Intermediate Temperature Solid Oxide Fuel Research Articles

Simultaneous Performance and Stability Enhancement in Intermediate Temperature Solid Oxide Fuel Cells by Powder‐Atomic Layer Deposited LSCF@ZrO2 Cathodes (Small Methods 1/2024)

Simultaneous Performance and Stability Enhancement in Intermediate Temperature Solid Oxide Fuel Cells by Powder‐Atomic Layer Deposited LSCF@ZrO₂ Cathodes (Small Methods 1/2024)

Influence of K+ substitution on germanium doped strontium silicate (Sr3-3xK3xSi3-3yGe3yO9-δ; 0 ≤ x ≤ 0.20, y=0.1) for application as solid electrolyte

The different alkali metal substitution strategies of the strontium meta-silicate based ion conductors have been enormously cross-examined to synthesize cost-effective novel electrolyte for Intermediate Temperature Solid Oxide Fuel Cells (IT-SOFCs). In the present investigation, crystal structure, phase formation, microstructure, total conductivity and stability of the Potassium and Germanium incorporated Sr3Si3O9 based system, Sr3-3xK3xSi3-3yGe3yO9-δ (0 ≤ x ≤ 0.20, y = 0.1), is examined for their application as solid electrolyte for electrochemical devices such as ITSOFCs. These samples have been made via solid state reaction route. X-ray Rietveld refinement method was used for the structural investigation. Raman and FT-IR spectroscopy were performed to examine the phase formation and absorption of light by the bonds of vibrating molecules to provide molecular characteristics and vibrational modes of the molecules. The X-ray Photoelectron Spectroscopy study was used to validate the characteristic valence states of the constituting elements. Thermo-gravimetric analysis was performed to inspect the thermal stability and weight changes in the compounds during heating process. In the SEM and EDS mapping, an amorphous phase of K2Si2O5 can be visualized which seems to segregate along grain boundaries and this amorphous complexion augmented with K+ dopant concentration. AC Electrical impedance spectroscopy studies suggest that the ionic conduction in Sr3-3xK3xSi3-3yGe3yO9-δ could be from the oxide ions along with mobility of K+ ions of the glassy phase. In this study, we also tried to get the optimal doping condition with compositions to minimize numerous concern of the system.

Preparation and characterisation of Ca3Co4-xCuxO9 (0 ≤ x ≤ 0.3) as cathode materials for intermediate temperature Solid Oxide Fuel Cell (SOFC)

Preparation and characterisation of Ca3Co4-xCuxO9 (0 ≤ x ≤ 0.3) as cathode materials for intermediate temperature Solid Oxide Fuel Cell (SOFC)

Simultaneous Performance and Stability Enhancement in Intermediate Temperature Solid Oxide Fuel Cells by Powder-Atomic Layer Deposited LSCF@ZrO2 Cathodes.

Employing porous structures is essential in high-performance electrochemical energy devices. However, obtaining uniform functional coatings on high-tortuosity structures can be challenging, even with specialized processes such as atomic layer deposition (ALD). Herein, a novel method for achieving a porous composite electrode for solid oxide fuel cells by coating La0.6 Sr0.4 Co0.2 Fe0.8 O3 -δ (LSCF) powders with ZrO2 using a powder ALD process is presented. Unlike conventional ALD, powder ALD can be used to fabricate extremely uniform coatings on porous electrodes with a thickness of tens of micrometers. The powder ALD ZrO2 coating is found to effectively suppress chemical degradation of the LSCF electrodes. The cell with the powder ALD coated cathode shows a 2.2 times higher maximum power density and 60% lower thermal degradation in activation resistance than the bare LSCF cathode cell at 700-750 °C. The result demonstrated in this study is expected to have significant implications for high-performance and durable electrodes in energy conversion/storage devices.

Influence of ZnO on Electrochemical and Physiochemical Properties of Lanthanum Strontium Cobalt Ferrite as Cathode for Intermediate Temperature Solid Oxide Fuel Cells

Influence of ZnO on Electrochemical and Physiochemical Properties of Lanthanum Strontium Cobalt Ferrite as Cathode for Intermediate Temperature Solid Oxide Fuel Cells

Morphological Evolution of La2NiO4 Coatings Synthesized by Reactive Magnetron Sputtering (RMS) at High Pressure as Cathode for Intermediate Temperature Solid Oxide Fuel Cell (IT-SOFC)

