Reversible Solid Oxide Research Articles

CFD and Artificial Intelligence-Based Machine Learning Synergy for the Assessment of Syngas-Utilizing Pre-Reformer in r-SOC Technology Advancement

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.

Application of novel Dy0.06Gd0.02Er0.02Bi1.9O3 oxide ion electrolyte for intermediate-temperature reversible solid oxide cells

Bismuth-based oxides are promising electrolyte materials for Reversible Solid Oxide Cells (RSOCs) due to their high ion conductivity and rapid surface oxygen exchange kinetics. In this work we propose a multi-element doping strategy to obtain a novel Dy0.06Gd0.02Er0.02Bi1.9O3 (DGESB) quaternary oxide bismuth material whose ionic conductivities and crystal structure are characterized by AC impedance and X-ray diffraction technique in the temperature range from 600 to 700 °C. Along with promising structure stability and durability, our novel DGESB showed a remarkable ionic conductivity that is 65 times higher than the commercial yttria-stabilized zirconia (YSZ) electrolyte at 700 °C. With composite electrode of DGESB + LCN (LaCo0.6Ni0.4O3) and DGESB/YSZ bilayer electrolyte consisting of RSOC symmetric cell, which achieves a high peak power density (PPD) of 1.62 W/cm2 in fuel cell mode which is 2.7 times higher than that of YSZ single-layer electrolyte, while the electrolysis current density is as high as 1.66 A/cm2 at 1.3 V under H2/H2O:50/50 in electrolysis mode at the same operation temperature of 700 °C. The electrochemical performance measurements revealed a certain stable operation for 200 h in fuel cell mode. The performance degradation can be attributed to the microstructure evolution at the interface between electrolyte and electrodes. The high ionic conductive DGESB proves to be an excellent intermediate electrolyte layer for improving cell performance in RSOCs

Revealing the degradation mechanism of calcium-based air electrodes in reversible solid oxide cells under chromium contaminants

Calcium-based perovskite La0.6Ca0.4Fe0.8Co0.2O3-δ (LCFC) with stable structure is the promising air electrode used in reversible solid oxide cells, and its application in cell stack must consider its Cr poisoning resistance ability. Herein, the Cr poisoning effect of it is studied in this work. The results indicate the strong reaction between LCFC and the Cr contaminations, forming undesirable CaCrO4 impurities, which significantly reduce the activity of ORR/OER. Both the decayed performance and reversible stability are also observed in SOFC and SOEC modes under the Cr contaminations, and the main reason comes from the reduced activity of the oxygen surface exchange processes and the blocked gas diffusion process by the impurities. A worse degenerated performance in SOFC mode than that in SOEC mode is also found in this work. Beyond that, the mechanism of the reaction between chromium contaminants and the Ca-segregation of the electrodes is discussed by the nucleation theory.

An active and stable PrOx-modified open-straight pore (La0.8Sr0.2)0.98MnO3-δ-Sc0.18Zr0.82O2-δ air electrode for reversible solid oxide cells

Air electrode supported reversible solid oxide cells (RSOCs) have drawn increasing attention for the capability of fuel flexibility and well bonding between the air electrode and electrolyte. However, the high concentration polarization and sluggish oxygen reduction/evolution reaction (ORR/OER) has significantly restricted the practical applications. Herein, finger-like (La0.8Sr0.2)0.98MnO3-δ-Sc0.18Zr0.82O2-δ (LSM98-SSZ) air electrode supported symmetrical and single cells are successfully fabricated by phase inversion tape-casting technology. The open-straight pores formed on the air electrode support can facilitate the gas transport and catalyst impregnation. The ORR/OER activity of LSM98-SSZ air electrode is largely increased with the introduction of impregnated PrOx nano catalyst, showing a low polarization resistance (Rp) of 0.06 Ω cm2 and great stability for 550 h at 700 oC. Furthermore, the LSM98-SSZ supported cell with PrOx modification shows a remarkable peak power density of 1.0 W cm-2 and electrolysis current density of 1.09 A cm-2 at 1.3 V at 750 oC. The enhanced performance is primarily ascribed to the facilitated oxygen surface exchange.

