Solid Oxide Fuel Cell Components Research Articles

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.

Advancements in Solid Oxide Fuel Cell Technology: Bridging Performance Gaps for Enhanced Environmental Sustainability

In light of the anticipated 50% increase in global energy demand by 2050, the demand for innovative, environmentally conscious, efficient, and dependable energy technologies is paramount. Solid oxide fuel cells (SOFCs) offer a promising solution for sustainable energy production. This comprehensive review provides a detailed analysis of SOFCs, covering their fundamentals, materials, performance, and diverse applications, while also addressing technological challenges and future prospects. The review emphasizes the key advantages of SOFCs, including their high efficiency of up to 60% and minimal environmental impact. It explores the significance of impurity resistance and durability in materials and manufacturing processes for SOFC components. Comparative evaluations demonstrate the superior energy efficiency and ecological effects of SOFCs compared to other fuel cell technologies. SOFCs’ versatility and potential are showcased through their applications in transportation, power generation and storage, portable devices, and residential usage. However, challenges such as cost, longevity, reliability, and integration with other energy systems are identified, emphasizing the need for supportive policies and regulations.

Tuning the thermo-mechanical synergies effect of solid oxide fuel cells with negative thermal expansion NdMnO3 in La0.6Sr0.4Co0.2Fe0.8O3-δ-based symmetric electrode

Solid oxide fuel cells (SOFCs) are efficient and clean energy conversion devices, but one of the major challenges for their marketization is the instability of different component materials under high temperature operating conditions. The existence of a certain internal stress gradient between materials with different thermal expansion characteristics in the process of SOFCs from low temperature assembly to high temperature use is the main reason of this instability, leading to the inability of SOFCs to repeat start-stop and the rapid decay of long-term stability performance. To improve these problems, a creative concept of fuel cell interface overall regulation is proposed, simplifying the complex interface between different components of SOFCs into a unified and adjustable quasi-zero difference thermal expansion interface. The composite of high catalytic activity electrode material and high stability negative thermal expansion material is used for electrolyte support structure symmetrical cell, which makes the whole cell “sandwich” structure thermally and mechanically compatible. As a concept verification, the classic high catalytic performance electrode material La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF), Gd0.2Ce0.8O2-δ (GDC) and NdMnO3 (NM) negative thermal expansion material with high chemical stability and mechanical stability were composited in equal proportions to form LSCF@GDC&NM electrode as the symmetrical electrode. After equal proportion compositing, the thermal expansion curve of LSCF@GDC&NM material can highly coincide with the thermal expansion curve of GDC, making the single cell with LSCF@GDC&NM electrode can withstand 25 power thermal cycles without significant performance decay, achieving 442 mW cm−2 at 800 °C and maintaining stably for 140 h without any degradation. These results show that using negative thermal expansion material to regulate electrode strategy is expected to make a whole zero difference thermal fuel cell configuration.

Innovations in Electric Current-Assisted Sintering for SOFC: A Review of Advances in Flash Sintering and Ultrafast High-Temperature Sintering

This review discusses the groundbreaking advancements in electric current-assisted sintering techniques, specifically Flash Sintering (FS) and Ultrafast High-Temperature Sintering (UHS), for their application in Solid Oxide Fuel Cells (SOFCs). These innovative sintering methods have demonstrated remarkable potential in enhancing the efficiency and quality of SOFC manufacturing by significantly lowering sintering temperatures and durations, thereby mitigating energy consumption and cost. By providing a detailed overview of the mechanisms, process parameters, and material characteristics associated with FS and UHS, this paper sheds light on their pivotal role in the fabrication of SOFC components such as electrolytes, electrodes, multilayered materials, and interconnect coatings. The advantages, challenges, and prospective opportunities of these sintering technologies in propelling SOFC advancements are thoroughly assessed, underlining their transformative impact on the future of clean and efficient energy production technologies.

