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–High-temperature Solid Oxide Electrolysis Cell (SOEC) may generate excessive local temperature differences during transient operation, which can affect its electrochemical performance and thermal safety. Therefore, this study develops a localized temperature difference control strategy based on a temperature observer, which can avoid a series of issues such as sealing failure caused by the installation of thermocouples. Firstly, a discrete thermoelectric coupling model was developed, dividing SOEC along the flow direction into five nodes. This model was rigorously validated and refined using actual sensor data, including voltage and outlet temperature. Subsequently, a temperature observer for the SOEC's local temperature distribution was designed using a NARX neural network. Finally, an adaptive PID algorithm-based local temperature difference controller was developed, employing the local temperature data provided by the observer as the controlled variable. The effectiveness of the controller was verified under conditions such as excessive electrolysis current and air leakage. The test results show that the response time of the open-loop NARX observer is only 2 s, with the observation error controlled within 0.09K, providing a stable and reliable control variable for the local temperature difference controller. The local temperature difference control strategy effectively ensures that all thermal safety indicators remain within the specified range, demonstrating higher safety and reliability compared to traditional inlet and outlet temperature difference control methods. • A discrete thermoelectric coupling model for the SOEC was developed and subsequently validated by experiments. • A temperature observer based on NARX neural network was designed to eliminate the need for thermocouple. • A local temperature difference control strategy based on adaptive PID algorithm was proposed to enhance SOEC thermal safety. [ABSTRACT FROM AUTHOR]

Durability is still a critical factor that limits solid oxide cell (SOC) technology industrialization. In order to maintain a good level of performance for the overall targeted lifetime of about 40 kh, the oxidation of the interconnects made of ferritic stainless steel and Cr volatilization from this material to the cell electrodes have to be restricted. CeCo-based coatings were applied by PVD HiPIMS on AISI441 alloy. Their ability to reduce the thickness of the poorly conductive formed oxide and improve Cr retention was studied at sample scale by measurements of weight gain and Cr content by ICP-OES after 5000 h of exposure in ambient air at 700 and 800 °C. In the testing conditions, post-test characterization by SEM/EDX showed that oxide scale thickness was reduced when coatings were applied compared to bare AISI441 steel. Moreover, the strong oxide scale spallation observed at 800 °C with bare AISI441 steel was avoided. Cr volatilization was also strongly decreased. Post-test SEM/EDX and ToF–SIMS characterization of a short stack integrating coatings on the air side in some repeat units (RU) confirmed the limited Cr diffusion in the strontium doped lanthanum manganite (LSM) contact layer when the coating is present after 5200 h of solid oxide electrolysis cell operation (SOEC). [ABSTRACT FROM AUTHOR]

Solid oxide cells (SOCs) are a promising dual‐mode technology for the production of hydrogen through high‐temperature water electrolysis, and the generation of power through a fuel cell reaction that consumes hydrogen. Switching between these two modes as the price of electricity fluctuates requires reversible SOC operation and accurate tracking of hydrogen and power production set points. Moreover, a well‐functioning control system is important to avoid cell degradation during mode‐switching operation. In this article, we apply nonlinear model predictive control (NMPC) to an SOC module and supporting equipment and compare NMPC performance to classical proportional‐integral (PI) control strategies, while switching between the modes of hydrogen and power production. While both control methods provide similar performance across various metrics during mode switching, NMPC demonstrates a significant advantage in reducing cell thermal gradients and curvatures (mixed spatial‐temporal partial derivatives), thereby helping to mitigate long‐term degradation. [ABSTRACT FROM AUTHOR]

Nickel/oxygen ion conducting ceramic composite powders (Ni/YSZ) are commonly used materials for fuel electrodes of solid oxide fuel cells and electrolyzers. One of the ways for increasing the activity of Ni/YSZ is infiltration/impregnation, where a formed porous electrode is impregnated with solutions of active elements, followed by thermolysis. In this study, Ni/YSZ electrodes simultaneously impregnated with nickel and ceria particles in different ratios are investigated. It is shown that the introduction of highly dispersed nickel only slightly increases the activity of the Ni/YSZ electrode and does not affect the pathway of the hydrogen oxidation reaction. If a minor amount of ceria particles is introduced into the electrode, it significantly increases its activity and partially changes the reaction mechanism. The best performance is obtained for the electrode impregnated with an equal volume solution of nickel and cerium nitrates. The polarization resistance of such an electrode in wet hydrogen is about 0.05 and 0.17 Ohm cm2 at 850 and 600 °C, respectively, which is about 10 and 65 times lower compared to initial Ni/YSZ. Long-term tests of more than 1100 h in a wet hydrogen atmosphere at 700 °C showed satisfactory stability of polarization resistance of all investigated electrodes. [Display omitted] • Ni/YSZ electrodes infiltrated with nickel and/or ceria were investigated. • The injection of nickel resulted in a negligible enhancement of Ni/YSZ activity. • Introduction of minor amounts of ceria leads to a partial change in HOR mechanism. • Introduction of close amounts of nickel and cerium is most effective. • Introduction of a significant amount of ceria completely changes the HOR mechanism. [ABSTRACT FROM AUTHOR]

The development of multi-functional and highly mixed ionic-electronic conductive perovskite oxide-based electrodes is becoming an established trend for designing and developing SOFC/SOEC reversible cells. Ideally, the same material can be employed at both electrodes provided that structural stability, high conductivity and catalytic activity are preserved in different operational atmospheres. Here, controlled Fe substitution with a small extent (0.5 mol%) of platinum at the B-site of a lanthanum strontium ferrite is proposed as an effective method to enhance the original oxide properties as both air and fuel electrode for solid oxide cells. The effects of low Pt-doping on La 0.6 Sr 0.4 FeO 3-δ structure, morphology and electrocatalytic activity are investigated and discussed. La 0.6 Sr 0.4 Fe 0.995 Pt 0.005 O 3-δ (05P-LSF) is first tested as air electrode, displaying lower area specific resistance as compared to the Pt-free perovskite. 05P-LSF structural stability and conductivity are assessed in 100 % CO 2 and 50 % CO 2 –50 % CO environments. Symmetric devices are then tested as SOECs in 100 % CO 2 , obtaining a current density output of 1.08 A/cm2 at 1.5 V. Electrochemical impedance spectroscopy (EIS) with distribution of relaxation times analysis (DRT) are used to provide insights on the electrode operation. Pt nanoparticle exsolution at the fuel electrode is induced by voltage application. The device stability under applied voltage is assessed for over 120 h. SOFC/SOEC characterization in a 50 % CO 2 /50 % CO mixture at 850 °C is also provided, obtaining a maximum power density of 270 mW/cm2 in SOFC mode, and a current density of 0.91 A/cm2 at 1.5 V in SOEC mode. [ABSTRACT FROM AUTHOR]