Correction to: Synergistic enhancement of electrochemical performance in reversible solid oxide cells via deficiency-induced oxygen vacancy and nanoparticle generation

Correction to: Synergistic enhancement of electrochemical performance in reversible solid oxide cells via deficiency-induced oxygen vacancy and nanoparticle generation

Optimal scheduling of virtual power plants with reversible solid oxide cells in the electricity market

Virtual power plants (VPP) can act as an independent entity to aggregate different distributed resources to participate in the electricity market, which is an inevitable trend in building green and low-carbon power systems. To investigate the beneficial effect of bi-directional electric-hydrogen conversion on market trading and optimal scheduling of VPP, this paper presents an optimal scheduling method for VPP with reversible solid oxide cells (RSOC) in the electricity market. Firstly, according to the Butler-Volmer equation and Faraday law, the relationship between the hydrogen flow rate and the electric power is established, and the equivalent physical models of the two RSOC working modes are developed based on the relationship. Then, the optimal scheduling model of the VPP participating in the energy and reserve joint market is proposed based on the two-stage robust optimization theory. The system operator reserve demand is used to describe the uncertainty of the transactions between VPP and reserve market. Finally, the column and constraint generation (C&CG) algorithm is used to solve the two-stage robust scheduling model. The simulation results show that RSOC can effectively promote renewable energy consumption and improve the VPP operating profit. Where, the operating profit can be increased by 46.5 % and the wind power consumption rate can be increased by 3.4 %, compared with the non-hydrogen VPP. Furthermore, compared with the traditional conversion equipment, RSOC can increase the VPP operating profit by 2.3 % and the wind power consumption rate by 1.85 %.

Active and stable plasma-enhanced ALD Pt@Ni-YSZ hydrogen electrode for steam reversible solid oxide cells

Designing and fabricating active and thermally stable bifunctional catalysts with minimal noble metal loadings are crucial for reversible solid oxide cells (rSOCs). This study employed Pt nanoparticles fabricated via plasma-enhanced atomic layer deposition (PEALD) to a nickel-yttria stabilized zirconia (Ni-YSZ) electrode to serve as effective catalysts in fuel cell and electrolysis modes. Despite the minimal Pt catalyst loading (<1 μg cm–2), the PEALD Pt@Ni-YSZ catalytic electrode exhibited superior electrochemical performance, (20 % higher than the bare cell), both in the fuel cell and electrolysis modes. Remarkably, this performance is sustained without any degradation over a 50 h duration at 700 °C. Dissimilar stabilization behaviors of the Pt catalysts occurred as distributed fine particles on Ni and anchored coarsened particles at the grain boundaries on YSZ surfaces. Furthermore, the mechanism of the enhanced hydrogen evolution/oxidation reactions with the PEALD Pt@Ni-YSZ electrode was verified using density functional theory simulations.

Optimization of reversible solid oxide cell system capacity combined with an offshore wind farm for hydrogen production and energy storage using the PyPSA power system modelling tool

AbstractEight scenarios where high efficiency reversible solid oxide cells (rSOC) are combined with an offshore wind farm are identified. Thanks to the PyPSA power system modelling tool combined with a sensitivity study, optimized rSOC system capacities, hydrogen storage capacities, and subsea cable connection capacities are investigated under various combinations of rSOC system capital cost, prices paid for hydrogen, and electricity prices, which give indications on the most profitable scenario for offshore hydrogen production from a 600 MW wind farm situated 60 km from shore. Low electricity prices (yearly average 45 £/MWh) combined with mild fluctuations (standard deviation 6 or 13 £/MWh) call for dedicated hydrogen production when the hydrogen price exceeds 4 £/kg. High electricity prices (yearly average 118 or 204 £/MWh), combined with extreme fluctuations (standard deviation between 73 and 110 £/MWh), make a reversible system economically profitable. The amount of hydrogen which is recommended to be reconverted into electricity depends on the price paid for hydrogen. Comparison of the optimized cases to the default case of a wind farm without hydrogen production improved profit by at least 3% and up to 908%. Comparison to the default case of dedicated hydrogen production, showed that in the case of low hydrogen prices, an unprofitable scenario can be made profitable, and improvement of profit in the case of a profitable default case starts at 4% and reaches numbers as high as 324%.

