Fabrication using sequence wet-chemical coating and electrochemical performance of Ni–Fe-foam-supported solid oxide electrolysis cell for hydrogen production from steam

Ni–Fe-alloy-foam supported solid oxide electrolysis cell with an arrangement of nickle and Sc_0.1Ce_0.005Gd_0.005Zr_0.89O₂ (Ni-SCGZ) cathode, SCGZ electrolyte and Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3-δ (BSCF) anode is successfully fabricated by the sequence wet-chemical coating. The multi-layer cathode with a gradient of thermal expansion coefficient (TEC) is deposited on the alloy-foam support. Two-step firing processes are applied including cathode pre-firing (1373 K, 2 h) and electrolyte sintering (1623 K, 4 h) using slow heating rate enhanced with compressive loading. The fabricated cell shows current density of ?0.95 Acm^?2 at 1.1 V with H₂O:H₂ = 70:30 and 1073 K, providing hydrogen production rate at 4.95 × 10^?6 mol s^?1. However, performance degradation was observed with the rate of 0.08 V h^?1, which can be ascribed to the delamination of BSCF anode under operating at high current density.     

Ba0·5Sr0·5(Co0·8Fe0.2)1-xTaxO3-δ perovskite anode in solid oxide electrolysis cell for hydrogen production from high-temperature steam electrolysis

Among perovskite anodes in solid oxide electrolysis cell (SOEC), Ba_0·5Sr_0·5Co_0·8Fe_0·2O_3-δ (BSCF) has gained much attention due to its dominantly high performance. However, the BSCF still suffers from chemical instability. In this study, the B-site of BSCF is partially substituted by a higher valence Ta⁵⁺ (5, 10, 15 and 20 mol%) to improve its structural stability - Ba_0·5Sr_0·5(Co_0·8Fe_0.2)_1-xTa_xO_3-δ (BSCFTax, 0 ≤ x ≤ 0.20). It is found that doping with higher valence Ta⁵⁺ increases both chemical stability and electrochemical performance of BSCF. Although the BSCFTa0.10 shows the lowest oxygen vacancies indicating by the ratio of adsorbed oxygen vacancies (O_adsorbed) to lattice oxygen (O_lattice), the electrochemical performance increases. The decrease in Co³⁺/Co⁴⁺ ratio results in increasing electronic conductivity in the anode. It is likely that proper amount of Ta⁵⁺ doping provide a balance between ionic and electronic conductivity in the anode and improved electrochemical performance. The symmetrical half-cells with electrolyte support (BSCFTa/YSZ/BSCFTa) are fabricated to determine the area specific resistance (ASR) and activation energy of conduction - BSCFTa0.10 shows the best performance. Cathode-supported Ni-YSZ/YSZ/BSCFTa0.10 also shows higher durability than Ni-YSZ/YSZ/BSCF (operating at current density ?0.45 A cm^?2 in electrolysis mode, 80 h, 800 °C and H₂O to H₂ ratio of 70:30).     

Ni–YSZ-supported tubular solid oxide fuel cells with GDC interlayer between YSZ electrolyte and LSCF cathode

Highly sinterable gadolinia doped ceria (GDC) powders are prepared by carbonate coprecipitation and applied to the GDC interlayer in Ni–YSZ (yttria stabilized zirconia)-supported tubular solid oxide fuel cell in order to prevent the reaction between YSZ electrolyte and LSCF (La_0.6Sr_0.4Co_0.2Fe_0.8O_3−δ) cathode materials. The formation of highly resistive phase at the YSZ/LSCF interface was effectively blocked by the low-temperature densification of GDC interlayer using carbonate-derived active GDC powders and the suppression of Sr diffusion toward YSZ electrolyte via GDC interlayer by tuning the heat-treatment temperature for cathode fabrication. The power density of the cell with the configuration of Ni–YSZ/YSZ/GDC/LSCF–GDC/LSCF was as high as 906 mW cm⁻², which was 2.0 times higher than that (455 mW cm⁻²) of the cell with the configuration of Ni–YSZ/YSZ/LSM(La_0.8Sr_0.2MnO_3−δ)–YSZ/LSM at 750 °C.     

