bluuebunny/crossref_metadata_2025_split huggingface dataset:
Micro Tubular Solid Oxide Reversible Cell Using LaGaO3 Electrolyte Film Prepared on Channel Size Controlled NiO-YSZ Substrate
Authors: Ishihara Tatsumi , Liu Bin , Song Jun Tae , Watanabe Motonori 
Published: September 2023

Reversible operation of SOFC is now important subjects from energy storage of renewable electric power from solar or wind power. At present, planer type cell design is widely used for this purpose, however, because of tight gas sealing, tubular type cell design is more suitable. In this study, micro tubular solid oxide cell using La0.9Sr0.1Ga0.8Mg0.2O3−δ (LSGM) thin electrolyte film was prepared by dip-coating and co-sintering process.
NiO-YSZ porous substrate with 10 mm diameter and 30 mm length was used for preparation of the cell. LaGaO3 based oxide film was deposited with dip coating method. Two kinds of NiO and YSZ particles with different particle size (0.91 and 0.65 mm for NiO and 0.62 and 0.25 mm for YSZ) were mixed and extruded for tubular substrate. 4 types of NiO-YSZ anode porous substrate were Average porosity of each 4 tubular substrate was ca. 70% after reduction. However, from SEM observation, channel size in NiO-YSZ substrate was changed and NiO-YSZ using larger NiO and YSZ particles shows larger channel diameter.
Power generation property of 4 tubular cell using different NiO and YSZ particle size for substrate. It was found that the cell deposited on NiO-YSZ using larger particles shows lager power density, in particular, the cell using both NiO and YSZ larger particles shows the largest power density (0.37 W/cm2 at 873 K), which is reasonably large power density. On the other hand, in case of electrolysis, channel size is also strongly influenced on the electrolysis current. As similar manner with fuel cell operation, the LSGM cell prepared on larger particles size of NiO and YSZ shows larger steam electrolysis current. Impedance analysis suggests that the effects of particle size of NiO and YSZ was explained by small concentration overpotential, and so larger channel size is effective for improving the initial performance of the SORC performance. Long term stability of the steam electrolysis was performed and it was found that the LSGM tubular cell prepared on NiO-YSZ with larger particles shows the reasonable stable electrolysis performance in long term stability (-4%/1000h average degradation rate). The main reason for degradation was assigned to the increased IR loss however overpotential was hardly changed over 600 h and so it seems most likely that the reoxidation of NiO or aggregation of NiO is the main reason for degradation of the cell.
This study reveals that the control of channel size in NiO-YSZ porous substrate is highly important for initial performance and long-term stability of SORC.
Life Testing and Redox Cycling of Ni- and Ru-Doped Strontium Iron Titanate Exsolution Fuel Electrodes in Electrolyte-Supported Solid Oxide Cells
Authors: Zhang Yubo , Horlick Samuel A , Dogdibegovic Emir , Barnett Scott A 
Published: September 2023

Recently perovskite materials have gained much attention as potential candidates for solid oxide cell (SOC) fuel electrodes due to their advantages of redox stability, coking resistance and sulfur resistance over their cermet counterparts. Enhanced electrochemical performance has also been observed for some of these perovskite materials resulting from exsolution, where nano-sized metal particles are formed on the material surface under reducing conditions. However, the degradation mechanism of these perovskite fuel electrodes has yet to be fully understood and the relationship between their long-term stability and operating envrionments (fuel-cell/electrolysis, fuel compositions, redox cycles, operating pressure, etc.) has not been fully investigated.
Here, life tests were conducted in open-circuit and reversible operation at 850oC on electrolyte-supported symmetric and full cells with Ni and Ru-doped strontium iron titanate (Sr0.95Ti0.3Fe0.63Ni0.07O3 and Sr0.95Ti0.03Fe0.63Ru0.07O3) as fuel electrodes (SrTi0.3Fe0.6Co0.1O3 used as the air electrode in the full cells). For both materials, higher degradation rate was observed when operated with 97% H2 + 3% H2O compared with 50% H2 + 50% H2O as fuel; an increase in ohmic resistance and gas adsorption/desorption resistance contributed to most of the degradation observed. STFN also showed higher degradation rates than STFRu in both fuel compositions. Exsolution from both compositions was confirmed by scanning electron microscopy (SEM) and scanning transmission electron microscopy (STEM) with both fuel compositions and in situ X-ray Diffraction (XRD) showed the simultaneous perovskite to Ruddlesden-Popper (RP) phase transformation. The faster perovskite-RP phase transformation is believed to be responsible for the higher degradation rates observed for cells using fuel electrode materials with less stable perovskite structure (STFN over STFRu) and tested in more reducing fuel compositions (97% H2 over 50% H2). Moreover, redox cycles were introduced for STFN and STFRu during life tests and partial performance recovery was observed; in situ XRD and SEM microstructural analysis suggests that the recovery resulted from a transformation from RP back to perovskite for both materials. Finally full cell reversible operation durability tests (6 hrs each in fuel cell and electrolysis modes at 0.8 A/cm2) conducted at 850oC with 50% H2 + 50% H2O as fuel at 1 atm showed reasonably good stability over 1000 h. Initial reversible life testing at 3 atm operating pressure showed higher degradation rates, and the possible reasons for this will be discussed.
Long-Term Tests and Advanced Post-Test Characterizations of the Oxygen Electrode in Solid Oxide Electrolysis Cells
Authors: Celikbilek Ozden , Sassone Giuseppe , Prioux Manon , Ferreira Sanchez Dario , Benayad Anass , Hubert Maxime , Morel Bertrand , Vulliet Julien , Léon Aline , Laurencin Jérôme 
Published: September 2023