Development of a Versatile and Reversible Multi-Stack Solid Oxide Cell System towards Operation Strategies Optimization

Abstract In context of Temperature Electrolysis based on Solid Oxide Cell technology, CEA LITEN has developed a new investigation tool (MURPHY) devoted to the operation of several Solid Oxide stacks. MURPHY enables stack operation in both the electrolysis (SOE) and the fuel cell (SOFC) modes. For the later, H2, CH4, and natural gas can be used as fuel. A compact Balance of Plant (BOP) is designed to (i) provide air by centrifugal blower, (ii) target high thermal integration and performances, (iii) preheat inlet gases, (iv) recycle fuel exhaust, and (v) control pressure levels. Instrumentation was defined to support modeling development and accurate process efficiencies characterization. &amp;#xD;MURPHY is currently compatible with four stacks of CEA standard base design (25 cells, of 100 cm² active area), the corresponding maximum power range of the module is -16/4 kWDC for supply and venting of gases produced.&amp;#xD;This report details system architecture. It also puts forward experimental results related in an environment controlled by thermal phenomena. Performance and efficiency curves obtained under parametric variations of temperature and flowrates are reported for both SOE and SOFC-H2 modes. A special attention is given to heat performance. In this view, flow parameters at several locations over circuitries are provide

Exergy based yearly performance analysis of a poly-generation system for a small-town application

The current study conducts a comprehensive year-round exergy analysis of an integrated system centered around a reversible solid oxide cell (RSOC), aimed at fulfilling the power and fresh water requirements of a small town, equivalent to 2.7 MW and 2000 m³/day, respectively. The integrated system encompasses four subsystems: the solar field, RSOC, organic Rankine cycle coupled with ejector cooling (ORC), and zero liquid discharge multi-effect desalination (MED-ZLD). The proposed system is analyzed using MATLAB. The annual exergy efficiency for each subsystem is examined, yielding average values of 11.9 %, 48.11 %, and 56.22 % for the solar field, ORC cycle, and MED-ZLD, respectively. Notably, the exergy efficiency of the Rankine cycle is higher in colder months compared to warmer ones. This phenomenon is attributed to the cycle's greater heat generation relative to the cooling it produces during the cold season. The RSOC exhibits noteworthy average exergy efficiencies of 93 % in electrolysis mode, 69.87 % in fuel cell mode, and an overall average exergy efficiency of 79.62 % throughout the year. The average exergy efficiency of the overall system is evaluated throughout the day, nighst, and the entire operational period. The results are values of 10.74 %, 34.31 %, and 23.34 %, respectively. This discrepancy is due to the primary energy supply source, which is solar energy during the day and input hydrogen during the night. The highest exergy efficiency is observed in December, while the lowest is in June. Furthermore, the study examines the distribution of exergy destruction and identifies cycles with significant impacts by analyzing the exergy destruction ratio across various months. The solar field is the primary contributor to daytime exergy destruction, peaking at 94.9 %. At night, the MED-SET cycle leads in exergy destruction, followed closely by the RSOC cycle operating as a fuel cell. The research also delves into exploring key contributors to exergy destruction in various cycles, shedding light on crucial insights into the intricate dynamics of the integrated system's performance.