A novel approach to tailoring the microstructure and electrophysical properties of Ni/GDC-based anodes by combining 3D-inkjet printing and layer-by-layer laser treatment

This work proposes an original method for tailoring the microstructure and electrical properties of Ni/GDC anodes by using 3D inkjet printing of high-viscosity functional compositions with intermediate laser treatment of each layer after each printing pass. Based on a mixture of highly dispersed oxides NiO and CeO2 doped with gadolinium (GDC), paste formulations for 3D inkjet printing have been developed. The effects of 3D printing and laser treatment conditions on the porosity and shrinkage ratio of the NiO/GDC anodes during sintering were investigated. The reduction of the anode support workpieces to produce Ni/GDC cermet was carried out and the effect of laser exposure on the morphology and electrical characteristics of the resulting samples was studied. It was found that an increase in the laser exposure values during layer-by-layer laser treatment of printing compositions leads to a two-fold increase in the porosity of the solid oxide fuel cell components, an increase in the average pore size from 0.2 to 0.3 to 2–5 μm, and to a five-fold decrease in the sintering shrinkage ratio. It was also found that the electrical conductivity of the Ni/GDC cermet, produced by the reduction of the laser treated NiO/GDC, increased by 5–10 times as the laser exposure values increased. The influence mechanism of the layer-by-layer laser treatment of the original NiO/GDC samples on the electrical conductivity of their reduced counterparts, Ni/GDC cermet anodes, has been proposed. An increase in the electrical conductivity was shown to be due to in situ reduction of NiO, partial sintering of Ni nanoparticles and the formation of a percolation network. This new method of hybrid 3D printing opens up great prospects for tailoring the morphological and electrical characteristics of SOFC anode supports.

Growth of proton conducting strontium cerate composites

The increased population and modern way of life have greatly depleted the effectiveness of traditional energy production methods. There is a strong demand for environmentally friendly and renewable alternatives to replace the old systems. Sustainable energy production systems have emerged as a vital replacement for the conventional use of fossil fuels. Among these, solid oxide fuel cells (SOFCs) play a significant role. Recently, researchers have developed electrolyte components for SOFCs using proton-conducting perovskites with excellent conductivity. This critical assessment presents a yearly overview of innovative strategies for utilizing doped strontium cerate perovskites in energy production systems, a novel approach. The importance of identifying dopants that can enhance conductivity and stability in strontium cerate composites is emphasized, creating a crucial element for high-performance energy systems. Through a comparative study, it's been found that rare earth elements with smaller ionic radii, such as thulium-doped strontium cerium zirconate in an additional composite form, can outperform the traditionally used ytterbium-doped strontium cerate composites in proton-conducting applications.

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.

Study on creep damage and life prediction of the planar solid oxide fuel cell by modeling of multiphysics coupled

In present paper, a strain-based creep damage and failure probability model is constructed to conduct time dependent mechanical performance analysis of solid oxide fuel cell (SOFC) with nonuniform temperature fields obtained by multiphysics coupled modeling at an operational temperature of 800 °C. It demonstrates that assuming uniform temperature fields significantly underestimates the creep damage and failure probability of SOFC components compared to nonuniform temperature fields. The upper interconnector reaches the critical damage value at 54 117 h and initiates a crack, located on the outer surface of the upper interconnector rib, positioned 39 mm from the fuel outlet. After 55 000 h, the failure probability of the anode support is rapidly increasing, reaching 0.185 after 80 000 h, which is 5–6 orders higher than other components. The upper interconnector and anode support are potential failure components, which should be subject to safety inspection to ensure structural integrity after 55 000 h of operation.