Solid Oxide cells (SOCs) are promising high-temperature electrochemical energy-conversion devices, which enable a fossil-free sustainable development. Nevertheless, performance degradation is still a bottleneck for the large-scale commercialization. The most commonly employed material for the air electrode is La1-xSrxCoy-1FeyO3-δ. The chemical decomposition of this material is known to considerably impact the cell performance [1,2].
The studied cells are composed of a La0.6Sr0.4Co0.2Fe0.8O3
-δ (LSCF) current collecting layer (CCL) and a LSCF-Ce0.8Gd0.2O2
-δ (LSCF-GDC) composite for the air electrode, GDC for the barrier layer, (Y2O3)0.08(ZrO2)0.92 (YSZ) for the electrolyte and Ni-YSZ for the functional layer and the support layer of the fuel electrode. The present study aims to investigate the degradation occurring in the air electrode of a complete cell aged at 750°C for 2000 h in electrolysis mode. The cell degradation is assessed by electrochemical measurements, such as polarization curves and electrochemical impedance spectroscopy (EIS), and post-mortem characterizations of the air electrode using high resolution multimodal chemical imaging based on synchrotron X-ray diffraction (µ-XRD) in Paul Scherrer Institut (PSI, microXAS), complemented by X-ray photoelectron spectroscopy (XPS).
The electrochemical characterizations performed at the beginning of the test and after ageing showed a decrease in the cell performance. Notably, a significant evolution at the high frequency region was observed in the impedance spectrum. However, the medium frequency region of the EIS, mainly ascribed to the air electrode using a physically-based multiscale model [3], did not show any particular evolution. Post-mortem characterizations using synchrotron µ-XRD technique showed an inter-diffusion layer (IDL) in between the GDC and YSZ layers, for both pristine and aged samples (Fig. 1). In addition, a slight increase in the LSCF unit cell volume was observed after ageing. Nevertheless, XPS results did not highlight any significant evolution in the Sr segregation after operation. According to the impedance spectra and the post-mortem analyses, the ageing of the air electrode seems to have a limited impact on the cell performance loss in these operating conditions.

References

[1] J. Laurencin, M. Hubert, D.F. Sanchez, S. Pylypko, M. Morales, A. Morata, B. Morel, D. Montinaro, F. Lefebvre-Joud, E. Siebert, Electrochimica Acta. 241 (2017) 459–476.
[2] M. Kim, H. Muroyama, T. Matsui, K. Eguchi, J. Electrochem. Soc. 166 (2019) F1269.
[3] G. Sassone, E. Da Rosa Silva, M. Prioux, M. Hubert, B. Morel, J. Laurencin. Under preparation.

