bluuebunny/crossref_metadata_2025_split huggingface dataset:
Long Term (4 Years) Performance of Co/Ce Coated 441 for SOFC Interconnect Applications
Authors: Goebel Claudia , Berger Robert , Lundberg Mats W , Westlinder Jörgen , Svensson Jan-Erik , Froitzheim Jan 
Published: February 2020

Ferritic stainless steel interconnectors are widely used in solid oxide fuel cells (SOFC) due to a combination of low cost, compatible thermal expansion properties and ease of manufacturing. However, their viability is hindered by some key technical hurdles. Most stainless steels suggested for SOFC applications rely on the formation of a fairly protective Cr2O3 scale. However, in air side environments Cr species evaporation leads to material failure and insufficient lifetimes. Coatings offer a way to mitigate Cr evaporation and in some cases decrease oxide scale growth. Numerous research papers have investigated different coating compositions and deposition techniques, however, the most commonly suggested material is (Mn,Co)3O4 (MCO). Instead of depositing MCO metallic Co can be applied. During operation Co is converted into Co3O4 and subsequently enriched in Mn from the underlying steel substrate. It has been shown that this type of coating effectively impedes Cr volatilization, even when only very thin layers (600 nm) are applied. Moreover the major advantage of metallic Co coatings are cost savings, since Co can be applied in a large scale roll-to-roll process before stamping the interconnect into its final shape. Furthermore, our previous work has shown that an additional layer of 10 nm Ce in combination with the Co coating results in the aforementioned mitigation of volatilization of Cr species, and also effectively reduces oxide scale growth. Oxide scale growth is detrimental for two reasons. First, a depletion of oxide scale forming element (Cr) can result in the formation of poorly protective iron oxide. Second, even a protective Cr2O3 scale grows with time. Since Cr2O3 is only a moderate electronic conductor this results in an increase of Area Specific Resistance (ASR) as the oxide scale grows in thickness. This eventually creates prohibitively high resistances. Both effects can be mitigated by addition of a thin Ce layer.
In the present work Ce/Co (10/600 nm) coated AISI 441 has been exposed for 4 years (35 000 h) at 800 °C. The mass gain of the samples over the course of exposure has been recorded at selected intervals. After 35 000 h a mass gain of 3.76 mg/cm2 has been measured. Over the entire exposure parabolic mass gain kinetics are observed indicating the absence of a poorly protective iron oxide. After 35 000 h the samples were moved to a different setup to measure Cr(VI) evaporation. It was found that despite the fact that the coating was only 600 nm in thickness, it effectively inhibits volatilization of Cr even after 4 years of exposure. Furthermore, samples were removed at selected intervals to measure ASR.
Advances in Low Temperature Coatings for Solid Oxide Fuel Cell Components
Authors: Kidner Neil J. , Ibanez Sergio , Seabaugh Matthew Mark , Swartz Scott 
Published: February 2020

In the development of solid-oxide fuel cells, coating technologies are essential to successful commercialization. Electrode coating technologies allow the cost-effective deposition of anode and cathodes on cell components at high volumes and high precision. Further, catalytic and corrosion resistant coatings for common steel alloys find application in gas delivery and fuel reforming components of the balance-of-plant. Such corrosion-resistant alloys are also combined with conductive and insulating oxide protective layers to making low-cost steel interconnectors corrosion-resistant at SOFC operating while maintaining low contact resistance and minimizing Cr volatilization.
Many of the first generation coating technologies that have found commercial implementation were designed for cell and stack operating temperatures of 750°C and higher. By design, conductive coatings for steels provide low contributions to the overall stack resistance (ASR < 0.05 ohm-cm2) at these operating temperatures. However, as stack operating temperatures push to the 600°C range, new protective coatings are required that achieve similar resistances at lower temperatures. In this paper, Nexceris will report on the development of new formulations designed to meet these needs, based on our patented approaches.
To complement these protective coatings, Nexceris has developed a suite of contact paste, insulating layer coatings and catalytic materials for SOFC stacks and balance of plant, all designed with the end-user needs in mind. Leveraging aerosol spray deposition approaches that have been scaled to commercial requirements, Nexceris can interleave these coatings to create uniquely functional interconnects, cells and reformer components. Examples of the flexibility of these coating approaches will be provided, with performance data.
Mechanical Investigation of Various Stack Designs for Solid Oxide Cells
Authors: Molla Tesfaye T , Kwok Kawai , Frandsen Henrik Lund 
Published: February 2020

