Application of Protonic Conduction in Perovskite-Type Oxides: Mixed Proton-Electron-Conducting Membrane for Hydrogen Separation

2006 ◽  
Vol 45 ◽  
pp. 2024-2032
Author(s):  
Hiroshige Matsumoto
Keyword(s):  
Base Material ◽  
Hydrogen Separation ◽  
Charge Carriers ◽  
Mixed Conductor ◽  
Electronic Charge ◽  
Protonic Conduction ◽  
Mixed Conductivity ◽  
Metal Doped ◽  
Key Techniques ◽  
Perovskite Type

Hydrogen separation is one of the key techniques for the forthcoming hydrogen economy. This paper describes a possible electrochemical method and materials for hydrogen separation: mixed proton-electron-conducting membrane that can permeate hydrogen selectively from hydrogen-containing gases, such as reformed gases of hydrocarbons. Proton-conducting perovskite-type solid electrolytes are first introduced as the base material of the mixed conductor. Some transition metal-doped perovskites are shown to have a mixed conductivity of protonic and electronic charge carriers, revealed by electrochemical and X-ray-spectroscopic measurements.

Electrical Conductivity of Ionic and Electronic Mixture

2001 ◽  
Vol 699 ◽  
Author(s):  
Gyeong Man Choi ◽  
Joon Hee Kim ◽  
Young Min Park
Keyword(s):  
Electrical Conductivity ◽  
Single Phase ◽  
Electronic Conductivity ◽  
Charge Carriers ◽  
Electronic Charge ◽  
Total Conductivity ◽  
Mixed Conductivity ◽  
Emf Measurements ◽  
Wide Range ◽  
Mixed Ionic Electronic Conductors

AbstractMixed ionic-electronic conductors (MIECs) which have both ionic and electronic species as charge carriers have a wide range of applications, such as electrodes in fuel cells, electrocatalytic reactors, and gas separating membranes. They may have either electronic or ionic species as the majority charge carriers. In addition to the single-phase mixed conductors, they may be fabricated by mixing two different phases of materials. Although these composites have been less studied than the single phase MIECs, the combined properties are often superior to single phase MIECs, and properties not seen in an individual phase may appear in the composite phase.YSZ-based composite systems were chosen to test the effect of transition-metal-oxide (TMO) addition on the electronic conductivity of composite. To induce mixed conductivity, electronic-conducting TMOs such as NiO and Mn2O3 were added into YSZ above the solubility limit. While the solid solubility of NiO in YSZ is limited that of Mn2O3 is large.In this work, mixed conducting yttria (8 mol%) stabilized zirconia (YSZ) - TMO composites were prepared in full composition range and the electrical conductivity of the composites was measured by 4-probe d.c. conductivity. Electromotive force (emf) measurements of the galvanic cell, current-voltage (I-V) measurements in ion blocking condition and the oxygen-partial-pressure dependent conductivity have been used to determine the contribution of the ionic and electronic charge carriers on the conductivity. Thus the composition-dependent electrical properties were used to explain the percolation behavior of electronic charge carriers in ionic matrix.Although the total conductivity of dense YSZ-TMO composite was variable with TMO content, the partial-electronic conductivity increased and the ionic conductivity decreased. The composition-dependent conductivity was discussed.

Relation Between Local Structure, Electric Dipole and Charge Carrier Dynamics in DHICA Melanin, a Model for Biocompatible Semiconductors

2019 ◽  
Author(s):  
Micaela Matta ◽  
Alessandro Pezzella ◽  
Alessandro Troisi
Keyword(s):  
Electronic Structure ◽  
Degrees Of Freedom ◽  
Structural Model ◽  
Computational Study ◽  
Oxidative Polymerization ◽  
Radical Scavenging ◽  
Charge Carriers ◽  
Electronic Charge ◽  
Polymer Semiconductors ◽  
Synthetic Pigments

<div><div><div><p>Eumelanins are a family of natural and synthetic pigments obtained by oxidative polymerization of their natural precursors: 5,6 dihydroxyindole and its 2-carboxy derivative (DHICA). The simultaneous presence of ionic and electronic charge carriers makes these pigments promising materials for applications in bioelectronics. In this computational study we build a structural model of DHICA melanin considering the interplay between its many degrees of freedom, then we examine the electronic structure of representative oligomers. We find that a non-vanishing dipole along the polymer chain sets this system apart from conventional polymer semiconductors, determining its electronic structure, reactivity toward oxidation and localization of the charge carriers. Our work sheds light on previously unnoticed features of DHICA melanin that not only fit well with its radical scavenging and photoprotective properties, but open new perspectives towards understanding and tuning charge transport in this class of materials.<br></p></div></div></div>

Charge Transport Properties of a Partially Reduced V2O5 Xerogel Intercalated with a Polymer Electrolyte

