Search Results (37)

Solid oxide cells (SOCs) are highly efficient and versatile devices capable of utilizing a variety of fuels, presenting promising solutions for energy conversion and renewable resource utilization. There is an urgent need for the strategic design of robust and high-efficiency materials to enhance both conversion and energy efficiencies before SOCs can be applied for large-scale industrial production. Nanocomposite electrodes, especially those fabricated through infiltration and metal nanoparticle exsolution, have emerged as highly active electrocatalytic materials that significantly improve the performance and durability of SOCs. This review systematically summarizes and analyzes recent advances in the nanoscale architecture of electrode materials fabricated via common nanoengineering strategies, including infiltration and in situ exsolution, with applications in CO₂/H₂O reduction, hydrocarbon electrochemical oxidation, solid oxide fuel cells, and reversible operation. Finally, this review highlights existing bottlenecks and promising breakthroughs in common nanotechnologies, aiming to provide useful references for the rational design of nanomaterials for SOCs. Full article

This study explored the selective recovery of Co, La, and Sr from end-of-life solid oxide cells (SOCs) using ultrasound-assisted leaching in HCl. HCl concentration (1, 5, and 10 M) and solid-to-liquid ratio (S/L, 100 and 200 g/L) were varied to optimize the efficiency and the selectivity of Co, La, and Sr leaching. Then, they were recovered as oxalates at pH 0.7, 1, and 4. Using 10 M HCl and an S/L ratio of 100 g/L on ball-milled samples achieved 96–99% leaching efficiency but led to Ni impurities from the underneath layers. Thermal pre-treatment at 800 °C decreased Ni leaching by 90% but decreased target metals’ recovery by 9%. Direct leaching (without pre-treatments) with 1 M HCl and an S/L ratio of 200 g/L achieved up to 91% leaching efficiency, recovering 42% of Co, 93% of La, and 33% of Sr with minimal Ni impurities. A preliminary economic analysis indicated that avoiding pre-treatments can cut expenses by 96%. An economic analysis indicated that direct leaching is the most cost effective, reducing expenses by up to 96% compared to thermal pre-treatment and high HCl concentrations. This study highlights the potential for an efficient and cost-effective method for recycling Co, La, and Sr from EoL SOCs. Full article

Solid oxide cells (SOCs) can operate efficiently in solid oxide fuel cell (SOFC) and/or solid oxide electrolysis cell (SOEC) modes, and are one of the most promising electrochemical devices for energy conversion and storage, facilitating the integration of renewable energies with the electric grid. However, the SOC electrodes suffer performance and stability issues, especially in the case of fuel electrodes when SOCs are fueled by cheaper and more available fuels such as methane and natural gas. Typical Ni-YSZ cermet fuel electrodes suffer problems of coarsening, carbon deposition, and sulfur poisoning. Therefore, developing new electrodes using novel design strategies for SOCs is crucial. In this review work, the fuel electrode development strategies including the in situ exsolution of nanoparticles, multi-elemental nanocatalysts, and nanofiber materials have been reviewed and summarized for the design of new electrodes for SOCs. Nanofiber electrodes with in situ exsolved nanoparticles, which combine the advantages of a unique nanofiber microstructure and stable and active exsolved nanoparticles, are of great interest and significantly contribute to the development of high-performance fuel electrodes for SOCs. Full article

This study demonstrates the significant advantages of integrating computational fluid dynamics (CFD) with artificial intelligence (AI)-based machine learning (ML) to optimize the pre-reforming process for reversible solid oxide cell (r-SOC) technologies. It places a distinct focus on the relationship between process variables, aiming to enhance the preparation of quality r-SOC-ready fuel, which is an indispensable element for successful operation. Evaluating the intricate thermochemistry of syngas-containing reforming processes involves employing an experimentally validated CFD model. The model serves as the foundation for gathering essential data, crucial for the development and training of AI-based machine learning models. The developed model forecasts and optimizes reforming processes across diverse fuel compositions, encompassing oxygen-containing syngas blends and controlled feedstock outlet process conditions. Impressively, the model’s predictions align closely with CFD outcomes with an error margin as low as 0.34%, underscoring its accuracy and reliability. This research significantly contributes to a deeper understanding and the qualitative enhancement of preparing high-quality syngas for SOC under improved process conditions. Enabling the early availability of valuable information drives forward sustainable research and ensures the safe, consistent operation assessment of r-SOC. Additionally, this strategic approach substantially reduces the need for resource-intensive experiments. Full article