Highly active and stable oxygen electrode PrBaCo2O5+δ-Ba2CoWO6 enabled by In Situ formed misfit dislocation interface for reversible solid oxide cell

The energy conversion efficiency and durability of the reversible solid oxide cell (RSOC) is restricted by the development of highly active and stable oxygen electrode. Herein, an in-situ formed composite PrBaCo2O5+δ-Ba2CoWO6 oxygen electrode is proposed, which consists of a highly active A-site double perovskite (A-DP) phase and a stable B-site double perovskite (B-DP) phase. Misfit dislocation interface is formed between these two phases, exerting lattice tensile stress on the A-DP phase, which enhances catalytic activity and inhibits Ba segregation. Additionally, the B-DP phase suppresses lattice expansion of A-DP phase through the dislocation interface, thereby improving thermo-mechanical stability. Consequently, the composite electrode demonstrates a low polarization resistance of 0.056 Ω cm2 at 650 °C, impressive stability at 650 °C for 500 h in symmetrical cell tests, and excellent thermal-mechanical stability under 29 thermal cycles. A maximum power density of 0.75 W cm−2 and an electrolysis current density of 0.84 A cm−2 at 1.3 V were achieved at 650 °C by the composite electrode on a 260 μm-electrolyte supported cell configuration, which surpass most of the reported oxygen electrode materials. Furthermore, the cell exhibits excellent operational stability, with low degradation rates of 0.49 × 10−1 mV h−1 and 1.5 × 10−1 mV h−1 in fuel cell and electrolysis cell modes, respectively. This work offers an effective method for designing highly active and stable oxygen electrodes for RSOCs.

High-performance Sr1.9Fe1.45Pd0.05Mo0.5O6−δ electrode for reversible symmetrical solid oxide cells

Reversible symmetrical solid oxide cells (RS-SOCs) have attracted much attention due to their high energy conversion efficiency and fabrication simplicity. The double perovskite with the general formula A2BB’O6 is often used as the electrode material. In this study, Fe was substituted with Pd in the B-site of Sr1.9Fe1.5Mo0.5O6−δ to enhance the electrochemical performance above 50 %. The characterization results showed that the doping of Pd promoted the kinetics of the electrode reaction and thus improved the electrochemical activity. A maximum power density of 870 mW cm−2 at 800 ℃ on a La0.9Sr0.1Ga0.8Mg0.2O3–δ (LSGM)-supported symmetrical cell with Sr1.9Fe1.45Pd0.05Mo0.5O6-δ electrode was achieved in the solid oxide fuel cells (SOFCs).

Reversible Long-Term Operation of a MK35x Electrolyte-Supported Solid Oxide Cell-Based Stack

High-temperature reversible solid oxide cells (rSOC) combine electrolyzer and fuel cell in one process unit which promises economic advantages with unrivaled high electrical efficiencies. However, large temperature gradients during dynamic rSOC operation can increase the risk of mechanical failure. Here, the degradation behavior of a 10-cell stack of the type “MK35x” with chromium-iron-yttrium (CFY) interconnects and electrolyte-supported cells (ESC) developed at Fraunhofer IKTS was investigated in rSOC operation at DLR. Its degradation was evaluated during nominal rSOC operation for more than 3400 h with 137 switching cycles between solid oxide fuel cell and solid oxide electrolysis cell operation of 24 h reflecting intermittent availability of solar energy. The voltage degradation rates of +0.58%/kh and −1.23%/kh in electrolysis and fuel cell operation, respectively, are among the lowest reported in literature. Comparison to a previously published long-term test in steam electrolysis did not show any indication for an increased degradation. Electrochemical impedance spectroscopy measurements were performed for all repeat units to evaluate the degradation behavior in detail. An overall polarization resistance decrease due to an improvement of the oxygen electrode was observed during electrolysis operation but was absent during fuel cell operation.

Anionic and cationic co-doping to enhance the oxygen transport property of Bi0.5Sr0.5FeO3-δ as a high-performance air electrode for reversible solid oxide cells

