Published 1958 .
Written in EnglishRead online
Thesis (D. Sc.)--The Queen"s University of Belfast, 1958.
|The Physical Object|
Download Conductivity of oxide cathodes (and other studies).
WORK FUNCTIONS AND CONDUCTIVITY OF OXIDE-COATED CATHODES 1. Introduction The oxide-coated cathode has many characteristics similar to those of an "excess" impurity semi-conductor.
By measurements of the thermionic work function ~th' the photoelectric work function P.E.' and the variation. The paper is the first of a series dealing experimentally with various aspects of the conductivity of oxide cathodes. The present Part starts with a brief survey of existing knowledge and then proceeds to examine the practical circumstances under which a non-uniformity of potential gradient can arise across the matrix under a modest continuous current by: 1.
The low-temperature conductivity of oxide-coated cathodes G S Higginson Thermionic and related properties of calcium oxide B J Hopkins and F A Vick A unified model of the oxide cathode which gives prominence to the role of localized surface states on small crystals Conductivity of oxide cathodes book A Surplice Charge localization on the surfaces of oxide-coated cathodes.
The conductivity of oxide cathodes. Part Influence of strontium ion migration on matrix conductivity. Author(s): G.H. Metson DOI: /pi-c For access to this article, please select a purchase option:Author: G.H.
Metson. The thermionic and photoelectric work functions and the temperature variation of coating conductivity have been measured for an oxide cathode. Thermionic and photoelectric currents were measured in both retarding and accelerating fields. The two work functions are found to be different, but not by the amount predicted by applying simple semi‐conductor theory to the by: Conductivity measurements on activated coatings give results similar to those of Vink and Loosjes.
Their theory implies barium concentration of at least 10 19 atoms/cm effect measurements indicate 10 14 electrons/cm 3 at 1 ° K, and free path 2 × cm.
This result may not in fact be inconsistent with the Vink-Loosjes theory. " " "Condensed version of thesis." Technical report (Massachusetts Institute of Technology. Research Laboratory of Electronics) ; (Emission and conductivity of oxide cathodes.), Google Scholar Crossref E.
Wagner, Electronics 1, (). (Preparation and activation of oxide cathodes.), Google Scholar; W. Albricht, Phys () (in Flemish).
(Relation between electron emission and conductivity of oxide during activation.) Google Scholar. Consequently, (La, Sr)CoO 3 cathode is not used even though the oxide ion conductivity is high.
Steele and co-workers have focused on development of new cathodes appropriate for intermediate temperature SOFCs and (La, Sr)(Co, Fe)03 cathodes have been optimised for use with CeO 2 -based electrolytes [ 11, 12 ], a typical composition being (La 0. Cathodes are now required to be have good conductivity of proton, oxygen ions and electrons, be highly stable at the operating temperature and oxidisation, to have a similar thermal expansion coefficient (TEC) as the electrolyte (Usually a form of barium cerium yttrium zirconate or BZCY and to provide good catalytic ability to the ORR.
The application range of oxide cathodes, e.g. in CRTs is limited by the critical dc current density (typically A/cm 2) and hence by the electrical conduction mechanism. The electrical conductivity σ el of the oxide layer has now been determined directly in a new procedure in a close-spaced planar diode configuration in an UHV chamber, together with thermionic emission data.
For the 3D microstructure shown in Fig. 5(b1) and (b2), effective ion conductivity in the x 3 direction is more important than that in the x 1 or x 2 directions because ions transfer mainly along the x 3 direction for the cathode.
The pore conductivity and ion conductivity of the LSM phase are set as 1e−8 but not 0 to improve numerical stability. The ac conductivity measurements have been carried out for the activated Ba/SrO cathode with additional 5% Ni powder for every h acceleration life time at the temperature around K.
The ac conductivity was studied as a function of temperature in the range K after conversion and activation of the cathode at K for 1 h in two cathodes face to face closed configuration. The relationship between the thermionic emission and the electrical conductivity of both “sintered” and normal oxide-coated cathodes has been investigated.
The “χ” values which obtained from the difference between the work functions and the activation energies of conductivity were much inconsistent between both cathodes. Nickel-rich layered oxide cathode materials for advanced lithium-ion batteries have received much attention recently because of their high specific capacities and significant reduction of cost.
However, these cathodes are facing a fundamental challenge of loss in performance as a result of surface lithium residue, side reactions with the electrolyte and structure rearrangement upon long-term. Thermal decomposition and electrical conductivity of oxide cathode emission materials used for cathode ray tubes (CRTs) have been studied under different heat treatment conditions for commercial sprayed cathode systems based on barium-strontium carbonate precursors.
Conversion of the carbonate precursor commenced at temperatures above. Accomplishments. The original objective of this project was to test the hypothesis that sol-gel encapsulated ionic liquids (ionogels) can be prepared with high aluminum ion conductivity (~ S/cm at room temperature) and high aluminum ion concentration (>1 mol/liter), and that aluminum reversibly reacts with nanocrystalline V 2 O 5 or MnO 2 from these liquids, paving the way for rechargeable.
