A new anode material for solid oxide electrolyser: The neodymium nickelate Nd2NiO4+δ

Neodymium nickelate, with composition Nd₂NiO_4+δ is integrated as oxygen electrode in a solid oxide electrolyte supported cell made of a TZ3Y electrolyte and a Ni-CGO hydrogen electrode. This cell is tested in both fuel cell (SOFC) and electrolysis (SOEC) mode and the reversible operation is proven, ASR values being slightly lower in electrolysis mode. Performances in SOEC mode are compared with a commercial cell based on the same electrolyte and cathode, but with lanthanum strontium manganite (LSM) as anode. For a voltage of 1.3 V, current densities of 0.40, 0.64 and 0.87 A cm⁻² are measured at 750, 800 and 850 °C, respectively; they are much higher than the ones measured in the same conditions for the LSM-containing cell. Indeed, for a voltage of 1.3 V, current densities are respectively 1.7, 3 and 4.2 times higher for the Nd₂NiO_4+δ cell than for the LSM one at 850, 800 and 750 °C, respectively. Consequently, Nd₂NiO_4+δ can be considered as a good candidate for operating below 800 °C as oxygen electrode for high temperature steam electrolysis.     

A promising strontium and cobalt-free air electrode Pr1-xCaxFeO3-δ for solid oxide electrolysis cell

A promising strontium and cobalt-free ferrite Pr_1-xCa_xFeO_3-δ (PCF, x = 0, 0.1, 0.2, 0.3, 0.4, 0.5) has been synthesized successfully by glycine-nitrate combustion method and used as the air electrode of solid oxide electrolysis cell (SOEC) for steam electrolysis. The crystal structure and electricity conductivity of PCF are investigated in detail. According to the conductivity test, Pr_0.6Ca_0.4FeO_3-δ (PCF64) with higher conductivity is selected as the air electrode to preparing the single cell with structure of PCF64|GDC|SSZ|YSZ-NiO. Under SOFC mode, the maximum power density of the single cell is 462.93 mW cm⁻² at 800 °C with hydrogen as fuel. Under SOEC mode, the current density reaches 277.14 mA cm⁻² and the corresponding hydrogen production rates is 115.84 mL cm⁻² h⁻¹ at 800 °C at 1.3 V. In the 10 h short-term stability test, the cell shows good electrolysis stability.     

Preparation and properties of PrBa0.5Sr0.5Co1.5Fe0.5O5+δ as novel oxygen electrode for reversible solid oxide electrochemical cell

In this work, double perovskite-type oxide PrBa_0.5Sr_0.5Co_1.5Fe_0.5O_5+δ (PBSCF) is synthesized by the conventional wet chemical method and firstly characterized as the oxygen electrode for reversible solid oxide electrochemical cells (RSOCs). The microstructure and electrochemical performance of RSOCs based on this oxygen electrode are investigated. The maximum power density of the cell reaches 986 mW/cm² at 800 °C and the cell has good stability in short-term test in fuel cell (SOFC) mode. In electrolysis cell (SOEC) mode, it displays an electrolysis current density as high as 1.3 A/cm² when the temperature, absolute humidity (AH) and applied voltage are 800 °C, 50 vol % and 1.3 V, respectively. The cells also exhibit excellent durability of 120 h in SOEC mode and present good reversibility. The results suggest that the RSOCs based on this oxygen electrode has a very promising prospect.     

Nano-structured LSM-YSZ refined with PdO/ZrO2 oxygen electrode for intermediate temperature reversible solid oxide cells

To promote the application of traditional (La_0.8Sr_0.2)_0.95MnO_3-δ-YSZ (LSM-YSZ) oxygen electrodes to both solid oxide fuel cells (SOFCs) and solid oxide electrolysis cells (SOECs) modes at intermediate temperatures, we select PdO as the catalyst and ZrO₂ as the PdO stabilizer to decorate the LSM-YSZ. The high active PdO particles enhance the electrocatalytic activity, and stable ZrO₂ can hinder the growth and agglomeration of the PdO particles. PdO and ZrO₂ are co-impregnated into the LSM-YSZ to form a nano-structured PdO/ZrO₂ -LSM-YSZ composite electrode. At 750 °C, the obtained cell attains a power density peak of 1.114 W cm⁻² in SOFC mode and shows significant improvement of the cell with LSM-YSZ composite oxygen electrode. As a SOEC, when the water content is 90 vol%AH (absolute humidity) at the hydrogen electrode, the cell exhibits an extraordinary current density of 2.322 A cm⁻² under applied voltage of 2.0 V at 750 °C. Moreover, the cell shows notable long-term stability during water electrolysis. Therefore, this study demonstrates that the nano-structured PdO/ZrO₂ -LSM-YSZ based material as a high active and stable oxygen electrode can greatly promote the application of LSM-YSZ electrode in reversible solid oxide electrolysis cell (RSOCs) field.     