The United States' focus on decarbonization has spawned interest among policymakers in deploying water electrolysis technology for clean hydrogen production. However, water electrolyzers also raise concerns regarding their substantial use of carbon-intensive materials. Here, we conduct a comprehensive life-cycle analysis (LCA) of three prominent water electrolyzer technologies to investigate the environmental implications of their manufacturing and life cycles under different energy sources. All electrolyzer technologies employing low-carbon energy (nuclear, solar, or wind) exhibit life-cycle greenhouse gas (GHG) emissions of 0.3–2.4 kg-CO 2-eq /kg-H 2. This is significantly lower than the corresponding GHG emissions for hydrogen production via both conventional steam methane reforming and alternative autothermal reforming with carbon capture and storage (by > 50%). The well-to-gate GHG emissions of low-carbon electrolyzers (0–0.36 kg-CO 2-eq /kg-H 2) qualify for Tier I of the production tax credit in the U.S.' Inflation Reduction Act of 2022, indicating their suitability for producing decarbonized hydrogen under this program. • Compares the life-cycle environmental impacts of SOEC, PEM, and AEC electrolyzers • Ni, Ti, Si, steel, Cu, and energy use dominate electrolyzers' manufacturing impacts • Electricity generation-related impacts dictate electrolyzers' life-cycle impacts • Low-carbon electrolysis outperforms other H 2 -producing technologies over life-cycle • Decarbonized H 2 production requires clean material production and low-carbon energy [ABSTRACT FROM AUTHOR]

The shale gas revolution bolsters ethane supply, thereby enhancing the economic viability of ethylene production from ethane. Presently, catalytic ethane dehydrogenation technology exhibits immense potential in the realm of ethylene production. This study achieves the electrochemical oxidative dehydrogenation conversion of ethane to ethylene via a solid oxide electrolysis cell (SOEC), effectively circumventing the issue of excessive oxidation during the ethane oxidative dehydrogenation process. An active electrode with an in situ grown metal-oxide interface significantly promotes the activation of the ethane C–H bond, leading to efficient ethylene production. Under the co-electrolysis mode of ethane with CO 2 , the Co@CeO 2 electrode demonstrates exceptional performance, achieving an ethane conversion rate of 33.1% and an ethylene selectivity of 88.9% at an applied voltage of 1.0 V. Moreover, the metal-oxide interface constructed via an in situ exsolved method effectively prevents the agglomeration of nanoparticles at high temperatures, thus enhancing the catalyst's resistance to coking and stability. Notably, the electrode's performance does not exhibit significant degradation even after 100 h of electrochemical reaction. • The electrochemical oxidative dehydrogenation of ethane effectively inhibited excessive oxidation. • The in situ grown metal-oxide interface has stability and promotes the activation of the ethane C–H bond. [ABSTRACT FROM AUTHOR]

Climate change is a major concern for the sustainable development of global energy systems. Hydrogen produced through water electrolysis offers a crucial solution by storing and generating renewable energy with minimal environmental impact, thereby reducing carbon emissions in the energy sector. Our research evaluates current hydrogen production technologies, such as alkaline water electrolysis (AWE), proton exchange membrane water electrolysis (PEMWE), solid oxide electrolysis (SOEC), and anion exchange membrane water electrolysis (AEMWE). We systematically review life cycle assessments (LCA) for these technologies, analyzing their environmental impacts and recent technological advancements. This study fills essential gaps by providing detailed LCAs for emerging technologies and evaluating their scalability and environmental footprints. Our analysis outlines the strengths and weaknesses of each technology, guiding future research and assisting stakeholders in making informed decisions about integrating hydrogen production into the global energy mix. Our approach highlights operational efficiencies and potential sustainability enhancements by employing comparative analyses and reviewing advancements in membrane technology and electrocatalysts. A significant finding is that PEMWE when integrated with renewable energy sources, offers rapid response capabilities that are vital for adaptive energy systems and reducing carbon footprints. [ABSTRACT FROM AUTHOR]

The remarkable stability, suitable thermomechanical characteristics, and acceptable electrical properties of donor-doped strontium titanates make them attractive materials for fuel electrodes, interconnects, and supports of solid oxide fuel and electrolysis cells (SOFC/SOEC). The present study addresses the impact of processing and thermochemical treatment conditions on the electrical conductivity of SrTiO3-derived ceramics with moderate acceptor-type substitution in a strontium sublattice. A-site-deficient Sr0.85La0.10TiO3−δ and cation-stoichiometric Sr0.85Pr0.15TiO3+δ ceramics with varying microstructures and levels of reduction have been prepared and characterized by XRD, SEM, TGA, and electrical conductivity measurements under reducing conditions. The analysis of the collected data suggested that the reduction process of dense donor-doped SrTiO3 ceramics is limited by sluggish oxygen diffusion in the crystal lattice even at temperatures as high as 1300 °C. A higher degree of reduction and higher electrical conductivity can be obtained for porous structures under similar thermochemical treatment conditions. Metallic-like conductivity in dense reduced Sr0.85La0.10TiO3−δ corresponds to the state quenched from the processing temperature and is proportional to the concentration of Ti3+ in the lattice. Due to poor oxygen diffusivity in the bulk, dense Sr0.85La0.10TiO3−δ ceramics remain redox inactive and maintain a high level of conductivity under reducing conditions at temperatures below 1000 °C. While the behavior and properties of dense reduced Sr0.85Pr0.15TiO3+δ ceramics with a large grain size (10–40 µm) were found to be similar, decreasing grain size down to 1–3 µm results in an increasing role of resistive grain boundaries which, regardless of the degree of reduction, determine the semiconducting behavior and lower total electrical conductivity of fine-grained Sr0.85Pr0.15TiO3+δ ceramics. Oxidized porous Sr0.85Pr0.15TiO3+δ ceramics exhibit faster kinetics of reduction compared to the Sr0.85La0.10TiO3−δ counterpart at temperatures below 1000 °C, whereas equilibration kinetics of porous Sr0.85La0.10TiO3−δ structures can be facilitated by reductive pre-treatments at elevated temperatures. [ABSTRACT FROM AUTHOR]

