bluuebunny/crossref_metadata_2025_split huggingface dataset:
Study of a Glass-Ceramic Seal Porosity
Authors: Moles Rémi , Laplace Annabelle , Begos Jean-Gabriel , Vallat Charlène , Regnier Elise , Schintu Lilou , Sierk Alexandre , Vulliez Karl 
Published: September 2023

Sealing is a major issue in high temperature electrolyzers used for hydrogen production. The specifications that seals must meet are particularly demanding. In addition to sealing, the material must have mechanical, thermomechanical and chemical properties, as well as sufficient electrical resistivity. The geometries are complex and the lengths to be sealed are important. These numerous constraints lead to the use of glass powder suspended in organic solvents. This process allows the installation of the seal by deposition of the suspension on the areas to be sealed. Then, a heat treatment is applied to shape the material and ensure the sealing of the system. The use of a composition that tends to crystallize is implemented to improve, a priori, the thermal and mechanical properties.
The reference heat treatment consists in a first temperature rise followed by a crystallization stage. As the temperature rises, the organic solvents evaporate producing CO2 and gas present in the atmosphere of the furnace is trapped during sintering, which causes porosity to appear. Early surface crystallization can compete with the sintering phenomenon and prevent the maximum densification of the glass ceramic by freezing the structure. The objective of the study is to obtain a seal material with maximum density, thus minimum porosity, by controlling the removal of organic solvents, sintering and crystallization. Indeed, a large and interconnected porosity can create preferential leakage paths and decrease the sealing performances of the stack. Moreover, a dense material is known to be mechanically more resistant than a porous one. Indeed, a pore can initiate a crack that will eventually propagate through the seal.
This paper will present in particular the study of the material porosity. A quantification by SEM image analysis allows to determine the evolution of the porosity (percentage, size, number) as a function of time and temperature. Swelling, coalescence and rising of the pores are observed at high temperature. Glass powder and slurry are studied.

Figure 1
Oxygen Transport in Higher-Order Ruddlesden-Popper Phase Materials
Authors: Yatoo Mudasir A , Skinner Stephen J 
Published: September 2023

A series of higher-order Ruddlesden-Popper phase materials – La3PrNi3O9.76 (L3P1N3), La2Pr2Ni3O9.65 (L2P2N3) and LaPr3Ni3O9.76 (L1P3N3) – were synthesised and investigated by neutron powder diffraction to understand the oxygen defect structure and propose possible pathways for oxygen transport in these materials. Further complimentary DFT calculations of the materials were performed to support the experimental analysis.
All of the phases were hypostoichiometric and it was observed that the majority of the oxygen vacancies were confined to the perovskite layers, with a preference for equatorial oxygen sites. A particular preference for vacancies in O(1) and O(5) sites at high temperatures was observed from neutron diffraction measurements which were further complimented by DFT calculations wherein the vacancy formation energy was found to be lowest at the O(1) site. Also, a preference for a curved oxygen transport pathway around the NiO6 octahedra was observed which agrees with the published literature for Ruddlesden-Popper phase materials.
Lattice parameters for all three compositions showed a linear increase with increasing temperature, but the increase was greatest in the c parameter while the b parameter showed only a slight increase when compared to the a parameter. The thermal expansion coefficient was calculated for all compositions and was found to be in the range 13.0 - 13.4 × 10-6 ˚C-1, which is compatible with the commonly used electrolyte materials for solid oxide fuel cells.

Figure 1
Correlation Between Microstructure and Performance of GDC-Based Electrodes
Authors: Sciazko Anna , Komatsu Yosuke , Shimura Takaaki , Sunada Yusuke , Shikazono Naoki 
Published: September 2023

