bluuebunny/crossref_metadata_2025_split huggingface dataset:
Co-Electrolysis with CFY-Stacks
Authors: Megel Stefan , Dosch Christian , Rothe Stefan , Folgner Christoph , Trofimenko Nikolai , Rost Axel , Kusnezoff Mihails , Reichelt Erik , Jahn Matthias , Michaelis Alexander , Bienert Christian , Brandner Marco 
Published: February 2020

The efficient high temperature electrolysis is of high interest for potential application in a renewable energy system. The possibility to use high temperature heat for the electrolysis reaction makes the SOEC technology an attractive option for the integration in process concepts for the production of valuable chemicals from renewable energies. Moreover, the SOEC allows the electrolysis of water and carbon dioxide in a so-called Co-electrolysis. The produced syngas can be used in a subsequent synthesis step, e.g. a Fischer-Tropsch synthesis. The development of these power-to-product processes as well as of necessary components are in focus of current research activities at IKTS. The main component is the high temperature electrolyzer (SOEC). In collaboration with Plansee SE, the CFY stack technology has been developed. This stack technology can be applied for SOFC, SOEC and reversible operation (rSOC) and establishes an universal platform for different applications.
Performance maps of a MK352 CFY stack in steam- (H2O) and Co- (H2O/CO2) electrolysis operation show a difference in electric power demand of less than 5 %. This low additional power demand of Co-electrolysis together with the advantages of direct syngas production makes it promising for highly efficient integration within a process concept for the production of valuable hydrocarbons. The output syngas can be directly adjusted by choosing appropriate operating conditions for the SOEC to typical compositions used for reactions like Fischer-Tropsch synthesis. Based on this approach the operating conditions were set and durability tests with stacks (>1500 h) were conducted. The results raised several scientific questions which were answered by splitting the “black box” of the stack in separate parallel investigated experiments in the fields of cell tests, tests of interconnect materials, contact resistances, protective layer and glasses.
The surprising behavior of reversible degradation of the stacks was analyzed by single cell experiments and could be reduced by adjusting of operating conditions and resulted in a fine tuning of the electrode design. Nevertheless still an irreversible degradation of about 1%/1000 h was detected. Several material tests consolidated the common understanding of degradation phenomena and will be shown with comparison to the real stack tests. The results show the excellent suitability of the CFY stack for electrolysis applications and give an outlook on further improvements.

Figure: 30-cell MK352 stack for SOFC/SOEC and rSOC operation

Figure 1
Electrochemical Upgrading of Bio-Oil
Authors: Elangovan S , Larsen Dennis , Bay Insoo , Mitchell Evan , Hartvigsen Joseph , Millett Byron , Elwell Jessica , Santosa Daniel , Elliott Douglas C 
Published: February 2020

Bio-oil produced by fast pyrolysis of biomass is a potential source of low carbon, renewable hydrocarbon fuel. However, the properties such as low heating value, incomplete volatility, acidity, instability, and incompatibility with standard petroleum fuels significantly restrict its use as fuel. The undesirable properties of pyrolysis oil result from its chemical composition that mostly consists of different classes of oxygenated organic compounds. The elimination of oxygen is thus necessary to transform bio-oil into a liquid fuel that would be broadly accepted and economically attractive. Hydrodeoxygenation (HDO) or hydrotreating involves high-temperature, high-pressure processing in the presence of hydrogen and catalyst to remove oxygen. HDO suffers from significant challenges such as coking, deactivation of HDO catalysts by the presence of water in the pyrolysis oil, requirement of significant quantities of hydrogen to remove oxygen, and economic availability of hydrogen at a scale suitable for distributed biomass conversion. An alternative economically feasible, less hydrogen dependent and decentralized process is required to convert bio-oil to refinery ready hydrocarbons.
A process of deoxygenation of bio-oil using solid-state, oxygen conductor based electrochemical cell is under investigation. The cell is operated at 500 – 550 °C to match the typical pyrolysis temperature for both physical and process integration of the two operations. The electrolysis process removes oxygen from the oxygenated organic molecule as well from steam to produce hydrogen in-situ. Thus, relatively small quantities of external hydrogen may be needed for deoxygenation, allowing for a distributed, small scale integrated upgrading unit. Mixtures of model compounds were tested using button cells and short stacks. The product from the electrochemical cell contained a suite of compounds with significantly lower oxygen content. Integrated testing of short stacks at the Pacific Northwest National Laboratory using a slip stream from a pyrolyzer shows that the product composition is similar to catalytic pyrolysis process. Additional tests are planned using improved electrode materials.
Acknowledgment: This material is based upon work supported by the Department of Energy under Award Number DE-EE0006288.
New Design Concept of Ni‒Doped-Ceria Cermet Anode for Solid Oxide Fuel Cells: Redox-Induced Self-Modification
Authors: Matsui Toshiaki , Eguchi Kohei , Shirai Keisuke , Okanishi Takeou , Muroyama Hiroki , Eguchi Koichi 
Published: February 2020

