Preparation and characterization of compounds in the BaBiO3–Ba(Ce1-xGdx)O3-x/2 system

1999 ◽  
Vol 14 (1) ◽  
pp. 124-131 ◽  
Author(s):  
R. Mukundan ◽  
P. K. Davies ◽  
W. L. Worrell
Keyword(s):  
Ionic Conductivity ◽  
Elevated Temperatures ◽  
Electronic Conductivity ◽  
Mixed Valence ◽  
Type Model ◽  
Pseudobinary System ◽  
Conducting Oxides ◽  
Oxygen Ion ◽  
Reducing Conditions ◽  
Electronic Conductivities

The structure, nonstoichiometry, and electrical conductivity of compositions in the BaBiO3– Ba(Ce1-xGdx)O3-x/2 system have been investigated in an attempt to prepare new mixed (ionic-electronic) conducting oxides. The substitution of Bi into Ba(Ce1-xGdx)O3-x/2 decreases the concentration of oxygen-ion vacancies, and the effective negative charge of the Gd dopant is compensated by the mixed valence of Bi (3+, 5+). For low Bi contents a decrease in ionic conductivity decreases the overall conductivity; however, higher levels of Bi introduce significant electronic conductivity, and for Ba(Bi0.5Ce0.5)O3, σtotal ≈ 1 S/cm at 800 °C in air. Compositions in the Ba(Bi0.5Ce0.5-xGdx)O3 pseudobinary system undergo a B-cation order-disorder transformation at 1300–1350 °C for x = 0.5 and at ≈1250 °C for x = 0.4; all other compositions retain a disordered B-site arrangement. While these disordered perovskites exhibit oxygen nonstoichiometry under reducing conditions at elevated temperatures, with the extent of reduction decreasing with increasing Gd content, their ordered counterparts remain close to stoichiometry. The electronic conductivities of this pseudobinary could be fitted to a “band-type” model, and, despite the presence of oxygen vacancies for the lower values of x, no significant ionic conductivity was observed.

Experimental Study on Electrical Conductivity of FexO-CaO-SiO2-Al2O3 System at Various Oxygen Potentials

2018 ◽  
Vol 37 (2) ◽  
pp. 121-125 ◽  
Author(s):  
Yan–Xiang Liu ◽  
Jun–Hao Liu ◽  
Guo–Hua Zhang ◽  
Jian–Liang Zhang ◽  
Kuo–Chih Chou
Keyword(s):  
Electrical Conductivity ◽  
Ionic Conductivity ◽  
Oxygen Potential ◽  
Electronic Conductivity ◽  
Transference Number ◽  
Free Oxygen ◽  
Total Electrical Conductivity ◽  
Oxygen Ion ◽  
Conductivity Increase ◽  
Temperature Dependences

AbstractThe electrical conductivity of FexO-CaO-SiO2-Al2O3 slags was measured by a four terminal method. The results show that the temperature dependences of total, electronic and ionic conductivity for different compositions obey the Arrhenius law and all of them increase as increasing the temperature. For all the studied slags, as increasing CO/CO2 ratio which is used to controlled the oxygen potential, both the total electrical conductivity and electronic conductivity increase, but the ionic conductivity decreases. It was also found that the electronic transference number exhibits a strong correlation with oxygen potential, but is independent of temperature. Under the condition of constant FexO content, the higher the basicity of slags is, the higher the total electrical conductivity and ionic/electronic conductivity will be, which is resulted from the increase of free oxygen ion.

scholarly journals Investigation of Ion and Electron Conduction in the Mixed Ionic-Electronic Conductor- La-Sr-Co-Fe-Oxide (LSCF) Using Alternating Current (AC) and Direct Current (DC) Techniques

2021 ◽  
Author(s):  
Chong Lei ◽  
Michael Simpson ◽  
Anil Virkar
Keyword(s):  
Ionic Conductivity ◽  
Electronic Conductivity ◽  
Electron Conduction ◽  
Oxygen Ion ◽  
Electronic Current ◽  
Mixed Ionic Electronic Conductor ◽  
Measurement Results ◽  
In Series ◽  
Mixed Ionic Electronic Conductors ◽  
Increasing Temperature

Abstract Among many mixed ionic electronic conductors (MIECs), lanthanum strontium cobalt iron oxide (LSCF) has been proven as a promising material for use as cathode in SOFCs. The ion and electron conduction in LSCF need to be studied separately. To measure the ionic conductivity of LSCF, YSZ disks were applied to block the electronic current, and multilayered samples were made with YSZ disks in series with an LSCF disk. Both AC and DC techniques were used for the measurements. An LSCF(porous)/LSCF(dense)/LSCF(porous) bar-shaped sample was made to measure the electronic conductivity of LSCF. DC technique was utilized for the measurement. Results show that the ionic conductivity of LSCF is much lower than its electronic conductivity. The ionic conductivity of LSCF increases with increasing temperature (600-900°C), and the electronic conductivity decreases with increasing temperature (600-900°C). Measurements were also made on a foil of silver to investigate oxygen transport through it. From this, oxygen ion conductivity through silver was estimated.