Porous 430L stainless steel disks made by tape casting with various pore-former sizes and volume fractions were evaluated as substrates for solid oxide cell (SOC) fabrication by plasma spraying. This work reports the substrate properties relevant to the SOC operation of disks made by using extra fine metal powder with dense sintering to minimize the fine porosity between particles. In contrast, the coarse porosity is introduced by the pore former. We found that the 60 μm pore former at a 45 vol% fraction has the best application fit; it gives an adequate gas permeability of 3.11 × 10⁻¹³ m² and an average open pore size of 45.90 μm. Compared to a commercial substrate with a similar porosity perimeter/steel area ratio, the porosity and gas permeability are 1.6 and 3 times higher, respectively. The detected maximum surface pore is 49 μm, allowing gas-tight electrolytes fabricated by plasma spray deposition. Full article

Proton-conducting ceramic materials have emerged as effective candidates for improving the performance of solid oxide cells (SOCs) and electrolyzers (SOEs) at intermediate temperatures. BaCeO₃ and BaZrO₃ perovskites doped with rare-earth elements such as Y₂O₃ (BCZY) are well known for their high proton conductivity, low operating temperature, and chemical stability, which lead to SOCs’ improved performance. However, the high sintering temperature and extended processing time needed to obtain dense BCZY-type electrolytes (typically > 1350 °C) to be used as SOC electrolytes can cause severe barium evaporation, altering the stoichiometry of the system and consequently reducing the performance of the final device. The cold sintering process (CSP) is a novel sintering technique that allows a drastic reduction in the sintering temperature needed to obtain dense ceramics. Using the CSP, materials can be sintered in a short time using an appropriate amount of a liquid phase at temperatures < 300 °C under a few hundred MPa of uniaxial pressure. For these reasons, cold sintering is considered one of the most promising ways to obtain ceramic proton conductors in mild conditions. This review aims to collect novel insights into the application of the CSP with a focus on BCZY-type materials, highlighting the opportunities and challenges and giving a vision of future trends and perspectives. Full article

Ceramic proton conductors have the potential to lower the operating temperature of solid oxide cells (SOCs) to the intermediate temperature range of 400–600 °C. This is attributed to their superior ionic conductivity compared to oxide ion conductors under these conditions. However, prominent proton-conducting materials, such as yttrium-doped barium cerates and zirconates with specified compositions like BaCe_1−xY_xO_3−δ (BCY), BaZr_1−xY_xO_3−δ (BZY), and Ba(Ce,Zr)_1−yY_yO_3−δ (BCZY), face significant challenges in achieving dense electrolyte membranes. It is suggested that the incorporation of transition and alkali metal oxides as sintering additives can induce liquid phase sintering (LPS), offering an efficient method to facilitate the densification of these proton-conducting ceramics. However, current research underscores that incorporating these sintering additives may lead to adverse secondary effects on the ionic transport properties of these materials since the concentration and mobility of protonic defects in a perovskite are highly sensitive to symmetry change. Such a drop in ionic conductivity, specifically proton transference, can adversely affect the overall performance of cells. The extent of variation in the proton conductivity of the perovskite BCZY depends on the type and concentration of the sintering aid, the nature of the sintering aid precursors used, the incorporation technique, and the sintering profile. This review provides a synopsis of various potential sintering techniques, explores the influence of diverse sintering additives, and evaluates their effects on the densification, ionic transport, and electrochemical properties of BCZY. We also report the performance of most of these combinations in an actual test environment (fuel cell or electrolysis mode) and comparison with BCZY. Full article

In this study, the transported entropy of ions for 8YSZ and 10Sc1CeSZ electrolytes was experimentally determined to enable precise modeling of heat transport in solid oxide cells (SOCs). The Peltier coefficient, crucial for thermal management, was directly calculated, highlighting reversible heat transport effects in the cell. While data for 8YSZ are available in the literature, providing a basis for comparison, the results for 10Sc1CeSZ show slightly smaller Seebeck coefficients but higher transported ion entropies. Specifically, at $700°\mathrm{C}$ and an oxygen partial pressure of $p_{{\mathrm{O}}_2}=0.21$ bar, values of $S_{{\mathrm{O}}^{2-}}^{*}=52\pm 10$ J/K·F for 10Sc1CeSZ and $S_{{\mathrm{O}}^{2-}}^{*}=48\pm 9$ J/K·F for 8YSZ were obtained. The transported entropy was also validated through theoretical calculations and showed minimal deviations when comparing different cell operation modes (O₂||O²⁻||O₂ and H₂, H₂O||O²⁻||O₂). The influence of the transported entropy of the ions on the total heat generation and the partial heat generation at the electrodes is shown. The temperature has the greatest influence on heat generation, whereby the ion entropy also plays a role. Finally, the Peltier coefficients of 8YSZ for all homogeneous phases agree with the literature values. Full article