Gadolinium doped ceria (GDC) gains increasing attention as a promising material for both solid oxide fuel cells (SOFCs) and solid oxide electrolysis cells (SOECs). The GDC-based electrodes demonstrate positive features, e.g. enhanced electrochemical performance in low operation temperatures, resistivity to sulfur poisoning and carbon deposition, etc. As GDC is a mixed electronic-ionic conductor in reducing atmosphere, electrochemical reactions can be supported by the double phase boundary (DPB) at the GDC surface. Several studies demonstrated that the DPB reaction may dominate the electrochemical performance over triple phase boundary (TPB) reaction in Ni-GDC electrodes, where it can account for as much as 95 % of the total reaction depending on the cermet microstructure [1]. Recent studies even show that pure ceria electrodes can achieve substantial power density [2,3]. In this context, the microstructure design principle for GDC-based electrodes should focus on maximizing GDC surface area. Particularly, GDC electrodes with infiltrated GDC nanoparticles or electro-catalytic nanoparticles may achieve competitive performance compared with the conventional Ni-YSZ electrodes. Although many strategies have been proposed to improve performance of GDC-based electrodes, it is difficult to quantitatively compare all the reported results. Furthermore, the correlation between microstructure and performance of pure GDC electrode are still scarce.
Several different types of GDC-based electrodes are fabricated and tested in the unified characterization procedure in this study. Four basic designs are considered, i.e. Ni-GDC, GDC-perovskite composites, GDC electrodes with deposited Ni nanoparticles and pure GDC electrodes. Several strategies to modify the GDC surface area are discussed. In addition, the substantial enhancements in the DPB density and electrochemical performance were achieved by precipitating Ni-nanoparticles directly on sub-micron GDC powders at 2wt.% loading. The performance of electrodes was evaluated by electrochemical impedance spectra measurements with various humidity and temperature conditions. The results showed clear dependance between GDC surface area and electrode performance. At the same time, it should be noted that the electrode active thickness depends on the electrode microstructure. In particular, it is in the range of 5 µm for the pure nano-GDC electrode. When the GDC electrode is thicker than the active thickness, it results in large Ohmic resistance due to the electronic conduction in the porous electrode.
[1] A. Nenning, M. Holzmann, J. Fleig, A.K. Opitz, Mater. Adv. 2 (2021) 5422–5431.
[2] M. Ouyang, A. Bertei, S.J. Cooper, Y. Wu, P. Boldrin, X. Liu, M. Kishimoto, H. Wang, M. Naylor Marlow, J. Chen, X. Chen, Y. Xia, B. Wu, N.P. Brandon, J. Energy Chemistry. 56 (2021) 98–112.
[3] W. Jung, K.L. Gu, Y. Choi, S.M. Haile, Energy Env. Sci. 7 (2014) 1685–1692.
Progress in SOFC & SOEC Development Activities at AGC Group
Authors: Tomeno Satoru , Toda Yoshitake 
Published: September 2023

The AGC Group operates in approximately 30 countries and regions with AGC Inc. as its core.
We provide building materials, automotive materials, display glasses, electronic components, chemical products, pharmaceutical & agrochemical related products and services and ceramics to customers in a wide range industries.
We also have two materials in SOFC business field. AGC holds electrode materials and glass seal materials. AGC Seimi Chemical contributes to improving the performance of SOFC through the highly uniform composite oxide powder produced by the citric acid-based synthesis, providing various powders such as LSM, LSCF, GDC, SDC, etc., and responding to individual needs for particle size and specific surface area.
AGC Electronics offers glass powders, pastes, and molded products for insulation, hermetic sealing, and protection purposes. As sealing materials for SOFC, we have SiO2-MgO and B2O3-MgO glass sealing materials with high sealing performance and high crystallinity to keep long-term durability.
Recently, because we thought that SOEC would be suite for reducing CO2 emission from our manufacturing processes, we have started to develop new type of electrode material and electrolyte that could be suitable for SOEC. We considered the complex oxide Ca12Al14O33 (C12A7) might be helpful to add to current group of materials that can be applicable for SOEC, due to its robustness and lowness of environmental load.
Influence of A-Site Deficiency and B-Site Composition on the Electrical and Crystallographic Properties of (La0.25Sr0.25Ca0.45)yTi0.95Ni0.05-xMnxO3-δ Solid Oxide Fuel Cell Anode
Authors: Korjus Ove , Moeller Priit , Kivi Indrek , Paydar Sara , Nurk Gunnar 
Published: September 2023

