Single Chamber Solid Oxide Fuel Research Articles

Investigation of Single-step Fabrication of a Cathode-supported Planar Single-chamber Solid Oxide Fuel Cell and Its Performance

This study presents a cathode-supported planar solid oxide fuel cell (SOFC) fabrication made via a single step co-sintering method and investigation of its performance. The materials used are NiO-CGO, CGO and CGO-LSCF for anode, cathode, electrolyte, respectively. Our study shows that increasing the cell size has a detrimental effect on cell single step co-sinterability. Increasing cathode thickness and reducing electrolyte thickness led to curvature decrease at the edges, however these adjustments were not enough to achieve a curvature-free cathode-supported cell. Thus, three porous alumina cover plates (total mass of 49.35 g) placed on the top of the cell during sintering were utilized to suppress curvature formation, and as a result, a nearly curvature- free cathode-supported cell was obtained. Performance of the cells were investigated. The results showed that increasing cathode thickness and decreasing electrolyte thickness had negative effects on cell performance despite enhanced single step co-sinterability of the cell. The maximum power density and OCV of the final planar cell (thickness 60-40-800 µm, anode-electrolyte-cathode) were found to be 1.71 mW cm-2 and 0.2 V, respectively, in a fuel rich condition (R:1.6). Additionally, the maximum OCV and power density among the all cells were measured from the cell (thickness 60-40-400 µm, anode-electrolyte-cathode) as 0.56 V and 24.79 mW cm-2, respectively, in a fuel rich condition (R:2.4).

A Study of the Electrochemical Characteristics of Single-Chamber Solid Oxide Fuel Cells Based on Platinum and Strontium-Doped Lanthanum Manganite Electrodes and Fed with a Methane–Air Mixture

A Study of the Electrochemical Characteristics of Single-Chamber Solid Oxide Fuel Cells Based on Platinum and Strontium-Doped Lanthanum Manganite Electrodes and Fed with a Methane–Air Mixture

Performance of Single-Chamber Solid Oxide Fuel Cells Based on Ni and Ni–Cu Alloy Anodes and Fed with a Methane–Air Mixture

Performance of Single-Chamber Solid Oxide Fuel Cells Based on Ni and Ni–Cu Alloy Anodes and Fed with a Methane–Air Mixture

Comparison of different infiltration amounts of CeO2 inside Ni-YSZ anodes to improve stability and efficiency of Single-Chamber SOFCs operating in methane

Electrochemically active oxide-based anodes capable of working in Single-Chamber Solid Oxide Fuel Cells (SC-SOFCs) were developed. Their performance is related to the selectivity of the electrodes. Tests are carried out on lab-scale devices with YSZ pellets as solid electrolytes in electrolyte supported cells. Selecting methane as a fuel, a gas mixture in the ratio CH4/O2 = 2 was chosen. The Ni-YSZ (NiO:YSZ=60:40) anode was optimized through CeO2 nanocatalysts infiltration to enhance the anode catalytic activity and make its reduction easier. Several infiltration amounts were compared, from null to 15% of the electrode weight. Both symmetric and complete cells (with LSCF-based cathodes) were tested in H2 and CH4/O2. For increasing amounts of infiltrated CeO2, symmetric cells tests describe an area specific resistance (ASR) reduction from 40 Ω cm2 to 1.7 Ω cm2 in hydrogen and from 11 Ω cm2 to 3.9 Ω cm2 in the methane/oxygen mixture. While complete cells tests displayed an ASR drop from 30 Ω cm2 to 2.9 Ω cm2 in H2, and from 8.7 Ω cm2 to 4.3 Ω cm2 in the methane/oxygen mixture, while OCP and power grew from 478 mV and 3.7 mW cm-2 to 766 mV and 13 mW cm-2.

