bluuebunny/crossref_metadata_2025_split huggingface dataset:
Configurations and Operation Methods of Diesel-Based Solid Oxide Fuel Cell System
Authors: Lu Yang , Liu Yaodong , Han Minfang 
Published: September 2023

Solid oxide fuel cell(SOFC) is a recently developed technology which has attracted increasing attention for its high efficiency and low emission. While the production and delivery of hydrogen still have giant obstacles, diesel will be a good substitute for its high heating value and low cost. However, it has not been widely used as the fuel for SOFC and researches on diesel-based SOFC system still remains to be further explored. In this work, a diesel steam reforming(SR)-SOFC system is studied. We proposed a series of system configurations of diesel-based SOFC and fitted key system units based on measured data of reforming and stack experiments. Moreover, the best system operation condition intervals were presented to achieve the maximize system efficiency and heat balance. The results suggest that a system with anode off-gas recirculation and electrodes off-gas mixture has the highest efficiency because it has higher syngas heat value and lower off-gas temperature; by adding a water condenser between reformer and SOFC stack, the system efficiency can be improved for higher percentage of H2 in syngas although the condenser will take away a part of the heat. Under this system configuration and the best system operation condition interval , the system efficiency can reach 58.2%(the stack efficiency is 45.8%), improving approximately 10% comparing with the system without anode off-gas recirculation. This research reveals the efficiency variance between different system configurations and gives a better system configuration as well as preferred operation methods, which lays a theoretical foundation for the upcoming design of a 100kw class physical system.
Keywords: solid oxide fuel cell, diesel reforming, system configurations, operation method
Towards an Impedance-Based Analysis of SOFC-Stacks
Authors: Golani Sadhana , Bausinger Holger , Mai Andreas , Weber Andre 
Published: September 2023

To understand the performance and durability limitations in SOFC stacks and systems, impedance spectroscopy is becoming increasingly important. However, in the analysis of entire stacks, gradients over the active cell area are averaged out, preventing access to local phenomena.
To get better insight into the spatial distribution of performance losses in a stack layer, incremental cells and repeat units with an active electrode area of 1 cm² are investigated in this study.
Impedance spectroscopy and the subsequent impedance data analysis by the distribution of relaxation times (DRT) is applied to deconvolute the polarization processes in the Ni/CGO fuel electrode and the LSM air electrode of the investigated electrolyte supported cell. To ensure an appropriate deconvolution of air and fuel electrode processes, next to full cells symmetrical anode and cathode cells are applied. In case of Ni/CGO fuel electrodes charge transfer and gas diffusion overlap in the spectrum and the assignment has to be done indirectly using inert gas mixtures [1].
In Figure 1 impedance spectra and DRTs of fuel and air electrode obtained from symmetrical cells are compared with the full cell spectrum. This analysis enables a clear allocation of the processes in the single cell to Ni/CGO fuel electrode and LSM air electrode.
Next to the cell testing in an inert, ideal environment namely an Al2O3 flow field with gold and nickel contact grids respectively, the study is expanded to stack like conditions. The additional losses due to contact resistances and gas supply limitations are studied similar to Kornely et al. [2] for single repeat units (single cell + contact layer + metallic interconnects). In this contribution a physio-chemical equivalent circuit model based on these measurements will be presented and the complex impedance behavior of single cells and repeat units will be discussed.

References:

[1] C. Grosselindemann et al. 2021 J. Electrochem. Soc. 168 124506.
[2] M. Kornely et al., J. Power Sources, 196, 7209-7216 (2011).
Figure 1: Impedance spectra and related distributions of relaxation times (DRTs) of full cell, fuel electrode, air electrode and sum of the impedance of fuel and air electrode

Figure 1
Development of Long Duration Button Cell Test Stands and Testing Protocols
Authors: Hartvigsen Jeremy , Kane Nicholas , Casteel Micah , Gomez Joshua , Priest Cameron , Wang Lucun , White Casey , Boardman Richard , Ding Dong 
Published: September 2023