(La,Sr)TiO3-δ has attracted specific attention over the past years due to its superior dimensional stability, high conductivity, and significant tolerance against sulfur poisoning and carbon depositions. To increase the catalytic activity and chemical stability, many different doping levels and stoichiometries for LaxSr1-xTiO3-δ (LST) have been investigated [1, 2]. Doping of B-site with Mn has been shown to promote electroreduction under SOFC conditions [3]. Furthermore, Mn is known to accept lower coordination numbers in perovskites, especially for Mn3+ (3d4), and so may enhance oxide-ion migration [4]. In addition, MnO is clearly stable under fuel conditions unlike Co or Ni oxides [4].
In this research influence of A-site deficiency and B-site chemical composition on electrical performance of La0.25Sr0.25Ca0.45Ti0.95Ni0.05-xMnxO3-δ (x=0-0.05) (LSCTNM-x) hydrogen electrode has been studied. The crystal structure and microstructure have been studied using X-ray diffraction and SEM to confirm the phase purity and visualize the microstructure of studied electrode layers. To understand the influence of MIEC material composition on electrical conductivities of LSCTNM, the DC four-probe conductivity measurements of porous electrode layers has been performed. Conductivities have been measured at two different atmospheres: 1% H2 + 1.7% H2O + 97.3% Ar and 98.3% H2 + 1.7% H2O. It has been shown that all materials with LSCTNM compositions behave like semiconductor and the conductivity is significantly dependent on composition. The maximal total electrical conductivity of porous electrode layers was characteristic for the LSCTNM materials with 10% A-site deficiency, in 98.3% H2 + 1.7% H2O atmosphere.

Keywords: solid oxide fuel cell; conductivity; perovskite; fuel electrode; MIEC.
[1] X. Li, H. Zhao, X. Zhou, N. Xu, Z. Xie, N. Chen, Electrical conductivity and structural stability of La-doped SrTiO3 with A-site deficiency as anode materials for solid oxide fuel cells, international journal of hydrogen energy 35 (2010) 7913-7918.
[2] A. Gondolini, E. Mercadelli, G. Constantin, L. Dessemond, V. Yurkiv, R. Costa, A. Sanson, On the manufacturing of low temperature activated Sr0.9La0.1TiO3-δ-Ce1-xGdxO2-δ anodes for solid oxide fuel cell, Journal of the European Ceramic Society, 38 (2018) 153–161.
[3] P. Holtappels, J. Bradley, J.T.S. Irvine, A. Kaiser, M. Mogensen, Electrochemical characterization of ceramic SOFC anodes, J. Electrochem. Soc. A 148 (2001) 923–929.
[4] S. Tao, J.T.S. Irvine, A redox-stable efficient anode for solid-oxide fuel cells, nature materials, 2 (2003) 320-323.
(Invited) Introduction of National Projects Concerning Fuel-Cells in Japan
Authors: Fujii Yosuke 
Published: September 2023

In 2017, the Japanese Government formulated the “Basic Hydrogen Strategy” as a future vision that Japan should aim to achieve by 2050. It also serves as an action plan through to 2030 to realize the vision in order to accomplish the first hydrogen society in the world. With the release of the Basic Hydrogen Strategy, the Government also revised the “Strategic Road Map for Hydrogen and Fuel Cells” in 2019. In addition, the Ministry of Economy, Trade and Industry in Japan (METI) and the New Energy and Industrial Technology Development Organization in Japan (NEDO) established the “Hydrogen Energy Ministerial Meeting” as a space for discussions among the cabinet members of major countries, and discussions about the actions taken by each country regarding their hydrogen policy were held from 2018 to 2022.
Furthermore, on December 25, 2020, METI formulated the “Green Growth Strategy towards 2050 Carbon Neutrality” in collaboration with related ministries and agencies in Japan. This strategy is an industrial policy targeting the challenging goal of achieving carbon neutrality by 2050. It emphasizes the importance of hydrogen utilization for a positive cycle of economic growth and environmental protection.
In this way, the Government of Japan is strongly promoting a wide variety of policies toward the increased use of hydrogen energy. And, as one of the largest organizations promoting national projects in this country, NEDO has implemented projects aimed at increased sophistication of performance in response to the spread and expansion of fuel cells under the cooperation of various leading researchers from industry, academia, and government.
One of the representative projects is introduced as follows:
1．Collaborative Industry-Academia-Government R&D Project for Solving Common Challenges Toward Dramatically Expanded Use of Fuel Cells and Related Equipment (Fiscal Years 2020-2024)
Based on the status survey of companies that launched household fuel cells and fuel-cell vehicles onto the market, NEDO determined that it was necessary to alleviate common issues in the industry and to initiate a new fuel cell project. Therefore, NEDO planned a project for fundamental technologies in the cooperative domain, as well as technologies to be deployed to applications other than conventional ones in order to realize a highly efficient, highly durable, and low-cost fuel cell system (including a hydrogen storage tank and so on) contributing to self-sustaining spread and expansion in 2030 and beyond. NEDO also publicly solicited new participants from 2020 to 2022 every year, and as a result, eighty-seven research groups were adopted to the project so far.
Flatness Enhancement of Metal-Supported Solid Oxide Fuel Cells with Additional Compensation Layer
Authors: Song Hyunghoon , Lee Jaeseok , Bae Joongmyeon 
Published: September 2023

