bluuebunny/crossref_metadata_2025 huggingface dataset:
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
(Digital Presentation) Phase-Field Modeling of the Reduction Process in Solid Oxide Fuel Cell Anode
Authors: Yang Wenyue , Jiao Zhenjun
Published: September 2023

It is well-known that the reduction process of nickel oxide-yttria-stabilized zirconia (NiO-YSZ) composite anode influences the initial performances and durability of solid oxide fuel cell. In this work, phase field method is used to simulate the reduction process of nickel oxide (NiO) in anode-supporting solid oxide fuel cell (SOFC), which captures the competition effects among diffusion, crystal phase transition of NiO to Ni, and sintering. A real three-dimensional microstructure of NiO-YSZ composite anode reconstructed using focused ion beam-scanning electron microscopy (FIB-SEM) technique is used to initialize the simulation. The simulation results are qualitatively compared to experimental results under different reduction conditions. The results reveal that the stress distribution in SOFC anode can be largely influenced by the interactions between the residual stress in yttria-stabilized zirconia (YSZ) and the reduction process. The results explain the phenomena of mechanical damage formed in SOFC single cell during reduction.

Figure 1
(Digital Presentation) (La0.7-xNdx )Sr0.3Co1-YFeyO3-
δ
(x = 0.35, y = 0.2) a Novel Perovskite Type Air Electrode Material for Protonic Conducting Solid Oxide Cell (H-SOC)
Authors: Ghosh Subhrajyoti , Tiwari Pankaj , Haider Mohammad Ali , Basu Suddhasatwa
Published: September 2023

Proton conducting solid oxide cell (H-SOC) is a highly efficient energy conversion device converting electrical energy into hydrogen by splitting water using solid oxide proton conductor at intermediate temperature range (500-700 0C) [1]. To enhance electrochemical performances in terms of efficient hydrogen generation, robust and durable air electrode materials are required to facilitate faster water oxidation and oxygen reduction reaction, which are the key steps for both electrolyser and fuel cell at a lower temperature [2-3]. In the present study, we have developed ‘La’ and ‘Nd’ A-site co-doped strontium cobaltite and cobalt ferrite: La0.35Nd0.35Sr0.3Co0.8Fe0.2O3-δ(LNSCF) a perovskite type cathode material exhibiting higher electrical and electrochemical performances. The electrical and O2- ion conductivity of the material shows metallic nature, and the highest conductivity values are 973 S cm-1 and 0.318 S cm-1 respectively at 400 oC. The higher value of electrical and ionic conductivity is attributed to highly efficient Co2+ to Co3+ and Fe3+ to Fe4+ transition. Electrochemical impedance spectroscopy analysis of the symmetrical cell (LNSCF/Zirconium and Yttrium doped Barium Cerate (BZCY)/LNSCF) revealed the value of Area Specific Resistance (ASR) to be 0.14, 0.47 and 3.06 Ω cm2 at 800,700 and 600 oC respectively. When operated in H-SOFC mode with humidified hydrogen as fuel and Air (3%H2O) as oxidant, the LNSCF based single cell: Ni-BZCY/BZCY (385m)/ LNSCF+BZCY achieves a maximum current density of 522, 383, and 231mA/cm2 at 800, 700, and 600 oC, respectively at 0.002 V. Whereas, in H-SOEC mode a maximum current density of -1380, -862 and -517 mA/cm2 are obtained at 800, 700, and 600 oC, respectively at 2.5 V. The contribution of different ions (O2- and H2+) and electrons (e-) in the electrochemical performances are evaluated using ion-blocking cells. The figure (1) below represents the Current Density versus Voltage (i-V) characteristic attributes for both H-SOFC and H-SOEC.

References:

Bi L., Boulfrad S., and Traversa E. 2014 Steam electrolysis by solid oxide electrolysis cell (SOEC) with proton-conducting oxides. Chem. Soc. Review 43 8255

Duan C., Kee R., Zhu H., Sullivan N., Zhu L., Bian L., Jennings, D., and O’ Hayre R. Highly efficient protonic ceramic electrochemical cell for fuel generation and power production. Nature Energy 4 230 -240

Choi S., Davenport TC., Haile SM. 2019 Protonic Ceramic electrochemical cells for hydrogen production and electricity generation: Exceptional reversibility, Stability and demonstrated faradaic efficiency. Energy and Environmental Sciences 12 206

