scholarly journals Particle size of several plutonium-238 oxide fuel samples from oxalate precipitation processes

2020 ◽  
Author(s):  
Roberta Nancy Mulford ◽  
Edward Goodfellow (Ned) Parker
Keyword(s):  
Particle Size ◽  
Oxide Fuel ◽  
Oxalate Precipitation ◽  
Precipitation Processes

Direct-Write Microfabrication of Single-Chamber Solid Oxide Fuel Cells with Interdigitated Electrodes

2006 ◽  
Vol 972 ◽  
Author(s):  
Melanie Kuhn ◽  
Teko Napporn ◽  
Michel Meunier ◽  
Daniel Therriault ◽  
Srikar Vengallatore
Keyword(s):  
Particle Size ◽  
Fuel Cells ◽  
Fuel Cell ◽  
Solid Oxide Fuel Cells ◽  
Size Distribution ◽  
Solid Oxide ◽  
Extrusion Pressure ◽  
Direct Write ◽  
Oxide Fuel ◽  
Single Chamber

AbstractMiniaturized single-chamber solid-oxide fuel cells (SC-SOFC) are a promising class of devices for portable power generation required in the operation of distributed networks of microelectromechanical systems (MEMS) in harsh environments. The single-face configuration, which consists of interdigitated (comb-like) array of electrodes on an yttria-stabilized zirconia (YSZ) electrolyte substrate, is of particular interest because of the ease of high-temperature microfluidic packaging and integration with MEMS. The primary design consideration for this configuration is the minimization of electrode widths and inter-electrode spacings to dimensions on the order of a few micrometers. This is necessary to minimize polarization resistance and increase fuel cell efficiency. Achieving these geometries using standard microfabrication methods is difficult because of the thickness, porosity, and complex chemistries of the electrodes. Here, we report the development of an innovative and rapid method for manufacturing SC-SOFCs with interdigitated electrodes using robot-controlled direct-writing. The main steps consist of: (i) formation of inks (or suspensions) using anode (NiO-YSZ) and cathode (lanthanum strontium manganite) powders, (ii) pressure-driven extrusion of inks through a micronozzle using a robot-controlled platform, and (iii) sequential sintering to form the fuel cell. The first-generation SC-SOFC device, with electrode widths of 130 μm and inter-electrode spacing of 300 μm, has been manufactured using direct-write microfabrication. The electrodes have been extensively characterized using electron microscopy and x-ray diffraction to assess porosity and to confirm phase identity. The primary process parameters in this approach are the particle size and size distribution, rheological properties of the suspension, extrusion pressure, nozzle size, stage velocity, and sintering conditions. As the first step in the development of detailed process-structure-performance correlations for the fuel cells, we have studied the effects of extrusion pressure (in the range 30-40 bar) and stage velocity (in the range 0.2-2.0 mm/s) on the geometry and size of electrodes, for fixed suspension viscosity and nozzle diameter. An optimal combination of speed and pressure has been identified and catalogued in the form of process maps. Similarly, the particle size distribution of the anode and cathode powders is found to have a significant effect on the microstructure, especially porosity, of the sintered electrodes. The implications of these results for the design of the next generation of SC-SOFC, with reduced electrode dimensions and improved electrochemical performance, will be discussed.

Electrochemical Performance of Barium Strontium Cobalt Ferrite -Samarium Doped Ceria- Argentum for Low Temperature Solid Oxide Fuel Cell

2020 ◽  
Vol 991 ◽  
pp. 94-100
Author(s):  
Umira Asyikin Yusop ◽  
Tan Kang Huai ◽  
Hamimah Abdul Rahman ◽  
Nurul Akidah Baharuddin ◽  
Jarot Raharjo
Keyword(s):  
Particle Size ◽  
Low Temperature ◽  
Composite Powder ◽  
Cobalt Ferrite ◽  
High Energy ◽  
Solid Oxide ◽  
Electrochemical Characteristics ◽  
Doped Ceria ◽  
Oxide Fuel ◽  
Barium Strontium

A low operating temperature is one of the concerns in commercialising solid oxide fuel cells (SOFCs) as a portable power source. The aim of this research is to develop a new cathode material, barium strontium cobalt ferrite–samarium doped ceria (BSCF-SDC) added with argentum (Ag) for low-temperature SOFCs (LT-SOFCs). The composite powder was prepared through high-energy ball milling at 550 rpm for 2 h with a BSCF:SDC powder ratio of 50:50. The composite powder was calcined at 950 °C for 2 h and then mixed with Ag (1wt%, 3wt% and 5wt%) via dry milling at 150 rpm. The phase stability of the resulting samples was examined by X-ray diffractometry, and powder particle sizes were determined by using a Zeta-Sizer Nano ZS. The thermal stability of each sample was determined on the basis of thermal expansion coefficients (TECs), and electrochemical characteristics were determined through electrochemical impedance spectroscopy to investigate the performance of BSCF-SDC-Ag in LT-SOFCs (400–600 °C). Phase analysis demonstrated no impurity phases existed. Particle size analysis revealed that increment in Ag content affect the particle size of BSCF-SDCC. TEC analysis demonstrated that BSCF-SDC-Ag1% has a mismatch value of 16.39%, which is within the acceptable TEC range of 15%–20%. BSCF-SDC-Ag1% showed a maximum conductivity of 39.37Scm-1 at 600 °C.