In order to support the accelerated testing of the H2New consortium, long term repeatable cell testing is a necessary step. Cross-lab comparability and long duration tests are needed in order to establish a baseline degradation. The use of long-term testing with existing test stands and techniques that were developed primarily for material screening led to modifications to better suit long-term testing.
The stability of sealing of cells and operation of cells with the ability to endure a thermal cycle is a key point of interest in the long duration button cell testing. Cells with the ability to maintain performance unplanned power cycles are critical to the long-term understanding of button cells. System upgrades to improve long term button cell system reliability include the following: back-up power systems, thermal cycle stable glass, current collector attachment improvement, power monitoring, and in-operando cell leakage monitoring. The system modifications to identify and correct the most common causes of long-term button cell test failures are discussed. Discussions and lessons learned from cell test stand development and cell preparation protocols are presented.
Experimental Investigation of Naphthalene Induced Degradation of Reversible Solid Oxide Cells Operated on Bio-Syngas
Authors: Steinrücken Benjamin , Herrmann Stephan , Feigl Karsten , Schwiers Alexander , Lenser Christian , Menzler Norbert H. , Spliethoff Hartmut 
Published: September 2023

To tackle the demand for renewable alternatives to natural gas and for renewable energy, the operation of reversible solid oxide cells (rSOC) with syngas from biomass gasification is a highly efficient option. The fuel gas, produced close to carbon neutrality by the gasifier can be either converted to electrical power via the fuel cell mode or energetically upgraded via the electrolysis mode for e.g. utilization in chemical synthesis processes. Due to the reversible operation, a system based on an rSOC perfectly fits in an energy system with a high share of fluctuating renewable energy. However, impurities in fuel gas result in a fast degradation of the cells performance. This requires a comprehensive syngas cleaning to enable a stable operation of the cell. For the design of such a system, a deeper knowledge about the degradation processes is required. Especially the influence of tars is part of an ongoing research due to their ambivalent role as fuel and poison.
In this work, the model tar Naphthalene is used to experimentally investigate the influence of polycyclic aromatic components on the performance of 10 x 10 cm² fuel-electrode supported solid oxide cells operated at artificial bio-syngas under internal reforming conditions. Two different fuel electrodes based on yttrium-stabilized zirconia (YSZ) and gadolinium-doped ceria (GDC) are investigated. A parameter study of the operational temperature and the operation mode is conducted with the YSZ based fuel electrode to quantify the effect on the degradation. The influence of the set-up is investigated by an experiment without the cell. The cell temperature distribution, the pressure drop and the fuel off-gas composition is measured. Electrochemical impedance spectroscopy is used to characterize the cell prior to the experiment and to monitor its performance during the poisoning and regeneration process. The measurements are interpreted via the distribution of relaxation times.
The electrolysis mode is observed to be more vulnerable towards poisoning with the tar than the fuel cell mode. The poisoning effects, whether it is a performance degradation or carbon deposition, are not only dependent on the tar but also on the operational conditions. The GDC fuel-electrode did not show the expected high robustness. The investigated cells are prototypes of an ongoing development process; hence a more detailed investigation is required when the development is finished.
Role of Operating Modes on the Performance Durability of Solid Oxide Cells: A Comparison between Potentiostatic and Galvanostatic Operations
Authors: Wang Yudong , Zhou Xiao-Dong 
Published: September 2023

The commercialization of solid oxide cells for power generation or hydrogen production requires extended cell lifetime and durability. A solid oxide cell can operate either under a potentiostatic or a galvanostatic mode. It remains unclear what’s the role of those two operating modes on the performance durability of solid oxide cells, which limits our understanding and subsequently predicting service life and reliability of solid oxide cells.
It is known that many degradation phenomena in solid oxide cells can be accelerated by the electrochemical operations, which manifest various distributions of oxygen chemical potential (μO2) across a solid oxide cell. The variation in the local μO2 is a central driving force for the phase transformation, demixing, and microstructure evolution, leading to a higher resistance of the cell components and decreasing cell performance. As a response to the degradation, the μO2 redistributes across the cell and the driving force for the degradation changes. The μO2 distribution differs when a cell operates at a constant current or a constant voltage. The driving force with different extents of degradation under both operation modes is compared to establish the optimum operation approach, which can shed light on identifying mitigation strategies to improve performance durability with existing cell configurations and materials.

