scholarly journals Suitability of Sm3+-Substituted SrTiO3 as Anode Materials for Solid Oxide Fuel Cells: A Correlation between Structural and Electrical Properties

Energies ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 4042 ◽  
Author(s):  
Saurabh Singh ◽  
Raghvendra Pandey ◽  
Sabrina Presto ◽  
Maria Paola Carpanese ◽  
Antonio Barbucci ◽  
...  
Keyword(s):  
Oxygen Content ◽  
Conduction Mechanism ◽  
Small Polaron ◽  
Solubility Limit ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Solid Solubility Limit ◽  
Polaron Hopping ◽  
Auto Combustion ◽  
Lower Oxygen

Perovskite anodes, nowadays, are used in any solid oxide fuel cell (SOFC) instead of conventional nickel/yttria-stabilized zirconia (Ni/YSZ) anodes due to their better redox and electrochemical stability. A few compositions of samarium-substituted strontium titanate perovskite, SmxSr1−xTiO3−δ (x = 0.00, 0.05, 0.10, 0.15, and 0.20), were synthesized via the citrate-nitrate auto-combustion route. The XRD patterns of these compositions confirm that the solid solubility limit of Sm in SrTiO3 is x < 0.15. The X-ray Rietveld refinement for all samples indicated the perovskite cubic structure with a P m 3 ¯ m space group at room temperature. The EDX mapping of the field emission scanning electron microscope (FESEM) micrographs of all compositions depicted a lower oxygen content in the specimens respect to the nominal value. This lower oxygen content in the samples were also confirmed via XPS study. The grain sizes of SmxSr1−xTiO3 samples were found to increase up to x = 0.10 and it decreases for the composition with x > 0.10. The AC conductivity spectra were fitted by Jonscher’s power law in the temperature range of 500–700 °C and scaled with the help of the Ghosh and Summerfield scaling model taking νH and σdc T as the scaling parameters. The scaling behaviour of the samples showed that the conduction mechanism depends on temperature at higher frequencies. Further, a study of the conduction mechanism unveiled that small polaron hopping occurred with the formation of electrons. The electrical conductivity, in the H2 atmosphere, of the Sm0.10Sr0.90TiO3 sample was found to be 2.7 × 10−1 S∙cm−1 at 650 °C, which is the highest among the other compositions. Hence, the composition Sm0.10Sr0.90TiO3 can be considered as a promising material for the application as the anode in SOFCs.

Strontium Dopant Concentrations Influence on Nd1-xSrxMnO3±δ Structural and Electrical Conductivity

2010 ◽  
Vol 660-661 ◽  
pp. 636-640
Author(s):  
Reinaldo Azevedo Vargas ◽  
Rubens Chiba ◽  
Marco Andreoli ◽  
Emília Satoshi Miyamaru Seo
Keyword(s):  
Electrical Conductivity ◽  
Perovskite Structure ◽  
Small Polaron ◽  
Ceramic Materials ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
X Ray Diffraction ◽  
Polaron Hopping ◽  
Different Types ◽  
Fuel Cell Cathode

Many different types of ceramic materials are currently being studied as possible cathodes in Solid Oxide Fuel Cells (SOFC), in an attempt to reduce operating temperatures. Strontium-doped neodymium manganite (Nd1-xSrxMnO3±δ) was used as an intermediate temperature solid oxide fuel cell cathode. X-ray diffraction and electrical conductivity of the Nd1-xSrxMnO3±δ system with a perovskite structure were studied in function of x equal to 0.10, 0.30 and 0.50. An orthorhombic pseudo-perovskite structure was assigned to all powder compositions prepared by standard ceramic technique. Electrical conductivity was described by the small polaron hopping conductivity model, as well as, increases due to regular increments of Sr content for all compositions. Electrical conductivity was measured at 25.2, 26.4 and 37.1Scm-1 for x = 0.10, 0.30 and 0.50, respectively at 800°C.