The high demand for natural gas (NG) worldwide has led to an increase in the size of the LNG carrier fleet. However, the heat losses from this type of ship's engines are not properly managed, nor is the excess boil-off gas (BOG) effectively utilised when generation exceeds the ship's power demand, resulting in significant energy losses dissipated into the environment. This article suggests storing the lost energy into green H2 for subsequent use. This work compares three different electrolysis technologies: solid oxide (SOEC), proton exchange membrane (PEME), and alkaline (AE). The energy required by the electrolysis processes is supplied by both the LNG's excess BOG and engine waste heat through an organic Rankine cycle (ORC). The results show that the SOEC consumes (743.53 kW) less energy while producing more gH2 (21.94 kg/h) compared to PEME (796.25 kW, 13.96 kg/h) and AE (797.69 kW, 10.74 kg/h). In addition, both the overall system and SOEC stack efficiencies are greater than those of PEME and AE, respectively. Although the investment cost required for AE (with and without H2 compression consideration) is cheaper than SOEC and PEME in both scenarios, the cost of the H2 produced by the SOEC is cheaper by more than 2 USD/kgH2 compared to both other technologies. [ABSTRACT FROM AUTHOR]

Additive manufacturing has emerged as a promising technique in energy device research, owing to its ability to fabricate programmable geometries. Nevertheless, it remains a significant challenge to prepare three-dimensional electrode structures with finely resolved features. Herein, we propose a vat photopolymerization (VP) 3D printing process for Nickel Oxide-Yttria Stabilized Zirconia (NiO-YSZ) anode structure of solid oxide fuel cell (SOFC). A photosensitive NiO-YSZ slurry was prepared with appropriate curing properties, low viscosity, and stability. Optimal debinding processes, determined through thermo-gravimetric analysis, were employed to prevent green part cracking and deformation. Microstructural analysis demonstrated a uniform and finely distributed pore structure in the anode. Remarkably, cells featuring the VP-printed NiO-YSZ anode demonstrated notable performance with peak power densities of 239 mW·cm−2, 364 mW·cm−2, and 536 mW·cm−2 at 750 °C, 800 °C, and 850 °C, respectively. This novel method opens avenues for enhancing the performance of SOFCs through the optimization of anode structure. [ABSTRACT FROM AUTHOR]

Oxygen mobility was studied by oxygen isotopic exchange on three electrodes used in Solid Oxide Electrolyser Cells under polarization (La0.8Sr0.2MnO3 (LSM), La0.6Sr0.4Co0.2Fe0.8O3‐δ (LSCF) and La2NiO4+δ (LNO)). The rate of the surface and the bulk mechanisms for oxygen mobility is depending on the type of conductivity (electronic conduction or mixed ionic and electronic conductivity). It is shown that a one oxygen atom exchange is dominant for the surface path whereas a two oxygen atoms mechanism dominates for the bulk path. The rate constant for the bulk path is much higher than the one for the surface path by two orders of magnitude. Additionally, polarized oxygen isotopic exchange revealed that electrode overvoltage increases significantly the rate constant for the surface path, whereas its impact on the bulk path is negligible. [ABSTRACT FROM AUTHOR]

Long-duration energy storage is the key challenge facing renewable energy transition in the future of well over 50% and up to 75% of primary energy supply with intermittent solar and wind electricity, while up to 25% would come from biomass, which requires traditional type storage. To this end, chemical energy storage at grid scale in the form of fuel appears to be the ideal option for wind and solar power. Renewable hydrogen is a much-considered fuel along with ammonia. However, these fuels are not only difficult to transport over long distances, but they would also require totally new and prohibitively expensive infrastructure. On the other hand, the existing natural gas pipeline infrastructure in developed economies can not only transmit a mixture of methane with up to 20% hydrogen without modification, but it also has more than adequate long-duration storage capacity. This is confirmed by analyzing the energy economies of the USA and Germany, both possessing well-developed natural gas transmission and storage systems. It is envisioned that renewable methane will be produced via well-established biological and/or chemical processes reacting green hydrogen with carbon dioxide, the latter to be separated ideally from biogas generated via the biological conversion of biomass to biomethane. At the point of utilization of the methane to generate power and a variety of chemicals, the released carbon dioxide would be also sequestered. An essentially net zero carbon energy system would be then become operational. The current conversion efficiency of power to hydrogen/methane to power on the order of 40% would limit the penetration of wind and solar power. Conversion efficiencies of over 75% can be attained with the on-going commercialization of solid oxide electrolysis and fuel cells for up to 75% penetration of intermittent renewable power. The proposed hydrogen/methane system would then be widely adopted because it is practical, affordable, and sustainable. [ABSTRACT FROM AUTHOR]

In contemporary power generation, enhancing efficiency and mitigating environmental contamination are of paramount importance. The imperative to curtail greenhouse gas emissions stands as a preeminent challenge within this sector. Concurrently, there is a marked surge in the exploitation of renewable energy sources, which, due to their intermittent nature, precipitates the imperative for advanced energy storage solutions. This paper introduces an integrated system designed to address both the reduction of CO2 emissions and the storage of energy. The advocated system integrates a Molten Carbonate Fuel Cell (MCFC), Solid Oxide Electrolysis Cell (SOEC), and a Sabatier reactor. The MCFC is employed for its proficient CO2 capture capabilities at the cathode, exhibiting remarkable efficiency, operational flexibility, and a high CO2 separation quotient. The SOEC is recognized for its effective hydrogen production, leveraging high operational temperatures to augment hydrogen output while diminishing electrical energy consumption through thermal energy substitution. The Sabatier reactor is utilized for catalytic methanation, transforming CO2 into Substitute Natural Gas—a compound predominantly comprising methane and hydrogen with minimal CO2 and water traces. This system facilitates the capture and utilization of over 80% of CO2 from exhaust fumes, achieving an overall energy efficiency of 71%. The system's design and off-design operational parameters were meticulously modeled and analyzed.

