Synthesis and Characterizations of Barium Zirconate–Alkali Carbonate Composite Electrolytes for Intermediate Temperature Fuel Cells

Abstract Composite materials based on yttrium-doped zirconate (BaZr0.9Y0.1 O2.95, BZY) and eutectic compositions of alkali carbonates (Li2CO3, Na2CO3 and K2CO3) are investigated. These materials were characterized by X-ray diffraction, scanning electron microscopy and impedance spectroscopy. This study evidences that the combination of BZY with carbonate promotes the densification and enhances the ionic conductivity which reaches 87 mS.cm-1 at 400°C for the BZY – LNK40 composite. In addition, the increase of the conductivity as a function of pH2 suggests that protons are the main charge carriers. The obtained results are interpreted by the transfer of protons from the ceramic to the carbonate phase in the interfacial region.

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Defect-Mediated Conductivity Enhancements in Na3-xPn1-xWxS4 (Pn = P, Sb) using Aliovalent Substitutions

10.26434/chemrxiv.9943961.v2 ◽

2019 ◽

Author(s):

Till Fuchs ◽

Sean Culver ◽

Paul Till ◽

Wolfgang Zeier

Keyword(s):

Ionic Conductivity ◽

Vacancy Concentration ◽

Sodium Ion ◽

High Ionic Conductivity ◽

Ionic Conductors ◽

X Ray Diffraction ◽

X Ray ◽

Solid State Batteries ◽

Ion Conducting ◽

Very High

The sodium-ion conducting family of Na3PnS4, with Pn = P, Sb, have gained interest for the use in solid-state batteries due to their high ionic conductivity. However, significant improvements to the conductivity have been hampered by the lack of aliovalent dopants that can introduce vacancies into the structure. Inspired by the need for vacancy introduction into Na3PnS4, the solid solutions with WS42- introduction are explored. The influence of the substitution with WS42- for PS43- and SbS43-, respectively, is monitored using a combination of X-ray diffraction, Raman and impedance spectroscopy. With increasing vacancy concentration improvements resulting in a very high ionic conductivity of 13 ± 3 mS·cm-1 for Na2.9P0.9W0.1S4 and 41 ± 8 mS·cm-1 for Na2.9Sb0.9W0.1S4 can be observed. This work acts as a stepping-stone towards further engineering of ionic conductors using vacancy-injection via aliovalent substituents.

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Defect-Mediated Conductivity Enhancements in Na3-xPn1-xWxS4 (Pn = P, Sb) using Aliovalent Substitutions

10.26434/chemrxiv.9943961.v1 ◽

2019 ◽

Author(s):

Till Fuchs ◽

Sean Culver ◽

Paul Till ◽

Wolfgang Zeier

Keyword(s):

Ionic Conductivity ◽

Vacancy Concentration ◽

Sodium Ion ◽

High Ionic Conductivity ◽

Ionic Conductors ◽

X Ray Diffraction ◽

X Ray ◽

Solid State Batteries ◽

Ion Conducting ◽

Very High

The sodium-ion conducting family of Na3PnS4, with Pn = P, Sb, have gained interest for the use in solid-state batteries due to their high ionic conductivity. However, significant improvements to the conductivity have been hampered by the lack of aliovalent dopants that can introduce vacancies into the structure. Inspired by the need for vacancy introduction into Na3PnS4, the solid solutions with WS42- introduction are explored. The influence of the substitution with WS42- for PS43- and SbS43-, respectively, is monitored using a combination of X-ray diffraction, Raman and impedance spectroscopy. With increasing vacancy concentration improvements resulting in a very high ionic conductivity of 13 ± 3 mS·cm-1 for Na2.9P0.9W0.1S4 and 41 ± 8 mS·cm-1 for Na2.9Sb0.9W0.1S4 can be observed. This work acts as a stepping-stone towards further engineering of ionic conductors using vacancy-injection via aliovalent substituents.

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Role of the Structure and Electronic Properties of Fe2O3-MoO3 Catalyst on the Dehydration of Isopropyl Alcohol

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19931591 ◽

1993 ◽

Vol 58 (7) ◽

pp. 1591-1599 ◽

Cited By ~ 3

Author(s):

Abd El-Aziz A. Said

Keyword(s):

Active Sites ◽

Isopropyl Alcohol ◽

Oxide Catalyst ◽

Flow System ◽

Charge Carriers ◽

X Ray Diffraction ◽

X Ray ◽

Catalyst Composition ◽

Surface Active

Molybdenum oxide catalyst doped or mixed with (1 - 50) mole % Fe3+ ions were prepared. The structure of the original samples and the samples calcined at 400 °C were characterized using DTA, X-ray diffraction and IR spectra. Measurements of the electrical conductivity of calcined samples with and without isopropyl alcohol revealed that the conductance increases on increasing the content of Fe3+ ions up to 50 mole %. The activation energies of charge carriers were determined in presence and absence of the alcohol. The catalytic dehydration of isopropyl alcohol was carried out at 250 °C using a flow system. The results obtained showed that the doped or mixed catalysts are active and selective towards propene formation. However, the catalyst containing 40 mole % Fe3+ ions exhibited the highest activity and selectivity. Correlations were attempted to the catalyst composition with their electronic and catalytic properties. Probable mechanism for the dehydration process is proposed in terms of surface active sites.