Solid oxide cells with cermet of silver and gadolinium-doped-ceria symmetrical electrodes for high-performance power generation and water electrolysis

A cermet of silver and gadolinium-doped-ceria (Ag-GDC) is investigated as novel symmetrical electrode material for (ZrO₂)_0.92(Y₂O₃)_0.08 (YSZ) electrolyte-supported solid oxide cells (SOCs) operated in fuel cell (SOFC) and electrolysis (SOEC) modes. The electrochemical performances are evaluated by measuring the current density-voltage characteristics and impedance spectra of the SOCs. The activity of hydrogen and air electrodes is investigated by recording overpotential versus current density in symmetrical electrode cells, respectively in hydrogen and air, using a three-electrode method. Conventional hydrogen electrode, Ni-YSZ, and oxygen electrode, LSCF (La_0.6Sr_0.4Co_0.2Fe_0.8O_3-δ)-GDC, are tested as comparison. The results show that, as an oxygen electrode, Ag-GDC is more active than LSCF-GDC in catalyzing both oxygen reduction reaction (ORR) in an SOFC and oxygen evolution reaction (OER) in an SOEC. As a hydrogen electrode, Ag-GDC is more active than Ni-YSZ in catalyzing hydrogen oxidation reaction (HOR) in an SOFC and hydrogen evolution reaction (HER) in an SOEC, especially in high steam concentration. An SOC with symmetrical Ag-GDC electrodes operated in a fuel cell mode, with 3% H₂O humidified H₂ as the fuel, displays a peak power density of 395 mWcm^?2 at 800 °C. Its polarization resistance at open circuit voltage is 0.21 Ω cm². Ag-GDC electrode can be operated even at pure steam. An SOEC operated for electrolyzing 100% H₂O, the current density reaches 720 mA cm^?2 under 1.3 V at 800 °C.     

Bi-doped La1.5Sr0.5Ni0.5Mn0.5O4+δ as an efficient air electrode material for SOEC

Bi-doped La_1.5-xBi_xSr_0.5Ni_0.5Mn_0.5O_4+δ (LBSNM-x, x = 0, 0.05, 0.1, 0.15) was investigated as a potential air electrode for solid oxide electrolysis cell (SOEC). The effect of Bi doping on the structure, electrical conductivity, chemical compatibility with GDC electrolyte, electrochemical performance and thermal expansion coefficients (TECs) were investigated. XRD characterization results show that the solid solution content of Bi is less than or equal to 0.1. XPS characterization results indicate that Bi doping increases the oxygen vacancy content of LBSNM-x air electrode and thus greatly benefits its oxygen evolution reaction. Among the Bi-doped samples, LBSNM-0.1 electrode has the best electrochemical performance with its lowest Rp (polarization resistance) of 0.28 Ω cm² at 800 °C based on LBSNM-0.1/GDC half-cell. LBSNM-0.1 single cell with 70%CO₂ + 30%CO fuel gas feed on the fuel electrode has achieved current density of 811 mA cm⁻² at 800 °C and 1.4 V, a 62.2% increase relative to that of LSNM single cell. In addition, LBSNM-0.1 single cell exhibits excellent stability at 800 °C and 1.3 V with 70%CO₂ + 30%CO feed gas on the fuel electrode. These results prove that Bi-doped LBSNM-0.1 is an efficient air electrode for SOEC.     

Degradation study of a reversible solid oxide cell (rSOC) short stack using distribution of relaxation times (DRT) analysis

Reversible solid oxide cells (rSOC) can convert excess electricity to valuable fuels in electrolysis cell mode (SOEC) and reverse the reaction in fuel cell mode (SOFC). In this work, a five – cell rSOC short stack, integrating fuel electrode (Ni-YSZ) supported solid oxide cells (Ni-YSZ || YSZ | CGO || LSC-CGO) with an active area of 100 cm², is tested for cyclic durability. The fuel electrode gases of H₂/N₂:50/50 and H₂/H₂O:20/80 in SOFC and SOEC mode, respectively, are used during the 35 reversible operations. The voltage degradation of the rSOC is 1.64% kh^?1 and 0.65% kh^?1 in SOFC and SOEC mode, respectively, with fuel and steam utilisation of 52%. The post-cycle steady-state SOEC degradation of 0.74% kh^?1 suggests improved lifetime during rSOC conditions. The distribution of relaxation times (DRT) analysis suggests charge transfer through the fuel electrode is responsible for the observed degradation.     

