm−2 for the cell with PBCC without Ni doping. Besides, better stability of PBCCNi0.0125 cathode on SOFCs operation conditions is also testified on a 200 h operating test. The optimization of oxygen defect concentration on PBCCNi0.0125 would be a possible explanation for the performance enhancement, indicating that PBCCNi0.0125 is a promising cathode material.

Numerical Study of the Effects of Heat Loss and Solid Thermal Conductivity on Syngas Production for Fuel Cells

Syngas can be used as feedstock for efficient energy conversion in solid oxide fuel cells (SOFCs). In the current paper, the conversion efficiency of methane to synthesis gas (H2 and CO) within a two-layer porous media reactor is investigated by a one-dimensional two-temperature model. A detailed chemical reaction mechanism GRI-Mech 1.2 is used to describe the chemical processes. Attention is focused on CO2 content in the methane/air mixture, heat loss to the surroundings, and solid thermal conductivity on temperature distribution and conversion efficiency. Numerical results show that addition of CO2 to the methane/air mixture improves the conversion efficiency. For a molar ratio of CO2/CH4 = 1, the conversion efficiency reaches 44.8%. An increase in heat loss to the surroundings leads to a decrease in conversion efficiency. A greater solid thermal conductivity can improve the conversion efficiency.

Elucidating the Sintering Mechanisms and Synergistic Doping Effects in CuO/Fe2O3 Codoped Gd-Doped Ceria Electrolytes for Advanced Low-Temperature Solid Oxide Fuel Cells (LT-SOFCs).

This paper presents a study of the synergistic effects on sintering activity and the electrical performance of a CuO and Fe2O3 codoped gadolinium-doped ceria (GDC) electrolyte. The isothermal sintering behavior is investigated, and the viscous flow sintering mechanism is validated. The findings indicate that when the molar ratio of CuO to FeO1.5 is 3:1, the sintering temperature can be reduced to 980 °C, which is approximately 450 °C lower than that of GDC (>1450 °C). The lowest sintering activation energy is found to be 389 kJ/mol when the molar ratio of CuO to FeO1.5 is 3:1. Additionally, the concept named "macrodensification temperature" is proposed in this research to describe the connection of the densification process at the microstructure and macrostructure scale. The macrodensification temperature is further verified by quasi-in situ observation and isothermal testing, meanwhile, Cu-Fe-Gd-O and Cu-Ce-O phases, which are beneficial for low-temperature sintering are first found in this work. Moreover, when the molar ratio of CuO to FeO1.5 is 3:1, the ionic conductivity reaches 0.041 S/cm@700 °C, which is 10% higher than that of GDC. The highest performance of the anode-supported cell is found when the electrolyte doping ratio of CuO to FeO1.5 equals 3:1. The open-circuit voltage is observed to be 0.82 V@700 °C, accompanied by a high-power density of 1.2 W/cm2@700 °C. The cell performance with GDC as the electrolyte is found to be 0.8 W/cm2@700 °C. In conclusion, the combined effects of CuO and Fe2O3 doping in GDC may offer a promising avenue for enhancing electrolyte performance and extending its applications to low-temperature solid oxide fuel cells (LT-SOFCs).

Comparative Study of Physicochemical Properties of Biochar Samples Derived from Nutshells as a Solid Fuel for Direct Carbon Solid Oxide Fuel Cells.

This paper presents the results of an investigation into the effect of the physicochemical properties of carbon chars (biochars) on the performance of direct carbon solid oxide fuel cells (DC-SOFCs). Biochars were obtained from walnut, coconut, pistachio, hazelnut and peanut shells by pyrolysis at a temperature of 850 °C. The results of structural studies conducted using X-ray diffraction and Raman spectroscopy reflected a low degree of graphitisation of carbon particles. Biochar derived from walnut shells is characterised by a relatively uniform content of alkali elements, such as sodium, potassium, calcium, magnesium and iron, which are natural components of the mineral residue and act as catalysts for the Boudouard reaction. This study of gasification of biochar samples in a CO2 atmosphere recorded that the highest conversion rate from solid phase to gaseous phase was for the biochar sample produced from walnut shells. The superior properties of this sample are directly connected to structural features, as well as to the random distribution of alkali elements. DC-SOFCs involving 10 mol% of Sc2O3, 1 mol% of CeO2, 89 mol% of ZrO2 (10S1CeZ) or 8 mol% of Y2O3 in ZrO2 (8YSZ) were used as both solid oxide electrolytes and components of the anode electrode. It was found that the highest electrochemical power output (Pmax) was achieved for DC-SOFCs fuelled by biochar from walnut shells, with around 103 mW/cm2 obtained for such DC-SOFCs involving 10S1CeZ electrolytes.