scholarly journals A novel and potentially scalable CVD-based route towards SnO2:Mo thin films as transparent conducting oxides

2021 ◽  
Author(s):  
Tianlei Ma ◽  
Marek Nikiel ◽  
Andrew G. Thomas ◽  
Mohamed Missous ◽  
David J. Lewis
Keyword(s):  
Thin Films ◽  
Photoelectron Spectroscopy ◽  
Mixed Valence ◽  
Chemical Vapour ◽  
X Ray Diffraction ◽  
X Ray ◽  
Conducting Oxides ◽  
Valence States ◽  
3 Omega ◽  
First Time

AbstractIn this report, we prepared transparent and conducting undoped and molybdenum-doped tin oxide (Mo–SnO2) thin films by aerosol-assisted chemical vapour deposition (AACVD). The relationship between the precursor concentration in the feed and in the resulting films was studied by energy-dispersive X-ray spectroscopy, suggesting that the efficiency of doping is quantitative and that this method could potentially impart exquisite control over dopant levels. All SnO2 films were in tetragonal structure as confirmed by powder X-ray diffraction measurements. X-ray photoelectron spectroscopy characterisation indicated for the first time that Mo ions were in mixed valence states of Mo(VI) and Mo(V) on the surface. Incorporation of Mo6+ resulted in the lowest resistivity of $$7.3 \times 10^{{ - 3}} \Omega \,{\text{cm}}$$ 7.3 × 10 - 3 Ω cm , compared to pure SnO2 films with resistivities of $$4.3\left( 0 \right) \times 10^{{ - 2}} \Omega \,{\text{cm}}$$ 4.3 0 × 10 - 2 Ω cm . Meanwhile, a high transmittance of 83% in the visible light range was also acquired. This work presents a comprehensive investigation into impact of Mo doping on SnO2 films synthesised by AACVD for the first time and establishes the potential for scalable deposition of SnO2:Mo thin films in TCO manufacturing. Graphical abstract

Conductivity-Temperature Dependent Studies on MG49 Doped Lithium Triflate Salt

2015 ◽  
Vol 1107 ◽  
pp. 181-186
Author(s):  
Zaidatul Salwa Mahmud ◽  
N.H.M. Zaki ◽  
R. Zakaria ◽  
Mohamad Faizul Yahya ◽  
Ab Malik Marwan Ali
Keyword(s):  
Ionic Conductivity ◽  
Elevated Temperatures ◽  
Ethylene Carbonate ◽  
Ionic Mobility ◽  
Ionic Conductors ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
Lithium Triflate ◽  
Mobility Of Charge Carriers ◽  
Solution Cast

This paper reports on the conductivity-temperature studies of gel polymer electrolytes (GPEs) based on 49% poly (methyl methacrylate) grafted-natural rubber (MG49) doped with lithium triflate salt (LiTf) and plasticized with ethylene carbonate (EC). The GPE films are prepared by solution cast technique. The X-ray diffraction (XRD) studies reveal the polymer electrolyte systems are amorphous. AC impedance spectroscopy is carried out in the temperature range between 303 and 373 K. The magnitudes of conductivity observed are strongly dependent on salt concentration and temperature. The high ionic conductivity at elevated temperatures of GPE is attributed to the high ionic mobility of charge carriers. The ionic migration is seen to follow the VTF behavior and approaches to Arrhenius rule at high and low at temperature. Ionic conductivity relaxation appears to be a characteristic of the ionic polarization and the modulus formalism studies confirmed the GPEs in the present investigation are ionic conductors.

Surface Modification of Solid Electrolytes for Advanced Chemical Sensors.

1988 ◽  
Vol 135 ◽  
Author(s):  
Werner Weppner
Keyword(s):  
Surface Modification ◽  
Solid State ◽  
Ionic Conductivity ◽  
Process Control ◽  
Environmental Protection ◽  
Chemical Sensors ◽  
Solid Electrolytes ◽  
Elevated Temperatures ◽  
High Ionic Conductivity ◽  
Ion Conductors

Solid State ion conductors are sucessfully employed in chemical sensors for gases such as oxygen for process control and environmental protection. The application requires elevated temperatures for sufficiently high ionic conductivity and is restricted to a few gases for which suitable solid electrolytes are available.

