Solid oxide electrolysis cells (SOECs) offer a promising route for renewable energy storage and CO2 utilization. However, the development of fuel electrodes with high activity and durability remains a notable challenge. Here in, this work proposes a simple strategy to simultaneously enhance the catalytic activity and stability of the La0.6Sr0.4FeO3-s fuel electrode through Sm doping SmxLa0.6-xSr0.4FeO3-s (SxLSF, x = 0, 0.15, 0.2, 0.25). Remarkably, the optimized S0.2LSF fuel electrode exhibits a 34.5% reduction in polarization resistance at 800 degrees C. Furthermore, a LSGM electrolyte supported single cell with S0.2LSF fuel electrode achieves a remarkable current density of as high as 1.68 A & sdot;cm-2 at 1.5 V and 800 degrees C, representing a 40.5% improvement compared to that with LSF fuel electrode. In addition, the single cell maintains excellent stability over 100 h. Combined density functional theory (DFT) calculations and experimental analysis reveal the underlying mechanism for the robust performance. Rare-earth Sm doping plays a dual role: it not only enhances the structural stability by reducing the thermal expansion coefficient but also synergistically promotes CO2 adsorption and dissociation by increasing oxygen vacancy concentration and conductivity, leading to a significant improvement in activity and stability of LSF fuel electrode. This work highlights Sm doping as an effective strategy for optimizing fuel electrode materials, providing valuable insights for the design of high-temperature CO2 electrolysis materials with excellent catalytic activity and stability.

The conventional cathode materials in solid oxide fuel cells (SOFCs) often suffer from insufficient activity of oxygen reduction. Herein, a simple strategy is employed to enhance catalytic activity and stability of La0.6Sr0.4Co0.2Fe0.8O3-s (LSCF) by impregnating Pr2Ni0.6Co0.4O4-s (PNC) on its surface. The cell with PNC/LSCF cathode achieves a maximum power density of 1707 mW cm- 2 at 800 degrees C, exhibiting a significant improvement compared with bare LSCF of 1051 mW cm- 2. Moreover, polarization resistance of composite cathode is notably reduced to 0.003 Omega cm2 at 800 degrees C. Furthermore, the cell with PNC/LSCF exhibits good stability for over 120 h without noticeable degradation. It is revealed that PNC self-assembles into PrOx and PrNi0.6Co0.4O3-s nanoparticles, forming a dual-phase coating on the surface of LSCF and creating abundant heterojunctions. This structure effectively accelerates oxygen surface exchange and suppresses Sr segregation. This also provides a new strategy for designing multiphase composite cathode in intermediate and low-temperature SOFCs.

The integration of solid oxide electrolysis cell (SOEC) stacks with intermittent renewable energy sources necessitates a deep understanding of their dynamic behavior under load changes. However, existing models often lack the multi-physics fidelity required to predict critical localized phenomena in large-scale stacks. This study presents a comprehensive 3D dynamic model of a multi-kW planar SOEC stack, integrating charge, mass, momentum, species, and energy transport within a realistic geometry. To achieve both high numerical accuracy and computational efficiency, an efficient two-stage adaptive time-stepping strategy is proposed and the grid setting is optimized through extensive testing. Validated against experimental data, the model accurately replicates both steady-state performance and dynamic voltage transients. The numerical model is capable of high-fidelity simulations of a complete response process of 30-cell/5 kW stack in under 10 h on a PC. Simulations with various load changes reveal that the dynamic response is thermally dominated. Overshoots of power and thermal gradient are observed for sudden current changes, but not for sudden voltage changes. However, the overshoot of thermal gradient can be suppressed by applying a proper air flow rate. This model provides a vital tool for optimizing the design and safe control strategies of SOEC systems for renewable hydrogen production.