Solid oxide fuel cells (SOFCs) are promising energy conversion systems for the next generation. High-temperature operation of this electrochemical device offers high fuel flexibility as well as high energy conversion efficiency. Currently, methane is widely utilized as the main fuel source for the residential SOFC cogeneration system, and the pre-reformed gas is supplied to the anode chamber. In this case, the anode is requested to be active for the reforming reaction of hydrocarbons as well as the electrochemical oxidation of fuels. The tolerance to carbon deposition is also an important property to provide against accidents of the reforming system because the hydrocarbon will be directly introduced to the anode.
Recently, Kubota has reported the strong chemical interaction between Ni and GDC (Gd2O3‒CeO2) for the Ni‒GDC cermet anode in solid oxide fuel cells [1]; CeO2 species migrated on the Ni surface after the exposure to the reducing atmosphere. Generally, such a chemical interaction is promoted by the redox treatment. In this study, then, the influence of redox treatment on the chemical interaction between Ni and doped ceria was studied to design the cermet anode with high tolerance to carbon deposition.
The Ni‒GDC cermet subjected to the redox treatment showed high tolerance to carbon deposition in dry methane. Furthermore, the redox treatment did not affect the mechanism of electrochemical hydrogen oxidation in wet hydrogen atmospheres. We also demonstrated the stable power generation of the single cell with the optimized Ni‒GDC anode in a wet methane atmosphere.
Acknowledgements
This study was supported by Japan Science and Technology Agency (JST), CREST.
Reference [1] J. Kubota, The 23th Symposium on Solid Oxide Fuel Cells in Japan, Extended Abstract, p34-37 (2014).
Modeling of Methanol-Fueled SOFC with Anode Offgas Recycling for Simplified System Design
Authors: Larose Sylvain , Labrecque Raynald , Mangin Patrice J. 
Published: February 2020

