Temperature Solid Oxide Fuel Cells Research Articles

Recent Advances in Barium Cobaltite-Based Perovskite Oxides as Cathodes for Intermediate-Temperature Solid Oxide Fuel Cells.

Solid oxide fuel cells (SOFCs) are considered as advanced energy conversion technologies due to the high efficiency, fuel flexibility, and all-solid structure. Nevertheless, their widespread applications are strongly hindered by the high operational temperatures, limited material selection choices, inferior long-term stability, and relatively high costs. Therefore, reducing operational temperatures of SOFCs to intermediate-temperature (IT, 500-800°C) range can remarkably promote the practical applications by enabling the use of low-cost materials and enhancing the cell stability. Nevertheless, the conventional cathodes for high-temperature SOFCs display inferior electrocatalytic activity for oxygen reduction reaction (ORR) at reduced temperatures. Barium cobaltite (BaCoO3-δ)-based perovskite oxides are regarded as promising cathodes for IT-SOFCs because of the high free lattice volume and large oxygen vacancy content. However, BaCoO3-δ-based perovskite oxides suffer from poor structural stability, inferior thermal compatibility, and insufficient ionic conductivity. Herein, an in-time review about the recent advances in BaCoO3-δ-based cathodes for IT-SOFCs is presented by emphasizing the material design strategies including functional/selectively doping, deficiency control, and (nano)composite construction to enhance the ORR activity/durability and thermal compatibility. Finally, the currently existed challenges and future research trends are presented. This review will provide valuable insights for the development of BaCoO3-δ-based electrocatalysts for various energy conversion/storage technologies.

Emulation tests of dynamics and control for a turbocharged SOFC system

This work regards experimental emulation activities for a Solid Oxide Fuel Cell (SOFC) pressurized by a turbocharger, focusing attention on the control system validation. The SOFC-based plant considered here was developed to couple high efficiency (due to pressurization) with reasonable capital costs. In detail, significant cost decrease (against SOFC hybrid plants including a microturbine) can be obtained with a turbocharger, due to large mass manufacturing process for these machines. Moreover, to pursue the zero emission target, the system was sized to operate with a renewable source fuel (biogas).Since this system has integration problems due to critical dynamic and control aspects, the University of Genoa designed and installed an experimental facility based on the coupling between a pressure vessel with a commercial turbocharger. The fuel cell is emulated equipping the vessel with a burner (to obtain the SOFC temperature range) and with inert ceramic material (to generate the same dynamic response).The tests presented in this work were obtained with this emulation rig operated in cyber-physical mode: the hardware interacted in real-time mode with previously validated software for components not physically included in the rig. The results demonstrated the system feasibility for load changes and validated the proposed control system, showing robustness and good prevention of critical conditions, such as SOFC thermal stress.

Development and Application of Low Temperature Solid Oxide Fuel Cell

Development and Application of Low Temperature Solid Oxide Fuel Cell

Numerical and Thermodynamic Analysis of the Effect of Operating Temperature in Methane-Fueled SOFC

This study examines the thermodynamic and numerical analyses of a methane-fed solid oxide fuel cell (SOFC) over a temperature range varying between 873 K and 1273 K. These analyses were conducted to investigate and compare the performance of the SOFC under various operating conditions in detail. As part of the thermodynamic analysis, important parameters such as cell voltage, power density, exergy destruction, entropy generation, thermal efficiency, and exergy efficiency were calculated. These calculations were used to conduct energy and exergy analyses of the cell. According to the findings, an increase in operating temperature led to a significant improvement in performance. At the initial conditions where the SOFC operated at a temperature of 1073 K and a current density of 9000 A/m2, it was observed that when the temperature increased by 200 K while keeping the current density constant, the power density increased by a factor of 1.90 compared to the initial state, and the thermal efficiency increased by a factor of 1.45. Under a constant current density, the voltage and power density values were 1.0081 V, 1.0543 V, 2337.13 W/m2, and 2554.72 W/m2 at operating temperatures of 1073 K and 1273 K, respectively. Under a current density of 4500 A/m2, the entropy generation in the cell was determined to be 29.48 kW/K at 973 K and 23.68 kW/K at 1173 K operating temperatures. The maximum exergy efficiency of the SOFC was calculated to be 41.67% at a working temperature of 1273 K and a current density of 1500 A/m2. This study is anticipated to be highly significant, as it examines the impact of temperature variation on exergy analysis in SOFC, validating both numerical and theoretical results, thus providing a crucial roadmap for determining optimized operating conditions.