Microscale Correlations Adoption in Solid Oxide Fuel Cell

2015 ◽  
Vol 12 (4) ◽  
Author(s):  
C. Wang
Keyword(s):  
Particle Size ◽  
Solid Oxide ◽  
Cell Performance ◽  
Oxide Fuel ◽  
Microstructural Parameters ◽  
Novel Approach ◽  
Real Cell ◽  
Microstructure Parameters ◽  
Definition Of ◽  
The Impact

In order to develop a predictive model of real cell performance, firm relationships and assumptions need to be established for the definition of the physical and microstructure parameters for solid oxide fuel cells (SOFCs). This study explores the correlations of microstructure parameters from a microscale level, together with mass transfer and electrochemical reactions inside the electrodes, providing a novel approach to predict SOFC performance numerically. Based on the physical connections and interactions of microstructure parameters, two submodel correlations (i.e., porosity–tortuosity and porosity–particle size ratio) are proposed. Three experiments from literature are selected to facilitate the validation of the numerical results with experimental data. In addition, a sensitivity analysis is performed to investigate the impact of the adopted submodel correlations to the SOFC performance predictions. Normally, the microstructural inputs in the numerical model need to be measured by experiments in order to test the real cell performance. By adopting the two submodel correlations, the simulation can be performed without obtaining relatively hard-to-measure microstructural parameters such as tortuosity and particle size, yet still accurately mimicking a real-world well-structured SOFC operation. By accurately and rationally predicting the microstructural parameters, this study can eventually help to aid the experimental and optimization study of SOFC.

Microstructure Modification of NiO/YSZ Anode in Solid Oxide Fuel Cell by Particle Size Gradation of YSZ

2012 ◽  
Vol 519 ◽  
pp. 32-35
Author(s):  
Qi Bing Chang ◽  
Xia Wang ◽  
Jian Er Zhou ◽  
Yong Qing Wang ◽  
Guang Yao Meng ◽  
...  
Keyword(s):  
Particle Size ◽  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
Bending Strength ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Mass Ratio ◽  
Obvious Effect ◽  
Microstructure Modification ◽  
Particle Size Gradation

The idealized microstructure of NiO/YSZ anode of solid oxide fuel cell (SOFC) is that YSZ structures the bone of the anode and NiO is segregated by YSZ to keep Ni from congregation. To obtain this microstructure, the mixture of coarse YSZ and fine YSZ was used. The effect of the particle size gradation of YSZ on the microstructure of anode was studied. The results show that the homogenous microstructure can be obtained when the mass ratio of the coarse YSZ (d50＝3.38µm) to the fine YSZ (d50＝0.4µm) is 7:3. The pre-sintering temperature has obvious effect on the porosity of the NiO/YSZ. The bending strength of NiO/YSZ and Ni/YSZ are 123MPa and 85MPa, respectively. The reduction of NiO to Ni has less effect on the bending strength for 40vol%Ni/YSZ (7/3).

scholarly journals Monte Carlo Investigation of Particle Properties Affecting TPB Formation and Conductivity in Composite Solid Oxide Fuel Cell Electrode-Electrolyte Interfaces

2011 ◽  
Vol 8 (5) ◽  
Author(s):  
Andrew Martinez ◽  
Jacob Brouwer
Keyword(s):  
Particle Size ◽  
Monte Carlo ◽  
Fuel Cell ◽  
Phase Contrast ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Particle Properties ◽  
Fuel Cell Electrode ◽  
Cell Electrode

A previously developed microstructure model of a solid oxide fuel cell (SOFC) electrode-electrolyte interface has been applied to study the impacts of particle properties on these interfaces through the use of a Monte Carlo simulation method. Previous findings that have demonstrated the need to account for gaseous phase percolation have been confirmed through the current investigation. In particular, the effects of three-phase percolation critically affect the dependence of TPB formation and electrode conductivity on (1) conducting phase particle size distributions, (2) electronic:ionic conduction phase contrast, and (3) the amount of mixed electronic-ionic conductor (MEIC) included in the electrode. In particular, the role of differing percolation effectiveness between electronic and ionic phases has been shown to counteract and influence the role of the phase contrast. Porosity, however, has been found to not be a significant factor for active TPB formation in the range studied, but does not obviate the need for modeling the gas phase. In addition, the current work has investigated the inconsistencies in experimental literature results concerning the optimal particle size distribution. It has been found that utilizing smaller particles with a narrow size distribution is the preferable situation for electrode-electrolyte interface manufacturing. These findings stress the property-function relationships of fuel cell electrode materials.

Random-packing model for solid oxide fuel cell electrodes with particle size distributions

2011 ◽  
Vol 196 (4) ◽  
pp. 1983-1991 ◽  
Author(s):  
Yanxiang Zhang ◽  
Yunlong Wang ◽  
Yao Wang ◽  
Fanglin Chen ◽  
Changrong Xia
Keyword(s):  
Particle Size ◽  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
Random Packing ◽  
Solid Oxide ◽  
Size Distributions ◽  
Oxide Fuel ◽  
Particle Size Distributions ◽  
Fuel Cell Electrodes ◽  
Packing Model
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