Reversible solid oxide cells (RSOCs) have attracted considerable interest due to their efficient energy conversion. However, the low catalytic activity of air electrodes limits the application of RSOCs. Bi0.5Sr0.5Fe0.9Ta0.1O3-δ developed in our previous work exhibits a comparatively desirable performance and is expected to be further optimized. Herein, a novel strategy of anionic F and cationic Ta co-doped Bi0.5Sr0.5Fe0.9Ta0.1O3-δ-xFx (x = 0, 0.05, 0.10, 0.15, denoted as, BSFTF0, BSFTF5, BSFTF10, BSFTF15) materials are obtained to enhance the oxygen transport property of Bi0.5Sr0.5FeO3-δ for RSOCs. The polarization resistance (Rp) of BSFTF10 (0.017 Ω cm2) decreases by 66 % compared with that of BSFTF0 (0.051 Ω cm2) at 800 °C. In fuel cell mode, the single cell with BSTF10 reaches the maximum power density of 908 mW cm−2, which is approximately 72 % higher than the only Ta-doped BSFTF0 (527 mW cm−2) at 800 °C. In electrolysis mode, the single cell with BSFTF10 exhibits a high electrolysis current density of 1679 mA cm−2, indicating an approximately 90 % increase compared to that of BSFTF0 at 800 °C and 1.5 V with 70 % CO2-30 % CO feed gas. The bulk chemical diffusion (Dchem) of BSFTF10 is up to 5.12 × 10−4 cm2 s−1, which is 4.3 times higher than that of BSFTF0. The superior oxygen transport property of BSFTF10 is attributed to the high electronegativity of F− (4.0) and low electronegativity of Ta5+(1.8), which may weaken the chemical bonding between B-site ions and O2−, generating more oxygen vacancies and accelerating the rate of oxygen transfer. The results indicate that F and Ta co-doping is an effective strategy to develop a highly catalytically active air electrode for RSOCs featuring oxygen transport properties.

Synergistic enhancement of electrochemical performance in reversible solid oxide cells via deficiency-induced oxygen vacancy and nanoparticle generation

Synergistic enhancement of electrochemical performance in reversible solid oxide cells via deficiency-induced oxygen vacancy and nanoparticle generation

Nonlinear model predictive control for mode‐switching operation of reversible solid oxide cell systems

AbstractSolid 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.

Reversible solid oxide cells-based hydrogen energy storage system for renewable solar power plants

The power-H2-power system based on reversible solid oxide cell is a promising pathway for large-scale renewable energy storage but not well understood due to the absence of comprehensive system analyses. In this study, a reversible solid oxide cell-based H2 energy storage system for a 100 % renewable solar power plant is proposed and analyzed through detailed modeling approach and optimization framework. The detailed parametric analyses and economic evaluations are performed in electrolysis (12:00 pm, sufficient solar energy) and power generation (6:30 am, insufficient solar energy) conditions. Notably, it is found that larger stack capacity (Ncell) and higher operating temperature (TReSOC) of the cell enhances system net H2 production and system economics despite additional investment cost. Afterwards, the optimal system performance is obtained (VH2,produce = 498.40 Nm3·h−1, Z=263.59 $·h−1 for electrolysis, and VH2,consume = 380.33 Nm3·h−1 for power generation) through multi-objective optimization by fully considering cell internal operating characteristics and system energy-exergy-economic factors. Besides, it is also found that the performance of power-H2-power system is still limited by remarkable fuel (H2) costs for nighttime power generation (daytime H2 production is smaller than nighttime H2 consumption when Wtot = 1 MW). Therefore, the critical power capacity (Pcritical) is obtained, offering a convenient approach to determine the maximum output capacity (Pcritical = 880 kW) to make the power-H2-power system profitable at specific solar energy input. This study provides valuable insights between system capacity, economics, and cell operating features in solar power plants, which are useful for the design and optimization of practical power-H2-power systems for renewable energy storage.