Figure 1
Solid Oxide Electrolysis Cells Fabrication: From Single Cells to Batch Production
Authors: Ureña Torres Violeta , Ruiz Kandela , Ciaurriz Paula , Judez Xabier , Aguado Mónica , Garbayo Iñigo 
Published: September 2023

Energy transition towards a net-zero emission scenario requires, primarily, a significant increase on the renewable energy production capabilities. However, the inherent intermittency of most common renewable sources, added to the limitations of full electrification in some important hard-to-abate sectors (heavy-duty transport, aviation, steel industry...), implies also the need of developing reliable solutions for energy conversion and storage. Here, hydrogen is gaining more and more popularity in the recent years as an effective solution as energy carrier, mostly for the decarbonization of the key industries and transport. Among the different technologies under development for power-to-hydrogen conversion, solid oxide electrolysis (SOE) outstands due to its high conversion efficiency, fuel flexibility (e.g. CO2 electrolysis) and possibility of working in reversible mode (the same device both as electrolyser and fuel cell).
Currently behind competing low temperature electrolysis technologies (AEL, PEMEL) in terms of technology readiness, main challenges of SOE today relate to long-term degradation, heat management and design and reliable fabrication of large stacks and systems. Although many projects are lately flourishing in this line, the number of players able to demonstrate an upscaled fabrication of SOE stacks and systems is still limited. The work presented here represents the first step carried out at CENER for the future demonstration of a pilot fabrication line of SOE stacks, from the optimization of functional materials and inks to the fabrication of single cells and building of 2-10 kW stacks.
In this study, a fabrication route for SOE planar cells (5x5 cm2) is proposed, including the optimization of every single step of the process: raw material pre-treatment, ink/slurry development, functional printing and sintering. Particular emphasis is placed on ensuring a reliable upscaling for batch production of cells and thus materials are processed in large quantities (~1 L/batch). In terms of functional materials, standard electrode and electrolytes are chosen in a first approach, viz. Ni-YSZ as hydrogen electrode, YSZ as electrolyte and LSM-YSZ as air electrode. For film deposition, tape casting and screen printing techniques are combined. The electrochemical characterization of the fabricated cells will be presented and compared with commercial ones, including degradation analysis.
Effect of Fabrication Processes on Electrochemical Performance of Metal-Supported Solid Oxide Fuel Cells
Authors: Yamaguchi Yuki , Sumi Hirofumi , Takahashi Hiroaki , Aso Shinobu , Tanabe Shigeyuki , Shimizu Hiroshi 
Published: September 2023

Metal supported solid oxide fuel cells (MSCs) which have the robust porous metal substrate are expected for the use in some mobilities. MSCs are prepared by various fabrication processes such as sputtering and screen printing. When the electrolyte layer is fabricated by the wet processes, the electrolyte must be sintered with metal substrate at a high temperature. However, it is difficult to obtain the dense electrolyte on porous metal substrate because sintering temperatures of an electrolyte ceramic and a metal material used in substrates are different. In this study, MSCs were fabricated on the sintered porous metal substrates by screen printing and spin coating with high-temperature sintering in reduced atmosphere. The electrochemical performance of MSCs strongly depended on the process conditions.
MSCs were prepared by the process which is similar to the process for anode supported cell fabrication. Anode paste including nickel oxide and scandia stabilized zirconia with a weight ratio of 60/40 was coated on the green compact of substrate by screen printing. After drying, the electrolyte layer is coated on it by same procedure. Samples were heat-treated around 400 ºC for 1 h to degrease the organic compounds included in cells. These are finally sintered at 1100 – 1250 ºC in reduced atmosphere. The relationship between the electrochemical performance and the structural property were investigated.
In order to obtain dense electrolyte, the shrinkage behavior of porous metal substrates is quite important. Large shrink of substrate can assist the densification of electrolyte in the sintering process. It was found that the degrease temperature affected the shrinkage behavior in sintering process. It was considered that the oxidation of metal particles in substrate affected on the shrinkage. When the sintering temperature were high to obtain the dense electrolyte, Fe and Cr diffused from the substrate to the anode layer. This metal elements diffusion strongly deteriorated the performance of the anode. Additionally, gas atmosphere also affected the metal elements diffusion. When the MSCs are prepared by wet process with high temperature sintering, controlling the sintering behavior of all components by adjusting the process parameter was quite important to low polarization resistance.
(Invited) The Status of SOFC and SOEC R&D in the Clean Hydrogen Partnership
Authors: Atanasiu Mirela , Aguilo-Rullan Antonio , Dirmiki Dimitra , Tsimis Dionysios , Kontonasiou Eleni 
Published: September 2023