Acknowledgement

We greatly appreciate the support from U.S. Department of Energy’s Office of Fossil Energy and Carbon Management under DE-FE0032110. Part of this work is supported by U.S. National Science Foundation under NSF-2119688.
Long-Term Stability of Perovskite-Based Fuel Electrode Material Sr2Fe2-XMoxO6-δ – GDC for Enhanced High-Temperature Steam and CO2 Electrolysis
Authors: Wolf Stephanie E. , Vibhu Vaibhav , Coll Carla L. , Eyckeler Niklas , Vinke Izaak C. , Eichel Rudiger-A , de Haart L.G.J. (Bert) 
Published: September 2023

Solid oxide electrolysis cells (SOECs) have proven to be a highly efficient key technology to produce valuable gases (H2, CO). SOECs utilize renewably generated electricity at temperatures between 600 - 900 °C, thereby providing a carbon-neutral method for energy storage. However, the successful industrial implementation of this technology requires long-term stability of all system components and is mainly delayed by the degradation of the electrodes over time. The state-of-the-art Ni-YSZ fuel electrode has been extensively studied and exhibits severe performance loss due to Ni particle agglomeration and Ni migration away from the active sites at the electrolyte/electrode interface under real operating conditions [1]. To mitigate this issue, we have investigated the Ni-free perovskite Sr2Fe2-xMoxO6-δ + 30% GDC as fuel electrode material. As mixed ionic and electronic (MIEC) perovskite structured oxides, these materials have shown excellent short-term redox stability in oxidizing and reducing atmospheres in addition to high conductivity and outstanding coking resistance [2]. These characteristics meet exactly the targeted requirements for new solid oxide electrolyzer materials. We have compared the long-term degradation of an SFM fuel electrode to an electrode made of SFM-GDC (Figure 1). The degradation was less severe for the mixed electrode of SFM-GDC. Impedance and post-test SEM-EDX analysis clarified the main degradation mechanisms of SFM as well as SFM-GDC in steam and CO2 electrolysis. The tested button cells showed demixing of the SFM phase and particle aggomeration in the fuel electrode.
[1] S. E. Wolf, V. Vibhu, E. Tröster, I. C. Vinke, R.-A. Eichel and L. G. J. de Haart, Energies, 15(15), 5449 (2022).
[2] L. Bernadet, C. Moncasi, M. Torrell and A. Tarancón, Int. J. Hydrog. Energy, 45(28), 14208–14217 (2020).

Figure 1
Strategies to Improve the Effectiveness of the Thin Film Coated Interconnects
Authors: Reddy Mareddy Jayanth , Almyren Isak , Svensson Jan-Erik , Froitzheim Jan 
Published: September 2023