Objective :
Methanol is a fuel that can be synthesized from either fossil fuel or biomass. Use of methanol as a fuel in SOFCs offers several advantages. A major advantage lies in its ease of storage, handling, distribution, and input, being found in liquid form under ambient conditions. Compared to most other fuels, methanol is rather easily produced, and is known to have a lesser tendency for carbon deposition when vaporized and heated at high temperature.
In this work, we conducted modeling and simulations of a methanol-fed SOFC system with anode gas recycling. Anode gas recycling provides water vapor in the fuel inlet, thus decreasing the tendency of the feed gas to form carbon deposits in the fuel cell stacks. This strategy also helps reduce thermal stresses in the stacks that would arise if the reforming was attempted in-situ with 100% water vapor originating from outside the SOFC system. The recycling also helps increase the fuel utilization. A thermodynamic analysis was conducted to calculate the energy generated, absorbed, or exchanged in the various blocks of the system, the expected system energy output, as well as conditions under which carbon deposition is prevented.
Results:
The model is based on an integrated energy process with anode gas recycling, a rated output electrical power of 100 kW, and an electrical efficiency of 50% to initiate simulations. Using the CHEMCAD software, equilibrium gaseous compositions were calculated. The oxygen flow rate and the cell temperature were set at five times the stoichiometric value and 800°C, respectively.
Thermodynamic calculations show that the gas mixture at the anode inlet will not lead to carbon deposition above 575°C. The energy generated in the cell by electrooxidation is calculated at 144.6 kW. 44.6 kW of thermal energy is thus generated at the stack level. This heat is removed by the anode and cathode outlet flows, as well as minor heat losses through the system walls. A mass recycle ratio of 1.47 was obtained. Energy involved in each of 9 system blocks was calculated. Overall system and electrical efficiencies of 75% and 57% were obtained from simulations based on lower heating value. A voltage ranging from 0.91 to 0.94 V across the cell stacks was obtained at a fuel utilization factor of 80% and a temperature of 800°C. Finally, simulation iterations lead to an output fuel cell power of 98.8 kW, which is close to the power value used as input at the start of simulations.
Conclusion:
The recycle ratio of 1.47 contributes to system efficiency. By contrast, it was reported that for propane, a fuel utilized in Northern Canada, a recycle ratio greater than 5 is required for reliable functioning of SOFC systems. Modeling and simulation results clearly showed that methanol has very little tendency to form carbon deposits during cracking in situ when used in a simple anode gas recycling system. A very good electrical efficiency is thus obtained.
Chromate-Based Oxide Anodes for Low-Temperature Operating Solid Oxide Fuel Cells
Authors: Abdul Jabbar Mohammed Hussain , Robinson Ian , Pan Ke-Ji , Blackburn Bryan M. , Pellegrinelli Christopher , Huang Yi-Lin , Wachsman Eric D. 
Published: February 2020

Doped-YCrO3 ceramic oxides were investigated as potential anode materials for low-temperature solid oxide fuel cells (LT-SOFC, 400-650°C). This material has shown orthorhombic symmetry with the space group pmmm. Electrical conductivity >1 S/cm at 650°C was measured under reducing gas conditions. The anode-supported SOFCs were prepared by laminating GDC and doped-YCrO3 tapes. A fired half-cell assembly was further deposited with a dense barrier layer made of electrolyte material. The function of the barrier layer at the interface of GDC electrolyte and anode was to prevent the interdiffusion of elements. Furthermore, the LSM/bismuth-based composite low-temperature cathode was deposited on the barrier layer and Ni-GDC precursor was infiltrated on the anode (to introduce catalytic activity for hydrogen oxidation). Peak power density of 700 mW/cm2 (at 2 A/cm2) was obtained at 650°C in H2/3% H2O.
Gallium Doped Sr(CoFe)O3 Perovskite as the Stable Electrodes of the Flexible SOFC and SOEC for Both Power Generation and Hydrogen Production
Authors: Xie Menghan , Meng Xiuxia , Yang Naitao , Shen Yichi , Meng Bo , Liu Shaomin , Tan Xiaoyao 
Published: February 2020

Cobalt and ion based perovskite such as Sr(CoFe)O3, Ba0.5Sr0.5Co0.8Fe0.2O3-
δ and La0.6Sr0.4Co0.2Fe0.8O3-
δare considered as promising cathodes of SOFC or anodes of SOEC. However, cobalt and iron oxides are easily reacted with the gases such as H2, CH4, CO2and water steam at high temperature, causing the perovskite structure to be easily decomposed. To stabilize the perovskite structure of the electrodes is a serious challenge for the fabrication of the long-life SOFC or SOEC.
In this work, gallium is used as a dopant to stabilize Sr(CoFe)O3, developing a SrCo0.8Fe0.1Ga0.1O3-δ(SCFG) perovskite material to work as the electrodes of flexible SOFC and SOEC with a microtubular structure.
SCFG show a high oxygen reducing performance when it is prepared into oxygen separation membrane, Obtaining an oxygen flux of 3~6 mL·min-1·cm-2 at the temperature of 800~950°C. Even under pure CO2, pure CH4 and H2(4vol%), SCFG membrane still works steadily for as long as 200 h with no decreasing.
A microtubular solid oxide cell in the configuration of Ni-YSZ|YSZ|GDC|SCFG is fabricated and tested in SOFC or SOEC modes from 550 to 850°C, using hydrogen as the fuel or as the product, respectively. Under SOFC mode, a maximum power density of 1044 mW cm-2 is obtained at 750°C. In the electrolysis mode, when the applied voltage is controlled at 2V, the electrolysis current density reaches 3.33A cm-2 at 850°C with the hydrogen production rate up to 22.9 mL min-1 cm-2
(STP). These results reveal that SCFG is a very promising oxygen electrode material for the application in both SOFC and SOEC.
Minimizing the Influence of Experimental Uncertainty for Delivered Methane/Steam Reforming Kinetic Equation by the Optimized Design of Experimentation
Authors: Sciazko Anna , Komatsu Yosuke , Brus Grzegorz Adam , Shikazono Naoki , Kimijima Shiniji , Szmyd Janusz S. 
Published: February 2020