Small polaron hopping conduction mechanism in Fe doped LaMnO3

2011 ◽  
Vol 135 (5) ◽  
pp. 054501 ◽  
Author(s):  
Wasi Khan ◽  
Alim H. Naqvi ◽  
Maneesha Gupta ◽  
Shahid Husain ◽  
Ravi Kumar
Keyword(s):  
Conduction Mechanism ◽  
Small Polaron ◽  
Hopping Conduction ◽  
Polaron Hopping ◽  
Small Polaron Hopping

Synthesis of Vanadium Oxide Colloidal Dispersions for Antistatic Coatings

1996 ◽  
Vol 432 ◽  
Author(s):  
Eric.D. Morrison
Keyword(s):  
Vanadium Oxide ◽  
Conduction Mechanism ◽  
Colloidal Particles ◽  
Small Polaron ◽  
Electronic Conductivity ◽  
Colloidal Dispersions ◽  
Thin Layers ◽  
Properties Of Coatings ◽  
Polaron Hopping ◽  
Dispersed Particles

AbstractVanadium oxide deposited in thin layers from aqueous colloidal dispersions exhibits electronic conductivity by a small polaron hopping conduction mechanism. Conductivity and static dissipative properties of coatings are unaffected by changes in humidity. Because vanadium oxide is highly colored, the deposition of effective antistatic coatings which are transparent and colorless requires that the percolative (networking forming) properties of the colloidal particles be maximized. The percolative properties of the colloid are strongly influenced by morphology of the dispersed particles and the extent to which they are well dispersed in the aquasol. These properties are determined by the synthetic route to the colloid. Vanadium oxide is the most potent antistatic agent known and has been found to provide antistatic properties even when as little as 1 milligram per square meter is used.

Synthesis and Characterization of Nanocrystalline La0.65Sr0.3 MnO3 and La0.8Sr0.2MnO3 Cathode Powders by Auto-ignition Technique for Solid Oxide Fuel Cells (SOFC)

2016 ◽  
Vol 19 (2) ◽  
pp. 065-076
Author(s):  
G. N. Almutairi ◽  
M. Ghouse ◽  
Y. M. Alyousef ◽  
F. S. Alenazey
Keyword(s):  
Fuel Cells ◽  
Solid Oxide Fuel Cells ◽  
High Efficiency ◽  
Single Cells ◽  
Average Crystallite Size ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Functional Layer ◽  
Auto Combustion

Solid Oxide fuel Cells (SOFCs) are considered to be one of the most promising energy conversion devices that have several advantages such as high efficiency, system compactness and low environmental pollution. In the present investigation La0.65Sr0.3MnO3 (LSM-1) and La0.8Sr0.2MnO3 (LSM-2) nanoceramic powders were prepared by citrate-nitrate route of auto-combustion with citrate to nitrate (c/n) ratio 0.50 to see the effect of these cathode powders on the performance of SOFC cells. The as prepared powder were calcined at 900oC for 4hrs using the Thermolyne 47900 furnace to remove carboneous residues and characterized them using SEM / EDS, XRD, TGA techniques and their results are presented . From calculations using Debye Scherrer’s equation, the average crystallite size of the powders were found to be around 16nm. The SEM indicates the particle sizes are within the range of around 200nm.The surface area of the calcined LSM-2 powder was found to be ~21m2/g. The TGA studies indicate the completion of combustion since there was no further weight loss after reaching temperature of ~ 650oC. Also, Electrochemical characterization of LSM cathode powders were carried out by coating these powders (as cathode functional layer CFL-Bottom and current collector layer CL- Top) using Screen printing on the SOFC half cells (NiO-YSZ+YSZ) procured from CGCRI, Kolkata, India with a cell size of 16mm dia x1.6mm and tested these cells with H2-O2 at 750-800oC with the flow rates of 100-200 sccm. The results of the performances of single cells are presented in this paper. The Current density and powder density values obtained are 0.80A/cm2 (at 0.7V) and 0.55 W/cm2 at 800oC with 200 sccm of hydrogen and oxygen respectively. The area surface resistance (ASR) values obtained were ~0.50 Ωcm2 at 0.7V at 800oC.

Highly conductive barium iron vanadate glass containing different metal oxides

2017 ◽  
Vol 89 (4) ◽  
pp. 419-428 ◽  
Author(s):  
Tetsuaki Nishida ◽  
Yukimi Izutsu ◽  
Mina Fujimura ◽  
Keito Osouda ◽  
Yuki Otsuka ◽  
...  
Keyword(s):  
Metal Oxides ◽  
Conduction Mechanism ◽  
Marked Decrease ◽  
Small Polaron ◽  
Electric Resistivity ◽  
Electron Configuration ◽  
Polaron Hopping ◽  
Vanadate Glass ◽  
Type Semiconductor ◽  
Vanadate Glasses