Gadolinium doped ceria-impregnated nickel-yttria stabilised zirconia cathode for solid oxide electrolysis cell

Steam electrolysis (H₂O → H₂ + 0.5O₂) was investigated in solid oxide electrolysis cells (SOECs). The electrochemical performance of GDC-impregnated Ni-YSZ and 0.5% wt Rh-GDC-impregnated Ni-YSZ was compared to a composite Ni-YSZ and Ni-GDC electrode using a three-electrode set-up. The electrocatalytic activity in electrolysis mode of the Ni-YSZ electrode was enhanced by GDC impregnation. The Rh-GDC-impregnated Ni-YSZ exhibited significantly improved performance, and the electrode exhibited comparable performance between the SOEC and SOFC modes, close to the performance of the composite Ni-GDC electrode. The performance and durability of a single cell GDC-impregnated Ni-YSZ/YSZ/LSM-YSZ with an H₂ electrode support were investigated. The cell performance increased with increasing temperature (700 °C-800 °C) and exhibited comparable performance with variation of the steam-to-hydrogen ratio (50/50 to 90/10). The durability in the electrolysis mode of the Ni-YSZ/YSZ/LSM-YSZ cell was also significantly improved by the GDC impregnation (200 h, 0.1 A/cm², 800 °C, H₂O/H₂ = 70/30).     

Anode-supported solid oxide fuel cell with yttria-stabilized zirconia/gadolinia-doped ceria bilalyer electrolyte prepared by wet ceramic co-sintering process

To protect the ceria electrolyte from reduction at the anode side, a thin film of yttria-stabilized zirconia (YSZ) is introduced as an electronic blocking layer to anode-supported gadolinia-doped ceria (GDC) electrolyte solid oxide fuel cells (SOFCs). Thin films of YSZ/GDC bilayer electrolyte are deposited onto anode substrates using a simple and cost-effective wet ceramic co-sintering process. A single cell, consisting of a YSZ (∼3 μm)/GDC (∼7 μm) bilayer electrolyte, a La_0.8Sr_0.2Co_0.2Fe_0.8O₃–GDC composite cathode and a Ni–YSZ cermet anode is tested in humidified hydrogen and air. The cell exhibited an open-circuit voltage (OCV) of 1.05 V at 800 °C, compared with 0.59 V for a single cell with a 10-μm GDC film but without a YSZ film. This indicates that the electronic conduction through the GDC electrolyte is successfully blocked by the deposited YSZ film. In spite of the desirable OCVs, the present YSZ/GDC bilayer electrolyte cell achieved a relatively low peak power density of 678 mW cm⁻² at 800 °C. This is attributed to severe mass transport limitations in the thick and low-porosity anode substrate at high current densities.     

Fabrication and characterization of a Ba0.5Sr0.5Co0.8Fe0.2O3−δ—Gadolinia-doped ceria cathode for an anode-supported solid-oxide fuel cell

Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3−δ (BSCF) and gadolinia-doped ceria (GDC) were synthesized via a glycine-nitrate process (GNP). A cubic perovskite of BSCF was observed by X-ray diffraction (XRD) at a calcination temperature above 950 °C. An anode-supported solid-oxide fuel cell was constructed from the porous NiO + YSZ as the anode substrate, the yittria-stabilized zirconia (YSZ) as the electrolyte, and the porous BSCF-GDC layer as the cathode with a GDC barrier layer. For the performance test, the maximum power density was 191.3 mW cm⁻² at a temperature of 750 °C with H₂ fuel and air at flow rates of 335 and 670 sccm, respectively. According to the AC-impedance data, the charge-transfer resistances of the electrodes were 0.10 and 1.59 Ω cm², and the oxygen-reduction and oxygen-ion diffusion resistances were 0.69 and 0.98 Ω cm² at 750 and 600 °C, respectively. SEM microstructural characterization indicated that the fuel cell as fabricated exhibited good compatibility between cathode and electrolyte layers.     