One of the important issues in the future development of Solid Oxide Fuel Cells (SOFC) is increasing the fuel flexibility of the commercially available units. In order to provide the accurate models for SOFC coupled with internal indirect reformer or with direct internal reforming reactions, it is necessary to provide the reliable description of the reaction kinetic of fuel reforming process. This research focuses on the methane/steam reforming process and method to develop effective experimental-calculation procedure to deliver the reliable kinetic reaction rate expression.
The experimental studies were conducted on the NiO:YSZ (60:40vol%) catalyst, one of the most typical materials, for Solid Oxide Fuel Cell anodes. The experimental conditions included various temperatures, methane flow, steam-to-carbon ratios and nitrogen-to-carbon ratios, which defines each of the measurement points. The goal of this study was to decrease the number of necessary experimental measurements for the calculations of the empirical parameters defining the kinetic of methane/steam reforming reaction. By the analysis with the Orthogonal Least Squares Method and an analysis of a-posteriori covariance matrix, the experimentation process has been optimized. The proposed systematic approach was applied to evaluate the minimal number of measurements required to achieve the assumed accuracy of final solution and to reveal the influence of distribution of experimental condition for the quality of final reaction kinetic equation.
It was proved that the number of experimental measurements can be reduced without significant deterioration in the quality of solution, if the dismissed measurements are properly chosen. In the paper the correlation between design experimental condition and quality of delivered model for the methane/steam reforming reaction is discussed. The proposed deliberation can be extended and provide useful strategy for the design of experimental procedures for the estimation of empirical reaction kinetic for various catalytic materials.
Preparation, Characterization and Oxygen Storage Capacity Analysis of La1-XSrXAlO3 Perovskite Materials as Promising Anode for SOFC
Authors: Dasari Harshini , Yaranal Naveen kumar , Neelapala Satya Deepika 
Published: February 2020

The Perovskite materials of structure ABO3 are of great interest because their properties can easily be tailored by partial substitution at the A-site, the B-site, or at both A- and B-sites [1]. The partial substitutions at A- and B-sites create structural defects such as oxygen vacancies, which greatly affect properties like electrical conductivity and thermal stability under oxidizing and reducing conditions [2,3,4]. Recent studies have shown that perovskite-like oxides can serve as possible replacements for Ni-based anode materials [5,6], primarily due to their reported coking resistance which is attributed to their high oxygen storage capacity.
To develop efficient materials possessing high oxygen storage capacity (OSC) for a number of catalytic applications, and also as anodes for SOFC, A series of Strontium doped LaAlO3 perovskites with formula La1-XSrXAlO3
−
δ (x=0–0.10) were prepared by precipitation of nitrate precursors followed by calcination at 800 °C in air for 24h. The material properties of the substituted perovskites were characterized by X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) analyses, Raman Spectroscopy, scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The doped materials exhibited a single perovskite phase in air up to the Sr doping of 0.4 mole % which was revealed from XRD and Raman analysis. The redoxability and size of the dopants were proposed to play a pivotal role in enhancing the OSC of the as-prepared materials. In this context, the oxidation state of a dopant located at the surface was determined by XPS, Soot oxidation experiments were further performed to examine the relative OSC of the La1-XSrXAlO3
−
δ based solid solutions and revealed that soot oxidation activities increased till the Sr doping of .05 mole% when compared to undoped LaAlO3. These results clearly shows that La1-XSrXAlO3
−
δ materials can be used as anode for SOFC.
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Microtubular SOFC (mSOFC) System in Mobile Robot Applications
Authors: Kendall Kevin , Liang B , Kendall Michaela 
Published: February 2020