This work focuses on the evolution of the morphology and structure of La2NiO4 (namely, LNO) coatings deposited by reactive magnetron sputtering (RMS) with subsequent annealing processes. The LNO coatings start to crystallize at 600 °C, and the LNO with K2NiF4 structure was formed at 700 °C. A small amount of La3Ni2O7 appeared in the La2NiO4 coatings at 1100 °C. Interestingly, the LNO coatings realize the transformation from dense to different porous morphologies due to the annealing process. The LNO coating with abundant pores was formed after annealing treatment at 1000 °C for 2 h. This porous morphology can be stably maintained after short-term thermal stability experiments at 750 °C for 120 h. The electrochemical impedance spectroscopy (EIS) measurement of the LNO/YSZ/LNO symmetrical half-cells shows that the LNO cathode coating after annealing at 1000 °C for 2 h exhibits lower polarization resistance (Rpol) and activation energy.

Physiochemical and Electrochemical Properties of Lanthanum Strontium Cobalt Ferum–Copper (II) Oxide Prepared via Solid State Reaction

Lanthanum strontium cobalt ferum (LSCF) with addition of copper oxide (CuO) can serve as an alternate cathode material in Intermediate Temperature Solid Oxide Fuel Cell (IT-SOFC) due to its strong catalytic activity for oxygen reduction process at intermediate temperatures and great chemical compatibility. This study was done to determine the viability of LSCF–CuO composite as a material for the IT-SOFC cathode. The cathode powder was synthesised using the conventional solid-state process at intermediate temperatures range (600ºC–900ºC). The thermogravimetric analysis demonstrated that when LSCF was calcined at temperatures over 600ºC, the weight loss curve flattened. In the meantime, x-ray diffraction revealed that the perovskite structure of LSCF-CuO was completely formed after calcined at 800ºC. Moreover, the Brunauer– Emmett–Teller (BET) and scanning electron microscope investigations demonstrated that as the calcination temperature rose, the LSCF–CuO particles tended to grow. The electrochemical impedance spectroscopy investigation revealed polarisation resistance of samples calcined at 800ºC (0.41 Ωcm2) was significantly lower than that of samples calcined at 600ºC (29.57 Ωcm2). Judging from chemical, physical and electrochemical properties, it is evidence that LSCF-CuO prepared via simple solid-state reaction has a potential to be used as cathode material for IT-SOFC.

Performance Evaluation of An Electrolyte-Supported Intermediate-Temperature Solid Oxide Fuel Cell (IT-SOFC) with Low-Cost Materials

Intermediate temperature solid oxide fuel cell (IT-SOFC) provides economic and technical advantages over the conventional SOFC because of the wider material use, lower fabrication cost and longer lifetime of the cell components. In this work, we fabricated electrolyte-supported IT-SOFC using low-cost materials such as calcia-stabilized zirconia (CSZ) electrolyte fabricated by dry-pressing, NiO-CSZ anode and Ca3Co1.9Zn0.1O6 (CCZO) cathode produced through brush coating technique. According to the XRD result, the monoclinic phase dominated over the cubic phase, and the relative density of the electrolyte was low but the hardness of the CSZ electrolyte was close to the hardness of commercial 8YSZ electrolyte. The performance of the single cell was performed with hydrogen ambient air. An open-circuit voltage (OCV) of 0.43, 0.46, and 0.45 V and a maximum power density of 0.14, 0.50, and 1.00 mW/cm2 were achieved at the operating temperature of 600, 700, and 800 °C, respectively. The ohmic resistance of the cell at 700 and 800 °C achieved 81.5 and 33.00 Ω, respectively due to the contribution of thick electrolyte and Cr poisoning in electrodes and electrolyte

(Invited) Electrical, Thermal, and H2o and CO2 Poisoning Behaviors of PrNi0.5Co0.5O3-δ Cathode for Proton Conducting Intermediate Temperature Solid Oxide Fuel Cell