Solid oxide fuel cells are high-temperature fuel cells which offer several advantages: high efficiency, fuel flexibility, high-quality waste heat, and the use of non-noble metal catalysts. Metal-supported solid oxide fuel cells, in which the ceramic mechanical support layer is replaced with the metal support, are considered as next-generation solid oxide fuel cells because of their enhanced mechanical/thermal ruggedness compared to conventional ceramic-supported solid oxide fuel cells. However, different thermomechanical behavior of metal support and ceramic layers during sintering makes metal-supported cells vulnerable to warping. Cell warpage must be minimized because it reduces not only uniformity of wet-chemical coating, but also actual contact area between electrode and interconnect, increasing the contact resistance.
In this study, causes of metal-supported cell warpage are identified, and the design that can minimize cell warpage is suggested for successful scale-up of metal-supported solid oxide fuel cells. Through thermomechanical and residual stress analyses, it is found that residual stress derived from coefficient of thermal expansion mismatch between electrode layers and the metal substrate is the main cause of the warpage of metal-supported solid oxide fuel cells. Based on these results, a novel design that has thicker metal protection layer on the opposite side of the electrolyte is proposed for minimizing cell warpage due to residual stress. Through the design modification, vertical deformation of 2-inch metal-supported solid oxide fuel cell can be successfully controlled to 17.36% of the previous design. Furthermore, electrochemical evaluation showed a 21% decrease in ohmic ASR and a 25% increase in peak power density after the design modification, implicating reduction of contact resistance as a result of increased contact area by enhanced flatness.
Synergistic Application of Machine Learning to Microstructural Characterization on Electrode Composites of Solid Oxide Fuel Cells
Authors: Hwang Heesu , Kim Dohyoung , Nam Yoonmi , Lee Jong-Ho , Hwang Jin-Ha 
Published: September 2023

Solid oxide fuel cells (SOFCs) have been recognized as one of the most potent next-generation energy conversion systems, owing to their higher efficiency, better fuel flexibility, and smaller amount of pollution, unlike their counterpart fuel cells. SOFCs can be analyzed as a highly-complex multi-component materials system consisting of porous electrodes (cathodes and anodes), densified electrolytes, interconnects, and sealing materials, which are sequentially layered and characteristic of heterogeneous and multi-phase materials. The resultant power generation is achieved through the electrochemical reactions involving electronic carriers, ionic carries, and gaseous transports at anodes and cathodes, influencing their electrical, mechanical, and thermal properties. In particular, both cathodes and anodes are typically constructed based on three components: mixed ionic/electronic electrodes, electrolytes, and a porous section. Those three constituents should be optimized at both electrodes with the aim of maximizing the electrochemical reaction sites, i.e., triple-phase boundaries in association with the gaseous transport involved in oxygen reduction reactions at cathodes and hydrogen oxidation reactions at anodes, which leads to high cell performance and guaranteed durability. The electrochemical performances are crucially dependent on their complex microstructures, demanding for highly informative analyses on the electron microscopy images under investigation.
This work reports quantitative microstructural analysis methodology incorporating machine learning-assisted microstructural analysis strategy. Quantitative microstructural interpretations were carried out without human involvement through an integrated combination of deep learning and focused ion beam-scanning electron microscopy (FIB-SEM) analytics on Ni/Y2O3-stabilized ZrO2 (Ni/YSZ) cermets. The Ni/YSZ/pore composites were analyzed for the automated extraction of microstructural parameters with the aim to preventing the subjective analysis problems and unavoidable artifacts frequently encountered in lengthy image processing tasks and eliminate biased evaluations. Considering the high volume of image data and future expectations for electron microscopy usage, FIB-SEM was efficiently combined with semantic segmentation targeted at detailed phase recognition on three constituents, i.e, Ni, YSZ, and pores. Traditional image processing analysis tools are in the synergistic manner combined with phase separation predictions by semantic segmentation algorithms, allowing for a quantitative evaluation of microstructural parameters. The combined strategy enables one to significantly enhance poor image quality originating from artifacts in electron microscopy, including charging effects, curtain effects, out-of-focus problems, and unclear phase boundaries encountered in searching for high-efficiency solid oxide fuel cells (SOFCs).
Influence of A-Site Modifications on the Electrical and Crystallographic Properties of Ln0.2Sr0.7-XCaxTi0.95Fe0.05O3-δ (Ln=La, Nd) Based Fuel Electrode for Solid Oxide Cell
Authors: Paydar Sara , Volobujeva Olga , Lust Enn , Nurk Gunnar 
Published: September 2023