Effective post-processing strategies of inkjet-printed ceramic cathodes for improved fuel cell performance

The reluctant effectiveness of the post-processing strategies of the inkjet-printed ceramic components in solid oxide fuel cells (SOFCs) limits the realization of high-power density. We herein report the detailed study on the influences of post-processing strategies including drying and sintering of inkjet-printed cathode layers on their final microstructural, mechanical and electrochemical properties. Results showed that the maximum power density at 0.7V achieved through furnace drying was 2.3 times that of the freeze-dried one, which was due to the high effective porosity of the inkjet-printed layer. The furnace-dried cell was further found to have better mechanical strength (H=2.14GPa, E=93.56GPa). With increased sintering temperature, the power density first increased and then decreased, contrary to its ohmic resistance and polarization resistance. The highest power density of 1084.70 mW cm−2 was reached when sintered at 900°C. This study offers effective post-processing strategies of drying and sintering for the inkjet-printed SOFC components for higher energy conversion efficiency.

A comprehensive review on durability improvement of solid oxide fuel cells for commercial stationary power generation systems

Solid oxide fuel cells (SOFCs) are recognized as an alternative for power generation applications due to their high efficiency and environment-friendly behaviour. The electronic devices and power age could be revolutionized with the commercialization of such devices. Stationary power generation systems based on SOFCs are a step closer to commercialization due to the latest developments in the technology that promises to overcome the inherent bottleneck of high-temperature fuel cells, i.e., durability. According to the US Department of Energy (DOE), the stationary power generation system should have a lifetime of 40,000 h continuous operation. The efficiency of SOFCs is mainly dependent on their components such as anode, cathode, interconnect, and electrolyte. There are numerous factors affecting the efficiency of SOFCs that include the composition of the fuel, kinetics, and thermodynamics of the cell, and working temperature. In this paper, we have presented a comprehensive review of the recent developments to produce durable SOFCs for commercial stationary power generation systems. The review summarizes several prominent degradation mechanisms involved in the SOFC components and methods to reduce the degradation process. In addition, the methods and techniques adopted for the degradation analysis are fully demonstrated, followed by a detailed durability diagnostic through in-situ and ex-situ durability testing. The review is complemented by a lucid presentation of future research challenges and the knowledge gaps coupled with potential recommendations to fill the gaps. The new engineering designs, the material development and the new knowledge presented in this study could provide useful guidance for the key stakeholders, policymakers and power generation entities to commercially implement the application of durable SOFCs for stationary power generation.

Design of High Specific Power Solid Oxide Fuel Cells

The development of solid oxide fuel cells (SOFCs) has progressed from the early Electrolyte Supported Cell (ESC) to state-of-the-art Anode Supported Cell (ASC), which allows the implementation of thinner electrolyte layer (less than 10 micron) and reduction in the operating temperature (below 800°C). The various components of SOFC are constantly being optimized by many research groups to further improve the overall stack performance, including specific power, power density, thermal shock resistance, rapid start-up, and thermal cycling exposure.Precision Combustion, Inc. (PCI) has been working on an advanced electrochemical-based energy storage and power generator design for meeting aggressive specific-power and specific-energy targets required for mobile and transportation applications, such as all-electric propulsion of ground and air vehicles. The key drivers are an exceptionally power-dense solid oxide fuel cell design operating with energy-dense liquid fuels and a hybridized system architecture that maximizes component efficiencies for ultra-high system efficiency. This effort builds on PCI’s experience in developing groundbreaking SOFC generators for mobile and space applications.PCI has developed and demonstrated a novel design of fuel cells with high specific power, that also allows for direct internal reforming of methane and hydrocarbon fuels within a SOFC stack. The system consists of interconnected internal reforming Microlith® metal mesh catalysts strategically embedded within the solid oxide stack. The fuel cell configuration was optimized to reduce CTE mismatch and to improve area specific resistance. The resulting enhanced heat transfer design of the combined components offers the potential for higher overall system efficiency and system simplification as well as enables further compactness and weight reduction of the fuel cell while improving the conditions for long system life. The approach also offers the potential to operate with a wide range of input fuels (i.e., high hydrocarbons as well as various levels of CO2 and water in the fuel inlet) without forming carbon. Carbon formation within the stack system has been known to be detrimental to the performance and durability. Our approach allows for the operation of a modular, advanced SOFC stack for generating power directly from hydrocarbon fuels. Computational design, process simulation, and qualification testing were performed to validate the concept.In this presentation, the results from a breadboard SOFC stack system operation will be highlighted, including the power density, efficiency, and durability. An improvement in the performance as a result of the design advancement, which could improve the stack lifetime, will also be described. The carbon avoidance in the stack while operating with hydrocarbon fuels and with a low water requirement was confirmed. Sensitivity study of the concept to temperature, flow rate, and anode fuel composition was performed and will be highlighted. Finally, preliminary results from the fuel cell design optimization activities will be summarized.