Co-adsorption of arsenite and arsenate on mixed-valence Fe(II,III) (hydr)oxides under reducing conditions

2018 ◽  
Vol 98 ◽  
pp. 418-425 ◽  
Author(s):  
Lei Lei ◽  
Guoqing Zhang ◽  
Jinru Lin ◽  
Xin Wang ◽  
Shaofeng Wang ◽  
...  
Keyword(s):  
Co Adsorption ◽  
Mixed Valence ◽  
Reducing Conditions

scholarly journals Mixed Ionic-Electronic Conductors Based on PEDOT:PolyDADMA and Organic Ionic Plastic Crystals

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1981
Author(s):  
Rafael Del Olmo ◽  
Nerea Casado ◽  
Jorge L. Olmedo-Martínez ◽  
Xiaoen Wang ◽  
Maria Forsyth
Keyword(s):  
Energy Storage ◽  
Ionic Conductivity ◽  
Electronic Devices ◽  
Electronic Conductivity ◽  
Ionic Conductivities ◽  
New Materials ◽  
Plastic Crystals ◽  
Energy Storage Applications ◽  
Mixed Ionic Electronic Conductors ◽  
Electronic Conductors

Mixed ionic-electronic conductors, such as poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS) are postulated to be the next generation materials in energy storage and electronic devices. Although many studies have aimed to enhance the electronic conductivity and mechanical properties of these materials, there has been little focus on ionic conductivity. In this work, blends based on PEDOT stabilized by the polyelectrolyte poly(diallyldimethylammonium) (PolyDADMA X) are reported, where the X anion is either chloride (Cl), bis(fluorosulfonyl)imide (FSI), bis(trifluoromethylsulfonyl)imide (TFSI), triflate (CF3SO3) or tosylate (Tos). Electronic conductivity values of 0.6 S cm−1 were achieved in films of PEDOT:PolyDADMA FSI (without any post-treatment), with an ionic conductivity of 5 × 10−6 S cm−1 at 70 °C. Organic ionic plastic crystals (OIPCs) based on the cation N-ethyl-N-methylpyrrolidinium (C2mpyr+) with similar anions were added to synergistically enhance both electronic and ionic conductivities. PEDOT:PolyDADMA X / [C2mpyr][X] composites (80/20 wt%) resulted in higher ionic conductivity values (e.g., 2 × 10−5 S cm−1 at 70 °C for PEDOT:PolyDADMA FSI/[C2mpyr][FSI]) and improved electrochemical performance versus the neat PEDOT:PolyDADMA X with no OIPC. Herein, new materials are presented and discussed including new PEDOT:PolyDADMA and organic ionic plastic crystal blends highlighting their promising properties for energy storage applications.

Coordination polymer-based conductive materials: ionic conductivity vs. electronic conductivity

2019 ◽  
Vol 7 (42) ◽  
pp. 24059-24091 ◽  
Author(s):  
Hai-Ning Wang ◽  
Xing Meng ◽  
Long-Zhang Dong ◽  
Yifa Chen ◽  
Shun-Li Li ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Ionic Conductivity ◽  
Coordination Polymer ◽  
Coordination Polymers ◽  
Electronic Conductivity ◽  
Structural Factors ◽  
Conductive Materials ◽  
Recent Developments

This review summarizes recent developments of coordination polymers and their derivatives for ionic and electrical conductivity with the discussion about synthetic strategies and possible mechanisms to identify the key structural factors.

Structural Characterization and Ionic Conductivity of Metastable Gd2(Ti0.65Zr0.35)2O7 Powders Prepared by Mechanical Milling

2006 ◽  
Vol 972 ◽  
Author(s):  
Antonio F. Fuentes ◽  
Karla J. Moreno ◽  
Jacobo Santamaria ◽  
Carlos Leon ◽  
Ulises Amador
Keyword(s):  
Ionic Conductivity ◽  
Mechanical Milling ◽  
Sintering Temperature ◽  
Ion Dynamics ◽  
Conductivity Relaxation ◽  
Electrical Conductivity Relaxation ◽  
Ion Interactions ◽  
Oxygen Ion ◽  
Fluorite Type ◽  
Powder Phase

AbstractWe analyze in this work the influence of ordering on the oxygen ion dynamics in the ionic conductor Gd2(Ti0.65Zr0.35)2O7, prepared by mechanical milling. As-prepared powder phase presents a metastable anion deficient fluorite-type of structure below 800°C becoming a disordered pyrochlore above this temperature. Such phase transformation implies a significant increase in the ionic conductivity of this material as a result of a systematic decrease in the activation energy for the dc conductivity, from 1.23 to 0.78 eV. Electrical conductivity relaxation is well described by the Kohlrausch-Williams-Watts (KWW) stretched exponential function with the fractional exponent n decreasing systematically with increasing sintering temperature (increasing ordering) as a result of decreasing ion-ion interactions in better ordered samples.

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