With the progress of the energy transition, the volatility of renewable energy sources requires storage systems to ensure a stable power supply. Reversible solid oxide cells (RSOCs), known for their high efficiency in both fuel cell and electrolysis modes, offer a promising solution. Nevertheless, their potential in integrated energy systems remains underexplored. This study develops a novel optimization framework for a wind-solar hybrid hydrogen production and energy storage system (HHES) based on the RSOCs. A co-optimization framework combining particle swarm optimization and mixed-integer linear programming is formulated to simultaneously determine the capacity configuration and operational strategy, effectively addressing the uncertainty of renewable generation. The optimization results demonstrate that the HHES with RSOCs achieves an 84.68% reduction in curtailed electricity compared to the HHES without RSOCs. Moreover, renewable energy utilization has increased by 11.8%. This study underscores the importance of managing integrated energy conversion units and provides a decision-support tool for designing cost-efficient and high-performance renewable hydrogen systems.

The cathode material is a key determinant in the advancement of solid oxide fuel cells (SOFCs). However, achieving a balance between high electrocatalytic activity and long-term stability is still a major challenge. In this work, an in situ self-assembly strategy was developed to fabricate Pr0.4Sr0.5Ce0.1Fe0.8Ni0.2O3-δ (PSCFNX) composite materials. During the calcination process, CeO2 and NiO secondary phases spontaneously segregate and grow on the surface of the Pr0.4Sr0.5Ce0.1Fe0.8Ni0.2O3-δ(PSCFN) phase. This process leads to the formation of intimate three-phase junctions and abundant bonded heterointerfaces, thereby expanding the electrochemically active area and significantly enhancing catalytic performance. The optimized PSCFNX material exhibits a low area-specific resistance of 0.081 Ω cm2 at 800 °C. Correspondingly, the cell with an optimized cathode achieves a high peak power density of 1.576 W cm−2 at 800 °C and exhibits a long-term stability exceeding 100 h. This study confirms that the Pr0.4Sr0.5Ce0.1Fe0.8Ni0.2O3-δ materials could enhance SOFC performance.

Solid oxide electrolysis cells (SOECs) offer a highly promising route for CO2 utilization and intermittent renewable energy storage by converting CO2 to CO at high temperatures. However, their widespread application is hindered by the low catalytic activity of fuel electrodes. Herein, this study presents a novel strategy to enhance the CO2 reduction reaction (CO2RR) performance of the Sr2Fe1.5Mo0.5O6-delta (SFM) fuel electrodes through the multi-factor optimization achieved by Sc doping at the Mo site (Sr2Fe1.5Mo0.5-xScxO6-delta, x = 0, 0.10, 0.20, 0.25, 0.30). Interestingly, the optimal Sc doping ratio (x = 0.25) reduces the polarization resistance of SFM by 30.47% in a CO2 atmosphere at 800 degrees C. Moreover, an LSGM electrolyte-supported single cell achieves an exceptional current density of 1.764 A cm-2 at 1.5 V and 800 degrees C, along with excellent operational stability over 100 h. Combined density functional theory (DFT) and experimental analyses demonstrate that the introduction of lowvalence Sc and free volume expansion synergistically increases the oxygen vacancy concentration. Simultaneously, the resultant shift in ion valence states improves the intrinsic conductivity, which facilitates charge transfer. This collective action of enhanced adsorption and accelerated kinetics ultimately promotes CO2 dissociation, significantly boosting the electrocatalytic activity and durability. This work provides a rational strategy for designing highly active fuel electrodes to enhance catalytic activity and accelerate surface reaction kinetics for SOECs.