Sodium-ion batteries (SIBs) are gaining attention as a safer, more cost-effective alternative to lithium-ion batteries (LIBs) due to their use of abundant and non-critical materials. A notable feature of SIBs is their ability to utilize aluminum current collectors, which are resistant to oxidation, allowing for safer storage at 0 V. However, the long-term impacts of such storage on their electrochemical performance remain poorly understood. This study systematically investigates how storage conditions at various states of charge (SOCs) affect open circuit voltage (OCV) decay, internal resistance, and post-storage cycling stability in two different Na-ion chemistries: Prussian white//hard carbon and layered oxide//hard carbon. Electrochemical Impedance Spectroscopy before and after storage shows a pronounced increase in internal resistance and a corresponding decline in cycling performance when SIBs are stored in a fully discharged state (0 V), particularly for layered oxide-based cells, illustrating the sensitivity of different SIB chemistries to storage conditions. Additionally, a novel reformation protocol is proposed that reactivates cell capacity by rebuilding the solid electrolyte interphase (SEI) layer, offering a recovery path after prolonged storage. These insights into the long-term storage effects on SIBs provide new guidelines for optimizing storage and transport conditions to minimize performance degradation, making them more viable for commercial applications. Full article

Lithium-ion batteries (LIBs) are employed in a range of devices due to their high energy and power density. However, the increased power density of LIBs raises concerns regarding their safety when subjected to external abuse. The thermal behavior is influenced by a number of factors, i.e., the state of charge (SoC), the cell chemistry and the abuse conditions. In this study, three distinct cylindrical Li-ion cells, i.e., lithium nickel cobalt aluminum oxide (NCA), lithium titanate oxide (LTO), and lithium iron phosphate (LFP), were subjected to thermal abuse (heating rate of 5 °C/min) in an air flow reactor, with 100% SoC. Venting and thermal runaway (TR) were recorded in terms of temperature and pressure, while the emitted products (gas, solid, and liquid) were subjected to analysis by FT-IR and ICP-OES. The concentrations of the toxic gases (HF, CO) are significantly in excess of the Immediate Danger to Life or Health Limit (IDLH). Furthermore, it is observed that the solid particles are the result of electrode degradation (metallic nature), whereas the liquid aerosol is derived from the electrolyte solvent. It is therefore evident that in the event of a LIB fire, in order to enhance the safety of the emergency responders, it is necessary to use appropriate personal protective equipment (PPE) in order to minimize exposure to toxic substances, i.e., particles and aerosol. Full article

Extensive research on transition metal perovskite oxides as electrodes in solid oxide cells (SOC) has highlighted the potential ability of Fe-based perovskite oxides to catalyze oxygen reduction/evolution reactions (ORR/OER). The layered perovskite-type system YSr₂Cu₂FeO_7+δ has been reported to possess attractive electrocatalytic properties. This work applies density functional theory (DFT) calculations to investigate oxygen ion diffusion in the YSr₂Cu₂FeO_7+δ system. For δ = 0.5, it is found that in the most stable configuration, the oxygen vacancies in the FeO_1+δ plane are arranged to form Fe ions in tetrahedral, square pyramid, and octahedral coordination. Ab initio molecular dynamics (AIMD) simulations for YSr₂Cu₂FeO_7.5 (δ = 0.5) yield an oxygen ion diffusion coefficient of 1.28 × 10⁻⁷ cm²/s at 500 °C (Ea = 0.37 eV). Complementary results for YSr₂Cu₂FeO_7.2 (δ = 0.2) and YSr₂Cu₂FeO_7.75 (δ = 0.75) indicate that the oxygen diffusion occurs in the FeO_1+δ plane, and depends on the oxygen vacancies distribution around the Fe centers. Full article