Figure 1
Steam Reforming Catalytic Layer on Anode-Supported and Metal-Supported Solid Oxide Fuel Cells for Direct Ethanol Operation
Authors: Machado Marina , Tabuti Francisco , Piazzolla Fernando , Moraes Tamara , Abe Ricardo , Guimarães Rafael Mariz , Miura Yohei , Fukuyama Yosuke , Fonseca Fabio Coral
Published: September 2023

A catalyst based on lanthanum chromite with exsolved metallic ruthenium nanoparticles (LaCrO3-Ru) was applied as a catalytic layer for internal ethanol steam reforming of anode-supported and metal-supported solid oxide fuel cells. Both the cermet anode and the metal supports exhibit limited catalytic properties for the ethanol steam reforming reaction. Thus, the LaCrO3-Ru catalysts were optimized for operating temperatures in the 600-700 °C range to promote stable ethanol reforming. The microstructure of the deposited catalytic layer was controlled using pore formers with low burnout temperature, and sintering of the catalytic layer was done in situ during cathode sintering of the metal-supported fuel cell. The performance of the fuel cells was evaluated at 700 °C under hydrogen, anhydrous ethanol, and water/ethanol mixtures. The LaCrO3-Ru catalytic layer had no significant impact on the electrochemical properties of the fuel cells, and samples with the catalytic layer or without it exhibited similar performance in hydrogen. Nonetheless, initial durability tests have shown that the catalytic layer plays a crucial role in the stability of both the anode and the metal-supported fuel cells under ethanol.
Effect of Mo-Doping on the Proton-Conducting BaCe0.9-xMoxY0.1O3-δ Electrolyte at Intermediate Temperature SOFCs
Authors: Hanif Muhammad Bilal
Published: September 2023

Perovskites have been attracting much attention because of their many potential applications as solid electrolytes in solid oxide fuel cells (SOFC). Among various kinds of perovskite materials, the Y2+ doped BaCe0.9Y0.1O3-δ (BCY) have been investigated extensively. It is noted that the doped BCY have good stability and relatively high protonic conductivity. However, the sintering temperature of BCY is very high above 1600 °C to achieve the required densification. High sintering temperature leads to evaporation of barium and the subsequent segregation of doped elements. As a result of this, the electrochemical properties of BaCe0.7Zr0.1Y0.2O3-δ electrolyte are reduced. At high temperatures, it’s difficult to maintain the porous structure of electrodes and causes the formation of impurity phases. So, in order to overcome this issue, we doped Mo- to BCY and reduce the sintering temperature of the electrolyte without comprising its performance. The sol-gel method was followed for the preparation of Ba1Ce0.9-xMoxY0.1O3-δ (BCMY, x=0.025%-0.2%) powder. The precursor's Ba(NO3)2, Ce(NO3)3.6H2O,
Y(NO3)3.6H2O, and (NH4)6Mo7O24.4H2O in the stoichiometric ratio were dissolved in a mixture of water, citric acid, and glycine used as chelating agents in the molar ratio of 1:2:1. The solution was heated at 100 °C and was constantly stirred till it becomes a gel. The dried precursor was then heated at 350 °C for 2 hrs to remove the organic residues through combustion. Afterward, it was calcined at a temperature of 1100 °C for 10 hrs and finally, a white powder of BCMY was obtained. The synthesized BCMY electrolytes were sintered at 900, 1000, and 1100 °C to observe the effects of low sintering temperature on the structural, morphological, and electrical properties of BCMY. All BCMY electrolyte materials exhibited a crystalline perovskite structure and were found to be thermally stable as shown in XRD (Fig. 1 (a, b)). The morphology and element distribution of the BCY and BCMY electrolyte were observed by the scanning electron microscope (SEM, (Fig. 1c)) and energy-dispersive x-ray spectroscopy (EDX). SEM images show that BaCe0.9Y0.1O3-δ electrolyte sinterability and densifications are significantly improved. Fully dense pellets are sintered by using 0.025-0.2 mole% Mo. Energy dispersive spectroscopy shows that sintering aids are uniformly distributed throughout the structure. This study demonstrates BCMY as a dense proton-conducting electrolyte for intermediate-temperature solid oxide fuel cells. The BCMY with Mo-doping appears to be a potential candidate for sintering at low temperatures. Sintering facilitates addition from oxygen vaccines, which ease ionic conduction through the electrolyte, result in a low activation energy of at moderate temperatures. Fully dense pellets are sintered by using 0.025-0.2 mole% Mo. This method of decreasing the BCMY sintering temperature is useful in improving the SOFC performance.
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.
Phase Evolution in (La0.6Sr0.4)0.95Co0.2Fe0.8O3-Δ Oxygen Electrodes after SOEC Operation
Authors: Liu Tian , Edwards Danny J. , Le Long , Coyle Christopher , Seymour Lorraine , Olszta Matthew , Meinhardt Kerry D , Marina Olga A
Published: September 2023