Direct ammonia solid oxide fuel cells (DA-SOFCs) are a promising carbon-free power generation technology, yet their large-scale application is limited by severe temperature nonuniformity and thermomechanical stresses caused by the coexistence of endothermic ammonia decomposition and exothermic electrochemical reactions at the anode. To gain a deeper understanding of the multiphysics field distribution within the cell, a three-dimensional coupled multiphysics numerical model of the direct ammonia fuel cell was developed and validated. The numerical simulation results reveal a temperature difference exceeding 70 degrees C between the inlet and outlet, as well as stress concentrations exceeding 200 MPa during high-current operation of the ammonia fuel cell. These factors pose a significant threat to the cell's lifespan and stability. An integrated direct ammonia solid oxide fuel cell model incorporating high-conductivity thermal bridges was proposed to optimize the internal temperature distribution and alleviate stress concentrations. By embedding thermal bridges within the interconnect, the pronounced temperature gradients induced by the coexistence of endothermic ammonia decomposition and exothermic electrochemical reactions were effectively mitigated. Numerical results show that the thermal bridges reduce the inlet-outlet temperature difference by more than 50 degrees C, enhance current density by 5% and 14% at 700 degrees C and 750 degrees C, respectively, and decrease the average stress by over 10 MPa. Furthermore, a comparative analysis of different thermal bridge configurations indicates that the layout with ten thermal bridges achieves a more favorable stress distribution than those with four or six bridges. Overall, the proposed thermal bridge design offers a synergistic improvement in electrochemical performance and thermomechanical reliability, providing an effective pathway for the integrated design and scalable deployment of high-power DA-SOFC systems.

When the operating temperature of a solid oxide electrolysis cell (SOEC) is lower than the outlet temperature of a nuclear reactor, the reactor can be directly coupled with the SOEC as a high-temperature heat source. However, the key to the efficiency and return on investment of this hybrid energy system lies in the expected lifetime of the SOEC. This study assessed Ni-YSZ|YSZ|GDC|LSC fuel electrode support cells’ long-term stability during electrolysis at 650 ^∘ C with a current density of -0.5 A cm^-2 over 1818 h. The average voltage degradation rate of 2.63% kh^-1 unfolded in two phases: an initial rapid decay (90 to 1120 h at 3.58% kh^-1 ) and a stable decay (1120 to 1818 h at 2.14% kh^-1 ), emphasizing SOECs’ probability coupling with nuclear reactors at 650 ^∘ C. Post-1818-hour electrolysis revealed nickel particle formation associated with Ni(OH)_x diffusion and re-deposition, alongside a strontium-containing layer causing interface cracking. Despite minimal strontium segregation in the EDS, XPS data indicated surface segregation of Sr. This study provides crucial insights into prolonged SOEC operation, highlighting both its potential and challenges.

Reversible solid oxide cells (RSOCs), combining solid oxide fuel cell and solid oxide electrolysis cell, usually utilize glass material as seals. The thermal cycle and long-term stability of seals are important in commercialization of RSOCs. In this study, the relationship between sealing performance and phase evolution of BaO-SiO2-B2O3-MgO-Al2O3 glass seal was investigated. Low leakage rates were obtained under different compressive loads and operating temperatures. Furthermore, the glass seal maintained low leakage, with a maximum leakage rate of 0.0023 sccm cm−1 after 1000 h at 750 °C and 0.0011 sccm cm−1 after 50 thermal cycles between 200 and 750 °C. Ba-Mg crystalline phases, including Ba5Si8O21, BaMg2Si2O7, and MgSiO3, appear inside of glass during operation, which the amount of crystalline phase is increasing with heating time extending. And the structure of glass after heat treatment remains dense and the crystalline phase is embedded in glass matrix, thereby making its physical structure stable. The sealing interface of interconnector/seal/NiO-YSZ anode with continuous layers after heat treatment are closely integrated, showing good chemical compatibility. Importantly, this study establishes correlations among leakage behavior, crystallization evolution, and interfacial compatibility, providing insight into the sealing stability of BaO-SiO2-B2O3-MgO-Al2O3 glass seal under RSOC-relevant conditions.