High Temperature Solid Oxide Electrolyte Fuel Cell Formulation: Non-Steady State Utilization of Fuel and Oxidant

The formulation presented in this paper was developed with the objective of its application to investigate the transient behavior of a high temperature solid oxide fuel cell (SOFC); especially with respect to the non-steady state consumption of fuel and oxidant reactants. Specifically, the chemical species transient amounts, their mole fractions, and total pressures in the cell anode-side fuel- (hydrogen) and cathode-side oxidant- (oxygen of the air) chambers can be predicted under the isothermal condition at a fixed cell-current level. The developed formulation is also capable of predicting the transient mole fraction profiles of fuel (hydrogen) and oxidant (oxygen) in the cell porous anode and cathode, respectively; thus, providing insight into the reactant species' effective transport and their utilization, via electrochemical reactions, in the cell porous electrodes. The presented formulation can be adapted for any fuel and oxidant combinations in any high temperature SOFC.

Comprehensive performance assessment of a novel biomass-based CCHP system integrated with SOFC and HT-PEMFC

The combination of biomass gasification and fuel cell is a promising way to enhance the system energy efficiency and decrease the fossil fuel consumption. In this study, a new biomass-based combined cooling, heating and power (CCHP) system considering high temperature proton exchange membrane fuel cell (HT-PEMFC) and solid oxide fuel cell (SOFC) is proposed. Syngas from biomass gasifier is utilized by SOFC and HT-PEMFC for power generation, waste heat derived from SOFC and HT-PEMFC are recovered by ORC and absorption chiller for electricity and cooling production, respectively. Energetic, exergetic, economic and environmental investigations are performed to illustrate system comprehensive performances. The results demonstrated that power generation ratio of SOFC to HT-PEMFC is 2.32, exergy and energy efficiency of CCHP system are 25.06% and 49.48%, respectively. Levelized cost of production and CO2 emission rate of multi-products are 0.069$/(kW·h) and 0.673kg/(kW·h), respectively. Moreover, steam to biomass ratio and equivalent ratio show different effects on system performances due to the distinction of syngas composition. Operating temperature of SOFC has a great influence on system exergy and energy efficiency, with increasing by 11.18% and 16.97% respectively. In general, this novel system provides a new pathway for integrating biomass with different fuel cell technologies.

A thermodynamic approach to analyze energy, exergy, emission, and sustainability (3E-S) performance by utilizing low temperature waste heat in SOFC–CHP-TEG system

Waste heat is one of the major problems associated with the energy system. This paper discusses an energy, exergy, and emissions approach for the hybrid system by utilizing waste heat to the maximum extent. A thermoelectric generator (TEG) is incorporated to utilize the low-temperature waste heat from a hybrid model of a solid oxide fuel cell (SOFC) and a combined heat and power (CHP) system. SOFC is an electrochemical cell that generates power at high temperatures through an electrochemical reaction. The high-temperature, unutilized fuel leaves the SOFC, which is burned in the afterburner. The afterburner temperature controls the operating temperature of SOFC. Here, three recuperators are used to utilize this high-temperature waste heat to improve the performance of SOFC and simultaneously generate heat power from the water or gas recuperator. TEG is an auxiliary power production technology that converts waste heat into energy. A novel integration of TEG with SOFC–CHP hybrid system to utilize the low temperature waste heat, is employed. The main goal of this study is to analyze a novel SOFC–CHP-TEG hybrid system in terms of its thermodynamics and emissions. A Two stage TEG is integrated with the SOFC–CHP hybrid system. The simulation model of high temperature fuel cell (SOFC) is developed on MATLAB and validated with published results. This study analyses the impact of pressure ratio and afterburner temperature on the performance of SOFC–CHP-TEG. To do this, perform energy and exergy assessments using the principles of the first and second laws of thermodynamics. A novel exergy-based sustainability index with emissions analysis for the proposed SOFC–CHP is presented. The achieved overall energy efficiency is 62.54% at a pressure ratio of 12 and an afterburner temperature of 1000 K. With an increase in pressure ratio and temperature, the level of CO emissions reduces significantly.