Higher electrolysis efficiency than that achieved with conventional electrolysis and integrated fuel production would help to reduce dependence on bio-energy further. In this regard, solid oxide electrolyzer (SOEC) technology is of particular interest because of its unrivaled conversion efficiency, due to the favorable thermodynamics and kinetics at higher operating temperatures. In particular, SOEC high-temperature co-electrolysis (HTCE) of CO2/H2O can convert CO2 into valuable chemicals and fuels, which will help to reduce reliance on fossil fuels and mitigate greenhouse gas emissions. In this report, we present a comprehensive overview of recent research progress made with SOEC HTCE of CO2/H2O. The main focus areas are the development history, the basic principle and the reaction mechanism of HTCE of CO2/H2O using SOEC. The fuel electrode and oxygen electrode materials for SOEC HTCE of CO2/H2O are classified and introduced. The factors that affect the co-electrolysis reaction process are also described in detail, and the optimization strategy of the process conditions is explained to provide a better understanding of the SOEC HTCE process. The challenges and possible future development directions are also suggested, as guidance for future research.

Sustainable aviation fuel (SAF) production from captured carbon dioxide and green hydrogen, is referred to as the key to decarbonize the hard-to-abate aviation sector. Fischer-Tropsch is a mature and reliable pathway for hydrocarbon synthesis, with a wide spectrum of technological options and high plant efficiency extending to more than 80 % of e-kerosene selectivity. In this work, an Aspen Hysys model, coupled with different Matlab simulations for Fischer-Tropsch, Hydrocracker and SOEC, was set up to estimate efficiency and selectivity. The results show that global efficiency is mainly linked to the efficiency of the production of H 2. Energetic efficiency reaches 48.06 % using the already existing commercial electrolyte supported cell in a SOEC electrolyser, but it could increase to 65.74 % if cathode supported cell was considered. • An energy analysis of the Power-to-Liquid process has been performed. • The system reaches a global efficiency of 48.06 % and up to 38.71 % of Power-to-Kerosene efficiency. • It is possible to increase global efficiency up to 65.74 % and Power to kerosene efficiency to 53.60 %. [ABSTRACT FROM AUTHOR]

Previous studies have found that in ceramic fuel cells using Ni 0·8 Co 0·15 Al 0·05 LiO 2 (NCAL) as the electrode, lithium compounds such as LiOH generated by reduction of NCAL anode by H 2 diffuse into oxide electrolyte membranes such as Gd 0.1 Ce 0·9 O 2 (GDC), and the "GDC-lithium compounds" composite electrolyte formed online is an excellent proton conductor. In this paper, the low-temperature electrolysis performance of proton conductor type solid oxide electrolysis cell (P-SOEC) with GDC as electrolyte and NCAL as electrode for direct electrochemical conversion of H 2 O into H 2 was investigated. It is found that at operation temperature of 550 °C, the current density of the SOEC prepared in this paper can reach 2.263 A cm−2 at 1.6 V. The composite electrolyte in the electrolysis cell reaches an ionic conductivity of 0.572 S cm−1 in the SOEC mode. The excellent hydrogen production performance proves that this new type of electrolysis cell with lithium compounds as electrodes is a promising and potential proton conductive low-temperature SOEC. • SOEC with NCAL electrodes was fabricated. • Proton conductivity of the composite electrolyte reaches 0.572 S cm−1 at 550 °C. • The electrolytic current density of the SOEC reaches 2.263 A·cm−2 at 1.6 V. • Provided a new type of SOEC and related electrolytic cell material. [ABSTRACT FROM AUTHOR]

As consequence of the transition towards sustainable energy sources, the future production of liquid energy carriers (e.g. methanol) via H2 supply pathways utilizing water electrolyzers (power-to-liquid) will most likely be based on fluctuating grid electricity or islanded renewable inputs. As a result, these production processes are subject to fluctuating operating conditions and varying production capacities, ultimately leading to uncertainties with respect to their process economics and profitability. Therefore, the impact of different electricity supply-side scenarios (static grid and intermittent grid or renewable supply) on the production economics of power-to-liquid processes needs to be assessed thoroughly for the upcoming decades. Methanol is considered as an essential base chemical which is widely known for its versatility and broad potential use contexts in future chemical industries and energy storage applications. Methanol production pathways powered by renewable electricity sources, also known as power-to-methanol processes, are characterized by low specific life-cycle emissions and are therefore of paramount interest. One possible renewable process chain features proton-conducting high temperature electrolyzers combined with a direct hydrogenation of CO2. In this paper, a techno-economic forecast study of this process chain is presented and specific production costs of renewable methanol under different electricity supply scenarios are determined and discussed for the years 2030 and 2050. The studies showed that flexible grid-supported scenarios through direct spot-market participation and renewable scenarios based on wind onshore production enable the largest production cost reduction potential in the upcoming decades. Minimum production costs of 740 € t−1MeOH (2030) and 415 € t−1MeOH (2050) are determined for a flexible operation of the system with spot-market participation, benefitting from times of low or even negative electricity prices. Among the renewable production scenarios, islanded power-to-methanol systems coupled to wind onshore plants were identified as the most beneficial configuration with ascertained production costs as low as 820 € t−1MeOH and 353 € t−1MeOH by 2030 and 2050, respectively.

Climate change is a major concern for the sustainable development of global energy systems. Hydrogen produced through water electrolysis offers a crucial solution by storing and generating renewable energy with minimal environmental impact, thereby reducing carbon emissions in the energy sector. Our research evaluates current hydrogen production technologies, such as alkaline water electrolysis (AWE), proton exchange membrane water electrolysis (PEMWE), solid oxide electrolysis (SOEC), and anion exchange membrane water electrolysis (AEMWE). We systematically review life cycle assessments (LCA) for these technologies, analyzing their environmental impacts and recent technological advancements. This study fills essential gaps by providing detailed LCAs for emerging technologies and evaluating their scalability and environmental footprints. Our analysis outlines the strengths and weaknesses of each technology, guiding future research and assisting stakeholders in making informed decisions about integrating hydrogen production into the global energy mix. Our approach highlights operational efficiencies and potential sustainability enhancements by employing comparative analyses and reviewing advancements in membrane technology and electrocatalysts. A significant finding is that PEMWE when integrated with renewable energy sources, offers rapid response capabilities that are vital for adaptive energy systems and reducing carbon footprints.