Catalyst design strategies based on constructing multiscale heterogeneous structures to optimize synergistic performance have attracted more attention. In this study, self-assembled multiphase material, Pr0.4Sr0.5Ca0.1-Fe0.8Ni0.2O3-s (M-PSF), was synthesized by Ca and Ni co-doping of Pr0.5Sr0.5FeO3-s (PSF). An anode-supported single cell employed with M-PSF1000 delivered a peak power density of 1.417 W/cm2, with polarization resistance (Rp) of 0.06 Omega cm2 at 800 degrees C. The superior electrochemical performance of M-PSF1000 was correlated with its unique structural characteristics. The secondary phase in M-PSF facilitates oxygen adsorption, dissociation, and incorporation into the lattice, thereby enhancing the oxygen reduction reaction (ORR) kinetics. Compared with PSF, Fe ions in M-PSF1000 exhibit a higher oxidation state and a shortened Fe-O bond length. Overall, the optimized phase composition, tailored microstructure and favorable defect chemistry of M-PSF1000 collectively endow it with outstanding electrocatalytic performance, making it a highly promising oxygen electrode material in intermediate-temperature solid oxide fuel cells.

Solid oxide electrolysis cells (SOECs) are regarded as an attractive platform for CO2 abatement and the application of renewable electricity. However, the development of SOECs is constrained by insufficient electrocatalytic activity and poor durability of fuel electrode. The Sr2Fe1.5Mo0.25Sc0.25O6-δ (SFMS) fuel electrode, previously established in our work, demonstrates favorable catalytic activity toward CO2 and holds considerable promise for further performance enhancement. In this work, PrCoO3-δ (PCO) nanoparticles are impregnated into the SFMS fuel electrode. Interestingly, the PCO can significantly decrease the polarization resistance by 31.46% compared to SFMS at 800 °C. A high current density of 1.322 A cm−2 is attained at 1.3 V by an electrolyte-supported single-cell, which exhibits stable performance throughout 100 h of continuous operation at 800 °C. The improvement is attributed to the PCO modification, which enlarges the unit cell volume of the pristine PCO and affects the Fe valence state in SFMS, leading to an increased oxygen vacancy. Moreover, the highly conductive PCO nanoparticles extend the triple-phase boundaries and synergistically interact with the SFMS scaffold to facilitate the CO2 reduction. This study demonstrates that the PCO impregnation strategy provides a viable approach for developing durable and efficient fuel electrode for CO2 electrolysis in SOECs.

Sluggish catalytic activity and long-term stability of oxygen electrode materials are the main challenges in the commercialization of solid oxide fuel cells (SOFCs). Herein, a Ruddlesden-Popper-structured Pr2-xLaxNiO4+delta (PLxN) by A-site lanthanum doping are investigated to enhance catalytic activity and stability of oxygen electrodes. Interestingly, the PL0.1N electrode exhibits low polarization resistance of 0.090 Omega cm2 at 800 degrees C, with 18.18% reduction compared to PNO. Furthermore, the Pr1.9La0.1NiO4+delta in anode-supported single cells exhibit peak power density of 1.468 W cm-2 at 800 degrees C and good operational stability over 100 h. Thereinto, La-doping induces lattice expansion and charge redistribution, which enriches surface active sites and accelerates oxygen reduction reaction kinetics. Overall, trace La-doping serving as an A-site defect engineering provides an efficient design strategy for high performance SOFC cathodes.

Solid oxide electrolysis cells (SOECs) offer a promising route for renewable energy storage by converting CO2 into value-added chemicals. However, their insufficient electrocatalytic activity and poor long-term stability remain major obstacles for further development. Our previous study has demonstrated that the Sm0.2La0.4Sr0.4FeO3-δ (SLSF) fuel electrode exhibits favorable catalytic activity for CO2 conversion and holds potential for further improvement. To enhance its catalytic activity and stability, BaCoO3-δ (BCO) nanoparticles are infiltrated into the SLSF electrode. Notably, after infiltration with 7.5 wt% BCO, the polarization resistance is reduced by 25.5% compared with that of SLSF. At 1.5 V, the current density of the electrolyte-supported single cell increases by 24.4% (2.09 A cm−2), and the cell exhibits stable performance during 100 h of continuous operation at 800 °C. The superior performance is attributed to the BCO surface decoration, which enhances the CO2 reduction reaction (CO2RR), increases electrical conductivity, and accelerates oxygen surface exchange kinetics. This work confirms that BCO nanoparticle infiltration is an effective strategy for modifying LSF-based electrodes, and further offers a general method to construct stable and highly active interfaces for high-temperature electrocatalytic systems.