This work aims to evaluate the microstructural and compositional changes in (La0.6Sr0.4)0.95Co0.2Fe0.8O3-δ (LSCF) electrodes in solid oxide electrolysis cells (SOEC) before and after testing at 750°C for 2800 hours at 1.3V. Scanning electron microscopy (SEM) examination of the LSCF electrodes before and after SOEC operation was conducted. In untested LSCF electrodes, LSCF perovskite was a predominant phase with very minor presence of La(Fe,Co) oxide, and Fe,Co spinel phases. The post-tested electrodes exhibited a change where the La(Fe,Co) oxide phase exhibited a broader composition range, most notably with respect to the La/Fe ratio and potential loss of Co, and there was a noticeable increase in the volume fraction of Fe,Co spinel from 1.5% in the untested cell to over 3% after testing. To better understand the phases and their compositions, a transmission electron microscopy (TEM) study of tested and untested electrodes was undertaken using an aberration (Cs) corrected JEM-ARM200CF microscope operated at 200 kV. TEM confirmed the presence of cubic spinel particles with a composition of 26 at.% Fe and 13-15 at.% Co, with little to no Sr or La present. The composition of the La(Fe,Co) phase was more variable in agreement with the SEM analysis, with the Co/Fe ratio higher in the untested cell versus the cell tested at 2800 hours.
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).
Evaluation of SOFC Durability Against Simultaneous Heat/Load Fluctuations
Authors: Joh Dong Woo , Hussain Amjad , Kim Tae-Hun , Shin Ji-Weon , Hong Jong-Eun , Lee Seungbok , Lim Tak-Hyoung , Song Rak-Hyun
Published: September 2023

Variable renewable energy sources (solar, wind, etc.) are difficult to maintain efficient hierarchical operation and stable power quality from the perspective of the power system. In preparation for this increase in the proportion of renewable energy, it is necessary to prepare counterplan for power system intelligence and flexibility, such as power backup systems, power storage devices, smart control, and demand response. It is expected that control the volatility of renewable energy and supply-demand balance can be solved by producing/storing hydrogen using idle power and generating electricity using fuel cells. High-efficiency SOFC technology that can manage with daily cycle load fluctuations is the best alternative. In this work, the goal is to develop basic technologies for energy network systems that can respond to daily cycle power fluctuations of renewable energy and increase system stability through SOFC cell/stack design and durability enhancement. In this study, in order to secure the ability to cope with the variability of the power system, it is intended to present durability evaluation criteria for simultaneous heat and load cycles. Stack evaluation was performed in the current range of 0 ~ 0.25 A/cm2 in the case of the load cycle test and 500 ~ 700 °C in the case of the temperature cycle test.
Status of SOC Development at Chaozhou Three-Circle
Authors: Chen Shuoshuo , Xiao Yu , Jiao Zhenjun
Published: September 2023

Chaozhou Three-Circle (Group) Co., Ltd. (CCTC) is a leading company in developing and manufacturing of electronic and ceramic components. Since more than 19 years ago, CCTC has been focusing on SOFC R&D and manufacturing, covering the complete value chain from powder to power. Based on anode-supported cell technology (ASC in fuel cell mode), the latest C2-stack in planar design using metallic interconnect exhibits a high efficiency of more than 69% (DC, LHV) at 1.5 kW. Long-term stack tests using pipeline natural gas have been conducted for 20,000 hours, with low degradation rates of below 0.4%/kh. In 2022, several 35 kW SOFC CHP systems were demonstrated with C2 stacks, which showed stable performance over 3,000 hours of operation. According to the verification test by Societe Generale de Surveillance S.A., the net AC efficiency of the system reached 64.1%, and the total efficiency was up to 91.2% after 1,000 hours of continuous operation. In parallel to the continuous progressing in SOFC, optimization in cells and stack designs dedicated for SOEC applications were also conducted in recent years. The status of both SOFC and SOEC development at CCTC will be presented.
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.
Chemical Stability of BaMg0.33Nb0.67-XFexO3-δ in High Temperature Methane Conversion Environments
Authors: Denoyer Luke H , Benavidez Angelica , Brearley Adrian , Ramaiyan Kannan , Garzon Fernando H.
Published: September 2023

