Advances in Research, Development, and Testing of Single Cells at Forschungszentrum Jülich

2009 ◽  
Vol 6 (2) ◽  
Author(s):  
V. A. C. Haanappel ◽  
N. Jordan ◽  
A. Mai ◽  
J. Mertens ◽  
J. M. Serra ◽  
...  
Keyword(s):  
Quality Assurance ◽  
Research And Development ◽  
Solid Oxide Fuel Cells ◽  
Power Output ◽  
Single Cells ◽  
Experimental Conditions ◽  
Microstructural Parameters ◽  
Long Term Stability ◽  
Measurement Results

This paper presents an overview of the main advances in solid oxide fuel cells (SOFCs) research and development (R&D), measurement standardization, and quality assurance in SOFC testing at the Forschungszentrum Jülich. These activities have resulted in both a significant improvement of the electrochemical performance and a better understanding of the electrochemical behavior of SOFCs. Research and development of SOFCs was mainly focused on two types of anode-supported cells, namely, those employing either La0.65Sr0.3MnO3 (LSM) or La0.58Sr0.4Co0.2Fe0.8O3−δ (LSCF) cathode materials. In both cases the optimization of processing and microstructural parameters resulted in satisfactory power output and long-term stability at reduced operation temperatures. Standardization and quality assurance in SOFC testing was also addressed with the goal of producing consistent and reliable tests and measurement results. At present, under optimized experimental conditions, SOFCs with LSM or LSCF cathodes can deliver a power output of about 1.0 W/cm2 and 1.9 W/cm2 at 800°C (700 mV), respectively.

scholarly journals The robotized stand for the diagnosing compression refrigerating machines

2018 ◽  
Vol 224 ◽  
pp. 02088
Author(s):  
Sergey Petrosov ◽  
Michael Lemeshko ◽  
Alexander Kozhemyachenko
Keyword(s):  
Energy Efficiency ◽  
Technical Diagnostics ◽  
Experimental Conditions ◽  
Automatic Mode ◽  
Simultaneous Evaluation ◽  
Measurement Results ◽  
Research Problems ◽  
Reducing Costs ◽  
Long Term Studies

The process of creation and improvement of small refrigerating machines, the way of increasing their energy efficiency and reducing costs should be provided with reliable means and effective technologies of technical diagnosing these machines. One of the methods for achieving this goal is the creation of robotic research complexes. The authors, using the example of the automated research stand, show a possible variant of solving research problems when the researcher needs to make a measurement program, including a program of varying experimental conditions. Long-term tests with recording measurement results are performed in automatic mode without the operator-researcher’s participation. The robotic stand usually replaces the research operator, and ensures the effective results of long-term studies as they can be carried out more qualitatively and deeply, with simultaneous evaluation of results and adjustments of the measurement plans. The scheme and description of the developed stand are given. The significant advantages of a robotic stand are shown in comparison with the known analogous means of technical diagnostics of small refrigerating machines.

Long-term stability of Ni–Sn porous metals for cathode current collector in solid oxide fuel cells

2017 ◽  
Vol 42 (17) ◽  
pp. 12567-12573 ◽  
Author(s):  
Chihiro Hiraiwa ◽  
Hiromasa Tawarayama ◽  
Hajime Ota ◽  
Takahiro Higashino ◽  
Kazuki Okuno ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Solid Oxide Fuel Cells ◽  
Current Collector ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Porous Metals ◽  
Term Stability ◽  
Long Term Stability ◽  
Cathode Current

Photodissolution of iron oxides. IV. A comparative study on the photodissolution of hematite, magnetite, and maghemite in EDTA media

1992 ◽  
Vol 70 (9) ◽  
pp. 2502-2510 ◽  
Author(s):  
Marta I. Litter ◽  
Miguel A. Blesa
Keyword(s):  
Reaction Rates ◽  
Thermal Reaction ◽  
Oxidation Products ◽  
Experimental Conditions ◽  
Spinel Type ◽  
Long Term Stability ◽  
Initiation Step ◽  
Edta Complexes ◽  
Photooxidation Reaction

The thermal and 254-nm photochemical dissolution reactions of magnetite (Fe3O4), maghemite (γ-Fe2O3), and hematite (α-Fe2O3) suspended in EDTA aqueous solutions were compared. γ-Fe2O3 and Fe3O4 are thermally and photochemically more reactive than α-Fe2O3. Both thermal and photochemical dissolution reactions are governed by an initiation step, which involves the production of FeIIaq, and a subsequent thermal reaction of these ions with the solid, to produce FeIIIaq. The initiation step under UV irradiation involves the photoreduction of surface >FeIII – EDTA complexes to yield FeIIaq and the photooxidation of adsorbed EDTA to yield CH2O and other oxidation products. After FeIII – EDTA complexes build up in solution through the following step, homogeneous photolysis is the main source of FeII and CH2O. Oxides with spinel type structure are characterized by faster rates in the two processes, and O2 may inhibit the dissolution processes by changing the stoichiometry of the initiation step to that of the autooxidation of EDTA. The relative importance of autooxidation and photodissolution depends on the nature of the oxide and the experimental conditions. Photooxidation reaction rates parallel those of the photodissolution initiation steps, and long-term stability towards photocorrosion (dissolution) implies low photocatalytic activity for the oxidation of EDTA. The set of differential equations describing all the reaction rates is discussed and applied to the different cases.