Interconnects made of ferritic stainless steel (FSS) are used in solid oxide cells (SOC), both in fuel cells and electrolyzers, owing to a coefficient of thermal expansion similar to that of ceramic components, high oxidation resistance, good thermal conductivity, and adequate electrical conductivity of Cr2O3 scale at high temperatures. However, corrosion of the FSS interconnects at operating conditions between 600 – 900°C leads to high degradation rates and is a critical area for improving the SOC's performance.
The two significant issues with the FSS interconnects are 1. Chromia scale growth 2. Chromium evaporation. Protective chromia scale forms on the FSS upon exposure to high temperature, which grows continuously with time. The growing chromia scale increases the resistance across the cell, reducing cell efficiency. Additionally, the chromia scale reacts with oxygen in the presence of water vapour to form volatile Cr(VI) species such as CrO2(OH)2. These volatile Cr (VI) species interact with the cathode materials and get deposited at the triple-phase boundaries, hindering the oxygen electrochemical reaction on the cathode. This results in a decrease in the activity of the oxygen reduction reaction at the cathode referred to as cathode/ chromium poisoning.
Despite developing speciality steels like Crofer 22H and ZMG232, chromium evaporation is very high for the long-term performance of SOFC. Applying coatings is a widespread solution to suppress chromium evaporation. Manganese cobalt oxide (MCO) based coatings are extensively studied for this purpose. Physical vapour deposition deposited metallic Ce/Co coatings, which form MCO up oxidation, have been extensively studied for up to 38000 hours. Most of these studies were performed on as-received coatings, as opposed to the conditions in the stack. Commonly stacks are conditioned at high temperatures, usually 100-250 °C above the operating temperatures, to ensure gas-tightness in the stack.
To understand the influence of stack preheating on the coated interconnects, Ce/Co coated AISI 441 and Crofer 22 APU were pre-oxidized at 950 °C for 2 hours. After the pre/oxidation, the exposures were conducted in horizontal quartz tube reactors at 850oC for 1000 hours in air humidified with 3 % H2O. The oxidation kinetics of these coated steels was studied. Area-specific resistance (ASR) measurements were studied ex-situ after 1000 hours on these coated steels. The samples are characterized after pre/oxidation and exposure using scanning electron microscopy (SEM) and energy-dispersive x-ray spectroscopy (EDX). With the appropriate heat treatment, the interconnect lifetime can be increased by a factor of 5. The ASR of the pre-oxidized steels is lower than the as-received steels.
Metal-Supported Solid Oxide Cells for Energy Conversion, Electrolysis, and Chemical Synthesis
Authors: Tucker Mike C , Hu Boxun , Zhu Zhikuan , Welander Martha M , Shen Fengyu , Skafte Theis Løye , Lau Grace Y. 
Published: September 2023

This talk will provide an overview and update of performance, durability, and applications of metal-supported solid oxide fuel cell (MS-SOFC) and electrolysis cell (MS-SOEC) technology developed at Lawrence Berkeley National Laboratory (LBNL). The unique LBNL symmetric cell architecture design, with thin zirconia ceramic backbones and electrolyte sandwiched between porous metal supports, offers a number of advantages over conventional all-ceramic cells, including low-cost structural materials (e.g. stainless steel), mechanical ruggedness, excellent tolerance to redox cycling, and extremely fast start-up capability. These features enable a wide variety of applications including vehicle range extenders, electrolysis for intermittent renewables, personal power generators, and distributed generation.
With infiltrated catalysts, the catalyst compositions can be easily tailored to a variety of reactions, without re-optimizing the entire cell. Recent efforts have developed catalysts for internal reforming of natural gas and ethanol, steam electrolysis to produce hydrogen, oxidative coupling of methane to synthesize ethylene, and oxygen generation from air. A recent focus is 1000+ hour continuous operation with detailed post-mortem analysis. Progress on cell performance and durability for each of these applications will be discussed.
Infiltrated catalysts, however, present a tradeoff between initial performance and long-term stability. Extremely high surface area promotes high electrochemical reaction rates, but also provides high surface energy leading to coarsening and facilitates Cr deposition. Recent approaches to mitigating catalyst coarsening and Cr deposition within the cathode include coatings to prevent Cr evaporation from the stainless steel components, and optimization of infiltrated catalyst processing to stabilize the microstructure during operation. The metal support structure has also been optimized for improved mass transport.
Influence of Temperature and Water Vapour on the High-Temperature Oxidation and Cr Evaporation Behaviour of High-Cr Alloys for SOFC Cathode Air Pre-Heaters
Authors: Zhang Kun , El-Kharouf Ahmad , Steinberger-Wilckens Robert 
Published: September 2023