Doped perovskite metal oxide catalysts of the form ABxC1-xO3-δ are of interest to the catalysis community due to the ability to fine tune the catalytic activity or chemical stability through doping. Doped barium niobate perovskites have shown remarkable stability in CO2 sensing and methane conversion measurements. However, the reason for the chemical stability is not well understood. Doping with transition metal cations for B site cations can lead to exsolution under reducing conditions. Many perovskites used for the oxidative coupling of methane (OCM) or the electrochemical oxidative coupling of methane (E-OCM) either lack long term stability, or catalytic activity within these highly reducing methane environments. Here, we present our results obtained with a highly stable Mg and Fe co-doped barium niobate perovskite BaMg0.33Nb0.67-xFexO3-δ (BMNF) that has shown activity in E-OCM setups over long term (>100 hour) experiments and stability in CO2 environments as a sensor.[1] The crystalline structure and atomic distributions within these synthesized materials analyzed via X-ray powder diffraction (XRD), scanning transmission microscopy (STEM), and X-ray photoelectron spectroscopy (XPS). Along with this, temperature programmed reaction (TPR) under 95% methane and 5% oxygen showed the effectiveness of the catalyst in an OCM setup, as well as the stability of the BMNF perovskite in methane. Through these analyses we posit that iron doping may increase the ionic conductivity of the BMNF material while change in Nb4+/5+ oxidation states prove stability in reducing environments.[2]

(1) Denoyer, L. H.; Benavidez, A.; Garzon, F. H.; Ramaiyan, K. P. Highly Stable Doped Barium Niobate Based Electrocatalysts for Effective Electrochemical Coupling of Methane to Ethylene. Adv. Mater. Interfaces
2022, 9 (27), 2200796. https://doi.org/10.1002/admi.202200796.

(2) Denoyer, L. H.; Benavidez, A.; Garzon, F. H.; Ramaiyan, K. P. Chemical Stability of BaMg0.33Nb0.67-XFexO3-δ in High Temperature Methane Conversion Environments. under communication - ECS Journal of Solid State Science and Technology.
Optimizing the Electrolyte Mixing in Industrial Tanks of Vanadium Redox Flow Batteries
Authors: Prieto-Diaz Pablo Angel , Vera Marcos
Published: September 2023

Redox flow batteries (RFB) are an emerging technology for large-scale grid energy storage. Different approaches have been adopted to investigate the operation of RFBs, such as experimental testing and mathematical modelling of the electrochemical cells [1]. However, the effect of the flow and mixing in the electrolyte tanks on the performance of RFBs has been largely overlooked and only recently has started to receive some attention [2]. In a recent work, the authors used numerical simulations to show how the fluid dynamics of the electrolytes within small lab-scale tanks can lead to different flow behaviors depending on whether forced or natural convection is dominant. The irregular transient mixing of the electrolyte in the tanks modifies both the cell potential and battery capacity with respect to those predicted under the widely used perfect mixing assumption (i.e., continuous stirred-tank reactor) [3]. However, this first attempt relied on several simplifying assumptions, such as two-dimensional geometries under small-cell (i.e., laminar) flow conditions, and thus provided only a qualitatively understanding of the flow in the tanks.

This work exploits the idea of using CFD simulations to investigate the effect of operating conditions on the electrolyte flow in the tanks and its impact on battery response, focusing on high capacity industrial tanks with high (i.e., turbulent) flow rates and less restrictive simplifying assumptions. Our numerical simulations show how turbulence improves mixing, but also produces quasi-steady flows where a turbulent jet crosses the tank leaving dead electrolyte regions. Different tank solutions are presented aiming to improve the mixing and increase the capacity of the battery, playing both with the tank geometry and the operating conditions. Results on the charging and discharging operations, cell potential and electrolyte mixing index are presented and discussed.

Acknowledgments

This work has been partially funded by FEDER/Ministerio de Ciencia, Innovación y Universidades – Agencia Estatal de Investigación Projects PID2019-106740RB-I00 and RTC-2017-5955-3/AEI/10.13039/501100011033, and by Grant IND2019/AMB-17273 of the Comunidad de Madrid.