Stress development in metallic interconnects during operational cycles of solid oxide cells (SOCs) could create permanent plastic deformations, which can cause contact losses in the interface between the interconnect and cells. The magnitude of these stresses and their distribution within the SOC stack are dependent on the overall design of the stack and its operational parameters/conditions. In this study, analysis of stress generation in metallic interconnects due to temperature and stack assembly loadings for different types of generic SOC stack designs operated under the same operational cycles is performed. The analysis includes stack design concepts with and without contact layers having cross-shaped and/or corrugated metallic interconnect. To consider the effect of thermal gradient over the surface of the stacks (due to electro-chemical reaction), stacks with two types of temperature profiles are studied. The analysis is performed numerically using finite element modeling of a standard repeating unit of SOC stack. Special focus is given to stresses that can cause possible delamination of the interconnect from the cell that subsequently leads to loss of electrical contact. Comparison of stress for different types of stack design concepts are presented. An effective way to minimize stresses in the interconnect is found to be through designing the micro-architectures of the interconnect and us eof contact layers materials.
Key words: Solid oxide fuel cells, Metalic interconnect, Creep, finite element modeling
Experimental Characterization of Low Temperature Solid Oxide Cell Stack
Authors: Tallgren Johan , Himanen Olli , Noponen Matti 
Published: February 2020

Reversible solid oxide cell (rSOC) and solid oxide electrolysis (SOE) are gaining growing interest because they can convert both electricity into a chemical fuel and fuel back to electricity with high efficiency. This work summarizes for the first time the electrochemical performance characterization of Elcogen E350 stack both in fuel cell and electrolysis modes. Elcogen E350 stack is composed of 15 unit layers all having an 121 cm2 active electrode area. The electrochemical characterization is conducted in temperature region 650 – 700 °C and with varying current densities, multiple steam-to-hydrogen ratios, reactant utilizations and air flow rates. Results indicate that the stack can be used not only as a fuel cell but also in electrolysis mode and it is capable to be operated up to 1 A/cm2current density already at 650 °C and can be operated also with high reactant utilization even in electrolysis mode.
Figure 1. (left) Elcogen E350 polarization at conditions: T[furnace] = 650°C, T[air,inlet] = T[fuel,inlet] = 640 °C, V[steam] = 21.1 Nl/min, V[H2] = 2.24 Nl/min, V[air] = 67 Nl/min. (right) Elcogen E350 polarization at conditions: T[furnace] = 650°C, T[air,inlet] = T[fuel,inlet] = 640 °C, V[steam] = 7.76 Nl/min, V[H2] = 7.76 Nl/min, V[air] = 33 Nl/min.

Figure 1
Reaction Mechanism and Rate-Determining Step Speculation of Reversible CO/CO2 Electrochemical Conversion on the Nickel Patterned Electrodes
Authors: Luo Yu , Li Wenying , Shi Yixiang , Cai Ningsheng 
Published: February 2020

The nickel(Ni)-patterned electrode enables researchers to quantify the triple-phase boundary (TPB) length and Ni surface area, exclude the influence of bulk gas diffusion and clearly separate the active regions of the chemical/electrochemical reactions. This tool has been studied for identifying the reaction mechanism in SOFC but rarely in SOEC. In this study, the Ni-patterned electrodes with the stripe width of 100 μm were tested in both the solid oxide fuel cell (SOFC) and solid oxide electrolysis cell (SOEC) modes at the atmosphere of H2O/H2 and further H2O/CO2/H2/CO. The experimental test shows the stability of the Ni-patterned electrode in the H2O/H2 atmosphere was much poorer than that in the CO/CO2 atmosphere due to the nickel reacting with steam. Thus, the Ni-patterned electrode needed to operate at a temperature of ≤700oC with the inlet H2/H2O molar ratio of >7 and the current-applied time shouldn’t be over 5 h to keep the accuracy of the TPB length and Ni surface area. The effects of the temperature, partial pressure of H2O and H2 are investigated. The activation energy of the Ni-patterned electrodes was 0.386 eV. The electrochemical performance had a positive correlation with both the partial pressure of H2 and H2O, especially showed higher sensitivity to the partial pressure of H2O. Further, a possible mechanism of the H2O/H2 electrochemical conversion was proposed according to the experimental data and existing literature, which contains two-step charge-transfer reaction: H(Ni)+O2-(YSZ)OH-(YSZ)+(Ni)+e- and H(Ni)+OH-(YSZ)H2O(YSZ)+(Ni)+e-. Based on the experiments, an analytical calculation was performed to investigate the rate-determining steps in the Ni-patterned electrodes by bridging the connection between the kinetic parameters and operating conditions. The results indicate the rate-limiting steps may be different for the SOFC and SOEC modes. In SOFC mode, the H2 electrochemical oxidation could depend more on the charge-transfer reaction H(Ni)+O2-(YSZ)→OH-(YSZ)+(Ni)+e-, however in SOEC mode, the rate-determining step of the H2O electrochemical reduction should be H2O(YSZ)+(Ni)+e-→OH-(YSZ)+H(Ni). In this way, a reversible mechanism could be applied for reversible SOFC (RSOFC) to describe the conversion between hydrogen and steam by different charge-transfer-reaction domination in the SOFC and SOEC mode.