Solvothermal Synthesis of PtNi Nanoparticle Thin Film Cathode with Superior Thermal Stability for Low Temperature Solid Oxide Fuel Cells

Solvothermal Synthesis of PtNi Nanoparticle Thin Film Cathode with Superior Thermal Stability for Low Temperature Solid Oxide Fuel Cells

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)

Design of an integrated system that combines the steam gasification of plastic waste and a solid oxide fuel cell for sustainable power generation

As part of sustainable development efforts, this study presents an innovative integrated system that combines the steam gasification of plastic waste with solid oxide fuel cells (SOFCs) to produce electricity. The proposed system is designed using Aspen Plus v10® with two primary units. The first, a steam gasification system to produce H2 from the steam gasification of plastic waste. The second is a H2 driven SOFC system that generates electricity and is developed using Python. The study evaluates the combined system output in terms of power, current and voltage based on variation of temperature, steam/feed ratio (0.5–2), and CaO/feed ratio (0–1.5) of the gasifier. The study observes a decrease in the voltage (0.864 to 0.859 V) and power (0.852 to 0.845 W) with increasing gasification temperature (923–1173 K). Conversely, a rise in the steam/feed ratio inversely impacts the SOFC output, which is attributed to a decline in the H2 flowrate. Optimal conditions are met at gasifier temperature of 973 K, steam/feed ratio of 1.5, and CaO/feed ratio of 1. Moreover, using H2 flow rates to assess SOFC performance reveal increasing activation and ohmic losses (0.04 to 0.09 V and 0 to 0.28 V) with a temperature increase (973–1473 K), while concentration losses decreased (0–0.10 V). Nernst voltage and SOFC output voltage also decreased (1.1 to 0.52 V and 1.1 to 0.78 V) as SOFC temperature increases. Power output increased (0.0 to 1.57 W) with temperature, and the current–voltage relationship demonstrated reduced voltage (1.1 to 0.53 V) as the current is increased (0.0 to 2.8 A). This study provides an in-depth exploration into the development, modelling, and performance of both units, emphasizing their synergistic potential in the realm of sustainable electricity generation.

Modelling of Ni Nitridation in NH3-Fueled Solid Oxide Fuel Cells

In the past decade NH3 fueled solid oxide fuel cells (SOFCs) are getting increasing attention. As compared to hydrogen, ammonia has the advantages of higher energy density and ease of storage and transportation. Due to the high operating temperature of SOFCs, typically in the range of 550-750C, NH3 can be easily decomposed into nitrogen and hydrogen over Ni-based cermet fuel electrodes. Previous studies have demonstrated NH3-fueled SOFCs with high power density, high efficiency and low emissions. One of the remaining challenges is the nitridation of Ni electrode. Under realistic operating conditions, Ni in the support and active layers of the fuel electrode has a tendency of being nitride when exposed to NH3, forming Ni3N and resulting in performance degradation. In this work, the thermodynamics of the Ni-N system is explored using the CALculation of PHAse Diagrams (CALPHAD) method. The kinetics of Ni3N formation in NH3-fuelled SOFCs is then predicted, taking into account the kinetics of both ammonia decomposition and Ni3N formation. The locations inside NH3-fuled SOFCs with potential risks of Ni nitridation are then predicted and strategies to avoid or reduce nitridation are further proposed.