Abstract20BaO·5ZnO·5Fe2O3·70V2O5 glass annealed at 450°C for 30 min showed a marked decrease in the electric resistivity (ρ) from 4.0×105 to 4.8 Ωcm, while 20BaO·5Cu2O·5Fe2O3·70V2O5 glass from 2.0×105 to 5.0 Ωcm. As for the conduction mechanism, it proved that n-type semiconductor model in conjugation with the small polaron hopping theory was most probable. Since ZnII and CuI have a 3d10-electron configuration in the outer-most orbital, Ga2O3- and GeO2-containing vanadate glasses were explored in this study. 20BaO·5Ga2O3·5Fe2O3·70V2O5 glass showed a less remarkable decrease of ρ from 4.5×105 to 100 Ωcm, and 20BaO·5GeO2·5Fe2O3·70V2O5 glass from 3.3×106 to 400 Ωcm. Activation energies for the conduction (Ea) of GeO2- and Ga2O3-contaning glasses before the annealing were respectively estimated to be 0.42 and 0.41 eV. It proved that barium iron vanadate glass with a smaller Ea value could attain the higher conductivity after the annealing at temperaures higher than the crystalization temperature.

Small polaron hopping conduction mechanism in Ni-doped LaFeO3

2010 ◽  
Vol 90 (22) ◽  
pp. 3069-3079 ◽  
Author(s):  
M. Wasi Khan ◽  
Shahid Husain ◽  
M.A. Majeed Khan ◽  
Maneesha Gupta ◽  
Ravi Kumar ◽  
...  
Keyword(s):  
Conduction Mechanism ◽  
Small Polaron ◽  
Hopping Conduction ◽  
Polaron Hopping ◽  
Small Polaron Hopping

ELECTRICAL BEHAVIOR OF SOME LANTHANUM-BASED RARE EARTH CMR MATERIALS

2005 ◽  
Vol 19 (23) ◽  
pp. 3619-3629 ◽  
Author(s):  
V. RAJA KUMARI ◽  
G. VENKATAIAH ◽  
P. VENUGOPAL REDDY
Keyword(s):  
Rare Earth ◽  
Conduction Mechanism ◽  
Small Polaron ◽  
Domain Boundary ◽  
Solid State Reaction Method ◽  
7 Tesla ◽  
Scattering Process ◽  
Rare Earth Ion ◽  
Polaron Hopping ◽  
Composition Formula

A lanthanum-based mixed rare earth manganite system with general composition formula La 0.33 Ln 0.34 Sr 0.33 MnO 3, (where Ln is a rare earth ion) has been prepared by the solid state reaction method. After usual characterization of these materials, a systematic study of the electrical resistivity both as a function of temperature (80–300 K) and magnetic field up to 7 Tesla was undertaken mainly to understand the conduction mechanism. On analyzing the experimental results, it has been concluded that the metallic (ferromagnetic) part of the resistivity (ρ) (below TP) fits with the equation ρ(T)=ρ0+ρ2T2+ρ4.5T4.5, indicating the importance of grain/domain boundary effects (ρ0), the electron-electron scattering process (ρ2T2) and the two magnon scattering process (ρ4.5T4.5). On the other hand, the paramagnetic insulating regime may be explained by using adiabatic small polaron hopping and variable range hopping mechanisms, thereby indicating that polaron hopping might be responsible for the conduction mechanism.

Auto-combustion synthesis and properties of Ce0.85Gd0.15O1.925 for intermediate temperature solid oxide fuel cells electrolyte

2011 ◽  
Vol 192 (1) ◽  
pp. 431-434 ◽  
Author(s):  
Nitish Kumar Singh ◽  
Prabhakar Singh ◽  
Manish Kumar Singh ◽  
Devendra Kumar ◽  
Om Parkash
Keyword(s):  
Fuel Cells ◽  
Solid Oxide Fuel Cells ◽  
Combustion Synthesis ◽  
Solid Oxide ◽  
Intermediate Temperature ◽  
Oxide Fuel ◽  
Auto Combustion

Sucrose‐nitrate auto combustion synthesis of Ce 0.85 Ln 0.10 Sr 0.05 O 2‐ δ (Ln = La and Gd) electrolytes for solid oxide fuel cells

2020 ◽  
Vol 44 (6) ◽  
pp. 4652-4663 ◽  
Author(s):  
Vishnu Vijaykumar ◽  
Gurudeo Nirala ◽  
Dharmendra Yadav ◽  
Upendra Kumar ◽  
Shail Upadhyay
Keyword(s):  
Fuel Cells ◽  
Solid Oxide Fuel Cells ◽  
Combustion Synthesis ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Auto Combustion
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