Methanol is a crucial commodity in the chemical industry and is employed as precursor for many products. It can be used to store fluctuating renewable energy, specifically benefiting from its liquid state at ambient temperatures. As the demand for green, renewable methanol is projected to soar in the next decades, environmentally friendly and sustainable pathways for its production have to be provided. Through the combination of proton-conducting high temperature electrolysis for the provision of dry H2 with a heterogeneously catalyzed hydrogenation of CO2, efficient and simple power-to-methanol production processes can be established. Here, a novel power-to-methanol system model capable of real-time transient simulation is presented and viable operating windows are determined for different key operating parameters of the respective main process stages. A techno-economic assessment is carried out to determine the specific production costs of renewable methanol. Specific methanol production costs of 2419 € t−1MeOH for small-scale applications (1.12 MW) were retrieved, which corresponds to a more than fourfold increase over the current market price of conventionally produced methanol. Increases in system scale are found to decrease the methanol production costs due to economy-of-scale effects. The sensitivity of the process economics is assessed with regards to crucial operational and capital characteristics.

The hydrogen economy is of crucial importance in energy policies worldwide. Moreover, there are many benefits to producing biomethanol because it can be used in engines to achieve high efficiency, zero emission and lower risks of flammability. This research aims to evaluate a biomethanol and natural gas generation system that uses biomass gasification and high-temperature electrolysis. Thermal integration is applied between the steam generators of the gasifier and electrolyzer. The LNG regasification unit and an open Brayton cycle are responsible for power and natural gas production. The flue gas leaving the gas turbine leads to additional production of biomethanol. Oxygen management is applied between three different subsystems and there is a large amount of CO 2 utilization as well. The results of energy analysis and thermodynamic modelling of an integrated system conducted in Aspen Plus indicate that the proposed cycle produces 16 644 ton/yr of natural gas, 1412 ton/yr of biomethanol, uses 3450 ton/yr of CO 2 , and has an efficiency of 81.96 %. Raising the methanol reactor temperature from 220 °C to 350 °C significantly enhances biomethanol capacity from 1015 ton/yr to 1930 ton/yr, leading to a 4 % increase in total energy efficiency. • The biofuels plant integrates gasifier, electrolyzer, and water-gas-shift reactor. • Energy efficiency of 81.96 % and CO 2 utilization of 3450 ton/yr are obtained. • The overall cold gas efficiency is found to be 58.35 %. • The high-temperature electrolysis cell consumes 75 % of input electricity. • Decreasing input water of electrolyzer enhances efficiency and CO 2 utilization. [ABSTRACT FROM AUTHOR]

Solid oxide electrolysis cells have emerged as a promising technology for renewable energy storage. The intermittent operation, however, could jeopardize durability. Understanding the transient response characteristics of the solid oxide electrolysis cell under diverse electrical inputs is crucial to comprehend the dynamic durability of the electrolysis cell. Yet, the electrochemical and temperature dynamic responses are challenging to be in-situ measured. In this study, a three-dimensional electrochemical-mass-heat coupled dynamic model of the solid oxide electrolysis cell is established and validated by the experimental I–V curve and electrochemical impedance spectroscopy data. The current and voltage manipulations on the transient responses are evaluated and the cause of voltage overshoot during current control is analyzed. The effects of amplitude and switching time of current upward manipulation on the electrochemical and thermal responses are also investigated. It is discovered that 40% current upward (60% power upward) slightly exceeds the upper limit of the temperature gradient of 8 K/cm and approaches the FU limit of 90%. On the other hand, the influence of switching time on safety performance is negligible. [Display omitted] • A 3D transient numerical model for solid oxide electrolysis cell is developed. • Dynamic response under current and voltage manipulations is compared. • Voltage overshoot is examined by thermal-decoupled analysis and EIS. • Amplitude and switching time of current upward is investigated. • Safety operation is discussed in regarding with temperature gradient and FU. [ABSTRACT FROM AUTHOR]

In the new hydrogen economy, bio-hydrogen derived from organic material can represent an opportunity to valorise current waste management systems. The present work deals with innovative systems for producing hydrogen from landfill gas combining Power-to-Gas plants and biogas reforming. To do so, Pressure Swing Adsorption (PSA) and Chemical Absorption (CA) have been assessed for biogas upgrading. Furthermore, both high-temperature electrolysis by SOECs (solid oxide electrolysis cell) and low-temperature electrolysis by PEM (proton exchange membrane) and Alkaline electrolysers are presented. The simulation results are compared in terms of Levelized Cost of Hydrogen (LCOH) at stack price and after compression and storage. Assuming a capacity factor equal to 70%, the potential hydrogen production rate in such hybrid configurations ranges between 26 and 28 kg H2 /h. Furthermore, the LCOH turns out to be in a range between 1.9 and 3.3 €/kg H2. Considering 2030 forecast, LCOH below 2 €/kg H2 at stack is feasible. • Green hydrogen production from landfill through power and thermal cogeneration. • Water electrolysis in low and high temperature. • Steam reforming process featuring PSA and CA. • Comprehensive technological and economic survey on the benchmark. • Comparison between ten potential hybrid energy systems in terms of LCOH. [ABSTRACT FROM AUTHOR]

For the direct reduction of CO2 and H2O in solid oxide electrolysis cells (SOECs) with cermet electrodes toward methane, a fundamental understanding of the role of elemental carbon as a key intermediate within the reaction pathway is of eminent interest. The present synchrotron-based in situ near-ambient-pressure X-ray photoelectron spectroscopy (NAP-XPS) study shows that alloying of Ni/yttria-stabilized-zirconia (YSZ) cermet electrodes with Cu can be used to control the electrochemical accumulation of interfacial carbon and to optimize its reactivity toward CO2. In the presence of syngas, sufficiently high cathodic potentials induce excess methane on the studied Ni/yttria-stabilized-zirconia (YSZ)-, NiCu/YSZ- and Pt/gadolinium-doped-ceria (GDC) cermet systems. The hydrogenation of carbon, resulting from CO activation at the triple-phase boundary of Pt/GDC, is most efficient. [ABSTRACT FROM AUTHOR]