Gd, Sm, and Yb Co-Doped Proton-Conducting Electrolytes for an Intermediate-Temperature Solid Oxide Fuel Cell

Gd, Sm, and Yb Co-Doped Proton-Conducting Electrolytes for an Intermediate-Temperature Solid Oxide Fuel Cell

Improving the Efficiency of an Energy System with an Internal Combustion Engine Using a Solid Oxide Fuel Cell

This paper explores the possibility of using a solid oxide fuel cell as part of an energy system with an internal combustion engine running on bioethanol, incorporating thermochemical waste gas heat recovery. The main goal of the research is to determine the efficiency of energy con-version in energy systems with deep waste gas heat recovery. To achieve this goal, the following tasks were set: based on experimental studies of a spark-ignition engine running on bioethanol, determine the parameters of the process for synthesizing gas through thermochemical conver-sion; theoretically investigate the efficiency of using a solid oxide fuel cell in combination with a bioethanol thermochemical conversion reactor. The most significant result is the determination of the volt-ampere characteristic of the solid oxide fuel cell and the identification of the poten-tial heat recovery capacity of the internal combustion engine exhaust gases through deep heat recovery. The significance of the obtained results lies in the theoretical and experimental valida-tion of efficient energy conversion of synthesis gas in a solid oxide fuel cell, achieving a high thermodynamic efficiency of the cell (0.95–0.75). The proposed energy system configuration, based on an internal combustion engine running on bioethanol with thermochemical waste heat recovery, allows for a 6.5% increase in the overall system power output. This contributes to re-duced fuel consumption and improved environmental performance. The research findings can be applied in the design and development of highly efficient energy systems with internal com-bustion engines for various applications.

Performance of Al2O3 Reinforced BaO-SiO2-CaO Glass as Sealing Materials for Solid Oxide Fuel Cells

Performance of Al2O3 Reinforced BaO-SiO2-CaO Glass as Sealing Materials for Solid Oxide Fuel Cells

The Development and Evaluation of a Low-Emission, Fuel-Flexible, Modular, and Interchangeable Solid Oxide Fuel Cell System Architecture for Combined Heat and Power Production: The SO-FREE Project

Within the framework of the SOCIETAL CHALLENGES—Secure, Clean, and Efficient Energy objective under the European Horizon 2020 research and innovation funding program, the SO-FREE project has developed a future-ready solid oxide fuel cell (SOFC) system with high-efficiency heat recovery. The system concept prioritizes low emissions, fuel flexibility, modular power production, and efficient thermal management. A key design feature is the interchangeability of two different SOFC stack types, allowing for operation under different temperature conditions. The system was developed with a strong emphasis on simplicity, minimizing the number of components to reduce overall plant costs while maintaining high performance. This paper presents the simulation results of the proposed flexible SOFC system, conducted using Aspen Plus® software version 11 to establish a baseline architecture for real plant development. The simulated layout consists of an autothermal reformer (ATR), a high-temperature blower, an SOFC stack, a burner, and a heat recovery system incorporating four heat exchangers. Simulations were performed for two different anodic inlet temperatures (600 °C and 700 °C) and three fuel compositions (100% CH4, 100% H2, and 50% H2 + 50% CH4), resulting in six distinct operating scenarios. The results demonstrate a system utilization factor (UFF) exceeding 90%, electrical efficiency ranging from 60% to 77%, and an effective heat recovery rate above 60%. These findings were instrumental in the development of the Piping and Instrumentation Diagram (P&ID) required for the design and implementation of the real system. The proposed SOFC system represents a cost-effective and adaptable energy conversion solution, contributing to the advancement of high-efficiency and low-emission power generation technologies.