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Influence of Li2CO3 addition on electrical and magnetic properties of Ni0.6Mg0.4Fe2O4

Journal of Advanced Dielectrics ◽

10.1142/s2010135x20500034 ◽

2020 ◽

Vol 10 (03) ◽

pp. 2050003

Author(s):

M. R. Hassan ◽

M. T. Islam ◽

M. N. I. Khan

Keyword(s):

Magnetic Properties ◽

Single Phase ◽

Low Frequency ◽

Solid State Reaction Method ◽

Charge Carriers ◽

X Ray Diffraction ◽

X Ray ◽

Electrical And Magnetic Properties ◽

Frequency Regime ◽

Xrd Patterns

In this research, influence of adding Li2CO3 (at 0%, 2%, 4%, 6%) on electrical and magnetic properties of [Formula: see text][Formula: see text]Fe2O4 (with 60% Ni and 40% Mg) ferrite has been studied. The samples are prepared by solid state reaction method and sintered at 1300∘C for 6[Formula: see text]h. X-ray diffraction (XRD) patterns show the samples belong to single-phase cubic structure without any impurity phase. The magnetic properties (saturation magnetization and coercivity) of the samples have been investigated by VSM and found that the higher concentration of Li2CO3 reduces the hysteresis loss. DC resistivity increases with Li2CO3 contents whereas it decreases initially and then becomes constant at lower value with temperature which indicates that the studied samples are semiconductor. The dielectric dispersion occurs at a low-frequency regime and the loss peaks are formed in a higher frequency regime, which are due to the presence of resonance between applied frequency and hopping frequency of charge carriers. Notably, the loss peaks are shifted to the lower frequency with Li2CO3 additions.

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Analysis on Microstructure of Laser Brazing Diamond Grits with a Ni-Based Filler Alloy

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.97-101.3879 ◽

2010 ◽

Vol 97-101 ◽

pp. 3879-3883 ◽

Cited By ~ 1

Author(s):

Zhi Bo Yang ◽

Jiu Hua Xu ◽

Ai Ju Liu

Keyword(s):

Active Element ◽

Steel Substrate ◽

Parameters Optimization ◽

Interfacial Region ◽

Filler Alloy ◽

X Ray Diffraction ◽

X Ray ◽

Cross Diffusion ◽

Electron Microscopes ◽

Scanning Electron Microscopes

Brazing diamond grits onto steel substrate using a Ni-based filler alloy was carried out via laser beam in an argon atmosphere. The microstructure of the interfacial region among the Diamond grits and the filler layer were investigated by means of scanning electron microscopes (SEM), X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDS). Meanwhile, the formation mechanism of carbide layers was discussed. All the results indicated that the active element chromium in the Ni-based alloy concentrated preferentially to the surface of the grits to form a chromium-rich layer, and the hard joint between the alloy and the steel substrate is established through a cross-diffusion of iron and Ni-based alloy through parameters optimization.

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ITO Thin Films on Silicon Buffer by Sol Gel Method

Materials Science Forum ◽

10.4028/www.scientific.net/msf.514-516.1155 ◽

2006 ◽

Vol 514-516 ◽

pp. 1155-1160 ◽

Cited By ~ 1

Author(s):

Talaat Moussa Hammad

Keyword(s):

Thin Films ◽

Indium Tin Oxide ◽

Optical Transmission ◽

Sol Gel ◽

Precursor Solution ◽

Charge Carriers ◽

X Ray Diffraction ◽

X Ray ◽

Ito Thin Films ◽

Uv Visible

Sol gel indium tin oxide thin films (In: Sn = 90:10) were prepared by the sol-gel dipcoating process on silicon buffer substrate. The precursor solution was prepared by mixing SnCl2.2H2O and InCl3 dissolved in ethanol and acetic acid. The crystalline structure and grain orientation of ITO films were determined by X-ray diffraction. The surface morphology of the films was characterized by scanning electron microscope (SEM). Optical transmission and reflectance spectra of the films were analyzed by using a UV-visible spectrophotometer. The transport properties of majority charge carriers for these films were studied by Hall measurement. ITO thin film with electrical resistivity of 7.6 ×10-3 3.cm, Hall mobility of approximately 2 cm2(Vs)-1 and free carrier concentration of approximately 4.2 ×1020 cm-3 are obtained for films 100 nm thick films. The I-V curve measurement showed typical I-V characteristic behavior of sol gel ITO thin films.