Electrocatalytic reduction of carbon dioxide (CO2) to carbon monoxide (CO) is an effective strategy to achieve carbon neutrality. High selective and low-cost catalysts for the electrocatalytic reduction of CO2 have received increasing attention. In contrast to the conventional tube furnace method, the high-temperature shock (HTS) method enables ultra-fast thermal processing, superior atomic efficiency, and a streamlined synthesis protocol, offering a simplified method for the preparation of high-performance single-atom catalysts (SACs). The reports have shown that nickel-based SACs can be synthesized quickly and conveniently using the HTS method, making their application in CO2 reduction reactions (CO2RR) a viable and promising avenue for further exploration. In this study, the effect of heating temperature, metal loading and different nitrogen (N) sources on the catalyst morphology, coordination environment and electrocatalytic performance were investigated. Under optimal conditions, 0.05Ni-DCD-C-1050 showed excellent performance in reducing CO2 to CO, with CO selectivity close to 100% (−0.7 to −1.0 V vsRHE) and current density as high as 130 mA/cm2 (−1.1 V vsRHE) in a flow cell under alkaline environment.

Glass-based materials are commonly used as effective seals in planar solid oxide fuel cell (SOFC) stacks, providing an essential role in joining adjacent components. However, uncontrolled crystallization within the glass will lead to delamination and microcracks, compromising seal integrity. To address this issue, alumina (Al2O3) was incorporated into a BaO-SiO2-CaO glass matrix to enhance both the sealing performance and thermal cycling stability of composite seals. Glass-based seals with 30 wt% Al2O3 addition (denoted as Y30) showed very low leakage rates (from 1 x 10-3 sccm/cm to 2.1 x 10-3 sccm/cm when tested at an operating temperature of 800 degrees C under input gas pressures varying between 10 kPa and 70 kPa. After 40 thermal cycles, the Y30 seals maintained excellent sealing performance, with gas leakage rates stabilizing around 8.5 x 10-3 sccm/cm after 32 cycles. Single-cell tests using various seals revealed that the Y30 seal supported an open-circuit voltage of 1.2 V and stable long-term operation. These research results confirm that the Y30 composite seal exhibits excellent sealing performance in high-temperature planar SOFCs and can operate stably over the long term.