Figure 1
Half-Cell Study of La and Ca Doped Strontium Titanates Anode for Direct Methane Solid Oxide Fuel Cell
Authors: Tiwari Pankaj Kr , Irvine John T. S. , Basu Suddhasatwa 
Published: February 2020

Solid oxide fuel cell (SOFC) has been providing high conversion efficiency of chemical energy to electricity without any pollution. One of the major advantages of SOFC over other fuel cell is use of direct natural gas at high temperature without any external reformer. Conventional Ni-yttria stabilized zirconia (YSZ) composite anode provides excellent catalytic property, current collection and stability for H2 oxidation but it is not tolerant towards sulphur poisoning and also accelerates coke deposition in presence of hydrocarbon fuels. It necessitates the use of alternate anode for direct hydrocarbon SOFC. In the present work, attempts have been made to apply A-site deficient La and Ca doped SrTiO3 (LSCTA-) as potential anode for direct methane SOFC. Electrolyte supported half-cells with LSCTA- anode backbone have been tested in H2 and humidified CH4 fuel. Low catalytic activity of LSCTA- towards electro oxidation of fuel is significantly improves in presence of metallic catalyst. 6% CeO2 loading in LSCTA- backbone improves the performance of the cell in H2 as well as in humidified CH4 at 800 °C. It has been observed that coke deposition did not degrade the anode active surface even after 6 h of exposure of CH4 at the elevated temperature of 800 °C. 4% Ni infiltration in 6%CeO2-LSCTA- enhances the performance from 131 mW cm-2 to 200 mw cm-2 at 800 °C in H2. In humidified CH4 environment, cell having 4% Ni-6% CeO2-LSCTA- anode shows lesser performance (140 mw cm-2 Power density) due to sluggish methane oxidation reaction but provided enhanced power density (216 mw cm-2) once H2 is again fed after 6 h cell operation in humidified CH4. i-V/ i-P analysis of half-cell shown in fig. 1 explains the performance in H2 as well as in CH4 at 800 °C. Maximum power density of cell is 200 mW cm-2 (554 mA cm-2) at 1 h of operation in H2, which increases up to 216 mW cm-2 (578 mA cm-2) in H2 after 6h of cell operation in humidified CH4. In humidified CH4 exposure, maximum power density of cell is 89 mW cm-2 (285 mA cm-2) at 1 h of operation, which increases up to 140 mW cm-2 (409 mA cm-2) at 6 h of operation. The performance of the cell is reasonably good as results presented here correspond to a cell having thick electrolyte (300 μm). The cells are found to be structurally robust even after 12 h of accelerated testing. LSCTA-is a potential anode backbone material for direct methane SOFC and could be an excellent anode for other hydrocarbons.
Key Words: A-site deficient SrTiO3, Direct Methane SOFC, LSCTA- anode, half-cell study.

Figure 1
Current Status of National SOFC Projects in Japan
Authors: Nirasawa Hitoshi 
Published: February 2020

The New Energy and Industrial Technology Development Organization (NEDO) has been conducting technology development and demonstrative research programs related to SOFC, as one of the most important and promising technologies for CO2 reduction and realizing dispersed power sources. One of their achievements was the-first-in-the-world commercialization of SOFC-based combined heat and power (CHP) system “ENE-FARM type S” in 2011.
In June 2014, the Ministry of Economy, Trade and Industry (METI) has compiled a Strategic Road Map for Hydrogen and Fuel Cells. It was established, releasing fuel cells for commercial and industrial use onto the market in 2017 as one of the processes of expanding the use of fuel cell technology. NEDO’s activities and recent trends on SOFC, including a program “Technology development for promoting SOFC commercialization” , will be overviewed.
Network Analysis of Fuel Cell Heat Engine Distributed Energy Systems
Authors: Williams Mark C , Gemmen Randall 
Published: February 2020

