Solid Oxide Research Articles

Comprehensive Thermodynamic Performance Evaluation of a Novel Dual-Shaft Solid Oxide Fuel Cell Hybrid Propulsion System

With the rapid growth of air travel, reducing carbon emissions in aviation is imperative. Electric aircraft play a key role in achieving sustainable aviation, especially for large civil aircraft, where reducing emissions, improving the fuel efficiency, and enabling flexible power regulation are essential. This study proposes a dual-shaft, separated-exhaust fuel cell hybrid aircraft propulsion system (HAPS), using a solid oxide fuel cell (SOFC) to replace the conventional turbine-driven compressor. The independent speed control of the high- and low-pressure spools is realized via a power distribution system. A thermodynamic model is developed, and performance evaluations, including parametric, exergy, and sensitivity analyses, are conducted. At the design point, the system delivers 36.304 kN thrust, 16.775 g/(kN·s) specific fuel consumption, 15.931 MW SOFC power, and 54.759% SOFC efficiency. The exergy analysis highlights the optimization of components like the heat exchanger and fan to reduce energy losses. The sensitivity analysis reveals that the spool speeds and fuel utilization significantly impact the performance. The findings provide valuable insights into optimizing control strategies and offer a novel, efficient, and low-carbon power solution for aviation, supporting the industry’s transition towards sustainability.

Suppressing surface segregation by introducing lanthanides to enhance high-temperature oxygen evolution reaction activity and durability

Abstract Ba0.5Sr0.5Co0.8Fe0.2O3−δ (BSCF) is a conventional anode material for solid oxide electrolysis cells (SOECs) to catalyze oxygen evolution reactions (OERs). However, the inferior chemical stability of BSCF results in severe surface segregation and performance degradation under high temperatures. A critical challenge lies in alleviating surface segregation and preserving the high OER performance of BSCF anodes. Herein, lanthanides are introduced to substitute the Ba in BSCF, labeled as Ln0.5Sr0.5Co0.8Fe0.2O3−δ (LnSCF, Ln = La, Pr, Nd, Sm), to regulate its stability and performance. The introduction of La and Pr effectively enhances stability, suppresses surface segregation and maintains high OER activity. Continuous lattice oxygen loss and Co ion oxidation of LnSCF are demonstrated upon annealing in oxidizing atmosphere; thus, we propose that surface segregation is a self-regulation mechanism of perovskite lattice to tolerant oxidizing atmosphere. Perovskite oxides maintain structurally stable via decreasing A-site valence state and forming surface segregation. SOECs with La0.5Sr0.5Co0.8Fe0.2O3−δ anodes deliver an optimal current density of 1.69 A cm−2 at 1.6 V and stability for CO2 electrolysis at 800 °C, shedding light on designing advanced catalysts for high-temperature OER.

Tuning dielectric properties in metal-doped NiO nanoparticles

Nickel Oxide (NiO) nanoparticles (NPs), doped with manganese (Mn) and cobalt (Co) at concentrations up to 8%, were synthesized using the composite hydroxide method (CHM). X-ray diffraction (XRD) analysis confirmed the formation of a cubic NiO structure, with no additional peaks detected, indicating successful doping. The average crystallite size was determined to range from 15 to 17.8 nm, depending on the dopant concentration. Scanning electron microscopy (SEM) images revealed mostly spherical, agglomerated particles, likely due to magnetic interactions. Fourier Transform Infrared Spectroscopy (FTIR) confirmed the incorporation of Mn and Co into the NiO lattice, consistent with the XRD results. The dielectric properties exhibited a high dielectric constant at low frequencies, which can be attributed to ion jump orientation and space charge effects. The imaginary part of the dielectric constant decreased with increasing frequency, as it became harder for electrons to align with the alternating field at higher frequencies. Both the real and imaginary dielectric constants showed behavior consistent with Koop’s theory, increasing at low frequencies and decreasing at higher frequencies. Dielectric loss was primarily attributed to dipole flipping and charge migration. AC conductivity increased with frequency, and exhibited higher conductivity at high frequencies due to small polaron hopping. These co-doped NPs show potential for applications in solid oxide fuel cells.