The Clean Hydrogen Partnership—the successor of the Fuel Cells and Hydrogen Joint Undertaking (FCH JU)—aims to accelerate the development and improvement of advanced clean hydrogen technologies. It builds on 13 years of cooperation between public and private sectors through the FCH JU to help innovative technologies graduate from the experimental phases to be exploited by industry, businesses, and consumers for the benefit of Europe. The three members of the partnership are the European Commission, fuel cell and hydrogen industries represented by Hydrogen Europe and the research community represented by Hydrogen Europe Research. Supported topics cover all fuel cell technologies, SOFC being mostly developed for the stationary heat and power applications, while SOEC technologies are considered for the hydrogen production applications.
There are different groups working in Europe on the SOFC/SOEC technologies and supported partially by the Clean Hydrogen partnership. So far, around €262 million have been allocated to support 71 projects, which address specifically SOFC or SOEC technologies. Largely thanks to this support, the EU is now a world leader on SOFC and SOEC technology with a well-established supply and value chain. In addition, several EU companies have commenced their efforts to increase their manufacturing capabilities with views to introduce their products beyond Europe. The mentioned figures do not include all projects of the first Call for Proposals 2022 of the Clean Hydrogen Partnership as some are still pending signature at the moment of writing. The Clean Hydrogen Partnership presentation will cover the status of R&D in Solid Oxide technologies in Europe including an overview of the European competitiveness in this sector.
Improved DRT Determination Through a Modified Sparse Spike Deconvolution
Authors: Bergmann Tobias , Schlüter Nicolas 
Published: September 2023

Impedance spectroscopy is a powerful characterization method to evaluate the performance of electrochemical systems. However, overlapping signals in the resulting impedance spectra oftentimes cause misinterpretation of the data. The distribution of relaxation times (DRT) method overcomes this problem by transferring the impedance data from the frequency domain into the time domain, which yields DRT spectra with an increased resolution. Unfortunately, the determination of the DRT is an ill-posed problem, and appropriate mathematical regularizations become inevitable to find suitable solutions. [1]
The Tikhonov algorithm is a widespread algorithm for the determination of the DRT
g
and is given by [2]
min

g

(||
Z
- A ⋅
g
|| + λ ⋅ ||L ⋅
g
||)
where the regularization parameter λ scales the penalty term. Unfortunately, this leads to unlikely spectra due to necessary boundaries. The sparse spike deconvolution is using the known positive distribution function for a ZARC-element. Thus this deconvolution leads to more natural spectra for the determination of the DRT. However, the sparse spike deconvolution has a very limited scope by using one single regularization parameter. Consequently, we replaced the scalar regularization parameter with a vector
P
and added a new regularization parameter k for the simultaneous minimization of the vector and the norm of the residuals. The minimization function of this method is given by [3]
min

P

(||
Z
- A ⋅ G(
P
) ⋅
c
|| ⋅ k + ||ln(1 -
P
)||)
Herein the G is a matrix with multiple impulse functions.
Literature:
[1] Ivers-Tiffée, E., & Weber, A., J.Ceram. Soc. Jpn. 2017, 125, 4.
[2] Gavrilyuk, A. L., Osinkin, D. A., & Bronin, D. I., Russ. J. Electrochem., 2017, 53, 6.
[3] Bergmann, T. G., & Schlüter, N., ChemPhysChem, 2022
Electrochemical Activation and NAP-XPS As Well As EIS Characterization of La0.31Sr0.58Ti0.97Ni0.03O3-δ Thin Film Electrode
Authors: Nurk Gunnar , Ainsar Mait , Kodu Margus , Kelp Glen , Romann Tavo , Lust Enn , Gallet Jean-Jacques , Kukk Edwin , Kooser Kuno , Möller Priit 
Published: September 2023