High performance and stability of nanocomposite oxygen electrode for solid oxide cells

Solid oxide electrochemical cell (SOC) is a highly promising alternative for fuel conversion and power-to-gas due to its high efficiency and low emission. However, degradation resulting from the electrolyte-electrode interface is a major challenge in both fuel cell mode and electrolysis mode. Here, a co-sintering tri-layer structure cell with nanocomposite oxygen electrode is developed to mitigate the interface issue. A 10 × 10 cm² NiO/YSZ||YSZ||YSZ-La_0.6Sr_0.4Co_0.2Fe_0.8O_3-δ (LSCF) cell has been conducted under different fuels in SOFC mode. A power density output of 558 mW/cm² @0.7 V-800 °C in wet H₂ and a durability of 300 h in simulated syngas have been obtained. The performance of LSF, LSCF and SSC oxygen electrodes have been studied in both SOFC and SOEC modes. It suggests that three oxygen electrodes have an order of SSC > LSCF > LSF in electrochemical performance, and an opposite order in stability of SOEC. The degradation of the LSCF and SSC can be derived from the solid-state reactions at the interface between Co-containing perovskites and YSZ during operation. It demonstrates that GDC and Ag modification can enhance the oxygen electrode stability by impeding the solid-state reactions and the nanoparticles sintering. Results suggest that GDC has a negative effect on the cell performance and Ag has a positive effect, implying that enhancing the electric conductivity of YSZ-LSCF is the key to improve the cell performance. Moreover, cell with YSZ-SFM/GDC has been applied in CH₄ assisted SOEC process (CH₄-SOEC), in which a significant reduction of electricity consume can be realized.     

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.     

A promising Bi-doped La0.8Sr0.2Ni0.2Fe0.8O3-δ oxygen electrode for reversible solid oxide cells

Reversible solid oxide cells (RSOCs) are clean and effective electrochemical conversion devices that require highly active electrodes and stable electrochemical performance for the practical application. Herein, we investigate a series of La_0.8-xBi_xSr_0.2Ni_0.2Fe_0.8O_3-δ (LBSNF-x, x = 0.0, 0.05, 0.1, 0.15) oxides as the potential oxygen electrode material for RSOCs. The properties of electrical conductivity, thermal expansion coefficient, and chemical compatibility with the Ce_0.9Gd_0.1O_1.95 (GDC) barrier layer of LBSNF-x oxides are evaluated. When LBSNF-0.1 and GDC forms a composite oxygen electrode with the ratio of 7:3, it shows the lowest polarization resistance with fastest oxygen reduction reaction activity in the symmetrical cell test. Then the cell with the configuration of Ni-YSZ/YSZ/GDC/LBSNF-0.1-GDC was prepared and evaluated both in fuel cell (FC) and electrolysis cell (EC) mode. The maximum power density of 824 mW cm⁻² is obtained at 800 °C in FC mode, and current density of 1.20 A cm⁻² is achieved under 50% steam content at 1.3 V in EC mode. Additionally, the cell exhibits good stability both in FC and EC mode after 80 h test at 700 °C. The results of this work provide a strong support for application of the LBSNF-0.1-GDC oxygen electrode for reversible solid oxide cells.     

A highly active and stable hybrid oxygen electrode for reversible solid oxide cells

Reversible solid oxide cells (RSOCs) have attracted increasing attention due to the potential realizing the deep coupling between hydrogen and electricity. An efficient and stable oxygen electrode is needed for developing RSOCs. Herein, we report a nanostructured hybrid with a nominal composition of BaZr_0.2Co_0.8O_3-δ as oxygen electrode. The chemical composition, crystal structure and physicochemical properties of the BaZr_0.2Co_0.8O_3-δ hybrid have been characterized. The results show that the sintered BaCo_0.8Zr_0.2O_3-δ has grown into a hybrid, consisting of cubic perovskite BaZr_0.82Co_0.18O_3-δ, hexagonal perovskite BaCo_0.96Zr_0.04O_2.6+δ and a small quantity of hexagonal perovskite BaCoO₃. The cell with BaZr_0.2Co_0.8O_3-δ hybrid oxygen electrode delivers a current density of 2.09 A cm⁻² @0.7 V in SOFC mode, and gives −1.43 A cm⁻² @1.3 V in SOEC mode for steam electrolysis. The BaCo_0.8Zr_0.2O_3-δ cell shows a smooth transition from SOEC to SOFC, and gives no obvious degradation after 100 times SOEC↔SOFC cycle operation.     