CO2 Electrolysis Using Metal-Supported Solid Oxide Cells with Infiltrated Pr0.5Sr0.4Mn0.2Fe0.8O3-δ Catalyst

Abstract Electrochemical conversion of CO2 to CO is demonstrated with symmetric-structured metal supported solid oxide cells (MS-SOC). Perovskite Pr0.5Sr0.4Mn0.2Fe0.8O3-δ (PSMF) and Pr6O11 catalysts were infiltrated into the MS-SOC cathode and anode, using 3 cycles with firing at 850C and 8 cycles with firing at 800C, respectively. Upon reduction during operation, the perovskite PSMF was transformed to Ruddlesden–Popper structure with a highly efficient electrocatalytic activity. The impact of operating temperature (600-800C) and overpotential (0-1.8 V) on the CO2 conversion was investigated. The highest CO2 conversion of 57.2% was achieved at 750C and 1.8 V. During extended operation for 150 h at 750C and 1.2V, a cell demonstrated relatively stable performance, with initial current density of 535 mA cm-2 and CO2 conversion of 23%. Degradation mechanisms were studied by posttest characterization.

Effect of Ammonia Catalytic Decomposition Coating on Electrochemical Performance in Direct Ammonia Solid Oxide Fuel Cells

Effect of Ammonia Catalytic Decomposition Coating on Electrochemical Performance in Direct Ammonia Solid Oxide Fuel Cells

Synergistic preparation of nano-sized PrBa0.5Sr0.5Co1.5Fe0.5O5+δ-LaCo0.6Ni0.4O3-δ cathodes of solid oxide fuel cells

Synergistic preparation of nano-sized PrBa0.5Sr0.5Co1.5Fe0.5O5+δ-LaCo0.6Ni0.4O3-δ cathodes of solid oxide fuel cells

Optimising the Design of a Hybrid Fuel Cell/Battery and Waste Heat Recovery System for Retrofitting Ship Power Generation

This research aims to assess the integration of different fuel cell (FC) options with battery and waste heat recovery systems through a mathematical modelling process to determine the most feasible retrofit solutions for a marine electricity generation plant. This paper distinguishes itself from existing literature by incorporating future cost projection scenarios involving variables such as carbon tax, fuel, and equipment prices. It assesses the environmental impact by including upstream emissions integrated with the Energy Efficiency Existing Ship Index (EEXI) and the Carbon Intensity Indicator (CII) calculations. Real-time data have been collected from a Kamsarmax vessel to build a hybrid marine power distribution plant model for simulating six system designs. A Multi-Criteria Decision Making (MCDM) methodology ranks the scenarios depending on environmental benefits, economic performance, and system space requirements. The findings demonstrate that the hybrid configurations, including solid oxide (SOFC) and proton exchange (PEMFC) FCs, achieve a deduction in equivalent CO2 of the plant up to 91.79% and decrease the EEXI and the average CII by 10.24% and 6.53%, respectively. Although SOFC-included configurations show slightly better economic performance and require less fuel capacity, the overall performance of PEMFC designs are ranked higher in MCDM analysis due to the higher power density.

Comparative energy analysis of hydrogen carriers as energy source on ships

Hydrogen carriers are attractive alternative fuels for the shipping sector. They are zero-emission, have high energy densities, and are safe, available, and easy to handle. Sodium borohydride, potassium borohydride, dibenzyltoluene, n-ethylcarbazole, and ammoniaborane are hydrogen carriers with high theoretical energy densities. The energy density is paramount to implementing hydrogen carriers as a high energy density enables compact and lightweight storage. The effective energy density depends on integrating heat and masses with energy converters. This combination defines the energy efficiency and, thus, the energy density of the system. This paper addresses the effective energy density of the hydrogen carriers, including the dehydrogenation process. Using a 0D model, we combined the five carriers with two types of fuel cells, namely proton exchange membrane (PEM) and solid oxide fuel cells (SOFC), an internal combustion engine and a gas turbine. N-ethylcarbazole and dibenzyltoluene offer medium energy densities, reaching almost 4 MJ/kg. However, the effective energy density of sodium borohydride and ammoniaborane is very high, up to 15 MJ/kg, including the energy converter. This is similar to the energy density of marine diesel oil combined with an internal combustion engine. Thus, we conclude hydrogen carriers are alternative fuels that deserve more attention because of their strong potential to make shipping zero-emission.