PrNi0.5Co0.5O3-δ (PNC) cathode material demonstrates total electrical conductivity on the order of ~300 S/cm at 400-600oC in air, and the conductivity shows a slight increase as temperature increases with an activation energy (from ln(σT) vs 1/T plot) of 10.9 kJ/mol. The introduction of water vapor (H2O) leads to a small (~0.16%) increase in total resistivity, which is reversible upon water removal and explained, tentatively, by the defect reaction of H2O + 2Oo x + 2h• = 2(OH)O • + 0.5O2. The thermal expansion coefficient (TEC) of PNC is measured to be 17.6×10-6/K by dilatometry and 18.43×10-6/K by in situ XRD up to 800oC. On the other hand, despite bulk chemical stability for both PNC and BZCYYb4411 powders against low percentage H2O and CO2, a PNC cathode symmetrical cell over proton conducting BaZr0.4Ce0.4Y0.1Yb0.1O3-δ (BZCYYb4411) electrolyte shows degradation (or increase) in interfacial resistance upon introduction of 3% moisture or 5% CO2 into simulated air at temperature in the range of 650 to 450oC. In comparison, oxygen ion conducting symmetrical cells with PNC cathode and Ce0.9Gd0.1O2-δ (GDC) electrolyte show no change upon H2O and CO2 introduction. The observed sensitivity of the PNC cathode proton conducting symmetrical cell to H2O and CO2 is attributed to the preferred adsorption of H2O and CO2 molecules onto the BZCYYb4411 proton conducting electrolyte surface than on the PNC cathode, and such an explanation is supported by temperature programmed desorption (TPD) measurements for H2O and CO2 on both PNC and BZCYYb4411 powders.

Electrochemical Evaluation of Nickel Oxide Addition toward Lanthanum Strontium Cobalt Ferrite Cathode for Intermediate Temperature Solid Oxide Fuel Cell (IT-SOFCS)

A mixture of lanthanum strontium cobalt ferrite (LSCF) and nickel oxide (NiO) makes for a desirable cathode material for an IT-SOFC due to its excellent oxygen reduction capability. This study investigates the effect of NiO addition into LSCF cathode on its physical and electrochemical properties. To optimise the amount of NiO addition, both electrochemical impedance spectra and bode phase were used to examine various weight ratios of nickel oxide and LSCF cathode. Brunauer-Emmett-Teller (BET) and thermal analyses validated the electrochemical observation that the LSCF:NiO ratio yields sensible oxygen reduction reaction and stoichiometric findings. Initial characterisation, comprising of phase and bonding analyses, indicated that LSCF-NiO was successfully synthesised at 800 °C using an improved modified sol gel technique. The addition of 5% nickel oxide to LSCF results in the lowest area specific resistance (ASR) value overall. The Bode phase implies that the addition of 5% nickel oxide to LSCF reduces the impedance at low frequencies by 64.28 percent, indicating that a greater oxygen reduction process happened at the cathode. After the addition of 5 wt% NiO, a single LSCF-NiO cell may function at temperatures as low as 650 °C and the LSCF cathode power density is increased by 25.35%. The surface morphology of the LSCF-NiO cathode reveals that the average particle size is less than 100 nm, and mapping analysis demonstrated a homogenous NiO distribution over the cathode layer. Consequently, the synthesis of LSCF-NiO at intermediate temperatures (800–600 °C) revealed outstanding chemical compatibility, bonding characteristics, and electrochemical performance.

Triple Perovskite Nd1.5Ba1.5CoFeMnO9-δ-Sm0.2Ce0.8O1.9 Composite as Cathodes for the Intermediate Temperature Solid Oxide Fuel Cells.

Triple perovskite has been recently developed for the intermediate temperature solid oxide fuel cell (IT-SOFC). The performance of Nd1.5Ba1.5CoFeMnO9−δ (NBCFM) cathodes for IT-SOFC is investigated in this work. The interfacial polarization resistance (RP) of NBCFM is 1.1273 Ω cm2~0.1587 Ω cm2 in the range of 700–800 °C, showing good electrochemical performance. The linear thermal expansion coefficient of NBCFM is 17.40 × 10−6 K−1 at 40–800 °C, which is significantly higher than that of the electrolyte. In order to further improve the electrochemical performance and reduce the thermal expansion coefficient (TEC) of NBCFM, Ce0.8Sm0.2O2−δ (SDC) is mixed with NBCFM to prepare an NBCFM-xSDC composite cathode (x = 0, 10, 20, 30, 40 wt.%). The thermal expansion coefficient decreases monotonically from 17.40 × 10−6 K−1 to 15.25 × 10−6 K−1. The surface oxygen exchange coefficient of NBCFM-xSDC at a given temperature increases from 10−4 to 10−3 cm s−1 over the range from 0.01 to 0.09 atm, exhibiting fast surface exchange kinetics. The area specific resistance (ASR) of NBCFM-30%SDC is 0.06575 Ω cm2 at 800 °C, which is only 41% of the ASR value of NBCFM (0.15872 Ω cm2). The outstanding performance indicates the feasibility of NBCFM-30% SDC as an IT-SOFC cathode material. This study provides a promising strategy for designing high-performance composite cathodes for SOFCs based on triple perovskite structures.

