bluuebunny/crossref_metadata_2025_split huggingface dataset:
Relationship between Electrochemical Properties and Electrolyte Partial Conductivities of Proton-Conducting Ceramic Fuel Cells
Authors: Matsuzaki Yoshio , Tachikawa Yuya , Somekawa Takaaki , Sato Koki , Kawabata Yasuharu , Sugahara Mariko , Matsumoto Hiroshige , Taniguchi Shunsuke , Sasaki Kazunari 
Published: February 2020

Proton ceramic fuel cells (PCFCs) have attracted attentions because of the high potential to enhance the electrical efficiency of SOFCs, in which proton-conducting ceramic is used as electrolyte instead of the yttria-stabilized zirconia (YSZ) which is the most common electrolyte material of SOFCs.
In previous study, we measured the P
O2 dependence of total electrical conductivities of the proton-conducting solid oxides, BaZr0.1Ce0.7Y0.1X0.1O3-
d (X = Ga, Sc, In, Yb, Gd), which were divided into partial conductivities of the respective charge-carriers, such as electron, ion, and hole, by using the difference in P
O2dependence of the charge-carriers.
In this study, we have investigated the electrochemical properties of the PCFCs with the various partial conductivities in the electrolytes. The electrochemical properties were found to have large dependences on operation condition. When ASR and external current density were given constant values of 0.383 ohm cm2 and 0.25 A cm-2, respectively, an influence of the dopant species on the electrical efficiencies η
xwas found to have the following sequential order:

η
x=SC > η
x=In > η
x=Ga > η
x=Y > η
x=Gd

When the external current density was given as a variable, increasing the external current density will result in the increase of the voltage drop and the decrease of a ratio of leakage current to external current. This suggests that according to the partial conductivities the external current density has an optimum value maximizing the electrical efficiency.
Acknowledgements
This research is supported by The Japan Science and Technology Agency (JST) through its “Center of Innovation Science and Technology based Radical Innovation and Entrepreneurship Program (COI Program)."
Three-Dimensional Modelling of a Microtubular SOFC: A Multiphysics Approach
Authors: Hodjati-Pugh Oujen , Dhir Aman , Steinberger-Wilckens Robert 
Published: February 2020

There is an increasing interest in the use of Microtubular Solid Oxide Fuel Cells (µ-SOFC) for a broad spectrum of applications with power demands ranging from a few watts to several hundred watts. µ-SOFC’s possess inherently favourable characteristics over alternate configurations such as high thermo-mechanical stability, high volumetric power density and rapid start-up times. The use of computational modelling at the design level is essential for minimising cost and maximising productivity, giving critical insight into the complex phenomena occurring during SOFC operation and their interrelationships.
To date, models have been limited by oversimplified geometries, often failing to account for cathode air supply complexities, gas distribution within pores and radiative heating effects[1-3]. In this study, a three-dimensional Computational Fluid Dynamics (CFD) model of an anode, electrolyte, cathode, current collectors, fuel inlet/outlet and furnace temperature effects is considered. The model has been validated with a mirroring experimental setup, varying fuel compositions, operating temperature and interconnect configuration. COMSOL Multiphysics is used to simulate the physics, describing the distribution of temperature, current density, electrical potential, pressure and gas concentrations throughout the cell. Results show good correlation with experimental data and the model is reliable for prediction of fuel cell performance as a function of operating conditions within these set parameters.

References

[1] D. Cui, B.Tu, M.Cheng, Journal of Power Sources, 297 (2015) 419-426
[2] M.Lockett, M.J.H. Simmons, K.Kendall, 8th Grove Fuel Cell Symposium, Elsevier Science Bv London, (2003)
[3] D.Cui, L.Liu, M.Cheng, Journal of Power Sources, 174 (2007) 246-254
Evolutionary Programming Based Approach for SOFC Cathode Characterization: A Case Study on Co-Free Mixed Conducting Perovskites
Authors: Oz Alon , Gelman Danny , Tsur Yoed , Singh Kalpana , Thangadurai Venkataraman 
Published: February 2020