Single chamber Solid Oxide Fuel Cells selective electrodes: A real chance with brownmillerite-based nanocomposites

In this contribution brownmillerite-based nanocomposite cathode for Single-Chamber Solid Oxide Fuel Cells is developed. These cells can be very attractive especially for small and cheap devices because of the absence of seals. The efficiency of SC-SOFCs is strictly connected to the selectivity of anode and cathode, the bottleneck for this technology. The development of a cathode inert in fuel oxidation is particularly challenging. Our strategy is to start from a catalytically un-active support (CFA = Ca2FeAl0.95Mg0.05O5) and induce the formation of iron oxide based nanoparticles, expected to activate oxygen. Symmetric (CFA + FeOx/CGO/CFA + FeOx) and complete cells (CFA + FeOx/CGO/Ni-CGO) are studied in air and methane/oxygen 2:1 mixture. The Area Specific Resistance of CFA + FeOx is less than 1/3 that of CFA. The high selectivity allows to reach an efficiency of 25%; power still needs to be increased but we demonstrated the possibility to develop selective low cost electrodes. The effect of air, methane/oxygen exposure and the heat treatments were carefully investigated.

Modeling and Optimization of the BSCF-Based Single-Chamber Solid Oxide Fuel Cell by Artificial Neural Network and Genetic Algorithm

Fuel cells could be a highly effective and eco-friendly technology to transform chemical energy stored in fuel to useful electricity and thus are presently appraised as a standout among the most encouraging advancements for future energy demand. Solid oxide fuel cells (SOFCs) have several advantages over other types of fuel cells, such as the flexibility of fuel used, high energy conversion, and relatively inexpensive catalysts due to high-temperature operation. The single chambers, wherein the anode and cathode are exposed to the same mixture of fuel, are promising for the portable power application due to the simplified, compact, sealing-free cell structure. The empirical regression models, such as artificial neural networks (ANNs), can be used as a black-box tool to simulate systems without solving the complicated physical equations merely by utilizing available experimental data. In this study, the performance of the newly proposed BSCF/GDC-based cathode SOFC was modeled using ANNs. The cell voltage was estimated with cathode preparation temperature, cell operating temperature, and cell current as input parameters by the one-layer feed-forward neural network. In order to acquire the appropriate model, several network structures were tested, and the network was trained by backpropagation algorithms. The data used during the training, validation, and test are the actual experimental results from our previous study. The optimum conditions to achieve maximum power of the cell were then determined by the genetic algorithm and the developed ANN.

Spatially Resolved Photoemission and Electrochemical Characterization of a Single-Chamber Solid Oxide Fuel Cell

The present paper pinpoints the feasibility of in operando near-ambient pressure characterization of an operating single chamber solid oxide fuel cell (SC-SOFC) by means of spatially resolved X-ray photoelectron spectroscopy. The results are based on an innovative and unique setup expanding the capabilities of the scanning photoelectron microscopes. In particular, the impact of getting access to the low mbar range on the very observability of chemical-state changes in an LSM cathode have been highlighted. Ex situ and in situ electrochemical measurements at OCP and close circuit cell conditions complemented the photoemission mapping and spectroscopy. The latter has evidenced the evolution of the chemical state of Sr upon the exposure of the typical SC-SOFC CH4–O2 gas feed.

Significantly Improving the Durability of Single-Chamber Solid Oxide Fuel Cells: A Highly Active CO2-Resistant Perovskite Cathode

The single-chamber solid oxide fuel cell (SC-SOFC) represents an attractive alternative to batteries for micropower applications given its simplified stack design, easy gas management, lower operation temperature, and quicker start-up. Its stable operation over long duration relies on the availability of CO2-resistant cathode materials with high oxygen reduction reaction (ORR) activity. Here, we reported a novel perovskite oxide cathode SrSc0.075Ta0.025Fe0.9O3−δ (SSTF75), which provides CO2 resistance and high ORR activity. A peak power density of 1430 mW cm–2 was achieved with the SSTF75/Sm0.2Ce0.8O1.9 cathode at 650 °C with a methane and oxygen gas mixture (1:1 v/v ratio). It retained stable voltage performance at 600 °C for an over 90 h duration when discharged at a current density of 1000 mA cm–2. This work not only represents an advancing step in the SC-SOFC field but also authenticates an effective codoping strategy for the design of a CO2-resistant cathode for low-temperature applications.