Solid oxide electrolytic cell(SOEC)is a green hydrogen production technology,with high efficiency,no use of precious metals,a variety of operating modes and other advantages,at high temperatures can effectively electrolyze CO2 and H2O,and the combination of heat sources and green electricity can achieve efficient conversion of electrical energy into chemical energy,such as hydrogen,CO,syngas,thereby helping to reduce carbon dioxide emissions.Compared with low temperature CO2 electrochemical reduction,CO2 electrolysis in SOEC has higher current density and energy efficiency.At present,SOEC electrolytic high temperature steam electrolysis is in a small demonstration stage,only hundreds of kilowatt scale devices can be used worldwide,and the cost per kilowatt is high,but because of its high operating temperature(800 ℃),it can be combined with low-cost thermal energy input in the synthesis process of industrial or downstream industries to reduce the cost of electricity required for hydrogen production.In the context of current energy structure adjustment and dual carbon emission reduction,the energy required for SOEC co-electrolysis can also be derived from redundant or discarded renewable energy,which is expected to further reduce costs,so it is a promising energy conversion and storage technology.At the same time,SOEC co-electrolysis of CO2/H2O synthesis gas is in the laboratory stage,especially the cathode material in the operation of carbon deposition led to performance decay and other problems.This review focuses on the development history,basic mechanism and research progress of key cathode materials of SOEC.In the process of co-electrolysis,SOEC cathode plays a vital role in controlling the stability of battery operation.However,the most commonly used Ni-YSZ cermet material has poor stability due to coarsing and agglomeration of Ni.Researchers are exploring ways to improve the stability of cermet electrodes.Attempts are also being made to find cathode materials that can replace cermet electrodes in SOEC co-electrolysis.Perovskite materials have been concerned by researchers due to their good mixed conductivity,carbon resistance,impurity tolerance,REDOX stability and durability,but their relatively low catalytic activity is the main challenge faced by most perovskite-related oxides.The researchers found that the oxygen vacancies on the surface of the material and the active three-phase interface can be increased through impregnation,doping,and dissolving technologies.These oxygen vacancies can be used as the host site to accommodate CO2 molecules at high temperature,thus reducing the polarization resistance of the electrode and improving the electrochemical performance of the electrode.Moreover,the impregnation method has the advantages of easy operation,high efficiency and low preparation temperature.The doping method has the advantages of simple doping process,no pollution and low cost,and the in situ dissolution method has the advantages of high stability,high efficiency and good performance,and is easy to be popularized later.Therefore,based on the existing problems and challenges of cathode materials such as cermet and perovskite,this paper summarizes the progress in improving the performance and stability of cathode materials by using impregnation,doping and dissolution technologies,and provides technical feasibility analysis for the commercialization of SOEC.

Glass materials are considered as excellent seals in reversible solid oxide cells (RSOCs), but the uncontrolled deformation and mechanical damages limit integrity and reliability of seals. In this work, adding various 5YSZ content into MgO-Al2O3-SiO2-BaO-B2O3-SrO glass to building a ceramic skeleton network reduce negative effects caused by uncontrolled deformation on gas tightness, structural and thermal stability. The composite seals with 40 wt% 5YSZ ceramic exhibited a low leakage rate of 0.0028 sccm/cm at an input gas pressure of 20.7 kPa with operating temperature ranging from 650 degrees C to 800 degrees C. Further thermal cycles analyses indicate that the leakage rates of GY60 seals are below 0.0199 sccm/cm with an input gas pressure of 20.7 kPa at 750 degrees C after 10 thermal cycles, which is consistent with minor microstructural changes and good interfacial bonding. Meanwhile, the leakage rates of GY-60 seal after 200 h long-term test is below 0.0053 sccm/cm with an input gas pressure of 6.9 kPa. The results demonstrate that the incorporation of 5YSZ effectively enhanced the thermal expansion compatibility, improved thermal shock resistance, and increased seals viscosity. Notably, the composite seals with suitable 5YSZ ceramic could remain integrity and thermal stability at high temperature, which could be applied in RSOC stacks.

Solid oxide electrolysis cells (SOECs) are high-temperature electrochemical devices that efficiently convert electricity and heat into storable chemical energy. Driven by cost-efficiency, power density, and system integration targets, the industry is toward larger cell structure. However, this scaling intensifies engineering challenges including fuel utilization efficiency, sealing, thermal gradient, and stress management. This consequently requires optimization of the structural configuration. In this study, a multi-physics model is developed to evaluate sealing reliability, thermal stress, temperature distribution, and electrochemical efficiency by comparing five cell designs with different aspect ratios (width to length, AR). The results indicate that while different aspect ratios have minimal impact on the electrochemical performance and hydrogen production rate, they significantly influence sealing reliability, temperature distribution, and thermal stress. The design with the largest aspect ratio achieves the shortest fluid flow path, minimizing pressure on the sealing, enhancing temperature uniformity, and reducing both failure probability and thermal stress by mitigating the isotopic constraint effect. Therefore, a cell design with a large aspect ratio provides superior in thermal and mechanical stability compared to the design of square or lower aspect ratios with the same footprint.