Working towards a more sustainable future with zero emissions, the International Future Laboratory for Hydrogen Economy at the Technical University of Munich (TUM) exhibits concerted efforts across various hydrogen technologies. The current research focuses on pre-reforming processes for high-quality reversible solid oxide cell feedstock preparation. An AI-based machine learning model has been developed, trained, and deployed to predict and optimise the controlled utilisation of methane gas. Using a blend of design of experiments and a validated 3D computational fluid dynamics model, pre-reforming process data have been generated for various syngas mixtures. The results of this study indicate that it is possible to achieve a targeted methane utilisation rate of 20% while decreasing the amount of catalyst material by 11%. Furthermore, it was found that precise process parameters could be determined efficiently and with minimal resource consumption in order to achieve higher methane fuel utilisation rates of 25% and 30%. The machine learning model has been effectively employed to analyse and optimise the fuel outlet conditions of the pre-reforming process, contributing to a better understanding of high-quality syngas preparation and furthering sustainable research efforts for a safe reversible solid oxide cell (r-SOC) process. Full article

Reversible symmetrical solid oxide cells (RS-SOCs) have attracted much attention due to their high energy conversion efficiency and fabrication simplicity. In this study, 10% Fe was substituted with Ni in the B-site of Sr_0.9Fe_0.9Mo_0.1O_3−δ to enhance the electrochemical performance of H₂O electrolysis. The characterization results and theoretical calculations indicated that Ni doping decreased the adsorption and reaction energy barrier of intermediates of H₂O electrolysis on the Sr_0.95Fe_0.8Mo_0.1Ni_0.1O_3−δ’s (111) surface, which promoted the kinetics of the electrode reaction, thus fabricating electrochemical activity and resulting in higher reaction dynamics. Consequently, a high power density of 1.145 W cm⁻² at 850 °C on a symmetrical cell was achieved in the solid oxide fuel cell (SOFC) mode, and a current density of 3.995 A cm⁻² was obtained at 850 °C and 1.6 V in the solid oxide electrolysis cell (SOEC) mode, indicating the Sr_0.9Fe_0.8Mo_0.1Ni_0.1O_3−δ oxide to be a promising SOFC electrode for power production and SOEC electrode for H₂ production. Full article

This study focuses on the preparation and characterization of composite gaskets designed for the sealing of the solid oxide cell stacks operating below 700 °C. The seals were fabricated with the addition of various amounts (10–90 wt.%) of 3 mol.% yttria partially stabilized zirconia to a BaO-Al₂O₃-CaO-SiO₂ glass matrix. The sample gaskets in the form of thin frames were shaped by tape casting. The quality of the junctions between the composites and Crofer 22APU steel commonly used as an SOC interconnect was evaluated after thermal treatment of heating to 710 °C, then cooling to the working temperature of around 620 °C and then leaving them for 10h in an air atmosphere, before cooling to room temperature. The samples were also studied after 3, 5, and 10 thermal cycles to determine the changes in microstructure and to evaluate the porosity and possible crystallization of the glass phase. The compression of the seals was calculated on the basis of differences in thickness before and after thermal treatment. The influence of zirconia additions on the mechanical properties of the seals was studied. The experimental results confirmed that glass–ceramic composites are promising materials for gaskets in SOC stacks. The most beneficial properties were obtained for a composite containing 40 wt.% of YSZ. Full article

In this study, we aim to adapt a solid oxide cell (SOC) to a membrane reactor for general chemical reactions to leverage the readily available multichannel design of the SOC. As a proof-of-concept, the developed reactor is tested for syngas production by the partial oxidation of methane using oxygen ion transport membranes (ITMs) to achieve oxygen separation and permeation. A La_0.6Sr_0.4Co_0.2Fe_0.8O_3−δ (LSCF) membrane and Ni/MgAl₂O₄ catalyst are used for oxygen permeation and the partial oxidation of methane, respectively. ANSYS Fluent is used to assess the reactor performance with the help of computational fluid dynamics (CFD) simulations. The membrane permeation process is chemical kinetics achieved by user-defined functions (UDFs). The simulation results show that the oxygen permeation rate depends on the temperature, air, and fuel flow rates, as well as the occurrence of reactions, which is consistent with the results reported in the literature. During isothermal operation, the product composition and the species distribution in the reactor change with the methane flow rate. When the molar ratio of fed methane to permeated oxygen is 2.0, the methane conversion and CO selectivity reach a high level, namely 95.8% and 97.2%, respectively, which agrees well with the experimental data reported in the literature. Compared to the isothermal operation, the methane conversion of the adiabatic operation is close to 100%. Still, the CO selectivity only reaches 61.6% due to the hot spot formation of 1491 K in the reactor. To reduce the temperature rise in the adiabatic operation, reducing the methane flow rate is an approach, but the price is that the productivity of syngas is sacrificed as well. In conclusion, the adaption of the SOC to a membrane reactor is achieved, and other reaction applications can be explored in the same way. Full article