Environmental sustainability by an integrated system based on municipal solid waste fluidized bed gasification using energy, exergy, and environmental analyses

As an eco-friendly method of waste disposal, municipal solid waste (MSW)-to-multi-generation energy systems based on gasification reduces the amount of waste sent to landfills, generates clean energy that can be used to power homes and businesses, reduces our reliance on fossil fuels, and helps to reduce greenhouse gas emissions. In this study, a novel system is developed based on MSW gasification by combining a fluidized bed gasifier, a solid oxide fuel cell (SOFC), and a heat recovery to produce heat and power. In-depth research is done on the power output, heating capacity, energy and exergy efficiencies, and emissions of this innovative combined heating and power system. Electrical and exergy efficiencies of the system are improved with the steam to MSW ratio from 40.6 % to 41.4 % and from 36.4 % to 37.0 %, respectively, and the emission is reduced. Increasing utilization factor enhances electrical (from 37.2 % to 44.4 %) and exergy (from 33.4 % to 39.6 %) efficiencies and declines the emission (from 955.2 to 800.7 kg/MW.s). Decreasing current density and increasing SOFC temperature boost the system performance from energy, exergy, and environmental viewpoints. The future of multi-generation energy systems based on MSW gasification looks bright, as they offer a sustainable way to manage waste while meeting the growing demand for clean energy.

Numerical performance analysis of the solid oxide fuel cell for aviation hybrid power system

A detailed three-dimensional model of solid oxide fuel cell (SOFC) is established to explore its performance under special requirements in the aviation SOFC - gas turbine hybrid system. In this context, the SOFC has the distinction of pressurization, lightweight and low pressure loss compared to its conventional independent application. Based on this, the SOFC performance is fully investigated in terms of different operating conditions and geometric dimensions, and in addition to typical electrochemical parameters, the power-to-weight ratio is also considered as evaluation indicator. The results indicate that high operating pressure is beneficial for improving SOFC electrochemical performance, but the performance enhancement becomes slow when pressure exceeds 0.5 MPa. The inlet velocities of fuel and air both affect fuel utilization and power density of SOFC. And the high air velocity is favorable to reduce the SOFC temperature and temperature gradient, but it also increases the pressure drop. Therefore, the air inlet velocity of 2 m/s-15 m/s is more suitable under comprehensive consideration. In addition, the optimal power density and power-to-weight ratio correspond to different rib widths, with the former having wider ribs and differing within 0.5 mm. And this characteristic is maintained at different pressure, contact resistance and interconnect density.

Advancements in Perovskite-Based Cathode Materials for Solid Oxide Fuel Cells: A Comprehensive Review.

The high-temperature solid oxide fuel cells (SOFCs) are the most efficient and green conversion technology for electricity generation from hydrogen-based fuel as compared to conventional thermal power plants. Many efforts have been made to reduce the high operating temperature (>800 °C) to intermediate/low operating temperature (400 °C<T<800 °C) in SOFCs in order to extend their life span, thermal compatibility, cost-effectiveness, and ease of fabrication. However, the major challenges in developing cathode materials for low/intermediate temperature SOFCs include structural stability, catalytic activity for oxygen adsorption and reduction, and tolerance against contaminants such as chromium, boron, and sulfur. This research aims to provide an updated review of the perovskite-based state-of-the-art cathode materials LaSrMnO3 (LSM) and LaSrCOFeO3 (LSCF), as well as the recent trending Ruddlesden-Popper phase (RP) and double perovskite-structured materials SOFCs technology. Our review highlights various strategies such as surface modification, codoping, infiltration/impregnation, and composites with fluorite phases to address the challenges related to LSM/LSCF-based electrode materials and improve their electrocatalytic activity. Moreover, this study also offers insight into the electrochemical performance of the double perovskite oxides and Ruddlesden-Popper phase materials as cathodes for SOFCs.