Fabrication and evaluation of a novel wavy Single Chamber Solid Oxide Fuel Cell via in-situ monitoring of curvature evolution

Wavy type Single Chamber Solid Oxide Fuel Cells (SC-SOFCs) are beneficial for improved triple phase boundary conditions contributing to higher performance, compared with planar type SC-SOFCs of the same diameter. This study presents a fabrication process for wavy-type, cathode-supported SC-SOFCs with a single fabrication step via co-sintering of a triple-layer structure consisting of NiO/CGO-CGO-LSCF, with a thickness ratio of 1:3:9 respectively. Curvature evolution occurs due to different sintering behaviour of each layer during the co-sintering process. In-situ observation of each layer during the co-sintering process allows for minimisation of mismatched stresses to avoid unnecessary warping and cracking. Bilayers, consisting of NiO/CGO-CGO and CGO-LSCF, are co-sintered at 1200°C. In-situ observation, to monitor the shrinkage of each material and the curvature evolution of the structures, is performed using a long focus microscope (Infinity K-2). Monitoring curvature behaviour in real time minimised the development of undesired curvature in the triple-layer structure. Performance testing of wavy cell is carried out in a methane-air mixture (CH4:O2=1:1). The wavy SC-SOFC generated 0.39V and 9.7mWcm−2 at 600°C, which produced 260% and 540% increments in OCV and in maximum power density, respectively, over the planar SC-SOFC under the same operational conditions.

Fabrication of Micro Single Chamber Solid Oxide Fuel Cell Using Photolithography and Pulsed Laser Deposition

This paper focuses on the fabrication of micro-coplanar interdigitated single chamber solid oxide fuel cell (μ-SC-SOFC) using a combination of micropatterning technique and thin-film deposition technology. Photolithography was used to generate the micro-interdigitated photoresist patterns on the substrates. Pulsed laser deposition (PLD) method was used to deposit thin films of microstructured electrolytes yttrium stabilized zirconia (YSZ) and electrodes (anode: YSZ + NiO and cathode: lanthanum strontium ferrous cobalt (LSCF)). Process parameters were optimized to obtain consistent functional microstructure and crystal morphology. This research shows good potential for combinatorial manufacturing methods to fabricate high quality and repeatable micro fuel cell components.

Redox Tolerance of Thin and Thick Ni/YSZ Anodes of Electrolyte‐Supported Single‐Chamber Solid Oxide Fuel Cells under Methane Oxidation Conditions

AbstractRedox tolerance of 50 and 500 μm thick Ni/YSZ (yttria‐stabilized zirconia) anodes supported on YSZ electrolytes were studied under single‐chamber solid oxide fuel cell conditions. Open circuit voltage, electrochemical impedance spectra, and discharge curves of the cells were measured under different methane/oxygen ratios at 700 °C. For the cell with the thin anode, a significant degradation accompanying oscillatory behaviors was observed, whereas the cell based on the thick anode was much more stable under the same conditions. In situ local anode resistance (Rs) results indicated that the Ni/NiO redox cycling was responsible for the oscillatory behaviors, and the cell degradation was primarily caused by the Ni reoxidation. Reoxidation of the thick anode took place at a low methane/oxygen ratio, but the anode can be recovered to its original state by switching to a methane‐rich environment. On the contrary, the thin anode was unable to be regenerated after the oxidation. Microstructure damage of the anode was attributed to its irreversible degradation.

BaLaIn2O5.5 Electrolyte Single Chamber Solid Oxide Fuel Cells with Novel Porous Electrolyte Surface Structure

not Available.