A thermodynamic and electrochemical framework transformed into an electrical network is used to analyze the power output and efficiency of high-temperature, ceramic fuel cell heat engine systems for the hydrogen oxidation reaction. It is interesting that the heat engine combustor subsystem performance was able to be recast in electrochemical and electrical network terms. The analysis includes the effect of temperature on the operation and performance of these ceramic, high-temperature systems. The power and efficiency responses of a distributed energy system operated at constant voltage to protect the fuel cell, using supplemental firing of the heat engine, and subjected to a cyclic load demand is presented. These systems are of interest to the emerging renewable energy grid. While the perfect fuel cell would undergo no degradation, practical fuel cells will degrade. The partition of power in a degrading distributed energy system is examined.
Gradual Conductivity Degradation of Nickel Doped Yttria Stabilized Zirconia by Phase Transformation at Operating Temperature
Authors: Ishiyama Tomohiro , Kishimoto Haruo , Bagarinao Katherine Develos- , Yamaji Katsuhiko , Horita Teruhisa , Yokokawa Harumi 
Published: February 2020

The conductivity degradation of yttria stabilized zirconia(YSZ) due to the phase transformation from cubic phase to tetragonal phase is one of the issue in solid oxide fuel cells [1,2]. The phase transformation is enhanced by the reduction of nickel oxide which dissolved into YSZ electrolyte when making an anode-support-type-cells. The correlation of conductivity degradation and phase transformation ratio and dependence on oxygen profile in electrolyte for the area of tetragonal formation region about the 1 mol % nickel doped 8mol% yttria stabilized zirconia (Ni-YSZ) at 1173K were reported in our previous studies [2,3,4]. In this study, in order to investigate the factor of temperature for this phase transformation phenomena in nickel doped YSZ electrolyte, conductivity degradation behaviors were measured at various conditions. Even at around 750oC which similar to operating temperature of industrial SOFCs, the tetragonal formation was slightly observed at the area where the reduction of nickel oxide was occurred after over 500h measurement. The time constant for the conductivity degradation due to the tetragonal formation is well fitted on the Arrhenius type plot. This results show the strong temperature dependence for phase transformation. This is an important factor for rapid evaluation of durability of SOFCs.
References: [1] H. Yokokawa, ECS Trans. 68 (2015) 1827–1836. [2] H. Yokokawa, H. Kishimoto, T. Shimonosono, K. Yamaji, M. Muramatsu, K. Terada, K. Yashiro, T. Kawada, J. Electrochem. En. Conv. Stor.
in press (Paper No: JEECS-16-1083). [3] T. Shimonosono, H. Kishimoto, M.E. Brito, K. Yamaji, T. Horita, H. Yokokawa, Solid State Ionics.
225(2012) 69–72. [4] H. Kishimoto, K. Yashiro, T. Shimonosono, M.E. Brito, K. Yamaji, T. Horita, H. Yokokawa, J. Mizusaki, Electrochim. Acta.
82 (2012) 263–267.
Multi-Scale, Multi-Physics Approach for Solid Oxide Fuel Cell Anode Reaction
Authors: Liu Shixue , Liu Shusheng , Saha Leton Chandra , Iskandarov Albert M , Jiao Zhenjun , Hara Shotaro , Ishimoto Takayoshi , Tada Tomofumi , Umeno Yoshitaka , Shikazono Naoki , Matsumura Syo , Koyama Michihisa 
Published: February 2020