Performance and structural stability of Gd0.2Ce0.8O1.9 infiltrated La0.8Sr0.2MnO3 nano-structured oxygen electrodes of solid oxide electrolysis cells

Effect of Gd_0.2Ce_0.8O_1.9 (GDC) infiltration on the performance and stability of La_0.8Sr_0.2MnO₃ (LSM) oxygen electrodes on Y₂O₃-stabilized ZrO₂ (YSZ) electrolyte has been studied in detail under solid oxide electrolysis cell (SOEC) operating conditions at 800 °C. The incorporation of GDC nanoparticles significantly enhances the electrocatalytic activity for oxygen oxidation reaction on LSM electrodes. Electrode polarization resistance of pristine LSM electrode is 8.2 Ω cm² at 800 °C and decreases to 0.39 and 0.09 Ω cm² after the infiltration of 0.5 and 1.5 mg cm⁻² GDC, respectively. The stability of LSM oxygen electrodes under the SOEC operating conditions is also significantly increased by the GDC infiltration. A 2.0 mg cm⁻² GDC infiltrated LSM electrode shows an excellent stability under the anodic current passage at 500 mA cm⁻² and 800 °C for 100 h. The infiltrated GDC nanoparticles effectively shift the reaction sites from the LSM electrode/YSZ electrolyte interface to the LSM grains/GDC nanoparticle interface in the bulk of the electrode, effectively mitigating the delamination at the LSM/YSZ interface. The results demonstrate that the GDC infiltration is an effective approach to enhance the structural integrity and thus to achieve the high activity and excellent stability of LSM-based oxygen electrode under the SOEC operating conditions.     

Investigation of single SOEC with BSCF anode and SDC barrier layer

In this paper, Sm_0.2Ce_0.8O_1.9 (SDC) is used as a barrier interlayer between Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3−δ (BSCF) anode and 8YSZ electrolyte to avoid solid state interaction of solid oxide electrolysis cells (SOEC) for high temperature application. The crystal structure and surface morphologies of BSCF and SDC powders were characterized, respectively. BSCF-SDC/YSZ/SDC-BSCF symmetric cells and BSCF-SDC/YSZ/Ni-YSZ single button cells were prepared and the related electrochemical performances were tested at 850 °C. The results showed that ASR data of BSCF-SDC/YSZ is 0.42 Ω cm² at 850 °C. The hydrogen production rate of the single SOEC using BSCF/SDC anode can be up to 177.4 mL cm⁻² h⁻¹, also the cell exhibits excellent stability, which indicates that it could be a potential candidate for the future application of SOEC technology.     

Effect of unsintered gadolinium-doped ceria buffer layer on performance of metal-supported solid oxide fuel cells using unsintered barium strontium cobalt ferrite cathode

In this study, a Gd_0.1Ce_0.9O_1.95 (GDC) buffer layer and a Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3−δ (BSCF) cathode, fabricated without pre-sintering, are investigated (unsintered GDC and unsintered BSCF). The effect of the unsintered GDC buffer layer, including the thickness of the layer, on the performance of solid oxide fuel cells (SOFCs) using an unsintered BSCF cathode is studied. The maximum power density of the metal-supported SOFC using an unsintered BSCF cathode without a buffer layer is 0.81 W cm⁻², which is measured after 2 h of operation (97% H₂ and 3% H₂O at the anode and ambient air at the cathode), and it significantly decreases to 0.63 W cm⁻² after 50 h. At a relatively low temperature of 800 °C, SrZrO₃ and BaZrO₃, arising from interaction between BSCF and yttria-stabilized zirconia (YSZ), are detected after 50 h. Introducing a GDC interlayer between the cathode and electrolyte significantly increases the durability of the cell performance, supporting over 1000 h of cell usage with an unsintered GDC buffer layer. Comparable performance is obtained from the anode-supported cell when using an unsintered BSCF cathode with an unsintered GDC buffer layer (0.75 W cm⁻²) and sintered GDC buffer layer (0.82 W cm⁻²). When a sintered BSCF cathode is used, however, the performance increases to 1.23 W cm⁻². The adhesion between the BSCF cathode and the cell can be enhanced by an unsintered GDC buffer layer, but an increase in the layer thickness (1-6 μm) increases the area specific resistance (ASR) of the cell, and the overly thick buffer layer causes delamination of the BSCF cathode. Finally, the maximum power densities of the metal-supported SOFC using an unsintered BSCF cathode and unsintered GDC buffer layer are 0.78, 0.64, 0.45 and 0.31 W cm⁻² at 850, 800, 750 and 700 °C, respectively.     