A Review of the Implications of Silica in Solid Oxide Fuel Cells

2011 ◽  
Vol 8 (5) ◽  
Author(s):  
Michael Lankin ◽  
Yanhai Du ◽  
Caine Finnerty
Keyword(s):  
Fuel Cell ◽  
Solid Oxide Fuel Cells ◽  
Solid Oxide Fuel Cell ◽  
Elevated Temperatures ◽  
Raw Materials ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Negative Effects ◽  
Long Term Stability

Silica is a well-known impurity in solid oxide fuel cell raw materials, namely NiO and yttria-stabilized zirconia (YSZ). At elevated temperatures silica will migrate to the grain boundaries, form insulating siliceous phases, and lead to a decrease in the ionic conductivity of the electrolyte. Furthermore, silica impurities have been shown to damage the anode/electrolyte interface, such that an overall decrease in cell performance and long-term stability is observed. Despite the fact that silica is ubiquitous in commercial-grade raw materials and can be incorporated from several extrinsic sources, it has negative effects on the solid oxide fuel cell, such that any further contamination should be avoided to prevent performance degradation and eventual cell failure. This paper reviews and outlines the sources and effects of silica on the solid oxide fuel cell, and attempts to determine a guideline for acceptable levels of silica contamination.

scholarly journals Polarization lidar: An extended three-signal calibration approach

2018 ◽  
Author(s):  
Cristofer Jimenez ◽  
Albert Ansmann ◽  
Moritz Haarig ◽  
Ronny Engelmann ◽  
Jörg Schmidt ◽  
...  
Keyword(s):  
Polarization Plane ◽  
Laser Pulses ◽  
Experimental Conditions ◽  
New Formalism ◽  
Long Term Stability ◽  
Receiver Unit ◽  
Water Cloud ◽  
Elliptically Polarized

Abstract. We present a new formalism to calibrate a three-signal polarization lidar and to measure highly accurate height profiles of the volume linear depolarization ratios under realistic experimental conditions. The methodology considers elliptically polarized laser light, angular misalignment of the receiver unit with respect to the main polarization plane of the laser pulses, and cross-talk between the receiver channels. A case study of a liquid-water cloud observation demonstrates the potential of the new technique. Long-term observations of the calibration parameters corroborate the robustness of the method and the long-term stability of the three-signal polarization lidar. A comparison with another polarization lidar shows excellent agreement regarding the derived volume linear polarization ratio of biomass burning smoke throughout the troposphere and the lower stratosphere up to 16 km height.

Enhanced coking tolerance of a MgO-modified Ni cermet anode for hydrocarbon fueled solid oxide fuel cells

2016 ◽  
Vol 4 (46) ◽  
pp. 18031-18036 ◽  
Author(s):  
Qi Yang ◽  
Fengtao Chai ◽  
Chao Ma ◽  
Chunwen Sun ◽  
Siqi Shi ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Solid Oxide Fuel Cells ◽  
Single Cell ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Term Stability ◽  
Long Term Stability

A single cell with a 2.5 wt% MgO-modified Ni–SDC anode exhibits great long-term stability in humidified CH4.

Electrochemical nanogravimetric studies of adsorption, deposition, and dissolution processes occurring at platinum electrodes in acid media

2010 ◽  
Vol 83 (2) ◽  
pp. 269-279 ◽  
Author(s):  
György Inzelt ◽  
Balázs B. Berkes ◽  
Ákos Kriston
Keyword(s):  
Proton Exchange ◽  
Platinum Electrodes ◽  
Experimental Conditions ◽  
Acid Media ◽  
Surface Mass ◽  
Long Term Stability ◽  
Platinized Platinum ◽  
Electrochemical Double Layer ◽  
Electrochemical Quartz Crystal Nanobalance

Polycrystalline smooth and platinized platinum electrodes have been extensively employed in electrochemistry. It is of utmost importance to gain a deeper insight into the processes occurring during their electrochemical transformations. Piezoelectric nanogravimetry by using electrochemical quartz crystal nanobalance (EQCN) is one of the most powerful tools for obtaining information on the events occurring at the electrode surface. This method has been exploited to monitor the surface mass changes as a function of the electrode potential varying the experimental conditions (time scale, solution composition, temperature), which allows one to draw conclusions in respect of the formation and removal of adsorbed and deposited species as well as changes in the electrochemical double layer. Furthermore, platinum dissolution processes, which are of importance (e.g., regarding the long-term stability of proton exchange fuel cells), are also discussed.

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