Interface Design Development for High Durability of SOFC Interconnectors Using Electrodeposition Coating

ENE-FARM type S equipped with solid oxide fuel cell (SOFC) stack has been commercialized since 2012. We have been working on improving the power generation efficiency, reducing costs, and the making them more compact by considering that market expansion and cost reduction are critical for the continued market spread of ENE-FARM type S. However, there is a trade-off between cost reduction and performance improvement and issues related to achieving both have emerged during the development process. In order to reduce costs, significant reduction of the number of cells were required. By reducing the number of cells, the current per cell increased, and the stainless steel connecting the cells as the SOFC interconnector was required to have further improvement in durability at high temperature. The degradation modes of the stainless steel used for SOFC mainly include the growth of an insulating oxide layer such as Cr2O3, Cr poisoning of the SOFC cathode, and anomalous oxidation due to decrease in the Cr concentration in the stainless steel. Therefore, ceramic coating is indispensable for the SOFC interconnector in order to suppress these degradations. Material properties of the coating film and coating manufacturing conditions are critical to the ceramic coating equipped on the SOFC interconnector. In addition, it has excellent physical properties such as high Cr diffusion suppression, barrier performance of oxygen gas diffusion, and good physical properties such as high electrical conductivity and good matching of thermal expansion coefficient with the SOFC components. In general, spinel-based oxide materials have been reported as the coating materials for SOFC interconnector, and many binary oxides containing transition metals such as MnCo2O4, MnCu2O4, and NiCo2O4. We have investigated (Zn, Mn, Co)3O4 because of matching the thermal expansion coefficient to the ferritic stainless steel and improving the sinterability at lower temperature. The total electrical conductivity and the thermal expansion coefficient were changed due to the Mn / Co ratio. In terms of these properties, the optimum composition in ZnMnCoO4 was found to be the Mn / Co ratio of around 1 / 1. We have evaluated the long-term durability of SOFC stack components for 12 years in a short period of time by temperature acceleration evaluation method. The voltage changes with the constant current density of 0.3 A cm-2 at a furnace temperature of 973 K shows no degradation over 45000 hours. Moreover, ZnMnCoO4 coated on the 22Cr-Fe alloy shows higher durability over 20000 hours at 1123 K. In 2016, we released the ENE-FARM type S equipped with the electrodeposition coating technology and achieved the highest power generation efficiency and the smallest size at that time. The electrodeposition coating technology has been used in all of ENE-FARM type S sold in Japan. Furthermore, this electrodeposition technology has contributed significantly to the increase in sales volume since 2016. The electrodeposition coating technology can be applied not only to SOFC but also SOEC and is expected to be used more and more widely in the future.

Theoretical Prediction of the Vapor Pressure of Solid Oxide Fuel Cell Components

Due to the high operation temperature solid oxide fuel cells, various chemical reactions can lead to degradation, e.g. based on Cr2O3 gas phase evaporation from the interconnect and subsequent reaction with SrO which originates from LSCF cathodes. Therefore, investigations of the potential chemical reactions and the sublimation process play an extremely important role to study the related chemical reactions in SOFCs.Here we propose a practical physical model based on density functional theory calculations and statistical mechanics, which is used to predict the vapor pressure of pure substances, which allows to extend thermodynamic database and to analyse the resulting chemical reactions inducing the new phase formation which leads to the degradation of SOFCs. These investigations serve as theoretical basis to understand and reduce degradation phenomena from a thermodynamic and kinetic perspective.