Tailoring the electrical conductivity of functional ceramics by introducing dislocations is a comparatively recent research focus, and its merits were demonstrated through mechanical means. Especially bulk deformation at high temperatures is suggested to be a promising method to introduce a high dislocation density. So far, however, controlling dislocation generation and their annihilation remains difficult. Although deforming ceramics generate dislocations on multiple length scales, dislocation annihilation at the same time appears to be the bottleneck to use the full potential of dislocations‐tailoring the electrical conductivity. Here, we demonstrate the control over these aspects using a micromechanical approach on yttria‐stabilized zirconia ‐ YSZ. Targeted indentation well below the dislocation annihilation temperature resulted in extremely dense dislocation networks, visualized by chemical etching and electron channeling contrast imaging. Microcontact‐impedance measurements helped evaluate the electrical response of operating individual slip systems. A significant conductivity enhancement is revealed in dislocation‐rich regions compared to pristine ones in fully stabilized YSZ. This enhancement is mainly attributed to oxygen ionic conductivity. Thus, the possibility of increasing the conductivity is illustrated and provides a prospect to transfer the merits of dislocation‐tuned electrical conductivity to solid oxygen electrolytes. [ABSTRACT FROM AUTHOR]

The high demand for natural gas (NG) worldwide has led to an increase in the size of the LNG carrier fleet. However, the heat losses from this type of ship’s engines are not properly managed, nor is the excess boil-off gas (BOG) effectively utilised when generation exceeds the ship’s power demand, resulting in significant energy losses dissipated into the environment. This article suggests storing the lost energy into green H2 for subsequent use. This work compares three different electrolysis technologies: solid oxide (SOEC), proton exchange membrane (PEME), and alkaline (AE). The energy required by the electrolysis processes is supplied by both the LNG’s excess BOG and engine waste heat through an organic Rankine cycle (ORC). The results show that the SOEC consumes (743.53 kW) less energy while producing more gH2 (21.94 kg/h) compared to PEME (796.25 kW, 13.96 kg/h) and AE (797.69 kW, 10.74 kg/h). In addition, both the overall system and SOEC stack efficiencies are greater than those of PEME and AE, respectively. Although the investment cost required for AE (with and without H2 compression consideration) is cheaper than SOEC and PEME in both scenarios, the cost of the H2 produced by the SOEC is cheaper by more than 2 USD/kgH2 compared to both other technologies.

Solid oxide electrolysis cell stacks are expected to experience dynamic conditions when using renewable electricity derived from wind or solar power. To address this scenario, (Mn,Co) 3 O 4 (MCO)-coated Crofer 22 APU interconnect coupons are subjected to thermal cycling, and intermittent current density, with gas compositions relevant to high-temperature electrolysis (elevated steam:hydrogen ratio and oxygen content). Defects are also intentionally introduced in the MCO coating, to assess whether the difference in oxidation properties of the adjacent coated and uncoated (defective) surfaces causes sufficient stress to damage the protective oxide scale. Specimens with defects are subjected to oxidation for 1000 h at 800 °C, or thermal cycling. Before thermal cycling, some specimens are pre-oxidized to create a thick oxide scale to mimic the scale thickness expected after ∼30 kh operation. In all cases, the coating and oxide scale remain well adhered with no cracking observed. Area-specific resistance (ASR) is monitored in both single-atmosphere and dual-atmosphere conditions, and the ASR is stable and is not impacted by dynamic cycling of the current density. This work provides confidence that the MCO coated interconnect will function as needed in dynamic operation conditions, even with coating defects. • Oxidation of coated interconnects is studied in SOEC environments. • Coating defects are intentionally added, and the scale remains protective. • Thick scale is generated before thermal cycling, and the scale does not crack. • The ASR is stable in dual and single atmospheres, with intermittent current. [ABSTRACT FROM AUTHOR]

The reversible operated high temperature solid oxide cell system (rSOC-System) seems to be a promising technology, enabling our future energy system to cope with the challenges of the transition to renewable electricity production and electrification. The rSOC-System provides energy storage capabilities and connects different energy carriers. This work provides insights into the coupling possibilities of such a system to industrial processes. Based on previously published investigations a flowsheet for the rSOC-System is chosen and described. To enable a quantitative analysis of the interaction with industries, a simulation model for this rSOC-System is created. This model is used for creating energy conversion and efficiency maps, which are then discuss with respect to the system behaviour. The increase of the system’s conversion efficiency is determined for a selection of thermal coupling and operation scenarios. This work concludes with an analysis of the scenario dependent effect of heat coupling and the consequences for the integration of a rSOC-System to industrial processes.

The concept of combining electrical impedance spectroscopy (EIS) with environmental transmission electron microscopy (ETEM) is demonstrated by testing a specially designed micro gadolinia‐doped ceria (CGO) sample in reactive gasses (O2 and H2/H2O), at elevated temperatures (room temperature—800 °C) and with applied electrical potentials. The EIS‐TEM method provides structural and compositional information with direct correlation to the electrochemical performance. It is demonstrated that reliable EIS measurements can be achieved in the TEM for a sample with nanoscale dimensions. Specifically, the ionic and electronic conductivity, the surface exchange resistivity, and the volume‐specific chemical capacitance are in good agreement with results from more standardized electrochemical tests on macroscopic samples. CGO is chosen as a test material due to its relevance for solid oxide electrochemical reactions where its electrochemical performance depends on temperature and gas environment. As expected, the results show increased conductivity and lower surface exchange resistance in H2/H2O gas mixtures where the oxygen partial pressure is low compared to experiments in pure O2. The developed EIS‐TEM platform is an important tool in promoting the understanding of nanoscale processes for green energy technologies, e.g., solid oxide electrolysis/fuel cells, batteries, thermoelectric devices, etc. [ABSTRACT FROM AUTHOR]