References

[1] A. Z. Weber, M. M. Mench, J. P. Meyers, P. N. Ross, J. T. Gostick, Q. Liu, Redox flow batteries: a review, Journal of Applied Electrochemistry 40 (10) (2011) 1137–1164. doi:10.1007/s10800-011-0348-2.

[2] Y. Wang, K. C. Smith, Numerical investigation of convective transport in redox flow battery tanks: Using baffles to increase utilization, Journal of Energy Storage 25 (2019) 100840. doi:10.1016/j.est.2019.100840.

[3] P. A. Prieto-Diaz, A. A. Maurice, M. Vera, Modelling the electrolyte flow in the tanks of vanadium redox flow batteries: A CFD perspective, ECS Meeting Abstracts MA2022-01 (48) (2022) 2009. doi:10.1149/MA2022-01482009mtgabs.
Li Electrodeposition Modeling for Analyzing the Effect of Li+ Redistribution in Li Metal Secondary Batteries
Authors: Kim Suhwan , Lim Minhong , Park Joonam , Jin Dahee , Lee Hongkyung , Lee Yong Min
Published: September 2023

To meet the high-energy-density requirement of Li secondary batteries for EV applications, Li metal is still being re-examined extensively beyond conventional carbon-based anode active materials. However, unlike intercalation mechanism-based anodes, Li metal anodes (LMAs), suffering from significant surface morphology changes during electroplating and stripping, can accompany several issues such as Li dendrite growth and continuous side reactions, thereby leading to the poor electrochemical performance and cycle stability. Among various reasons of the Li dendrite formation, inhomogeneous and slow Li+ transport to the LMAs are representatively known, accelerating irregular electrodeposition and rapid Li+ depletion on the LMA surface.

In this study, we attempted to simulate Li dendrite growth under practical current conditions by developing a 2D Li electrodeposition model. Based on this model, we analyzed the geometric-electrochemical characteristics of Li metal interface depending on Li+ concentration distribution in the electrolyte and SEI. Furthermore, in order to verify a nanomaterial-based micro-convection effect in the electrolyte for improving mass transfer, the Li+ concentration change nearby the interface was calculated while simulating the Li dendritic growth. Also, real 2D morphologies of the Li dendrites were reconstructed and analyzed together in a similar way. As a result, the micro-convection enables relatively uniform Li+ distribution at the LMA interface and enhances the mass transport in the electrolyte, which can suppress the Li dendrite growth even at 5.0 mA cm-2.
A Recyclable Solid Electrolyte for Li-Ion Batteries Composed of Supramolecular Nanostructures
Authors: Cho Yukio , Fincher Cole D. , Chiang Yet-Ming , Ortony Julia
Published: September 2023

The recyclability of Li-ion batteries is a critical goal but is technically challenging and often impractical due to the complex structure of mixed materials and the irreversible process of production. We investigated the use of organic small molecule self-assembled nanoribbons as an electrolyte material because they offer precise spatial arrangement, high surface areas, tunable surface chemistry, and most notably here, reversible structural formation. In this study, we synthesized nanoribbons by self-assembly of aramid-containing amphiphiles that overcome structural stability problems, and we systematically modified the surface chemistry to promote Li-ion conductivity. We investigated the performance and transport mechanism of these supramolecular nanomaterials as a solid electrolyte for Li-ion batteries. Furthermore, we show direct recyclability of the end-of-life cell.

Figure 1
A Study on Na1.2Mn0.8O1.5F0.5 Na-Rich Cathode Material for High Capacity and Superior Stability Sodium Solid-State Battery
Authors: Ganesan Bala Krishnan , Moorthy Megala , Kim Yeong-A , Dhanasekaran Hariharan , Song Jeong-Hyeon , Lee Yun-Sung
Published: September 2023

Sodium ion batteries are considered as a cost-effective and promising alternative to lithium-ion batteries for next generation large-scale energy storage applications. However, the sluggish intercalation kinetics and poor stability plagues the efficient applications. Recently, sodium rich cathode materials are emerging as a promising system to retain high specific energy with improved durability. Benefitting from the high Na ion mobility by P2-type structure and reduced John-Teller active Mn site, improved stability has been achieved for this Na-rich cathode. In this work, we developed a high performing Na rich cathode with Sodium Manganese Oxyfluoride (Na1.2Mn0.8O1.5F0.5
) as a battery positive electrode. The corresponding structural and electrochemical performances are analysed in solid-state battery. The highly favourable cathode architecture demonstrated a high specific capacity of 178 mAh/g at 10 mA/g in half-cell configuration. To further harness its performance, the cathode material was coupled with solid-electrolyte and interface modified anode. Solid-state battery demonstrated an enhanced capability towards ion storage and better stability.
Dendrite Growth Suppression and in-Situ Surface Observation of Lithium Battery Under an Optical Microscope
Authors: Ding Tianyao , Qu Deyang , Zheng Dong , Zhang Xiaoxiao , Qu Huainan , Qiu Dantong , Liu Miao
Published: September 2023