Efficient and stable heterostructured air electrode for solid oxide steam electrolysis

High performance and excellent durability are essential for the practical application of solid oxide electrolysis cell (SOEC). Here we have demonstrated efficient and durable solid oxide steam electrolysis by constructing active La_0.8Sr_0.2CoO_3-δ/Gd_0.2Ce_0.8O_2-δ (LSC/GDC) heterointerface in air electrode using a simple co-impregnation method. The heterostructured air electrode exhibits the outstanding activity for oxygen evolution reaction, and its exchange current density (557 mA cm^?2) is 69 times higher than that of the traditional LSM-YSZ. The resulting cell reaches ?1.86 A cm^?2 @1.3 V and ?2.30 A cm^?2 @1.5 V at 800 °C and 50% absolute humidity (A.H), and the polarization resistance from the oxygen electrode only is 0.02 Ω cm². Most importantly, the heterostructured cell presents excellent long-term stability for the 1035 h steam electrolysis operation and excellent durability for 100 times charge-discharge cycles. In the heterostructured air electrode, the problem of electrode delamination is avoided due to the reduced oxygen partial pressure at anode/electrolyte resulting from easy diffusion of O^2? at the interphase, and the coarsening of LSC and GDC nanoparticles is limited because of the LSC/GDC percolative interfaces from phase segregation process. This work proposes a simple and effective strategy to design heterointerface for efficient and durable solid oxide steam electrolysis.     

Performance of solid oxide electrolysis cells based on composite La0.8Sr0.2MnO3−δ – yttria stabilized zirconia and Ba0.5Sr0.5Co0.8Fe0.2O3−δ oxygen electrodes

The electrochemical performance of solid oxide electrolysis cells (SOECs) having barium strontium cobalt ferrite (Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3−δ) and composite lanthanum strontium manganite–yttria stabilized zirconia (La_0.8Sr_0.2MnO_3−δ–YSZ) oxygen electrodes has been studied over a range of operating conditions. Increasing the operating temperature (973 K to 1173 K) significantly increased electrochemical performance and hydrogen generation efficiency for both systems. The presence of water in the hydrogen electrode was found to have a marked positive effect on the EIS response of solid oxide cell (SOC) under open circuit voltage (OCV). The difference in operation between electrolytic and galvanic modes was investigated. Cells having BSCF oxygen electrodes (Ni–YSZ/YSZ/BSCF) showed greater performance than LSM-YSZ-based cells (Ni–YSZ/YSZ/LSM-YSZ) over the range of temperatures, in both galvanic and electrolytic regimes of operation. The area specific resistance (ASR) of the LSM-YSZ-based cells remained unchanged when transitioning between electrolyser and fuel cell modes; however, the BSCF cells exhibited an overall increase in cell ASR of ∼2.5 times when entering electrolysis mode.     

Characterization of infiltrated (La0.75Sr0.25)0.95MnO3 as oxygen electrode for solid oxide electrolysis cells

Porous strontium doped lanthanum manganite (LSM)-yttria-stabilized zirconia (YSZ) composite has been made by an impregnation method as oxygen electrodes for solid oxide electrolysis cells. X-ray diffraction and SEM results showed that LSM powders with well-crystallized perovskite phase uniformly distributed in the porous YSZ matrix. Impedance spectra and voltage-current density curves were measured as a function of absolute humidity at different temperatures to characterize the cell performance. The LSM infiltrated cell has an area specific resistance (ASR) of 0.20 Ω cm² at 900 °C at open circuit voltage with 50% absolute humidity (AH), which is relatively lower than that of the cell with LSM-YSZ oxygen electrode made by a conventionally mixing method. Electrolysis cell with LSM infiltrated oxygen electrode has demonstrated stable performance under electrolysis operation with 0.33 A/cm² and 50 vol.% AH at 800 °C.     

Low temperature processed composite cathodes for Solid-oxide fuel Cells

Low temperature processed composite cathodes for solid-state fuel cell (SOFC) have been developed, consisting of La_0.6Sr_0.4Ti_0.1Fe_0.9O₃ and Ag, as low as 800 °C process temperature. Using micro-tubular design, the performances of the cathodes have been investigated at the operating temperatures of 650 and 700 °C. The cell consists of NiO-Y stabilized zirconia (YSZ) as an anode (support tube), Sc stabilized zirconia (ScSZ) as an electrolyte, Gd doped ceria (GDC) for an inter-layer between the electrolyte and the cathodes. The single performance has varied depending upon the types of cathodes, and the composite cathode with 50 wt% La_0.6Sr_0.4Ti_0.1Fe_0.9O₃ and 50 wt% Ag has shown comparable performance to the cell with standard LSCF-GDC cathode.     