Deeper Understanding of Ternary Eutectic Carbonates/Ceria-Based Oxide Composite Electrolyte through Thermal Cycling

Due to a high conductivity of about 0.1 S·cm−1, Li-Na-K carbonate eutectic and Sm-doped ceria composite material is a good electrolyte candidate for hybrid fuel cells operating between 500 °C and 600 °C. The present paper aims at a deeper understanding of the species and mechanisms involved in the ionic transport through impedance spectroscopy and thermal analyses, in oxidizing and reducing atmospheres, wet and dry, and during two heating/cooling cycles. Complementary structural analyses of post-mortem phases allowed us to evidence the irreversible partial transformation of molten carbonates into hydrogenated species, when water and/or hydrogen are added in the surrounding atmospheres. Furthermore, this modification was avoided by adding CO2 in anodic and/or cathodic compartments. Finally, a mechanistic model of such composite electrical behavior is suggested, according to the surrounding atmospheres used. It leads to the conclusions that cells based on this kind of electrolyte would preferably operate in molten carbonate fuel cell conditions, than in solid oxide fuel cell conditions, and confirms the name of “Hybrid Fuel Cells” instead of Intermediate Temperature (or even Low Temperature) Solid Oxide Fuel Cells.

Enhanced Long‐Term Cathode Stability by Tuning Interfacial Nanocomposite for Intermediate Temperature Solid Oxide Fuel Cells

AbstractPerformance durability is one of the essential requirements for solid oxide fuel cell materials operating in the intermediate temperature range (500–700 °C). The trade‐off between desirable catalytic activity and long‐term stability challenges the development and commercialization of electrode materials. Here an oxygen cathode material, Ba0.5Sr0.5(Co0.7Fe0.3)0.69−xMgxW0.31O3−δ (BSCFW‐xMg), that exhibits excellent electrocatalytic performance through the addition of an optimized amount of Mg to the self‐assembled nanocomposite Ba0.5Sr0.5(Co0.7Fe0.3)0.69W0.31O3−δ (BSCFW) by simple solid‐state reaction is reported. Distinct from the bulk and surface approaches to introduce vacancies and defects in materials design, here the Mg2+ ions concentrate at the single perovskite/double perovskite interface of BSCFW with dislocations and Mg2+‐rich nanolayers, resulting in stressed and compositionally inhomogeneous interface regions. The interfacial chemistry within these nanocomposites provides an additional degree of freedom to enable performance optimization over single phase materials and promotes the durability of alkaline‐earth based fuel cell materials.

Structural and electrical characterizations of Gd doped NBT perovskite nanocrystals synthesized by mechanical alloying

Recently, a new family of oxide-ion conductors based on the ferroelectric perovskite Sodium Bismuth Titanate (Na0.5Bi0.5TiO3, NBT) has been reported. NBT has been investigated intensely as solid electrolytes for Intermediate Temperature Solid Oxide Fuel Cells (IT-SOFCs). This work focuses on the structural and electrical properties of Gadolinium doped Sodium Bismuth Titanate for its possible application as an electrolyte material in SOFCs. Gd doped nanomaterial has been synthesized by mechanical alloying. X-ray diffraction analysis confirms the formation of the rhombohedral phase of Gd doped NBT perovskite with space group R3c. FESEM micrograph confirms agglomerated spherical grains and EDX spectra confirms the existence of the major constituent atoms. Ac conductivity has been found to follow the universal Jonscher’s power law. Structural and electrical characterization of the sample provide its effectiveness as an electrolyte material in SOFCs.

Structural and electrical performance of Ce0.33Ca0.34Ti0.33O1.66 based solid oxide fuel cell electrolyte fabricated using ball milling techniques

In the present work, calcium and titanium are doped with ceria in an effort to create a unique, effective electrolyte for solid oxide fuel cell applications (Ce0.33Ca0.34Ti0.33O1.66 (CCT-33)). CCT-33 is prepared through solid state method through ball milling and calcination. XRD analysis of the CCT-33 revealed cubic fluorite crystal structure favorable for oxygen ion conduction. Electron microscopy analysis of the sintered pellets revealed good compactness of the phase pure powders and crystallinity. The conductivity studied using impedance analysis is 10−3–10−4 S cm−1 in the temperature region of 500–630 °C. At 700 °C the highest value of 2.86 × 10−2 S cm−1 in considered temperature region was obtained. The present work introduces innovative, modified material for Intermediate Temperature Solid Oxide Fuel Cell (IT-SOFCs).