Electrochemical performance of La0.65Sr0.35MnO3 oxygen electrode with alternately infiltrated Sm0.5Sr0.5CoO3-δ and Sm0.2Ce0.8O1.9 nanoparticles for reversible solid oxide cells

La_1-xSr_xMnO₃ is a well-known oxygen electrode for reversible solid oxide cells (RSOCs). However, its poor ionic conductivity limits its performance in redox reaction. In this study, we selected Sm_0.5Sr_0.5CoO_3-δ (SSC) as catalyst and Sm_0.2Ce_0.8O_1.9 (SDC) as ionic conductor and sintering inhibitor to co-modify the La_0.65Sr_0.35MnO₃ (LSM) oxygen electrode through an alternate infiltration method. The infiltration sequence of SSC and SDC showed an influence on the morphology and performance of LSM oxygen electrode, and the influence was gradually weakened with the increasing infiltration time. The polarization resistance of the alternately infiltrated LSM-SSC/SDC electrode was 0.08 Ω cm² at 800 °C in air, which was 3.36% of the LSM electrode (2.38 Ω cm²). The Ni-YSZ/YSZ/LSM-SSC/SDC single cell attained a maximum power density of 1205 mW cm^?2 in SOFC mode at 800 °C, which was 8.73 times more than the cell with LSM electrode. The current density achieved 1620 mA .cm^?2 under 1.5 V at 800 °C in SOEC mode and the H₂ generation rate was 3.47 times of the LSM oxygen electrode.     

Optimizing La1-xSrxFeO3-δ electrodes for symmetrical reversible solid oxide cells

Reversible solid oxide cells (RSOCs) are prone to material thermal property mismatching problems between electrodes and electrolyte, which greatly reduces their energy efficiency and causes irreversible performance degradation. One solution is to develop symmetrical RSOCs (SRSOCs) employing identical electrode materials to effectively address thermal property mismatching related issues and also simplify the manufacturing process. Herein, La_1-xSr_xFeO_3-δ (x = 0–0.20) perovskites are developed and applied as both fuel and air electrode materials for SRSOCs for the first time. The impact of Sr substitution for La on the crystal structures, conductivities and electrochemical performance of LaFeO₃ oxides is systematically investigated. It is found, after doping with Sr, overall properties of the LaFeO₃ oxides show an obvious improvement, especially for the sample of La_0·9Sr_0·1FeO_3-δ (LSF9010). The peak power density of SRSOCs featuring LSF9010 can stand at 0.575 W cm⁻² at 800 °C under the solid oxide fuel cell (SOFC) working model. Under solid oxide electrolysis cell (SOEC) model, the current density stands at 0.84 A cm⁻² at 800 °C and 1.5 V. More importantly, the La_0·9Sr_0·1FeO_3-δ symmetrical cell can operate steadily for 128 h under SOFC mode and 25 h under SOFC-SOEC cycle mode, respectively, with almost no performance degradation found. The outcomes of the current study show that the developed LSF9010 may be used as an outstanding multifunctional electrode material in SRSOCs.     

Highly active and stable A-site Pr-doped LaSrCrMnO-based fuel electrode for direct CO2 solid oxide electrolyzer cells

Direct CO₂ electrolysis has been explored as a means to store renewable energy and produce renewable fuels. La chromate-based perovskite oxides have attracted great attention as fuel electrode materials for solid oxide electrolyzer cells. However, the electrochemical catalytic activity of such oxides is relatively low, and their stability has not been confirmed. In this study, Pr is doped into La_0.75Sr_0.25Cr_0.5Mn_0.5O_3-δ (LSCM) and the applicability of the resulting fuel electrode to direct CO₂ electrolysis is investigated. The polarization resistance of the resulting electrode at 800 °C is decreased by 25%. Distribution function of relaxation times analysis indicates that the observed improvements may be attributed to increased oxygen ion conductivity. A full cell of Pr-doped LSCM-gadolinium-doped ceria (GDC)|scandia-stabilized zirconia|La_0.6Sr_0.4Co_0.2Fe_0.8O_3-δ-GDC achieves an electrolysis current of 0.5 A cm⁻² at 1.36 V and a Faradaic efficiency close to 100%. Short-term (210 h) stability testing of the cell under an electrolysis current of 0.5 A cm⁻² at 800 °C with pure CO₂ as the feedstock reveals a decrease in applied voltage at a rate of 7 mV kh⁻¹, thereby indicating excellent stability. Thus, given its satisfactory performance and stability, the Pr-doped LSCM electrode may be considered a promising candidate material for direct CO₂ electrolysis.     