Perovskite oxides, in particular SrTiO3–based compounds have attracted particular attention over the past years due to their decent conductivity, good dimensional stability and high tolerance and resistance towards sulfur poisoning and carbon depositions [1, 2]. Optimal doping and stoichiometry levels on A- (La, Nd etc.) and B-sites (Fe, Ni etc.) of SrTiO3 based compounds allow to improve catalytic activity, electrical conductivity and chemical stability [2]. In addition, doping of A-site with calcium is predicted to enhance the electronic conductivity because it should decrease the unit cell volume bringing the conduction orbitals of titanium closer to each other [3].
In this research influence of chemical composition of A-site on electrical and electrochemical performance of Ln0.2Sr0.7-xCaxTi0.95Fe0.05O3-δ (Ln=La, Nd) (x=0.35, 0.45) (LSCTF-x, NSCTF-x) hydrogen electrode has been investigated. The crystal structure and microstructure have been studied using X-ray diffraction and SEM to confirm the phase purity and visualize the microstructure of studied electrode layers. To understand the influence of MIEC material composition on electrical conductivities of LSCFT and NSCTF, the DC four-probe conductivity measurements of porous electrode layers has been performed. Conductivities have been measured at two different atmospheres: 1% H2 + 3% H2O + 96% Ar and 97% H2 + 3% H2O. It has been shown that the both LSCTF and NSCTF materials behave like semiconductor and the conductivity is significantly dependent on composition. The maximal total electrical conductivity of porous electrode layers were 5.5 S cm−
1 and 4.8 S cm−
1 at 850 °C characteristic for the La0.2Sr0.25Ca0.45Ti0.95Fe0.05O3-δ (LSCTF-45) and Nd0.2Sr0.35Ca0.35Ti0.95Fe0.05O3-δ (NSCTF-35) materials, respectively, in 97% H2 + 3% H2O atmosphere.

Keywords: solid oxide fuel cell; perovskite; fuel electrode; MIEC; LST.
[1] X. Li, H. Zhao, X. Zhou, N. Xu, Z. Xie, N. Chen, Electrical conductivity and structural stability of La-doped SrTiO3 with A-site deficiency as anode materials for solid oxide fuel cells, international journal of hydrogen energy 35 (2010) 7913-7918.
[2] A. Gondolini, E. Mercadelli, G. Constantin, L. Dessemond, V. Yurkiv, R. Costa, A. Sanson, On the manufacturing of low temperature activated Sr0.9La0.1TiO3-δ-Ce1-xGdxO2-δ anodes for solid oxide fuel cell, Journal of the European Ceramic Society, 38 (2018) 153–161.
[3] A.D. Aljaberi, J.T.S. Irvine, Ca-substituted, A-site deficient perovskite La0.2Sr0.7TiO3 as a potential anode material for SOFCs. J. Mater. Chem. A 2013, 1, 5868-5874.