Dendrite growth is a major obstacle to the commercialization of lithium metal batteries. A dendrite formed on a Li anode can cause thermal run-aways and permanent capacity loss. Despite previous research efforts, the behavior of lithium dendrite growth is elusive since it is related to multiple factors. An in-situ optical techniques is considered as one of the major methods to study the dendrites growth behaviors and morphologies real-time.

A better knowledge of the physico-chemical processes and the side reactions during a battery operation can be gained.

A home-designed in-situ optical cell with a digital optical microscope was used to investigate the behavior of Li deposition on a metallic Li electrode under different electrochemical operation conditions. The impacts of electrolytes, additives and cycling conditions on the dendrite formation were investigated. The changes of the morphology and the shape of the dendrites were investigated correspondingly. Guiding by the in-situ optical observation results, polycyclic aromatic hydrocarbons (PAHs) were introduced as additives to suppress the dendrite growth. It was observed in an in-situ optical experiment, that the freshly formed dendrites can be dissolved and dispersed throughout the surface, eventually a dynamic elastic protection layer was formed. With the liquid electrolyte trapped in the protection layer, the thickness of the layer could be self-adjusted to compensate for the volume change of the Li anode during the battery cycling. Among the eight additives added to the electrolyte, several PAH additives have significant effect on suppressing dendrite growth and greatly enhance the cyclability of the Lithium electrode in a symmetry Li/Li cell.

Tarascon, J.-M., & Armand, M. (2001). Issues and challenges facing rechargeable lithium batteries. Nature, 414(6861), 359–367.

Tripathi, A. M., Su, W.-N., & Hwang, B. J. (2018). In situ analytical techniques for battery interface analysis. Chemical Society Reviews, 47(3), 736–851.

Figure 1
Pre-Treatment of Li-Metal Anode with Hydrohalic-Acid for Stable Cycling of Li-Metal Batteries Under Practical Conditions
Authors: Seo Jiyeon , Lee Jaeho , Lim Minhong , Lee Hongkyung , Kim Gunyoung , Lee Hyuntae
Published: September 2023

Lithium (Li) metal anodes (LMAs) are considered as an ultimate choice for beyond Li-ion batteries because of their high capacity (3860 mAh g–1) and low working potential (–3.04 V vs. SHE). However, due to extremely high surface reactivity, uncontrollable dendritic plating, and infinite volume expansion, making Li-metal batteries (LMBs) has long encountered fatal challenges. Heterogeneous solid-electrolyte interphase (SEI) can be the main reason for Li dendrite growth, stemming from the electrolyte byproducts and native LMA surface. In this regard, uniform passivation of LMAs and homogenous SEI at the initial stage is necessary which can occur uniform Li+ ion flux. Furthermore, halogenated SEI is considered as promising component for achieving superior mechanical strength, insulating properties and thermodynamic stability.

In this study, we present a simple LMA treatment using hydrohalic acids (HXs, X = F, Cl, Br, and I) to regenerate native passivation layer (NPL) of as-manufactured LMAs and evenly nourish halogenated compounds. The water molecules of aqueous HXs can dissolve the existing inorganic Li-compounds in the NPL, e.g., Li2O, LiOH, and Li2CO3, rendering the chemical reactions of HXs with pure Li, enriching the LiX compounds within the NPL. A comparative study was done to reveal which LiX compounds is beneficial to stabilize the LMA surface and to enhance the cycling stability of LMBs. Furthermore, it is elucidated that the pivotal role of LiX compounds was proved in the interfacial reaction when using localized high concentration electrolyte (LHCE) as an advanced electrolyte in LMBs. Through comparative study, building LiCl-rich SEI at the initial stage effectively reduces the energy barrier of Li nucleation and interfacial resistances, thereby enhancing the cycling performances in LMBs even under practical conditions.