Theoretical Prediction of the Vapor Pressure of Solid Oxide Fuel Cell Components

Due to the high operating temperature of solid oxide fuel cells, various chemical reactions can lead to degradation, for instance, based on Cr2O3 gas phase evaporation from the interconnect and subsequent reaction with SrO which originates from LSCF cathodes. Therefore, investigations of the potential chemical reactions and the sublimation process play an extremely important role to study the related chemical reactions in SOFCs. Here we propose a practical physical model based on density functional theory calculations and statistical mechanics to predict the vapor pressure of pure substances. This model is allowed to extend the thermodynamic database and to analyze the resulting chemical reactions inducing the new phase formation which leads to the degradation of SOFCs. These investigations serve as a theoretical basis to understand and reduce degradation phenomena from a thermodynamic and kinetic perspective.

Figure‐of‐Merit Compatibility of Solid Oxide Fuel Cells

Solid oxide fuel cell (SOFC) is one of the most efficient energy converters which can produce electricity from reactions of gaseous chemicals. However, a high operating temperature (T o) of 800–1200 °C is required to achieve the highest peak performance. Such high T o triggers miscellaneous problems, that is, mechanical disintegration with further degradation of its electrical performance for a long‐term application. Despite accomplishing various approaches for the improvement of SOFC performance, the standard level to determine SOFC performance has never been achieved. To date, a quantitative analysis is only pinpointing the power output density (P out). The SOFC cannot be simply determined by a mere P since other parameters that is chemical stability between SOFC components, mismatch of thermal expansion coefficient, and area‐specific resistance also contribute to the mechanical durability and electrochemical stability of the SOFC. Hence, herein, a novel idea is proposed to characterize the overall performance of SOFC through the figure‐of‐merit compatibility (χ cp) of SOFC cells. The χ cp can reflect a level of SOFC performance, thus it can be utilized for future improvements.

Performance evaluation for Ag and Au nanoparticle containing K 2 O‐MgO‐B 2 O 3 ‐Al 2 O 3 ‐SiO 2 ‐F glass sealants for SOFC application

Performance evaluation for Ag and Au nanoparticle containing K ₂ O‐MgO‐B ₂ O ₃ ‐Al ₂ O ₃ ‐SiO ₂ ‐F glass sealants for SOFC application

Progress in nanomaterials fabrication and their prospects in artificial intelligence towards solid oxide fuel cells: A review

As an excellent source of sustainable green energy, solid oxide fuel cells (SOFCs) become a compelling energy conversion and storage device which has been attractive to stakeholders worldwide for their high fuel efficiency, lower air pollution, reduced cost, and admirable steadiness. The electrodes, anode, and cathode, are the significant components of SOFC, facilitate byproducts transportation via electrochemical reaction, and fuel oxidation with electron and ion transportation. SOFCs with a lower operating temperature will reduce system and operating costs while increasing long-term durability. The performance of electrodes in SOFCs has been developed and investigated using a variety of material compositions, as the key determinant of efficiency is dependent on lower operating temperatures. Nanostructured materials, in particular, have demonstrated the greatest potential for improving electrodes at low operating temperatures by enhancing the surface area and improving electrocatalytic activity. Artificial intelligence (AI) is used to create the theoretical SOFC model to minimize the time necessary to identify the operational optimum over a wide range of parameters as well as the total cost of the system. In this review, we have highlighted the development of nanostructured electrodes, their preparation techniques, and the function of AI in the creation of a range of nanoelectrodes and SOFC modeling as well as their significant roles in improving SOFC performance.