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Nanosheets of CuCo2O4 As a High-Performance Electrocatalyst in Urea Oxidation

Applied Sciences ◽

10.3390/app9040793 ◽

2019 ◽

Vol 9 (4) ◽

pp. 793 ◽

Cited By ~ 5

Author(s):

Camila Zequine ◽

Fangzhou Wang ◽

Xianglin Li ◽

Deepa Guragain ◽

S.R. Mishra ◽

...

Keyword(s):

Fuel Cells ◽

Photoelectron Spectroscopy ◽

High Performance ◽

Nickel Foam ◽

Low Cost ◽

Agricultural Waste ◽

Bifunctional Catalyst ◽

X Ray Diffraction ◽

X Ray ◽

Electroactive Material

The urea oxidation reaction (UOR) is a possible solution to solve the world’s energy crisis. Fuel cells have been used in the UOR to generate hydrogen with a lower potential compared to water splitting, decreasing the costs of energy production. Urea is abundantly present in agricultural waste and in industrial and human wastewater. Besides generating hydrogen, this reaction provides a pathway to eliminate urea, which is a hazard in the environment and to people’s health. In this study, nanosheets of CuCo2O4 grown on nickel foam were synthesized as an electrocatalyst for urea oxidation to generate hydrogen as a green fuel. The synthesized electrocatalyst was characterized using X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy. The electroactivity of CuCo2O4 towards the oxidation of urea in alkaline solution was evaluated using electrochemical measurements. Nanosheets of CuCo2O4 grown on nickel foam required the potential of 1.36 V in 1 M KOH with 0.33 M urea to deliver a current density of 10 mA/cm2. The CuCo2O4 electrode was electrochemically stable for over 15 h of continuous measurements. The high catalytic activities for the hydrogen evolution reaction make the CuCo2O4 electrode a bifunctional catalyst and a promising electroactive material for hydrogen production. The two-electrode electrolyzer demanded a potential of 1.45 V, which was 260 mV less than that for the urea-free counterpart. Our study suggests that the CuCo2O4 electrode can be a promising material as an efficient UOR catalyst for fuel cells to generate hydrogen at a low cost.

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Electrochemical Study of Anodized Titanium in Phosphoric Acid

Advances in Materials Science and Engineering ◽

10.1155/2020/5769071 ◽

2020 ◽

Vol 2020 ◽

pp. 1-11

Author(s):

M. Khadiri ◽

M. Elyaagoubi ◽

R. Idouhli ◽

Y. Koumya ◽

O. Zakir ◽

...

Keyword(s):

Electrochemical Impedance ◽

Charge Carriers ◽

Flat Band ◽

X Ray Diffraction ◽

X Ray ◽

Type Semiconductor ◽

Anodized Titanium ◽

Spectroscopy Studies ◽

Schottky Model ◽

Good Agreement

The anodization of the Ti-Cu (2%) alloy was carried out in a 5M H3PO4 solution for 2 minutes. The obtained layers are characterized by XPS, X-ray diffraction, and Raman spectroscopy. The results showed that the obtained films are composed of poorly crystallized TiO2 oxide. Electrochemical Impedance spectroscopy studies revealed that the thickness of the formed film increases with increasing anodization potential. Additionally, the resistance of charge transfer becomes higher when the anodization potential increases. Thus, the Mott Schottky model revealed that the formed film is an n-type semiconductor. The density of charge carriers is in good agreement with those found in the literature. Also, it is found that the flat-band potential increases with increasing treatment potential.

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Fully soluble self-doped poly(3,4-ethylenedioxythiophene) with an electrical conductivity greater than 1000 S cm−1

Science Advances ◽

10.1126/sciadv.aav9492 ◽

2019 ◽

Vol 5 (4) ◽

pp. eaav9492 ◽

Cited By ~ 24

Author(s):

Hirokazu Yano ◽

Kazuki Kudo ◽

Kazumasa Marumo ◽

Hidenori Okuzaki

Keyword(s):

Electrical Conductivity ◽

Critical Parameter ◽

Colloidal Particles ◽

Average Distance ◽

Charge Carriers ◽

High Electrical Conductivity ◽

X Ray Diffraction ◽

X Ray ◽

Atomic Force ◽

Technical Issues

Wet-processable and highly conductive polymers are promising candidates for key materials in organic electronics. Poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) is commercially available as a water dispersion of colloidal particles but has some technical issues with PSS. Here, we developed a novel fully soluble self-doped PEDOT (S-PEDOT) with an electrical conductivity as high as 1089 S cm−1without additives (solvent effect). Our results indicate that the molecular weight of S-PEDOT is the critical parameter for increasing the number of nanocrystals, corresponding to the S-PEDOT crystallites evaluated by x-ray diffraction and conductive atomic force microscopic analyses as having high electrical conductivity, which reduced both the average distance between adjacent nanocrystals and the activation energy for the hopping of charge carriers, leading to the highest bulk conductivity.

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