Perovskite Sr2Fe1.5Mo0.5O6−δ as electrode materials for symmetrical solid oxide electrolysis cells

Perovskite Sr₂Fe_1.5Mo_0.5O_6−δ (SFM) has been successfully prepared by a microwave-assisted combustion method in air and employed as both anode and cathode in symmetrical solid oxide electrolysis cells (SOECs) for hydrogen production for the first time in this work. Influence of cell operating temperature, absolute humidity (AH) as well as applied direct current (DC) on the impedance of single cells with the configuration of SFM|La_0.9Sr_0.1Ga_0.8Mg_0.2O₃ (LSGM)|SFM has been evaluated. Under open circuit conditions and 60 vol.% AH, the cell polarization resistance, R_P is as low as 0.26 Ω cm² at 900 °C. An electrolysis current of 0.88 A cm⁻² and a hydrogen production rate as high as 380 mL cm⁻² h have been achieved at 900 °C with an electrolysis voltage of 1.3 V and 60 vol.% AH. Further, the cell has demonstrated good stability in the long-term steam electrolysis test. The results showed that the cell electrolysis performance was even better than that of the reported strontium doped lanthanum manganite (LSM) – yttria stabilized zirconia (YSZ)|YSZ|Ni–YSZ cell, indicating that SFM could be a very promising electrode material for the practical application of SOEC technology.     

Preparation and electrochemical behavior of dense YSZ film for SOEC

High Temperature Electrolysis (HTE) through a solid oxide electrolytic cell (SOEC) had been receiving more and more attentions recently because of its high conversion efficiency (45–59%) and its potential usage for large-scale hydrogen or synthetic fuels production. One of the key technologies associated with SOEC fabrication was to prepare dense yttria-stabilized zirconia (YSZ) electrolyte film on the surface of hydrogen electrode. A novel screen-printing method was developed to fabricate gas-tight YSZ films on porous NiO-YSZ to reduce ohmic resistance of electrolytes and improve electrochemical performance of cells in this paper. The effects of pre-calcining temperature of cathodes, numbers of printing layers and sintering temperature of YSZ films were investigated in detail. SEM and EIS analyses revealed that the selected process parameters had significant influences on the microscopic morphology of YSZ electrolyte film, the OCVs and power density of the prepared cells. After optimization, a 10 μm dense YSZ film was prepared successfully on porous NiO-YSZ support with an OCV of 1.069 V and the electrolysis current density up to 0.681 A/cm² at 1.50 V and 850 °C.     

Coelectrolysis of steam and CO2 in a solid oxide electrolysis cell with ceramic composite electrodes

Lanthanum strontium vanadate (LSV) was used as the cathode of a solid oxide electrolysis cell (SOEC) containing a yttria-stabilized zirconia (YSZ) electrolyte for the coelectrolysis of steam and CO₂. Pd and CeO₂ were added to the composite cathode, and the electrolysis mechanism in the coelectrolysis mode changed according to the type of catalyst in the LSV/YSZ composite cathode. The effect of steam on the coelectrolysis performance was investigated by varying the steam vapor pressure. The electrolysis performance under dry CO₂ without steam degraded with time under electrochemical reduction conditions owing to the deactivation of catalysts.     

Measurement of oxygen chemical potential in Gd2O3-doped ceria-Y2O3-stabilized zirconia bi-layer electrolyte, anode-supported solid oxide fuel cells

Solid oxide fuel cells (SOFC) were fabricated with gadolinia-doped ceria (GDC)-yttria stabilized zirconia (YSZ), thin bi-layer electrolytes supported on Ni + YSZ anodes. The GDC and YSZ layer thicknesses were 45 μm, and ∼5 μm, respectively. Two types of cells were made; YSZ layer between anode and GDC (GDC/YSZ) and YSZ layer between cathode and GDC (YSZ/GDC). Two platinum reference electrodes were embedded within the GDC layer. Cells were tested at 650 °C with hydrogen as fuel and air as oxidant. Electric potentials between embedded reference electrodes and anode and between cathode and anode were measured at open circuit, short circuit and under load. The electric potential was nearly constant through GDC in the cathode/YSZ/GDC/anode cells. By contrast, it varied monotonically through GDC in the cathode/GDC/YSZ/anode cells. Estimates of oxygen chemical potential, μO₂, variation through GDC were made. μO₂ within the GDC layer in the cathode/GDC/YSZ/anode cell decreased as the current was increased. By contrast, μO₂ within the GDC layer in the cathode/YSZ/GDC/anode cell increased as the current was increased. The cathode/YSZ/GDC/anode cell exhibited maximum power density of ∼0.52 W cm⁻² at 650 °C while the cathode/GDC/YSZ/anode cell exhibited maximum power density of ∼0.14 W cm⁻² for the same total electrolyte thickness.     