Sr2Fe1.5+xMo0.5O6-δ cathode with exsolved Fe nanoparticles for enhanced CO2 electrolysis

Solid oxide electrolysis cell (SOEC) can perform CO₂ electrolysis to produce CO feedstock. In this work, we show Sr₂Fe_1.5+xMo_0.5O_6-δ with exsolved Fe nanoparticles to enhance the activity to CO₂ electrolysis. A single SOEC with a configuration of SF_1.5+xM-SDC/LSGM/LSM-SDC shows a current density of 1.16 A cm⁻² at 1.8 V, which presents the CO production rate of 6.85 mL min⁻¹ cm⁻² and the current efficiency of up to 96.3% at 850 °C. We further demonstrate a stable electrolysis performance without obvious degradation being observed even after a long-time operation of 100 h. The exsolved metal-oxide interfaces function as three phase boundary which transports gas molecules, oxygen ions and electrons and therefore accommodate CO₂ splitting in electrochemical process.     

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.     

Preparation of LSM–YSZ composite powder for anode of solid oxide electrolysis cell and its activation mechanism

Sr-doped LaMnO₃ and Yttria stabilized zirconia (LSM–YSZ) composite powder is synthesized by the preparation of LSM on submicron-sized YSZ particles using an in-situ glycin–nitrate combustion method for solid oxide electrolysis cells (SOEC) in this paper. LSM–YSZ composite powder and the relevant LSM powder are characterized by XRD and FESEM. The results show that LSM–YSZ is net-porous composite powder while YSZ and LSM do not react with each other during synthesis process. The electrochemical test of the single button cells indicates that the in-situ LSM–YSZ powder shows better electrolysis performance and lower discharging capability than traditionally direct mixture LSM and YSZ oxygen electrode. When operating in SOEC mode with constant current electrolysis at a current density of 0.33 A cm⁻² and 900 °C, the electrolytic voltage decreases from 1.21 V to 1.02 V, which indicates that LSM–YSZ electrode has an activation process at the initial testing stage. A mechanism which involves the incorporation of SrO segregated on the surface into the LSM lattice and the generation of oxygen vacancies in the LSM electrode is proposed for the activation process with O²⁻ oxidation on LSM electrodes.     

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).     

Steam electrolysis performance of intermediate-temperature solid oxide electrolysis cell and efficiency of hydrogen production system at 300 Nm h

The steam electrolysis performance of an intermediate-temperature solid oxide electrolysis cell (SOEC) was measured at 650 °C at various steam concentrations. The cell voltage decreased with increasing steam concentration, which was attributed to a decrease in the steam electrode polarization. The highest performance of the SOEC was 1.32 V at 0.57 A cm⁻². On the basis of the electrolytic characteristics of this cell, the efficiency of a hydrogen production system operating at a capacity of 300 N m³ h⁻¹ was estimated. The system efficiency reached a higher heating value (HHV standard) of 98% due to the effective recovery of thermal energy from exhaust gas.     

Application of CuNi–CeO2 fuel electrode in oxygen electrode supported reversible solid oxide cell

The oxygen electrode-supported reversible solid oxide cell (RSOC) has demonstrated distinguishing advantages of fuel flexibility, shorter gas diffusion path and more choices for fuel electrode materials. However, there are serious drawbacks including the difficulty of co-firing the oxygen electrode and electrolyte, and the inefficient electrochemical performance. In this study, a (La_0.8Sr_0.2)_0.95MnO_3-δ (LSM) supported RSOC with the configuration of La_0.6Sr_0.4Fe_0.9Sc_0.1O_3-δ (LSFSc)-YSZ/YSZ/CuNi–CeO₂-YSZ is fabricated by tape casting, co-sintering and impregnation technologies. The single cell is evaluated at both fuel cell (FC) and electrolysis cell (EC) mode. Significant maximum power density of 436.0 and 377 mW cm^?2 is obtained at 750 °C in H₂ and CH₄ fuel atmospheres, respectively. At electrolysis voltage of 1.3 V and 50% steam content, current density of ?0.718, ?0.397, ?0.198 and ?0.081 A cm^?2 is obtained at 750, 700, 650 and 600 °C respectively. Much higher electrolysis performance than FC mode is exhibited probably due to the optimized electrodes with increased triple phase boundary (TPB) area and faster gas diffusion (oxygen and steam) and electrochemical reactions for water splitting. Additionally, the short-term stability of single cell in H₂ and CH₄ are also studied.