(Invited) Gradient Ni-SDC Anode By Reactive Co-Sputtering for Low Temperature Solid Oxide Fuel Cells

Solid oxide fuel cells (SOFCs) are attracting attention as next-generation energy conversion devices due to their high efficiency, eco-friendliness, and scalability. However, the high operation temperature of conventional SOFCs (> 800°C) has posed several practical issues such as thermal degradation and limited material choice. To overcome this limitation, low-temperature SOFC (LT-SOFC, operation temperature <600°C) is actively being researched these days. Ni-YSZ (nickel-yttria stabilized zirconia) is commonly used as anode material in SOFCs. Ni-YSZ anodes are reasonably conductive at high operating temperatures and stable under harsh reducing conditions. However, at lower operating temperatures, the low conductivity of Ni-YSZ becomes an issue for use as an anode. Using doped ceria instead of YSZ is considered an alternative because the doped ceria has higher conductivity compared to YSZ due to the co-existence of multivalent states, i.e., Ce3+ and Ce4+, which can be further improved by doping. Moreover, if one adopts a carefully designed anode structure, e.g., gradient structure, the electrochemical performance of Ni-doped ceria anode can be further improved. Employing nanoscale components, e.g., thin films, are also one of the strategies to improve the electrode kinetics at the low operating temperature of LT-SOFCs. Thin film electrodes with short electronic and ionic paths as well as high surface area contribute to low ohmic and activation resistances. While high uniformity, reproducibility and throughout are practical concerns in thin film fabrication, reactive sputtering, which can produce uniform ceramic thin films from metal target in reactive gas environment in high reproducibility ad deposition rate, is a suitable candidate for thin film components for SOFCs. In this study, we fabricate a Ni-Samaria doped ceria(SDC) gradient anode by reactive co-sputtering. We prepare and characterize the cells with homogeneous and gradient-structured Ni-SDC thin film anodes. The gradient Ni-SDC thin film anode is composed of three layers, whose compositions are graded in a way that the Ni content increases from bottom (near electrolyte-anode interface) to top (anode top-surface). Possibly due to the combination of facilitated ionic conduction near electrolyte-anode interface and higher catalytic activity at anode surface, we observe the improved anode kinetics with lower activation resistance in the cell with gradient-structured Ni-SDC anode compared to the one with homogeneous anode.

Effects of methane steam reforming on the mechanical stability of solid oxide fuel cell stack

Thermal stress-induced mechanical failure is a critical issue for practical application of solid oxide fuel cells (SOFCs). Due to the lack of study on the thermo-mechanical behavior of SOFC with different methane steam pre-reforming ratios (R), a 3D thermo-mechanical model is developed to systematically evaluate the mechanical performance of SOFC running on methane fuel. The model fully considers the coupled transport and reaction processes in the SOFC. The numerically obtained temperature is imported to a mechanical sub-model to determine the thermal stress and strain of SOFC components under various operating conditions, namely with different R values. Covering all R conditions, glass–ceramic sealant is the most dangerous component, while cathode is in sub-critical state. When R < 0.4, the electrolyte has the minimum failure probability. When R > 0.4, the anode becomes the safest component in SOFC stack. With the increase of R, the failure probability of anode decreases all the way and always stays in the safe range, while first decreases then increases for electrolyte, cathode and sealant. R within range of 0.4–0.7 is favorable for the reliability of the whole SOFC stack. This study is useful for identifying optimal operating conditions for efficient and stable operation of SOFC running on alternative hydrocarbon fuels.

Optimal control strategy for solid oxide fuel cell‐based hybrid energy system using deep reinforcement learning

This paper proposes a self-adaptive control strategy for solid oxide fuel cell (SOFC) based hybrid energy system using deep reinforcement learning (DRL) techniques. Highly efficient use of hydrogen in a hybrid energy system with the aid of SOFC could create a new paradigm of renewable energy ecosystem and a series of operation principles. Instead of modeling the energy system operation decision-making process as an optimization problem, a DRL framework is used to seek the optimal control strategy with consideration of various physical constraints in the SOFC components and hybrid energy system operation. Specifically, a deep deterministic policy gradient (DDPG) algorithm is used to solve the operation problem and provide the optimal policy guiding the control actions of a tubular SOFC stack, which involves various dynamic characteristics besides the electric measurement. The learnt control strategy may not produce the best result every time, but can guarantee the ultimate benefit in a non-deterministic way in the long-term operation.