The weak link in mobile robots at present is the battery. A typical robotic device for consumer applications contains a 1kWh battery which runs down with time. Also, the battery requires swapping or lengthy recharging after each shift. The purpose of this paper is to discuss battery extension by adding an mSOFC generator running on propane. This keeps the battery at a high voltage, removing deep discharge problems, while giving a factor 10 longer running time with rapid turnaround because the on-board propane tank can be swapped in 1 minute. An international research project was initiated in 2016 to develop these ideas under the heading PERT (PODS: Extending Robot Traction). This paper describes results from the first 12 months of the project and shows that mSOFCs operating on small mobile robots can give substantial benefits in several applications. The alternative is to stack several batteries on the robot. This paper shows that extra battery weight increases the energy expenditure in a predictable way, demonstrating that the battery hybridised with lightweight fuel cell plus fuel is beneficial.
NMR Transport Study of LiPF6 and NaPF6 in Glymes for Use in Supercapacitors
Authors: Morales Daniel Jaime , Gobet Mallory , Greenbaum Steven , Ruther Rose E. , Nanda Jagjit 
Published: February 2020

Electric double-layer capacitors (EDLC) store ionic charge electrostatically at the interface of high surface area electrodes such as carbon in a liquid electrolyte. Despite significant improvements in electrode and materials design, virtually all state-of-the-art nonaqueous electrochemical capacitors use the same electrolyte: tetraethylammonium tetrafluoroborate (TEABF4) in acetonitrile (ACN). This electrolyte has an exceptionally high conductivity which minimizes resistive losses and enables capacitors to operate at very high power. However, this electrolyte has a practical voltage window around only 2.7 V, beyond which the capacitor lifetime is significantly shortened. Since the energy stored in a capacitor increases quadratically with voltage, extending this electrochemical window could significantly improve the energy density. In this study we report on electrolytes consisting of LiPF6 or NaPF6 in tetraethylene glycol dimethyl ether (TEGDME or tetraglyme or G4), bis(2-methoxyethyl) ether (diglyme, or G2) and dimethoxyethane (DME or G1) which clearly show a 4 V electrochemical window. The extended voltage window doubles the energy density that can be achieved with any given capacitor electrode. Electrolyte conductivities range from 1-10 mS/cm, which are comparable to ionic liquids and adequate for moderate power applications. Futhermore, glyme-based electrolytes have good chemical stability and low flammability. Importantly, all salts and solvents are commercially available, which should enable these electrolytes to be as cost-effective and scalable as the current generation of commercial supercapacitor electrolytes.
NMR experiments were performed on 0.1m LiPF6 and 0.1m/0.8m NaPF6, each dissolved in G1, G2, and G4. Using Pulsed Field Gradient (PFG) NMR, the solvent and ionic self-diffusion coefficients, D, of 1H, 7Li, 19F, and 23Na were measured, at both 25°C and 60°C. As NMR does not distinguish between the movement of single ions and ion pairs, it can be difficult to accurately determine the true conductivity of the material. However, the diffusion measurements were used to find the limiting conductivity, σNMR
, of each material via the Nernst-Einstein equation:

σNMR = F2[C]/(RT)*(Dcation+Danion)

Direct comparison with conductivity values obtained by electrochemical impedance spectroscopy measurements yields the degree of ion association, α:

α = 1 - (σdirect/σNMR)

Both diffusion and conductivity decrease with increasing solvent size, primarily attributed to viscosity effects. However the degree of ion association is significant, determined to be 85% for both 0.1m LiPF6 and 0.1m NaPF6 in G2. In glyme solvents, ion association tends to decrease with increasing solvent molecular mass, and increase with increasing temperature. These results will be discussed in the context of practical use of glyme-based electrolytes for electrochemical capacitors.