Boosting the performance of La0.5Sr0.5Fe0.9Mo0.1O3-δ oxygen electrode via surface-decoration with Pr6O11 nano-catalysts

Cobalt-free La0.5Sr0.5Fe0.9Mo0.1O3-δ (LSFM) oxide is particularly investigated as a durable and efficient oxygen electrode material for the reversible solid oxide cells (RSOCs) in this study. Pr6O11 nano-catalysts are introduced into LSFM oxygen electrode as synergistic catalysts to enhance and optimize the electrode reactions. Results demonstrate an effectively promoted oxygen reduction and evolution reaction kinetics of the Pr6O11 decorated LSFM electrode. Polarization resistances (Rp) of LSFM electrode are dramatically reduced with the increasing Pr6O11 nano-catalysts and the lowest Rp of 0.039 Ω cm2 is obtained at 800 °C, which is ∼97% lower than that of the LSFM electrode. The Pr6O11 decorated LSFM oxygen electrode also displays a superior durability under cyclic anodic and cathodic polarizations. Furthermore, both the maximum power density and electrolytic current density of the Pr6O11 decorated cell are more than 2 times that of the LSFM cell. Results make clear reliability of the Pr6O11 decorated LSFM to be a promising oxygen electrode for RSOCs.

In Situ Electrochemical Recovery: Sediment Transformation under Chromium Poisoning in Reversible Solid Oxide Cells with La0.6Sr0.4Co0.2Fe0.8O3-σ-Based Oxygen Electrodes.

Reversible solid oxide cells (RSOCs) are an all-solid-state electrochemical device, which can convert H2 into electricity in the fuel cell (SOFC) mode and electrolyze H2O into fuel gas in the electrolytic cell (SOEC) mode, exhibiting good application prospect in the development of carbon neutrality. However, the degradation of the air electrode caused by Cr-containing steel interconnects is a major obstacle that limits the broader application of RSOCs. Herein, the Cr poisoning effect on La0.6Sr0.4Co0.2Fe0.8O3-σ (LSCF)-based oxygen electrodes under the electrolysis mode was systematically investigated. The phase transition of the sediment during the chromium poisoning process was captured and monitored. When tested under the presence of Fe-Cr interconnects at 800 °C for 40 h, SrCrO4 on the surface of LSCF was clearly identified through XRD and Raman analysis as the main deposition, and with the prolonged operating time, LaCrO3 slowly emerged. Due to the much higher electrical conductivity of LaCrO3 compared to SrCrO4, the negative effect induced by Cr poisoning was offset along with test progressing due to the deposition transition phenomenon. Inspired by the interesting discoveries, transition from SrCrO4 to LaCrO3 can be artificially facilitated by switching the operating mode to the SOEC mode, which can partially recover the dramatic degradation caused by the Cr poisoning effect under the SOFC mode. The feasibility of the in situ electrochemical recovery method was also verified by the experimental results. The peak power density of the cells decreased from 0.829 to 0.505 W/cm2 when operating under the SOFC mode with an Fe-Cr metal connector, and after in situ electrochemical recovery in the SOEC mode, the peak power density recovered to 0.630 W/cm2. This study provides a new strategy for achieving high performance and stability of RSOCs.

B-site nickel tuned high active Sr and Co-free Ba0.8Ca0.2Fe0.8Ni0.2O3-δ air electrode for reversible solid oxide cells

Reversible solid oxide cells (RSOCs) have aroused wide concern as a promising technology in conversion between chemical energy and electrical power. However, the double conducting (O2−/e−) air electrode with high electrocatalytic activity and thermomechanical stability keeps a significant challenge for practical application. Herein, a perovskite Ba0.8Ca0.2Fe0.8Ni0.2O3-δ (BCFNi) oxide is synthesized and used as the air electrode material, which is experimentally and theoretically demonstrated to have excellent oxygen reduction/evolution reactions (ORR/OER) activity. The density functional theory (DFT) calculations indicate that BCFNi oxide accelerates the oxygen desorption/desorption, thus promoting the OER/ORR kinetics. The cell with BCFNi air electrode achieves a peak power density of 1.29 W cm−2 in the fuel cell (FC) mode and an electrolysis current density of 1.47 A cm−2 with 50 % H2O-H2 at 1.3 V applied voltage in the electrolysis cell (EC) mode at 800 °C. Moreover, it maintains favorable durability of 225 h in the FC, reversible, and EC modes at 750 °C, respectively. The results suggest that the Ni doping in B-site of perovskite oxide is beneficial to improve the ORR/OER activity and BCFNi material has great potential as an air electrode for RSOCs.