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)

Self‐Assembled Perovskite Nanocomposite With Beneficial Lattice Tensile Strain as High Active and Durable Cathode for Low Temperature Solid Oxide Fuel Cell

AbstractThe sluggish kinetics of oxygen reduction reaction (ORR) at low temperatures and the fast degradation of the cathode are the main obstacles to the commercialization of solid oxide fuel cells (SOFCs). However, it is still very challenging to achieve both high catalytic activity and favorable stability for single‐phase materials. Herein, a highly active and durable nanocomposite cathode (Ba0.5Sr0.5)0.75Pr0.25Co0.575Fe0.3W0.125O3‐δ (BSPCFW) for low‐temperature SOFC (≤650 °C) is presented, which self‐assembles into two cubic perovskites: the simple perovskite Pr0.38Ba0.25Sr0.37Co0.62Fe0.38O3‐δ (PBSCF‐c) and the B‐site cations ordered double perovskite Ba1.30Sr0.70Co1.0Fe0.25W0.75O6‐δ (BSCFW‐c). The former PBSCF‐c serves as the highly conductive and active catalyst for ORR, while the latter BSCFW‐c with a large lattice parameter introduces a key beneficial lattice tensile strain into the PBSCF‐c phase through a coherent interface, which significantly promotes the ORR activity at low temperatures with the area specific resistance of 0.034 Ω cm2 at 650 °C, and the long‐term stability of 2 years storage and 1280 h operation in symmetrical cell. The introduction of the beneficial lattice tensile strain in self‐assembled composite catalysts is an effective way to synergistically enhance the electrochemical activity and durability of the electrode materials for electrochemical devices.

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.

Enhancing the oxygen reduction reaction activity of SOFC cathode via construct a cubic fluorite/perovskite heterostructure

Pr2NiO4+δ-based (Ruddlesden-Popper) perovskite-structured oxide materials are promising candidates for low and intermediate temperature solid oxide fuel cells (SOFCs) systems. In this study, we prepared a high-performance cubic-fluorite/perovskite heterostructure Pr6O11-Pr1.2Sr0.8NiO4+δ (PO-PSNO) cathode for intermediate temperature SOFCs by solution impregnation method. By changing the impregnation amount of Pr6O11, the micro-morphology of the heterostructure was regulated, so that the heterostructure interface had the best reactive site. The oxygen reduction reaction (ORR) performance of Pr1.2Sr0.8NiO4+δ is improved, and the content of surface Sr in the heterostructure electrode material is reduced. Our results indicate that the synergistic effect of PO particles and PSNO skeleton makes the heterostructure exhibit a high oxygen surface exchange properties and catalytic performance. When the impregnation amount of PO particles reaches about 10% of the PSNO skeleton, the heterostructure has the best ORR activity. The oxygen surface exchange coefficient (Kchem) of 2-PO-PSNO is 5.8 × 10-4 cm·s−1, being 1.45 times as that of PSNO at 750 °C. Meanwhile, the polarization impedance (Rp) of 2-PO-PSNO is reduced by 66% to only 0.114 Ω cm2. Our study provides a new approach for developing high-performance RP structured perovskite cathodes and demonstrates practical applications in the field of SOFCs.

Improvement of thermal cycle stability of YSZ-glass composite seals for intermediate temperature solid oxide fuel cell

Glass ceramic seals have been widely used in solid oxide fuel cell (SOFC). However, the sealing performance of seals is a big challenge for SOFC operating at high temperature. In this work, the gas tightness, chemical compatibility and thermal cycle stability of the glass-based seals with various proportions of YSZ and glass are evaluated and discussed. The study showed that when 20 wt% YSZ is added to H4 glass, the as-prepared glass ceramic seal (denoted as H4-20) exhibited extremely low leakage rate of 0.00171 sccm cm−1 under input pressure of 20.7 kPa and wide temperature range from 650°C to 800°C. In addition, the leakage rate of H4-20 glass ceramic seal below 0.004 sccm cm−1 was obtained after 10 thermal cycles at 750 °C. The SEM analysis indicated that the H4-20 glass ceramic seal could form well bonding interface between the interconnect/seal/cell. The above results prove the possibility of the H4-20 glass ceramic seals to be considered for intermediate temperature SOFC application.