Synthesis and Characterization of Bi2o3–Based Solid Solutions Co–Doped with Nd2o3, Sm2o3, La2o3, and Tb4o7 for Intermediate Temperature–Solid Oxide Fuel Cells (It–Sofcs)

Synthesis and Characterization of Bi2o3–Based Solid Solutions Co–Doped with Nd2o3, Sm2o3, La2o3, and Tb4o7 for Intermediate Temperature–Solid Oxide Fuel Cells (It–Sofcs)

Synthesis and Characterization of High Temperature Properties of YBa2Cu3O6+δ Superconductor as Potential Cathode for Intermediate Temperature Solid Oxide Fuel Cells

YBa2Cu3O6+δ (YBC) oxygen deficient perovskite was synthesized by an auto-combustion method and was studied as potential cathode for Intermediate Temperature Solid Oxide Fuel Cell (IT-SOFC). Synchrotron X-ray thermodiffraction in air shows a phase transition from orthorhombic Pmmm to tetragonal P4/mmm space groups at ~ 425 °C. The chemical compatibility with Ce0.9Gd0.1O1.95 (GDC) electrolyte was investigated in air where certain reactivity was observed above 800 °C. However, the main phase is Ba(Ce1-xYx)O3, a good ionic conductor. The catalytic performance in air was obtained by electrochemical impedance spectroscopy (EIS) measurements on YBC/GDC/YBC symmetrical cells. The area specific resistance (ASR) values change from 13.66 to 0.14 Ω cm2 between 500 and 800 °C, with activation energy (Ea) of 0.41 eV. The results suggest potential applications of YBC as IT-SOFC cathode.

Ionic Conductivity of Ce0.91Ca0.09O2 as an Electrolyte for Intermediate Temperature Solid Oxide Fuel Cells

The search for new cost-effective electrolyte materials for IT-SOFC towards its mass scale commercialization has gained momentum in recent years. The Ca- doped ceria having composition Ce0.91Ca0.09O2 was prepared using the facile conventional solid-state method. The structural and electrical properties of low sintered ceramic samples have been characterized by X-ray diffraction (XRD), UV–VIS diffuse reflectance spectroscopy (DRS) and A.C. impedance technique respectively. The oxide ion conductivity was measured between the temperatures 573 K−973 K in air. The obtained results showed that total conductivity is mainly dependent on the grain boundary effect. The nanocrystalline Ce0.91Ca0.09O2 exhibited the high total ionic conductivity of 7.36  103 S cm1 at 973 K with a lower activation energy of 0.96 eV. The obtained results highlight the use of cost-effective dopant in ceria lattice to develop commercially viable electrolyte materials for IT-SOFC.

Electrochemical Performance of NiCo2O4 Spinel Cathodes for Intermediate Temperature Solid Oxide Fuel Cells

It is a great challenge to develop the highly efficient cathode material for solid oxide fuel cells (SOFCs) at intermediate temperature, while high electronic conductivity, good thermal and chemical compatibility, and superior electrochemical performance of the AB2O4‐type spinel is attractive electrode material. Herein, the NiCo2O4 spinel is developed using the glycine‐nitrate process (GNP) method as a cathode material for IT SOFCs. The characterization of the phase structure, microstructure, and electrochemical performance are done using X‐ray diffraction, scanning electronic microscopy, and electrochemical impedance spectroscopy. The results show that NiCo2O4 exhibited a single cubic structure and good chemical compatibility with a ((Sc2O3)0.1(CeO2)0.01(ZrO2)0.89) (ScCeSZ) electrolyte material at 900 °C for 10 h. Furthermore, a NiO–YSZ anode |NiO–YSZ, AFL | ScCeSZ |NiCo2O4 SOFC cell exhibits the maximum power density (MDP) of 0.73 and 1.04 W cm−2 at 750 and 800 °C, respectively. These results recommend the spinel‐structured NiCo2O4 is a potential cathode material for IT SOFC application.

High-Performance Cu-Doped (Mn, Co)3O4 Spinel Based Composite Cathodes for Intermediate Temperature Solid Oxide Fuel Cells

Mn1.3Co1.3Cu0.4O4 (MCCO) spinel has been developed as a new oxygen catalyst for intermediate temperature solid oxide fuel cell (SOFC) applications. The addition of Cu into the (Mn,Co)3O4 spinel effectively promoted oxidation states of Mn ions, which were mostly positioned at octahedral sites. Hence, this effect promotes small polaron hopping with a narrow bandgap resulting in high electrical conductivity. SOFCs using MCCO-Sc0.1Zr0.89Ce0.01O1.95 composite cathode showed remarkably high power densities of 1.92 and 1.38 W cm-2 at 800 oC and 700 oC, respectively. As far as we know, this result is the best performance of all SOFCs using spinel-based cathodes to date.