High performance in intermediate temperature solid oxide fuel cells requires improvements especially in the microstructure of the cathode layer. New cobalt‐free cathode materials are used because cobalt‐containing cathodes have higher thermal expansion coefficients, poor long‐term chemical stability, and lower mechanical stability. Recently cobalt‐free cathodes have been proposed to solve these issues by using deposition methods other than electrospray deposition (ESD). In this study, ESD method is used to develop a cobalt‐free cathode layer. The electrolyte layer is gadolinium‐doped ceria that is deposited with La0.3Sr0.7Fe0.7 Cr0.3O3−δ (LSFCr) prepared by 2‐butoxyethanol and ethylene glycol solvents as opposed to conventional solvents. Experimental ESD parameters are tested at different levels and combinations by applying statistical experimental design methods to optimize the microstructure. Coating deposited as such demonstrated higher electrochemical performance than similar electrodes fabricated by other methods. [ABSTRACT FROM AUTHOR]

Solid oxide electrolysis cells (SOECs) and solid oxide fuel cells (SOFCs) are the leading high-temperature devices to realize the global “Hydrogen Economy”. These devices are inherently multi-material (ceramic and cermets). They have multi-scale, multilayer configurations (a few microns to hundreds of microns) and different morphology (porosity and densification) requirements for each layer. Adjacent layers should exhibit chemical and thermal compatibility and high-temperature mechanical stability. Added to that is the need to stack many cells to produce reasonable power. The most critical barriers to widespread global adoption of these devices have been their high cost and issues with their reliability and durability. Given their complex structure and stringent requirements, additive manufacturing (AM) has been proposed as a possible technological path to enable the low-cost production of durable devices to achieve economies of scale. However, currently, there is no single AM technology capable of 3D printing these devices at the complete cell level or, even more difficult, at the stack level. This article provides an overview of challenges that must be overcome for AM to be a viable path for the manufacturing of SOECs and SOFCs. A list of recommendations is provided to facilitate such efforts.

Oxidation behavior of porous P434L ferritic stainless steel, used for the fabrication of metal-supported solid oxide electrolysis cells (MS-SOEC), is studied under oxygen-side and steam-side conditions. The impact of oxygen content on the oxygen side and steam:hydrogen ratio on the steam side is determined at 700 °C for bare, as-sintered samples. For these conditions, oxidation is more aggressive in the steam-side atmosphere. Oxygen with 3% humidification and steam:hydrogen ratio of 90:10 are selected for further assessment with pre-oxidized, catalyst-coated, and CuMn 1·8 O 4 -coated samples. The rapid oxidation at 700 °C and breakaway oxidation at 600 °C observed for bare stainless steel in 90:10 steam:hydrogen is mitigated by pre-oxidizing the sample in air before exposure. In oxygen, addition of the catalyst or CuMn 1·8 O 4 coatings moderately increases the oxidation rate, due to consumption of Cr via reaction between the coatings and Cr-oxide scale. The results for ex-situ controlled oxidation are similar to oxidation observed after 1000 h operation of a full MS-SOEC. In general, the oxidation behavior at 700 °C is found to be acceptable. • Oxidation of porous stainless steel is studied in SOEC environments. • Breakaway oxidation at high steam content is mitigated by pre-oxidation. • The impact of Cr-blocking coating and catalyst coatings is assessed. [ABSTRACT FROM AUTHOR]

Over the past few decades, reducing CO2 emissions has attracted attention at an industrial level worldwide. This study focuses on utilizing both the byproduct gas, including CO2, and waste heat produced from the steel-making process to produce synthetic fuel by integrating solid oxide electrolyzer cell (SOEC) technology with downstream Fischer-Tropsch and hydrocracking processes. CO2 can be collected from the byproduct gas and used as a feed for the SOEC, and waste heat from the steel-making process can be utilized as the main heat source for operation of the SOEC at high temperatures and to generate electrical power through heat recovery and steam generation (HRSG) as an energy source for the SOEC. The syngas (H2 and CO) produced from the SOEC is then converted to synthetic oil through the FT process, and the yield of the synthetic oil is increased via the hydrocracking process by converting heavy oil to lighter fractions. The entire process was modeled using Aspen HYSYS software, and pinch technology was adopted to maximize the energy efficiency of the process. As a result, CO2 release was reduced by 452 tons/day and syngas was produced by 336.8 tons/day. The syngas produced was then converted to synthetic oil (306.7 tons/day) and light gas (44.24 tons/day). Economic assessment was completed based on the discounted cash flow method for two cases: electricity tariffs and new renewable energy prices. When the electricity tariff is implemented, profit is achieved in seven years, whereas the system becomes profitable in four years when newly regenerated surplus energy is utilized. If the price of renewable energy is reduced, profits may be achieved earlier. [ABSTRACT FROM AUTHOR]

China's carbon peaking and carbon neutrality goals present a significant challenge for coal chemical technology, which is critical to securing the energy structure. Combining coal chemical industry technology with new energy is an effective approach to transform the development of the coal chemical industry. This paper proposes and studies a novel coal-to-methanol (CTM) technology of gasification integrated solid oxide electrolysis cell (SOEC). SOEC electrolytic hydrogen production technology is an advanced electrolytic water technology with the advantages of large scale and high efficiency, which is very suitable to be combined with industrial technology and can solve the painful problem of H 2 deficiency in the conventional coal to methanol process. In this study, from mechanistic analysis and model simulations, it is observed that by increasing the SOEC capacity, the novel CTM system can create more methanol at the same coal consumption and simultaneously reduce CO 2 emissions. The novel CTM system can produce up to 2.2 times more methanol and reduce CO 2 emissions by 94% by replacing the water-gas-shift (WGS) process with the SOEC unit. The novel CTM increases energy consumption. In addition, the novel CTM technology will effectively improve the economics of coal to methanol, taking into account the carbon tax. At the methanol price of 2900 RMB/t and SOEC capacity of 250 MW, the economic benefits of novel CTM were 2.1 times greater than CTM technology. • Propose a novel coal-to-methanol technology of gasification integrated electrolysis. • The novel coal-to-methanol technology can produce more methanol and reduce CO 2 emissions. • The novel technology can offer better economics when methanol price is higher than 2900 RMB/t. [ABSTRACT FROM AUTHOR]