Electrode processes in solid oxide fuel cells are intensively studied to increase the system efficiency to compete with that of the state-of-the-art LNG-fueled combined cycle thermal power plant. Because the electrode performance depends both on electrode materials and microstructure, we are obliged to breakdown the complexity of phenomena in the porous electrode into elementary processes by best utilizing both the advanced measurement and the simulation techniques. Closely examining the efforts in literature [1-7], we have taken the combined top-down and bottom-up approach.
The most difficult issue has lied on the meso-scale modeling, which typically is based on microkinetic modeling [5-8]. To guarantee the predictivity of the modeling, it is inevitable to realize the simulation without arbitrary fitting parameters that are not necessarily based on realistic physics. For this purpose, we first exhaustively summarized literature data followed by the careful examinations. Next, we have made exhaustive simulations assuming different combinations of parameters in literature.
Finally, we obtained a set of parameters that matches with experimental observations within reasonable differences.
The details together with the results of top-down and bottom up simulations will be introduced together with future perspectives.
Acknowledgements
The activities of INAMORI Frontier Research Center is supported by Kyocera Co. Ltd. The activities of Advanced Automotive Research Collaborative Laboratory in Hiroshima University are supported by Mazda Corporation. The part of the research is supported by CREST, Japan Science and Technology Agency.
References
[1] J. Mizusaki, H. Tagawa, T. Saito, T. Yamamura, K. Kamitani, K. Hirano, S. Ehara, T. Takagi, T. Hikita, M. Ippommatsu, S. Nakagawa, K. Hashimoto, Solid State Ionics, 70/71, 52 (1994)
[2] W. Yao and E. Croiset, Can. J. Chem. Eng., 93, 2157 (2015)
[3] A. Bieberle, L. P. Meier, L. J. Gauckler, J. Electrochem. Soc., 148, A646 (2001)
[4] A. Utz, H. Störmer, A. Leonide, A. Weber, E. Ivers-Tiffée, J. Electrochem. Soc., 157 B920 (2010)
[5] W. G. Bessler, S. Gewies, M. Vogler, Electrochim. Acta, 53, 1782 (2007)
[6] W. G. Bessler, Solid State Ionics, 176, 997 (2005)
[7] M. Vogler, A. Bieberle-Hütter, L. Gauckler, J. Warnatz, and W. G. Bessler, J.
Electrochem. Soc., 156, B663 (2009)
[8] H. Kohno, S. Liu, T. Ogura, T. Ishimoto, D. S. Monder, K. Karan, M. Koyama, ECS Trans., 57(1), 2821 (2013)
Design of Leakage Gas Induction Channels for Reliable Planar-Type Solid Oxide Fuel Cell Stacks
Authors: Yoon Heesung , Jang Inyoung , Kim Chanho , Kim Sungmin , Paik Ungyu 
Published: February 2020

Managing the leakage gas in a planar solid oxide fuel cell (SOFC) stack is one of the important factors associated with stack degradation. When the fuel leaks to the air electrode, the catalytic property of the cathode deteriorates. Further, when air leaks to the anode using Ni metal, the electrolyte thin film is peeled from the anode surface by reoxidizing Ni with NiO. Therefore, one of the ways to prevent deterioration characteristics of the SOFC stack is to effectively manage the sealing method to shut off the leaking gases. However, when the SOFC stack is used over a long period of time, gas leakage may occur due to degradation of the sealing material. In this study, we developed a stack of specially designed channels in a sealing gasket to prevent gas leakage to the fuel and air electrodes for the stability of the SOFC stack. The stack was evaluated using 10 x 10 cm2 anode support cells. This stack design can be operated for thermal cycling from operating temperature to room temperature, and ensuring the reliability of the stack even in the event of momentary interruption of air or fuel.
High Efficiency Direct Ammonia Type Fuel Cells based on BaZr
x
Ce0.8-X
Y0.2O3/Pd Oxide-Metal Junctions
Authors: Aoki Yoshitaka , Yamaguchi Tomoyuki , Kobayashi S , Zhu Chunyu , Habazaki Hiroki 
Published: February 2020

Recently, ammonia has attracted a considerable interest as a prospective carbon-free fuel source for fuel cells due to the low cost, ease in liquefaction and transportation at ambient temperatures, and high volumetric energy density. The proton conducting ceramic fuel cells (PCFCs) using proton-conducting oxides, such as BaZr
x
Ce0.8-x
Y0.2O3-

d

, as an electrolyte is promising as a direct ammonia type fuel cells. The water formation in PCFCs is mainly progressive at the cathode side, unlike solid oxide fuel cells (SOFCs), and therefore, the contamination of the ammonia fuels into the exhaust water is precluded, thereby eliminating re-purification of water exhaust and simplifying total systems. Hydrogen membrane fuel cell (HMFC), which was firstly proposed by Ito et al., consists of an ultrathin proton conducting ceramic electrolyte supported on a dense hydrogen permeable metal anode. The cell facilitates efficient power generation, giving 900 mW cm-2 at 400°C, since reduced electrolyte thickness can significantly decreases the ohmic loss at lower temperatures. This unique cell configuration could be advantageous for ammonia fuel cells because 1) the NO
x
formation at the anode is perfectly prevented because NH3 gases are isolated from the oxide electrolytes by Pd solid anode and 2) Pd is expected to capture efficiently the hydrogen gases produced by the pyrolysis of ammonia due to the large ahydrogen sorption ability. Herein, we demonstrated the high efficiency power generation of the direct ammonia type HMFC due to the hydrogen pumping effects realized by BaZr0.1Ce0.7Y0.2O3-

d
(BZCY) and Pd heterointerface. Ohmic characteristics of the heterojunctions, altogether with hydrogen solubility of Pd, can facilitate the hole proton exchange between Pd and BZCY regardless of the lowered hydrogen concnetartion in NH3-fed anodes. The cell gained the maximum power density of 0.52 W cm-2 at 600°C, which was much higher than the champion data of ammonia PCFCs.