Electrochemical impedance spectroscopy (EIS) is a powerful technique to characterize the performance of solid oxide fuel cells (SOFCs). Given a proper analysis technique, EIS data can shed light on the different contributions to the total impedance. The most common analysis technique is equivalent circuit modelling (ECM), where a combination of resistors, capacitors, constant phase elements, etc. represents the physical response of the sample. ECM has its known drawbacks, e.g. non-uniqueness and obscure physical meaning of the chosen model. Using impedance spectroscopy genetic programming (ISGP), based on evolutionary programming, those challenges are better tackled. Our analysis focuses on finding the distribution function of relaxation times (DFRT). The analysis procedure using ISGP yields a DFRT model comprised of known mathematical peaks. Each peak in the model is characterized by its height, width and relaxation time. It is possible to assign each peak to one or more process, and to calculate its area. Thus, we are able to determine the contribution of each process to the total impedance. By plotting the DFRT as a function of frequency it is possible to identify the different polarization processes and gain additional information, which may be convoluted and therefore undetected in other analysis techniques.
Here, we report the electrochemical performance of perovskite-type Co-free cathodes such as Ba0.5Sr0.5Fe0.91Al0.09O3-δ, Ba0.5Sr0.5Fe0.8Cu0.2O3-δ, and Ba0.5Sr0.5Fe0.8Nb0.2O3-δ with oxide ion conducting La0.8Sr0.2Ga0.8Mg0.2O3-δ (LSGM) and proton conducting Ba0.5Sr0.5Ce0.6Zr0.2Gd0.1Y0.1O3-δ electrolytes have been investigated by ISGP. Composites of cathode with electrolytes were screen printed on both sides of electrolyte in order to get symmetrical cells for evaluating cathode performances. EIS of symmetrical cells at different experimental conditions were analyzed by ISGP. Thus, by changing parameters and monitoring corresponding changes in the peaks’ relaxation times and areas, in-depth understanding of the operation of various components of the symmetrical cells such as the oxygen reduction reactions, mass transfer limitations and the electrolyte ionic conductivity can be achieved.
Methane Pulse Study on Nickel Impregnated Gadolinium Doped Ceria
Authors: Ouyang Mengzheng , Boldrin Paul , Brandon Nigel P. 
Published: February 2020

Nickel/gadolinium doped ceria (Ni/CGO) has been a popular SOFC anode material for decades for its superior mix conductivity and excellent oxygen storage capacity. However, the study of Ni/CGO in a realistic working condition is still lacking. Also, not much research has linked the chemical properties of CGO with the carbon resistance which is essential when using hydrocarbon as fuels.
In this research, Ni/CGO powder was prepared via impregnation-calcination method. A novel pulse experiment has been conducted on impregnated powder. We did certain pulses of a fixed amount of methane into the sample at 600℃.The outlet gas composition was monitored by a quadrupole mass spectrometer.
The product gas was composed of several species including hydrogen, steam, carbon monoxide, carbon dioxide, and methane that was not participated to the reaction.
The major reaction was the partial oxidation of methane that produced carbon monoxide and hydrogen. With the increase of pulsing numbers, the product and shape of product peaks changed a lot. Also, we observed a “tail” after each carbon monoxide production peak which extend with the number of pulsing. This was deduced to be caused by the self-oxidation of carbon by the bulk migrated oxygen. These changes revealed the changing of CGO during methane oxidation.
After detailed quantitative analysis of the shape and integrated intensity of the peaks and tails. We confirmed that the majority of methane partial oxidation reaction on Ni/CGO follows a deposition-oxidation route rather than direct oxidation of methane. Also we were able to evaluate the ability of carbon self-oxidation with different ceria oxidation state. Consequently, a model was proposed to elucidate the relation between carbon self-oxidation rate, surface oxygen concentration and bulk oxygen migration rate of CGO, in forms of partial differential equation.
In-situ Raman spectroscopy was performed during the pulse experiment to give a direct parallel evidence. We observed the change of CGO surface oxygen stoichiometry and deposited carbon. Thus we can confirm the conclusion deduced by pulse experiments to prove its validation, and directly relate the carbon self-oxidation rate with bulk oxygen migration rate of CGO.
The results provided a novel yet facile method to evaluate the oxygen storage properties of materials and gave an insight into the design and modification of ceria based SOFC anode materials.
Dependence of Syngas Composition on Microstructure of La0.8Sr0.2Cr0.5Mn0.5O3–δ Based Cathode for CO2 and H2O Co-Electrolysis
Authors: Maide Martin , Lillmaa Kadi , Nurk Gunnar , Lust Enn 
Published: February 2020