Solid Oxide Fuel Cell Voltage Prediction by a Data-Driven Approach

Solid Oxide Fuel Cell Voltage Prediction by a Data-Driven Approach

Optimal Fuel Consumption in Solid Oxide Fuel Cell based Hybrid Electric Tractor Using Improved Walrus Optimization Technique (IWaOT)

The global demand for electrical energy is rising rapidly due to industrialization and modernization. While fossil fuels are commonly used to meet this demand, their drawbacks—such as global warming, limited availability, and harmful emissions—restrict their long-term use. To address these challenges, there is a growing need for sustainable and environmentally friendly energy sources. Over the past two decades, fuel cells have gained significant attention as a renewable energy option due to their zero-emission operation and high efficiency. Among them, the solid oxide fuel cell (SOFC) stands out for its high operating efficiency and temperature. SOFCs are particularly advantageous because they can directly utilize natural gas. Known for their versatility and quick response, SOFCs are increasingly seen by manufacturers as a promising solution for generating electrical energy. This research proposes an improved approach to enhance efficiency and reduce fuel consumption in Solid Oxide Fuel Cell-based Hybrid Electric Tractors (SOFC-HET). Central to this strategy is the use of the Improved Walrus Optimization Technique (IWaOT), a predictive controller designed to anticipate the tractor’s power demand and the fuel cell’s operating conditions. By leveraging these predictions, IWaOT optimizes key control parameters, including power distribution, fuel flow, air flow, and temperature. This targeted optimization not only reduces hydrogen fuel consumption but also improves overall efficiency and extends the fuel cell system's lifespan.

Exploring the Feasibility of Using Ammonia as a Sulfur Remover to Restore Sulfur-Poisoned Ni-Based Anodes in Solid Oxide Fuel Cells

Exploring the Feasibility of Using Ammonia as a Sulfur Remover to Restore Sulfur-Poisoned Ni-Based Anodes in Solid Oxide Fuel Cells

Review of the Application of Metal-Supported Solid Oxide Fuel Cell in the Transportation Field

Review of the Application of Metal-Supported Solid Oxide Fuel Cell in the Transportation Field

Efficient and Robust Nanocomposite Cermet Anode with Strong Metal–Oxide Interaction for Direct Ammonia Solid Oxide Fuel Cells

AbstractDirect ammonia solid oxide fuel cells (DA‐SOFCs) offer a promising pathway for the efficient utilization of carbon‐free ammonia fuel. However, the nitridation of nickel‐based cermet anodes in ammonia causes rapid microstructural coarsening, leading to durability problems. Herein, an efficient, ammonia‐tolerant Fe‐modified Ni‐Gd0.1Ce0.9O1.95 (NiFe‐GDC) nanocomposite anode is developed by coupling a self‐assembly synthesis process with a sintering‐free electrode fabrication technique. The as‐synthesized nanocomposite oxides self‐assemble into multiple phases, with GDC firmly grown on preformed NiO and NiFe2O4 nanoparticles, which are subsequently in situ alloyed in a reducing atmosphere to form a unique NiFe@GDC encapsulation structure with strong metal–oxide interactions. This NiFe‐GDC nanocomposite not only provides abundant active sites for ammonia decomposition and electrochemical oxidation, but also exhibits exceptional resistance to nitridation and microstructural coarsening. Density functional theory calculations reveal that in situ‐formed NiFe alloy lowers the energy barriers for ammonia adsorption and dehydrogenation while enhancing the nitrogen desorption process. An electrolyte‐supported DA‐SOFC with the NiFe‐GDC nanocomposite anode achieves a peak power density of 0.61 W cm−2 at 800 °C and exhibits outstanding operational stability for 100 h. This work offers new insights into the development of active and durable nickel‐based nanocomposite anodes for DA‐SOFCs.

Comparative Electrochemical Performance of Solid Oxide Fuel Cells: Hydrogen vs. Ammonia Fuels—A Mini Review

Solid oxide fuel cells (SOFCs) have garnered significant attention as a promising technology for clean and efficient power generation due to their ability to utilise renewable fuels such as hydrogen and ammonia. As carbon-free energy carriers, hydrogen and ammonia are expected to play a pivotal role in achieving net-zero emissions. However, a critical research question remains: how does the electrochemical performance of SOFCs compare when fuelled by hydrogen vs. ammonia, and what are the implications for their practical application in power generation? This mini-review paper is premised on the hypothesis that while hydrogen-fuelled SOFCs currently demonstrate superior stability and performance at low and high temperatures, ammonia-fuelled SOFCs offer unique advantages, such as higher electrical efficiencies and improved fuel utilisation. These benefits make ammonia a viable alternative fuel source for SOFCs, particularly at elevated temperatures. To address this, the mini-review paper provides a comprehensive comparative analysis of the electrochemical performance of SOFCs under direct hydrogen and ammonia fuels, focusing on key parameters such as open-circuit voltage (OCV), power density, electrochemical impedance spectroscopy, fuel utilisation, stability, and electrical efficiency. Recent advances in electrode materials, electrolytes, fabrication techniques, and cell structures are also highlighted. Through an extensive literature survey, it is found that hydrogen-fuelled SOFCs exhibit higher stability and are less affected by temperature cycling. In contrast, ammonia-fuelled SOFCs achieve higher OCVs (by 7%) and power densities (1880 mW/cm2 vs. 1330 mW/cm2 for hydrogen) at 650 °C, along with 6% higher electrical efficiency. Despite these advantages, ammonia-fuelled SOFCs face challenges such as NOx emissions, nitride formation, environmental impact, and OCV stabilisation, which are discussed alongside potential solutions. This mini review aims to provide insights into the future direction of SOFC research, emphasising the need for further exploration of ammonia as a sustainable fuel alternative.