Mixed conductive perovskites, like LaxSr0.9-xTiyNi1-yO3-d, LaxSr1-xCryMn1-yO3-d are attractive materials for SOFC anodes. These structures are flexible to adopt different cations into the structure. To improve catalytic activity of these materials, doping of perovskite B-site with metals like Ni, Co, Mo or Cu has been proposed. It has been demonstrated, that at elevated temperatures and in reducing atmosphere these dopants exsolve to perovskite surface to form nanometre scale catalyst particles [1,2]. Exsolution process could be accelerated by using electrochemical polarization. Other phenomena which has been observed in the case of these materials is the segregation of A-site elements because of elastic and electrostatic interactions of ions in the surface layer [3]. The extent of aforementioned effects is connected to the oxidation state of the B-site elements, which is a function of the chemical composition and the stoichiometry of the electrode material, the oxygen partial pressure in electrode compartment and temperature. To improve the understanding how the chemical composition of electrode surface depends on the electrode stoichiometry and environmental conditions it’s necessary to carry out in situ or operando characterization of electrode materials.
In the present study thin film electrodes with La0.31Sr0.58Ti0.97Ni0.03O3-δ composition was deposited using pulsed laser deposition (PLD) technique. Current collectors were made from Pt (using magnethron sputtering) and placed under the thin film electrode layer.
Electrodes were characterized usin XPS and EIS method at near ambient pressure conditions (1-5 mbar) at 650 °C, activated electrochemcally and characterized again to see the effect of activation. Changes on the electrochemical performance as well as on XPS data caused by electrochemical activation were observed and analyzed.
[1] Homel et al., J. Power Sources 195, 6367 (2010)
[2] Steiger, P., et al., Mater, 31, 748−758 (2019).
[3] Lee et al., J. Am. Chem. Soc. 135, 7909 (2013).
In Situ Construction of Metal/Ruddlesden-Popper Oxide Heterointerface for Promoting CO2 Electrolysis in Solid Oxide Electrolysis Cells
Authors: Choi Junil , Jang Daehee , Ha Jungseub , Kim Won Bae 
Published: September 2023

Recently, solid oxide electrolysis cells (SOECs) have been suggested as an efficient CO2 conversion system with its fast electrode kinetics and high-energy efficiency. However, conventional Ni/YSZ cathode has been suffered from serious degradation problems, such as particle agglomeration and carbon deposition, etc. Herein, we designed the metal/oxide heterointerface on Ruddlesden-Popper (R.P.) oxide by in situ exsolution strategy.[1] The cathode catalyst, La1.2Sr0.8Mn0.4Fe0.6O4−
δ (R.P.LSMF) decorated with exsolved Fe nanoparticles (NPs), was prepared by simple in situ annealing of La0.6Sr0.4Mn0.2Fe0.8O3-
δ (LSMF) in H2 atmosphere and showed high current densities of 2.04, 1.43, and 0.884 A·cm−2 at 850, 800, and 750 °C, respectively. This superior electrolysis performance can be attributed to the in situ construction of Fe NPs anchored on R.P. oxide and to the increased contents of oxygen vacancies in R.P.LSMF. Furthermore, we also investigated the effect of dopant on the catalytic activity and the reduction stability of reduced LSMF. The Ni dopant on the B site can facilitate the formation of Ni-Fe alloy NPs during the exsolution process, while doping of Mo6+ species can enhance the phase stability of the R.P. oxide due to its high valence states.
[1] J. Choi et al., J. Mater. Chem. A, 2021,
9
, 8740-8748.
Se-Doped Porous Carbon Supported Pt to Boost Selective Oxidation of Ethylene Glycol to Glycolic Acid
Authors: Jang Daehee , Maeng Junbeom , Kim Jihoon , Park Gwan Hyeon , Kim Won Bae 
Published: September 2023

Biomass-derived polyols can be reformed to value-added chemicals by electrochemical selective oxidation process. Ethylene glycol (EG) and glycerol (GLY) are produced in a large surplus, hence rational design of electrocatalysts for efficient selective oxidation of these biomass-derived molecules should be required to utilize the EG and GLY. Various organic acids such as glycolic acid (GCA), oxalic acid (OXA) and formic acid (FA) can be produced in the oxidation pathway of EG.[1] In particular, EG selective oxidation targeted at the production of GCA, which has broad applications in skin care, textile industry and adhesives.
Herein, we fabricated heteroatom doped porous carbons as support materials of highly dispersed Pt nanoparticles and applied to selective oxidation of EG to GCA. By introducing Se in carbon materials, the highly selective production of GCA was achieved with significant conversion of EG over 90%. The porous structure of carbon support led to well dispersed Pt nanoparticle and this morphology was observed by SEM and TEM. XPS and Raman analyses revealed that doped Se atoms changed electronic properties of carbon materials and induced defects into the carbon lattice structure. These properties greatly enhanced the electrocatalytic activity and stability of Pt/SePC, resulting that GCA yield reached to and remained around 85% during several repeated tests for the EG selective oxidation. Our study could highlight favorable strategy of catalyst design with heteroatom doping for ethylene glycol conversion to glycolic acid.
[1] D. Jang, H. Han, J. Maeng, W. Yoon, M. Park and W. B. Kim, Highly active PdSb catalysts on porous carbon for electrochemical oxidation reactions of biomass-derived C1–C3 alcohols, Mater. Adv., 2022, 3, 5964-5973.