Ceramic materials with perovskite structure have attracted attention as possible redox stable, sulfur- and carbon tolerant cathode materials for solid oxide electrolysis cells 1,2. For example, composite cathode based on La0.8Sr0.2Cr0.5Mn0.5O3-δ (LSCM) are used for high temperature electrolysis of steam and co-electrolysis of steam and carbon dioxide 3,4. However, the limitation of electrochemical performance of electrolysis cell due to insufficient electrocatalytic activity can be a serious challenge 5.
In this study, catalytically active nickel and copper nanoparticles were grown on the surface of A-site deficient LSCM via redox exsolution. Influence of water-gas shift reaction activity conditions of electrolysis and nanocatalyst properties on the outlet gas composition were evaluated.
Electrolysis cells were prepared by sandwiching dense Zr0.89Sc0.10Ce0.01O2-δ (ScCeSZ) electrolyte layer between porous ScCeSZ layers and followed by wet impregnating of electrocatalytically active electrodes into the porous matrix. Impregnated salt mixture is decomposed at 400 °C, calcined and then sintered at 1400°C for 5 h. The thicknesses of the dense electrolyte and the porous scaffold were approximately 100 μm and 40 μm, respectively. Scanning electron microscopy, X-ray diffraction, FIB-TOF-SIMS and ICP-MS methods were used to characterize materials. Electrochemical characterization and analysis of outlet gas composition using gas chromatography was carried out at temperature range from 650 to 850 °C in various H2O, CO2, H2 and Ar inlet concentrations.
As expected, the activity of composite cathode was greatly enhanced by the exsolved nickel and copper nanoparticles. For gas compositions the influence of water-gas shift (WGS) for nickel was greater than for copper.
Thus, it has been demonstrated that both nickel and copper nanoparticles can enhance the electrolytic activity of the cathode for steam electrolysis and co-electrolysis of steam and carbon dioxide. Influence of water-gas shift reaction at co-electrolysis conditions and properties of nanocatalysts on the outlet gas composition were evaluated.
References:
1. O. A. Marina, L.R. Pederson, M.C. Williams, G.W. Coffey K.D. Meinhardt, C.D. Nguyen and E.C. Thomson, J. Electrochem. Soc., 154, B452 (2007).
2. S.-E. Yoon, J.-Y. Ahn, B.-K. Kim, and J.-S. Park, Int. J. Hydrogen Energy, 40, 13558 (2015).
3. X. Yang,J. T. S. Irvine, J. Materials Chemistry, 18, 2349-2354 (2008).
4. R. Xing, Y. Wang, S. Liu, J. Power Sources, 208, 276-281 (2012).
5. X. Yue, J. T. S. Irvine, Solid State Ionics, 225, 131-135 (2012).
Materials Properties for the Simulation of Electro-Chemo-Mechanical Coupling Behavior of SOFC
Authors: Yashiro Keiji , Kawada Tatsuya , Watanabe Satoshi , Muramatsu Mayu , Sakamoto Tadashi , Hashimoto Shin-ichi , Terada Kenjiro , Sato Masami , Hashida Toshiyuki , Sato Kazuhisa , Iguchi Fumitada , Yugami Hiroo , Amezawa Koji , Nakamura Takashi , Kimura Yuta , Unemoto Atsushi 
Published: February 2020

Research and development of solid oxide fuel cells (SOFCs) have been mainly conducted from the aspect of electrochemistry and materials science to improve cell- and stack performances. Long-term reliability and durability are of great importance for the commercialization of SOFCs. Mechanical behaviors of ceramics components, including cell fracture, are necessary to be understood in order to ensure stability of SOFCs. For the multiscale simulation of the thermo-chemo-mechanical behavior, various related materials properties are indispensable. This paper reports the evaluation procedure for comprehensive analysis of chemically- and thermally induced mechanical behavior of SOFCs.
Metal Supported SOFCs: Electrochemical Performance under Various Testing Conditions
Authors: Haydn Markus , Bischof Cornelia , Udomsilp David , Opitz Alexander Karl , Bimashofer Gesara , Schafbauer Wolfgang , Brandner Marco , Bram Martin 
Published: February 2020