A comprehensive multiphysics 3D model of an anode‐supported planar reversible solid oxide cell (rSOC) with a half‐channel‐unit‐cell geometry is created and validated. The physical phenomena that are modeled include reversible electrochemistry/charge transport, coupled with momentum/mass/heat transport. Several electrode microstructures comprising the homogeneous and functionally graded porosity distributions are applied to the validated model, to evaluate and compare the current‐voltage (j‐V) performance in both fuel cell mode and electrolysis mode. The results indicate that increasing the porosity in a homogeneous porous electrode does not always promote the cell's j‐V performance. An optimal porosity emerges where the effect of porosity on the mass transport is maximized, which ranges between 0.5 and 0.7 in the working conditions of the present study. Compared with homogeneous porous electrodes, the heterogeneous porous electrode design with a functionally graded porosity distribution is found to be a potential option to better the overall j‐V performance of the rSOC. Furthermore, it is discovered that theoretically grading the porosity in the width direction (i.e., increasing porosity from the center of each gas channel to the center of each adjacent rib) brings an outsize benefit on the cell's performance, compared to the traditional way of improving the porosity along the cell thickness direction. [ABSTRACT FROM AUTHOR]

Solid oxide cells (SOC) are an efficient and cost-effective energy conversion technology able to operate reversibly in fuel cell and electrolysis mode. Electrolyte-supported SOC have been recently fabricated employing 3D printing to generate unique geometries with never-explored capabilities. However, the use of the state-of-the-art electrolyte based on yttria-stabilized zirconia limits the current performance of such printed devices due to a limited oxide-ion conductivity. In the last years, alternative electrolytes such as scandia-stabilized zirconia (ScSZ) became more popular to increase the performance of electrolyte-supported cells. In this work, stereolithography 3D printing of Ytterbium-doped ScSZ was developed to fabricate SOC with planar and corrugated architectures. Symmetrical and full cells with about 250 μ m- thick electrolytes were fabricated and electrochemically characterized using impedance spectroscopy and galvanostatic studies. Maximum power density of 500 mW cm ^−2 in fuel cell mode and an injected current of 1 A cm ^−2 at 1.3 V in electrolysis mode, both measured at 900 °C, were obtained demonstrating the feasibility of 3D printing for the fabrication of high-performance electrolyte-supported SOC. This, together with excellent stability proved for more than 350 h of operation, opens a new scenario for using complex-shaped SOC in real applications.

For the direct reduction of CO2 and H2O in solid oxide electrolysis cells (SOECs) with cermet electrodes toward methane, a fundamental understanding of the role of elemental carbon as a key intermediate within the reaction pathway is of eminent interest. The present synchrotron-based in situ near-ambient-pressure X-ray photoelectron spectroscopy (NAP-XPS) study shows that alloying of Ni/yttria-stabilized-zirconia (YSZ) cermet electrodes with Cu can be used to control the electrochemical accumulation of interfacial carbon and to optimize its reactivity toward CO2. In the presence of syngas, sufficiently high cathodic potentials induce excess methane on the studied Ni/yttria-stabilized-zirconia (YSZ)-, NiCu/YSZ- and Pt/gadolinium-doped-ceria (GDC) cermet systems. The hydrogenation of carbon, resulting from CO activation at the triple-phase boundary of Pt/GDC, is most efficient.

The mixture of H2 and CO, the so-called syngas, is the value-added product of H2O and CO2 co-electrolysis and the feedstock for the production of value-added chemicals (mainly through Fischer-Tropsch). The H2/CO ratio determines the process in which syngas will be utilized and the type of chemicals it will produce. In the present work, we investigate the effect of H2O/CO2 (steam/carbon dioxide, S/C) ratio of 0.5, 1 and 2 in the feed, on the electrochemical performance of an 8YSZ electrolyte-supported solid oxide cell and the H2/CO ratio in the outlet, under co-electrolysis at 900 °C. The B-site iron doped lanthanum strontium chromite La0.75Sr0.25Cr0.9Fe0.1O3-δ (LSCF) is used as fuel electrode material while as oxygen electrode the state-of-the art LSM perovskite is employed. LSCF is a mixed ionic-electronic conductor (MIEC) operating both under a reducing and oxidizing atmosphere. The cell is electrochemically characterized under co-electrolysis conditions both in the presence and absence of hydrogen in the feed of the steam and carbon dioxide mixtures. The results indicate that under the same concentration of hydrogen and different S/C ratios, the same electrochemical performance with a maximum current density of approximately 400 mA cm−2 is observed. However, increasing p(H2) in the feed results in higher OCV, smaller iV slope and Rp values. Furthermore, the maximum current density obtained from the cell does not seem to be affected by whether H2 is present or absent from the fuel electrode feed but has a significant effect on the H2/CO ratio in the analyzed outlet stream. Moreover, the H2/CO ratio seems to be identical under polarization at different current density values. Remarkably, the performance of the LSCF perovskite fuel electrode is not compromised by the exposure to oxidizing conditions, showcasing that this class of electrocatalysts retains their reactivity in oxidizing, reducing, and humid environments. [ABSTRACT FROM AUTHOR]

High efficiency, raw material availability, and compatibility with downstream systems will enable the Solid Oxide Electrolysis Cell (SOEC) to play an important role in the future energy transition. However, the SOEC stack's performance should be improved further by utilizing a novel flow-field design, and the channel shape is a key factor for enhancing gas transportation. To investigate the main effects of the novel channel design with fewer calculations, we assumed ideal gas laminar flows in the cathode channel. Furthermore, the cathode support layer thickness and electrical contact resistance are ignored. The conventional channel flow is validated first with mesh independence, and then the performance difference between the conventional and novel designs is analyzed using COMSOL Multiphysics. The process parameters such as velocity, pressure, current density, and mole concentration are compared between the conventional and novel designs, demonstrating that the novel design significantly improves electrolysis efficiency. Furthermore, it directly increased the concentration of product hydrogen in the novel channel. In addition to enhancing convection and diffusion of reaction gases in neighboring channels, the simple structure makes it easy to manufacture, which is advantageous for accelerating commercial use of the novel design. [ABSTRACT FROM AUTHOR]