High-Entropy Spinel Oxide Nanostructures as Stable Cathodes for Solid Oxide Fuel Cells.

Solid oxide fuel cells (SOFCs) represent a promising clean energy technology for efficient chemical-to-electrical energy conversion with minimal environmental impact. However, the development of cathode materials that can maintain both high performance and long-term stability remains challenging, particularly due to the degradation of nanostructured cathodes caused by particle coarsening. This study employs an impregnation method to fabricate high-entropy spinel oxide (Mg0.2Fe0.2Co0.2Ni0.2Cu0.2)Fe2O4 (MFCNCF) nanoparticles with varying loadings on a porous Ce0.9Gd0.1O1.95 (GDC) skeleton. The optimized cathode with 30 wt % MFCNCF loading achieves a remarkably low polarization resistance of 0.12 Ω·cm2 and maximum power density of 1063.94 mW·cm-2 at 800 °C. Most significantly, the entropy stabilization effect enables the high-entropy spinel oxide nanoparticles to maintain their microstructure throughout 240 h of operation with negligible performance degradation. The study introduces a novel strategy combining high-entropy design with nanostructure engineering to develop stable and high-performance cathode materials for SOFCs.

Operational Conditions for an Internal Combustion Engine in a SOFC-ICE Hybrid Power Generation System

Hybrid power generation systems utilizing pressurized Solid Oxide Fuel Cells (SOFCs) have gained considerable attention recently as an effective solution to the increasing demand for cleaner electricity sources. Among the various hybridization options, gas turbines (GT) and internal combustion engines (ICE) running on SOFC tail gas have been prominent. Although spark ignition (SI) tail gas engines have received less focus, they show significant potential for stationary power generation, particularly due to their ability to control combustion. This research experimentally characterized an SI engine fueled by simulated SOFC anode gas for five blends, which correspond to overall system power level and loads. The study aimed to optimize the engine operating conditions for each fuel blend and establish operational conditions that would sustain maximum performance. The results showed efficiencies as high as 31.4% at 1600 RPM, with a 17:1 compression ratio, equivalence ratio (φ) of 0.75, and a boost pressure of 165 kPa with low NOx emissions. The study also emphasizes the benefits of optimizing boost supply to minimize parasitic loads and improve brake thermal efficiency. Additionally, installing a catalytic oxidizer would enable the system to comply with new engine emission regulations. A proposed control scheme for automation includes regulating engine power by controlling the boost of the supercharger at a fixed throttle position. The results of this study help to promote the development of this SOFC-based clean energy technology.

Anion-Deficient Transition Metal Oxynitrides as Anode Materials for Solid Oxide Fuel Cells.

Transition metal oxynitrides, with their unique electronic structures and excellent conductivity, hold significant promise as anode materials in fuel cells. In this study, we synthesized and characterized two novel anion-deficient transition metal oxynitrides: Ca4La8V4O8N12 and Sr3La9V4O7N13. Their crystal structures were determined via Rietveld refinement of X-ray and neutron diffraction data, revealing a higher concentration of anion vacancies in Sr3La9V4O7N13. As a result, Sr3La9V4O7N13 exhibits significantly enhanced electrical conductivity compared to Ca4La8V4O8N12. Density functional theory (DFT) calculations indicate that Sr3La9V4O7N13 possesses higher defect formation energies, influencing its band structure and facilitating electron transitions, thereby enhancing conductivity. This study underscores the role of anion deficiencies in modulating the electronic properties of transition metal oxynitrides and offers new insights for designing high-performance anode materials for solid oxide fuel cells (SOFCs).