Effective Ca and Ti co-doping in La0.80Ca0.20Mn0.80Ti0.20O3 perovskite as high-performance cathode material for solid oxide fuel cells

Effective Ca and Ti co-doping in La0.80Ca0.20Mn0.80Ti0.20O3 perovskite as high-performance cathode material for solid oxide fuel cells

Precise Regulation of In Situ Exsolution Components of Nanoparticles for Constructing Active Interfaces toward Carbon Dioxide Reduction.

Metal nanocatalysts supported on oxide scaffolds have been widely used in energy storage and conversion reactions. So far, the main research is still focused on the growth, density, size, and activity enhancement of exsolved nanoparticles (NPs). However, the lack of precise regulation of the type and composition of NPs elements under reduction conditions has restricted the architectural development of in situ exsolution systems. Herein, we propose a strategy to attain a regulated distribution of exsolved transition metals (Cu, Ni, and Fe) on Sr2Fe1.2Ni0.2Cu0.2Mo0.4O6-δ medium-entropy perovskite oxides by varying the oxygen partial pressure (pO2) gradient in the mixture. At 800 °C, the unitary Cu, binary Cu-Ni, and ternary Cu-Ni-Fe NPs are exsolved as pO2 decreases from high to low. Combining experimental and theoretical simulations, we further corroborate that solid oxide electrolysis cells with ternary alloy clusters at the CNF@SFO interface exhibit superior CO2 electrolytic performance. Our results provide tailored strategies for nanostructures and nanointerfaces for studying metal oxide exsolution systems, including fuel electrode materials.

Highly conductive and stable electrolytes for solid oxide electrolysis and fuel cells: fabrication, characterisation, recent progress and challenges

Solid oxide electrolyser (SOE) technology emerges as a promising alternative, typified by high-efficiency water-splitting capability and lower cost for large-scale hydrogen production. Electrolytes are the critical part of SOECs and SOFCs, which affect the performance and operation temperatures.

Techno-economic analysis and life cycle assessment of renewable methanol production from MSW integrated with oxy-fuel combustion and solid oxide electrolysis cell

Techno-economic analysis and life cycle assessment of renewable methanol production from MSW integrated with oxy-fuel combustion and solid oxide electrolysis cell

Performance analysis of a MW-scale reversible solid oxide cell energy storage system utilizing steam-hydrogen chemistry

Performance analysis of a MW-scale reversible solid oxide cell energy storage system utilizing steam-hydrogen chemistry

Transfer learning-based deep neural network model for performance prediction of hydrogen-fueled solid oxide fuel cells

Transfer learning-based deep neural network model for performance prediction of hydrogen-fueled solid oxide fuel cells

Recent advances in cathode materials for solid oxide fuel cell

Recent advances in cathode materials for solid oxide fuel cell

First-principles study of oxygen conductivity in LSCF cathodes of solid oxide fuel cells

First-principles study of oxygen conductivity in LSCF cathodes of solid oxide fuel cells

In situ self-assembled Fe–Co–Ni–Cu multi-metal nanoparticles modified high catalytic activity electrodes for symmetric solid oxide fuel cells

In situ self-assembled Fe–Co–Ni–Cu multi-metal nanoparticles modified high catalytic activity electrodes for symmetric solid oxide fuel cells

A highly stable co-doping induced phase structural transformation Sr-free oxygen electrode for reversible solid oxide cells

A highly stable co-doping induced phase structural transformation Sr-free oxygen electrode for reversible solid oxide cells

Accelerating the electrochemical performance of solid oxide fuel cells using a Ce(Gd, Bi, Yb)O2−δ diffusion barrier layer acting as an oxygen reservoir at high-current loading conditions

Ce(Gd, Bi, Yb)O2−δ with high oxygen storage capacity (OSC) facilitates stable oxygen supply to SOFCs under high current operation, leading to enhanced performance.

Novel solid oxide electrochemical cell for simultaneous processing of carbon dioxide and ethane

Novel solid oxide electrochemical cell for simultaneous processing of carbon dioxide and ethane