Performance and stability of (La,Sr)MnO3–Y2O3–ZrO2 composite oxygen electrodes under solid oxide electrolysis cell operation conditions

The electrochemical performance and stability of (La,Sr)MnO₃–Y₂O₃–ZrO₂ (LSM-YSZ) composite oxygen electrodes is studied in detail under solid oxide electrolysis cells (SOECs) operation conditions. The introduction of YSZ electrolyte phase to form an LSM-YSZ composite oxygen electrode substantially enhances the electrocatalytic activity for oxygen oxidation reaction. However, the composite electrode degrades significantly under SOEC mode tested at 500 mA cm⁻² and 800 °C. The electrode degradation is characterized by deteriorated surface diffusion and oxygen ion exchange and migration processes. The degradation in electrode performance and stability is most likely associated with the breakup of LSM grains and formation of LSM nanoparticles at the electrode/electrolyte interface, and the formation of nano-patterns on YSZ electrolyte surface under the electrolysis polarization conditions. The results indicate that it is important to minimize the direct contact of LSM particles and YSZ electrolyte at the interface in order to prevent the detrimental effect of the LSM nanoparticle formation on the performance and stability of LSM-based composite oxygen electrodes.     

A comparative study of surface segregation and interface of La0·6Sr0·4Co0·2Fe0·8O3-δ electrode on GDC and YSZ electrolytes of solid oxide fuel cells

Electrode/electrolyte interface plays a critical role in the performance and stability of solid oxide fuel cells (SOFCs). In the case of La_0·6Sr_0·4Co_0·2Fe_0·8O_3-δ (LSCF) cathode, it is well known that cathodic polarization promotes the Sr segregation and diffusion towards the LSCF electrode and Y₂O₃–ZrO₂ (YSZ) electrolyte interface, leading to the formation of SrZrO₃ secondary phase and the disintegration of LSCF structure at the interface. On the other hand, LSCF is chemically stable with doped ceria electrolytes such as Gd-doped CeO₂ (GDC). However, there appears no comparative studies on the intrinsic relationship between the surface segregation, interface reaction and stability of LSCF in YSZ and GDC electrolytes. Here, a comparative study has been carried out on the segregation and interface formation of LSCF on GDC and YSZ electrolyte under identical cathodic polarization conditions at 750 °C and 1000 mAcm^?2 using focused ion beam and scanning transmission electron microscopy (FIB-STEM) techniques. Segregation of Sr occurs in the LSCF-GDC system, however, the inertness of GDC electrolyte suppresses the segregation process of Sr species. Instead, surface segregation of B-site Co cation becomes dominant under the cathodic polarization, forming isolated CoO_x particles. The results indicate that the existence of chemical catchers such as Zr in the case of YSZ electrolyte for the segregated Sr species is kinetically the driving force for the Sr segregation and stability of LSCF electrodes under SOFC operation conditions.     

Microstructural characterization and electrochemical properties of Ba0.5Sr0.5Co0.8Fe0.2O3−δ and its application for anode of SOEC

Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3−δ (BSCF) was synthesized successfully by a novel citric acid–nitrate combustion method and employed as the anode of solid oxide electrolysis cells (SOEC) for hydrogen production for the first time in this paper. The crystal structure, chemical composition and electrochemical properties of BSCF were investigated in detail. The results showed that BSCF is in good stoichiometry of Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3−σ formation. ASR of BSCF/YSZ is only 0.077 Ω cm² at 850 °C, remarkably lower than the commonly used oxygen materials LSM as well as the current focus materials LSC and LSCF. Also, BSCF electrode exhibited much better performance than LSM under both SOEC and SOFC operating modes. The hydrogen production rate of BSCF/YSZ/Ni-YSZ can be up to 147.2 mL cm⁻² h⁻¹, about three times higher than that of LSM/YSZ/Ni-YSZ, which indicates that BSCF could be a very promising candidate for the practical application of SOEC technology.