1995 ◽  
Vol 393 ◽  
Author(s):  
Joyce Albritton Thomas ◽  
Grant M. Kloster ◽  
D. Shriver ◽  
C. R. Kannewurf
Keyword(s):  
Charge Transport ◽  
Transport Properties ◽  
Polymer Electrolyte ◽  
Variable Temperature ◽  
Sol Gel ◽  
Electronic Conductivity ◽  
Charge Carriers ◽  
Electronic Charge ◽  
Ionic Charge ◽  
Intimate Contact

ABSTRACTRecently, there has been considerable interest in advanced materials and processing techniques for practical applications. V2O5 xerogels have generated much attention because they are layered materials that undergo reversible redox intercalation with lithium. The sol-gel process has been used to intercalate V2O5 xerogels with the polymer electrolyte, oxymethylene linked poly(ethylene oxide) - lithium triflate [(a-PEO)n(LiCF3SO3)]. The resulting nanocomposite is a mixed ionic-electronic conductor in which the ionic charge carriers in the polymer electrolyte are in intimate contact with the electronic charge carriers in the V205 xerogel. Variable-temperature electronic conductivity and thermoelectric power measurements have been performed to examine the charge transport properties.

Electronic Functions in Liquid-Crystalline Nanostructures with High Polarization

MRS Advances ◽  
2019 ◽  
Vol 4 (31-32) ◽  
pp. 1733-1740
Author(s):  
Masahiro Funahashi
Keyword(s):  
Liquid Crystalline ◽  
Carrier Transport ◽  
Ferroelectric Phase ◽  
Photovoltaic Effect ◽  
Charge Carriers ◽  
Side Chain ◽  
Electronic Charge ◽  
Internal Electric Field ◽  
Alkyl Side Chain ◽  
Perylene Bisimide

AbstractMultifunctionality was created by coupling an electronic charge carrier transport with ionic conductivity or ferroelectricity in polarized liquid crystal phases. Liquid-crystalline perylene bisimide derivatives bearing cyclotetrasiloxane rings and triethylene oxide chains formed nanosegregated columnar structures which could conduct ions as well as electrons. The spin-coated thin films could be insolubilized by the exposure on acid vapors and display electrochromism. Phenylterthiophene derivatives bearing a chiral alkyl side chain exhibited a ferroelectric phase, in which a photovoltaic effect was caused by the interaction between photogenerated charge carriers with the internal electric field formed by the spontaneous polarization of the ferroelectric phase.

Preparation and Properties of Multi-Elements Doped Perovskite-Type Mixed Conductors for IT-SOFC Cathodes

2014 ◽  
Vol 989-994 ◽  
pp. 759-762
Author(s):  
Jiang Fu ◽  
Jie Zhao ◽  
Yong Fu ◽  
Rong Rong Li
Keyword(s):  
Perovskite Phase ◽  
Mixed Conductors ◽  
Forming Process ◽  
Mixed Conductivity ◽  
Conventional Solid State Reaction ◽  
Thermal Expansion Coefficients ◽  
Pure Perovskite Phase ◽  
Expansion Coefficients ◽  
Perovskite Type ◽  
Semiconducting Behavior

Multi-elements doped LaCoO3-based mixed conductors La0.7Sr0.1Ca0.1Co0.8Fe0.2O2.9 (LSCCF-112) and La0.7Sr0.2Ca0.1Co0.7Fe0.3O2.85 (LSCCF-213) were synthesized by conventional solid state reaction (CSSR). The forming process, microstructure and crystal structure of the prepared samples were analyzed by TG/DTA, SEM and XRD. The mixed conductivities of the samples were measured using DC four-terminal method in 150-950 °C. Thermal expansion coefficients (TEC) of the samples were tested in 20-950°C. LSCCF-112 and LSCCF-213 exhibit pure perovskite phase and porous structure after sintered at 1200 °C. The average TECs of LSCCF-112 and LSCCF-213 are 18.17×10-6 K-1 and 17.52×10-6 K-1 respectively. The mixed conductivity of the samples shows semiconducting behavior up to 700-750°C and then decreases as the temperature is further raised. At intermediate temperature (IT), the conductivity values of the samples are both much higher than 100 S/cm.

Point Defects and Protonic Conduction in A3B'B”2O9 Compounds

1994 ◽  
Vol 369 ◽  
Author(s):  
Yang Du ◽  
A.S. Nowick
Keyword(s):  
Electrical Conductivity ◽  
Ir Spectra ◽  
Point Defects ◽  
Defect Structure ◽  
Complex Perovskite ◽  
Divalent Ions ◽  
Protonic Conduction ◽  
Protonic Conductors ◽  
Lower Activation ◽  
Perovskite Type

AbstractWe have investigated the defect structure and protonic transport properties of nonstoichiometric complex perovskite-type compounds of the type A3B'1+xNb2-xO9-δ. where A and B' are both divalent ions. Protons are incorporated by treatment in H2O vapor and their presence is manifested by the appearance of an OH band in the IR spectra, as well as by the large increase in electrical conductivity to produce excellent protonic conductors, with lower activation energies. A non-classical isotope effect, in which the Arrhenius plots for D+ and H+ cross over, can be explained by a modification of the classical ART hopping theory.

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