CHARACTERISTICS OF BSCF5582 POWDER AND FUEL CELL PERFORMANCE UNDER SINGLE CHAMBER CONDITIONS EVALUATION

The Ba0.5Sr0.5Co0.8Fe0.2O3 (BSCF5582) powder is synthesized as the cathode material for Single Chamber Solid Oxide Fuel Cell (SC-SOFC) La1.8Dy0.2Mo2O9 (LDM) based electrolyte. The crystal size, which was calculated from the XRD result, is around 48.59 nm by taken the (110) plane. The morphology of cell cross-section is good adhesion without any reaction between layers. The single cell NiO+GDC/LDM/i-GDC/GDC-BSCF5582 consisting 26 μm-thick cathode generates peak power density of 200 mW/cm2 at 650 oC under flowing mixture of CH4/air in temperature range of 575-675 oC. The BSCF5582 can be used for SC-SOFC using LDM electrolyte under single chamber conditions.

Fabrication of High Performance BaLaIn2O5.5 Electrolyte Single Chamber Solid Oxide Fuel Cell by Using Sublimation Materials as Pore Former in Electrode Preparation

not Available.

Investigations on Single Chamber Solid Oxide Fuel Cells: From Single Cell to Micro-Stack

In this paper, some investigation results of our research group about single chamber solid oxide fuel cells including single cells and micro-stacks are presented. On single cell investigations, both electrolyte-supported (ES) and anode- supported (AS) membrane ones were studied. The primary work focused on reducing the inner resistance, improving the open circuit voltage (OCV) as well as power density, and enhancing the operation stability. On 2-cell short stacks, our investigation focused on AS type stacks with different configurations and the structure parameter effect. To develop useful SC-SOFC system, more stack configurations have been designed and tested. Many efforts have been made to optimize the gas flow field of multi-cell micro-stacks in order to enhance the OCV, power output and fuel utilization. Configurations of SC-SOFC stacks, including star-type, array type and micro-stack with root gas tubes have been designed and tested successfully.

Numerical Approach of a Single-Chamber Solid Oxide Fuel Cell without Mixed Reactant Feeding

Satisfactory power densities for Single Chamber Solid Oxide Fuel Cells (SC-SOFC) can be obtained with ceramic materials already used in dual chambers SOFC. In order to increase the oxygen access trough the cathode, the authors propose to combine a SC-SOFC and a dual chamber SOFC by using a porous ceramic membrane. In this computing work, species transport is governed by convection-diffusion equations in the gas channel and the porous media. In addition, momentum balances are solved using Brinkman formulation through the porous cell. Charge transfer occurs at the electrode/electrolyte interface and is described by the general Butler-Volmer equation. Simulations allow the calculation of the distributions of partial pressures for all the gas species within the cell (CH4, H2, CO, CO2, H2O, O2, N2). As expected, the injection of only 3% of the steam water increases the chemical conversion of methane.

The Performance of a Single-Chamber Solid Oxide Fuel Cell Operated under Thin Oxygen Condition within Methane Fuel

An anode-supported single-chamber solid oxide fuel cell (SC-SOFC) with dense yttria-stabilized zirconia film as the electrolyte was fabricated by the slurry spin coating technique. The single cell was operated at a temperature range between 500°C and 700°C in a mixture gas of methane and oxygen with a quit lower oxygen concentration than usual. A stable methane-oxygen mixture (total flow rate: 150 ml/min) was used and the O2 percentage was varied from 5% to 25%. A maximum OCV can be achieved near the oxygen percentage of 10%. At 600°C, the maximum power density was 6.43 mW/ cm2. The performance indicates that SC-SOFC under such low oxygen concentration still have potential for portable applications.

Investigations on Single Chamber Solid Oxide Fuel Cells: From Single Cell to Micro-Stack

not Available.

The Performance of a Single-Chamber Solid Oxide Fuel Cell Operated under Thin Oxygen Condition within Methane Fuel

not Available.

140 燃料にメタノールを用いた一室型固体酸化物燃料電池におけるカソード材の評価(環境工学,一般講演)

140 燃料にメタノールを用いた一室型固体酸化物燃料電池におけるカソード材の評価(環境工学,一般講演)