Chromium evaporation and oxide scale growth are among the key degradation mechanisms associated with Solid Oxide Fuel Cells (SOFCs). It is often underestimated how the cathode air pre-heater (CAPH) made of high Cr-containing alloys in SOFC systems can contribute to cathode degradation. This study examines the effect of exposure temperature and water content on both degradation mechanisms in Inconel 625, SS309 and AluChrom 318. For the influence of water content, samples of Inconel 625, SS309 and AluChrom 318 were isothermally exposed at 850°C in dry air and air containing 1%, 3% and 9% of H2O at a high flow rate for 168 hours. For the influence of temperature, samples of Inconel 625, SS309 and AluChrom 318 were isothermally exposed at 650°C, 750°C and 850°C in a 6.0 L/min air stream containing 3% H2O for 168 hours. The evaporated Cr (VI) species were collected using the denuder technique. The formed oxide scales were subsequently analysed using XRD and SEM/EDX. The results of the surface characterisation indicated that the oxide scales formed on Inconel 625, SS309 and AluChrom 318 at high temperatures were Cr2O3, (Cr,Mn)3O4 spinel and Al2O3, respectively.
The results of this study show that Cr evaporation and oxidation rates were dramatically reduced at the lower temperature used for Inconel 625 and SS309. AluChrom 318 exhibited an increased oxidation rate with increasing temperature, but it demonstrated a reverse trend to the temperature dependent Cr evaporation compared to Inconel 625 and SS309. It was also found that the amount of Cr evaporated from an alloy solely depended on the partial pressure of Cr presented on the oxide surface. At 850°C, the total mass of evaporated Cr(VI) species was found as follows: Cr2O3 (Inconel 625) > (Cr,Mn)3O4 spinel (SS309) >> Al2O3 (AluChrom 318). However, at 650 and 750°C, the total mass of evaporated Cr(VI) species was found to be: (Cr,Mn)3O4 spinel (SS309) > Cr2O3 (Inconel 625) > > Al2O3 (AluChrom 318). The significant effect of water vapour on the three tested materials appeared to be the further enhancement of Cr2O3 evaporation. At 850°C, the amount of evaporated Cr2O3 from the alloys exposed at the same humidity level corresponded to the Cr partial pressure on the surface, as follows: Cr2O3 (Inconel 625) > (Cr,Mn)3O4 spinel (SS309) > Al2O3 (AluChrom 318). The water vapour slightly increased the growth rate of Cr2O3 and (Cr,Mn)3O4 spinel formed on the Inconel 625 and SS309 surface, respectively. However, no evidence of change in the growth rate of the alumina on AluChrom 318 under the influence of water vapour in oxidising atmosphere was observed for the tested period in this study.

Figure 1
Temperature-Dependent Sheet and Contact Resistivity Measurements on Ag and Ag-Ni Circuit Pastes
Authors: Bhatlawande Aishwarya , Hu Genzhi , Nicholas Jason , Hogan Timothy 
Published: September 2023

The metal circuits and brazes used in electronic, energy conversion, and/or energy storage devices often have difficulty wetting and adhering to ceramic and/or ceramic-passivated metal substrates. Here, a novel Particle Interlayer Directed Wetting and Spreading (PIDWAS) technique is demonstrated that utilizes screen printing, the low wetting angle of silver on nickel, and the high work of adhesion between nickel and various ceramics to produce well-adhered, self-assembled silver patterns on ceramic and/or stainless-steel substrates not normally wet by silver. The resulting Ag-Ni circuits have higher sapphire adhesion strengths (up to 30 MPa on sapphire), higher densities (>97% on sapphire), and similar high-temperature electronic resistivities to those made using commercially-available Heraeus C8710 or DAD-87 silver circuit pastes. Similarly, Ag-Ni brazes between a variety of ceramic and/or stainless-steel substrates have better microstructural stability with rapid thermal cycling, reduction-oxidation cycling, and dual atmosphere isothermal aging than conventional Ag-CuO brazes. In addition, the residual Ni in these Ag-Ni circuits and brazes can be used to chemically getter surface segregated Al, ensuring low contact resistances on a variety of chromia- and/or alumina-passivated stainless steels.
Reference:
[1] Hu G, Zhou Q, Bhatlawande A, Park J, Termuhlen R, Ma Y, Bieler TR, Yu HC, Qi Y, Hogan T & Nicholas JD. Patterned Nickel Interlayers for Enhanced Silver Wetting, Spreading and Adhesion on Ceramic Substrates. Scripta Materialia, 2021; 196, 113767. 10.1016/j.scriptamat.2021.113767
[2] Park J, Phongpreecha T, Nicholas JD & Qi Y. Enhanced Liquid Metal Wetting on Oxide Surfaces via Patterned Particles. Acta Materialia, 2020; 199, 551-560. 10.1016/j.actamat.2020.08.037