Since many years solid oxide fuel cells (SOFCs) are used in stationary systems, in a range from 0.1 up to 1,000 kW, to generate electric power or combined heat and power (CHP). For these applications, electrolyte or anode supported cells (ESCs, ASCs) are the preferred SOFCs and have been demonstrated in different installation environments. In the last years lots of research has been done on metal supported solid oxide fuel cells (MSCs) for mobile applications e.g. auxiliary power units (APUs) or range extenders. For this type of cell, a powder-metallurgically manufactured metal substrate (e.g. Fe26Cr) works as backbone of the cell. This substrate is highly porous and its coefficient of thermal expansion (CTE) matches quite well with the commonly used 8YSZ (8 mol% Y2O3 fully stabilized ZrO2) ceramic electrolyte material. This adopted CTE avoids cracks within the electrolyte layer during heating-up and cooling-down procedures as well as the operation itself. Besides, the ductile substrate together with the thin electrolyte is very robust against vibrations. The anode is applied onto the metal substrate via screen printing and sintering and consists of porous Ni/8YSZ, which is a very well-known SOFC anode material. The anode reduces the pore size of the coarse porous metal substrate by more than one order of magnitude and enables the thin electrolyte to gas-tightly separate the porous anode from the cathodic side. The electrolyte (8YSZ) is rather thin being applied by a special PVD-process, a gas flow sputtering process. Compared to ESCs or ASCs, this thinness enables lower operation temperatures, which is advantageous for mobile applications. Lastly, the cathode is applied via screen printing and consists of porous LSCF (La0.6Sr0.4Co0.8Fe0.2O3-δ), which is also well-known in the SOFC community.
To show the performances and reliabilities of MSCs, a series of electrochemical characterizations on button cells were performed. The cell conditioning during heat-up will be described as it is slightly different to that of ASCs and ESCs. The main focus of this proceeding is to show the influence of gas-flow rates, gas compositions and operational temperatures on recorded i-V-curves. To do so, some of the testing parameters work at high fuel utilization rates, which is not commonly used for button cell experiments. However, with this parameters, it was interesting to see, how the anode and the metal substrate handle high humidity. Furthermore, significant performance improvements with recently developed anodes and cathodes will be presented.
To sum up, this conference proceeding gives an overview on (i) manufacturing, (ii) appropriate test procedures, and (iii) electrochemical testing of MSCs.
Methane-Fueled Proton-Conducting Ceramic Fuel Cell Stacks
Authors: Ding Hanping , Le Long Quoc , Sullivan Neal P 
Published: February 2020

We present our recent work on scale-up and stack development of fuel cells based on proton-conducting ceramic materials. Through steady improvement in materials and fabrication methods, protonic ceramics are emerging from the laboratory as potential solutions in electricity generation, energy storage, and chemical synthesis. “Button-scale” protonic ceramic fuel cells (PCFCs) based on barium zirconates have demonstrated high power density at low operating temperatures, reaching 450 mW / cm2 at 500 ºC under hydrogen fuel, and 300 mW / cm2 at 550 ºC under direct methane-steam fuel. While these materials show great promise, scale up of protonic-ceramic fuel cells beyond the “button-cell” level remains limited.
In this presentation, we review our progress in extending previous button-cell experiments to small fuel-cell stacks. First, fabrication procedures have been developed to increase PCFC active area by a factor of 10. These planar, circular membrane electrode assemblies (MEAs) are packaged within the stack architecture shown in the figure. MEAs are bonded within a ceramic frame, and the frame is packaged within ferritic-steel interconnects. Numerous multi-cell stack prototypes have been demonstrated. A three-cell stack based on BaCe0.2Zr0.6Y0.2O3-d (BCZY26) electrolyte shows near-theoretical open-circuit voltage and promising power density under methane fuel (183 mW / cm2 at 500 ºC). In this presentation, we will review our continuing efforts to improve the performance and durability of protonic-ceramic fuel cell stacks.

Figure 1
Effects of Non-Proton-Conducting Anode Supports on the Performance of Thin-Film Protonic Ceramic Fuel Cells
Authors: Bae Kiho , Kim Dong Hwan , Jang Dong Young , Choi Hyung Jong , Son Ji-Won , Shim Joon Hyung 
Published: February 2020

Protonic ceramic fuel cells (PCFCs) have been proposed as a ceramic fuel cell effectively operating at intermediate temperature range (IT) of 500‒700 °C (1‒5). Key to developing high performance PCFCs is the incorporation of thin protonic ceramic (PC) electrolytes as ohmic resistance by ion transport across the electrolyte membrane accounts for a significant portion of the energy loss during fuel cell operation. In order to stably accommodate the thin-film electrolyte, it is important to prepare a good anode support. Composite wafers composed of NiO and electrolyte ceramics are most commonly used as anode supports (3‒5). For example, PCFCs with yttrium-doped barium zirconate (BZY) electrolytes typically use the NiO-BZY compound as anode support. However, it is difficult to prepare NiO-PC composites because of the different sintering temperatures between NiO (~1200 °C) and PC (~1700 °C for BZY). These discrepancies tend to result in excessive growth of NiO and unevenly distributed pores, which labilize the overall stacks during fuel cell operation.
To solve this problem, we have recently proposed to use NiO-yttrium doped zirconia (YSZ) as the anode support (5). This material is the most common anode support for solid oxide fuel cells that have been proven to work effectively. This approach requires to tightly integrate the PC electrolyte onto the NiO-YSZ surface and to minimize thermal stresses at the interface. To this end, a thin NiO-PC interlayer was prepared before depositing the PC electrolyte. As a PC material, yttrium-doped barium zirconate cerate (BZCY) was used. As a result, PCFCs with Ni-YSZ anode supports tightly accommodating thin-film BZCY electrolytes have successfully demonstrated open circuit voltages (OCV) over 1 V and power outputs of 740 mW/cm2at 650 °C (5). In this presentation, we will discuss this achievement in more details and recent progresses on this topic.
1. J. H. Shim, J. S. Park, J. An, T. M. Gur, S. Kang, and F. B. Prinz, Chem. Mater., 21, (2009) 3290-3296.
2. K. Bae, D. Y. Jang, H. J. Jung, J. W. Kim, J. W. Son, and J. H. Shim, J. Power Sources, 248, (2014) 1163-1169.
3. C. Duan, J. Tong, M. Shang, S. Nikodemski, M. Sanders, S. Ricote, A. Almansoori, and R. O’Hayre, Science, 349, (2015) 1321-1326.
4. K. Bae, S. Lee, D. Y. Jang, H. J. Kim, H. Lee, D. Shin, J.-W. Son, and J. H. Shim, ACS Appl. Mater. Interfaces, 8, (2016) 9097-9103.
5. K. Bae, H.-S. Noh, D. Y. Jang, J. Hong, H. Kim, K. J. Yoon, J.-H. Lee, B.-K. Kim, J. H. Shim, and J.-W. Son, J. Mater. Chem. A, 4, (2016) 6395-6403.
Investigation of Cr Poisoning on the LSCF Cathode Under Different Temperatures for Solid Oxide Fuel Cell
Authors: Xiong Chunyan 
Published: February 2020

The Cr poisoning effect on cathode is identified as a considerable negative factor for the long-term performance of Solid Oxide Fuel Cells(SOFCs). With the lowering of the operating temperature of SOFCs, more high performance cathode materials could be used. In this study, the relation between testing temperature of SOFC and the Cr poisoning effect on La0.6Sr0.4Fe0.8Co0.2O3-δ - Ce0.9Gd0.1O2-δ symmetric cells is investigated . Combined with the SEM and XRD , a secondary phase, identified as SrCrO4 is found formed on the surface of cathode to cause serious cathode degradation. The EIS shows that as the increasing of performance temperature from 550°C to 750°C, the Cr poisoning effect firstly increases to the maximal poisoning effect on 650°C and then decreases as the increasing of testing temperature. The evaporation of Cr from metallic interconnect could increase with the rising of testing temperature, However , the surface incorporation and exchange of Cr or O2 may not obey the tendency of temperature. With the DRT calculation, the Cr is more easily to occupy the Co sites on the LSCF but O is more tend to occupy the Sr sites, which may lead to the existence of the peak performance temperature for the remarkable Cr poisoning effect on LSCF.
Energy Storage and Heat to Power Conversion and with Non-Aqueous All Copper Redox Flow Batteries
Authors: Peljo Pekka , Maye Sunny , Atek Imene 
Published: February 2020

In this presentation we will describe a new approach for conversion of heat into chemical energy, stored in a battery. A thermo-electrochemical system with a redox flow battery (RFB) is proposed to allow the conversion of heat at relatively low temperature into chemical energy. The electroactive species of the battery are copper ions in an organic solvent mixture containing acetonitrile as a complexing agent, resulting in a cell voltage of 1.2 V. Water is avoided because its presence reduces considerably the cell voltage. This non-aqueous hybrid redox flow battery can be utilized for electrochemical energy storage, and the efficiency of the system for this purpose will be discussed.
More interestingly, the battery can be also charged with heat. For thermal charging, the Cu(I) complex with acetonitrile can be destabilized by a heat source of around 170°C (or more). At these temperatures all the acetonitrile is distilled off and the destabilized Cu(I) species disproportionates into metallic Cu and Cu(II) species dissolved in the electrolyte. Following separation and recovery of the distilled acetonitrile the system can be discharged again. Now the chemical energy stored in the battery be converted into electricity with the Cu oxidation and Cu(II) reduction in the different half cells.
In this presentation we shall discuss the electrochemistry of copper in acetonitrile and propylene carbonate mixtures, the thermodynamic properties of the copper electrolytes as well as the heat required for the thermal regeneration, as has been evaluated by differential scanning calorimetry. Additionally, we will present our latest results with non-aqueous copper slurry electrolytes and report the efficiency of the full cycling consisting of electrochemical discharge followed by thermal charge.
The theoretical efficiency of the heat-to-power conversion has been evaluated as 30%, close to the Carnot efficiency with T
cold at 298 K and T
hot at 443 K. The losses of the cell will decrease the practical efficiency, so further improvement of the flow battery is required.