The superior performance of lithium metal oxide cathode materials is a key aspect for the advanced development of lithium-ion battery (LIB) technology in portable electronics and high-end applications such as renewable energy units, electric vehicles (EVs) and hybrid electric vehicles (HEVs) r, this battery technology suffers from some critical problems related to electrochemical.
Conductivity of Solid Oxide Fuel Cell Cathode Materials. By Benjamin Gray. Abstract. Fuel cells offer a clean and efficient method of generating electricity. However, current technology requires the use of hydrogen, a synthetically produced gas, as fuel. Solid Oxide Fuel Cells can use various fuels, including some hydrocarbons, more.
ONLY two values of the thermal conductivity of barium strontium oxide have been published: cal. deg.−1 cm.−1 sec.−1 obtained by Clausing and Ludwig1, and – cal.
deg. To this end, we investigate the effect of delithiation on thermal conductivity of LiCoO 2, a common Li-ion cathode material, by using non-equilibrium molecular dynamics simulations and lattice dynamics analysis. A significant reduction (exponential decay behavior) in thermal conductivity is observed in the delithiation (charging) process.
3 Electrical resistivity of ceramic (oxide) materials – over 20 orders of magnitude 10 2 10 7 Conductivity, Ω-1m-1 Insulators Semiconductors Conductors Superconductors. 21 hours ago Composite positive electrode materials (1−x) LiNiMnCoO2∙xLi2SO4 (x = –) for Li-ion batteries have been synthesized via conventional hydroxide or carbonate coprecipitation routes with subsequent high-temperature lithiation in either air or oxygen atmosphere.
A comparative study of the materials prepared from transition metal sulfates (i.e., containing sulfur) and. Bismuth is doped to lanthanum strontium ferrite to produce ferrite-based perovskites with a composition of LaxBixSrFeO3-δ (0 ≤ x ≤ ) as novel cathode material for intermediate-temperature solid oxide fuel cells.
The perovskite properties including oxygen nonstoichiometry coefficient (δ), average valence of Fe, sinterability, thermal expansion coefficient, electrical. An investigation has been carried out into the use of conductive phase additions to enhance the conductivity and emission behavior of the oxide cathode coating as used in CRTs.
Electrical and emission characteristics have been studied for various additions of filamentary nickel (Ni) added to the sprayed strontium-barium carbonate precursors prior to spray deposition, followed by conventional. Solid oxide fuel cell (SOFC) cathodes were prepared by infiltration of 35 wt % La()Sr()FeO(3) (LSF) into porous scaffolds of three, zirconia-based electrolytes in order to determine the.
A solid oxide fuel cell (or SOFC) is an electrochemical conversion device that produces electricity directly from oxidizing a fuel. Fuel cells are characterized by their electrolyte material; the SOFC has a solid oxide or ceramic electrolyte.
Advantages of this class of fuel cells include high combined heat and power efficiency, long-term stability, fuel flexibility, low emissions, and. Some of the Pr-doped orthoferrites display good performance as cathode materials in high-temperature solid oxide fuel cells because of their mixed, electronic and ionic, conductivity.
In particular, Pr Sr Fe Ni O 3− δ presents low electrical resistivity and good oxygen ion conductivity [ 41 ]. The maximum conductivity of the investigated samples was found to be 6 × S/cm for optimum composite film (25 wt% GNP) at room temperature.
Room temperature rechargeable magnesium batteries are constructed from Mg as anode material, (V2O5)1-x(GNP)x as a cathode material and the simple non-aqueous electrolyte based MgNO36H2O.
conductivity of cathodes with different amounts, types, and archi-tectures of conductive additives and active materials and ii to iden-tify the best blends of active materials, conductive additives, and binder to achieve the highest conductivity among combinations studied.
Methods Conduction experiments in our prior work31 and others36 have. Zinc‐ion batteries (ZIBs) have attracted intensive attention due to the low cost, high safety, and abundant resources. Recent advances regarding microstructural engineering on various ZIB cathode mat.
Graphene oxide, which has C/O ratio of 2/1, is non conductive. It usually has a conductivity of less than a micro S/m. Reducing graphene oxide to C/O ratio above 6 is required to make graphene. The garnet-type fast Li+ conducting oxide, Li7-xLa 3 Zr 2-x TaxO 12 (x =LLZTO), is considered as a good candidate for SE because of its good ionic conducting property and high.
A new composite cathode material made of La Sr Co Fe O 3 − δ (LSCF), a mixed oxygen-ion/electron conductor, and BaZr Pr Y O 3 − δ (BZPY30), a mixed proton /electron conductor, is here developed for application in intermediate temperature solid oxide fuel cells (IT-SOFCs) based on proton conducting electrolytes.
The wet chemical synthesis route allows sub. A high rate Li-rich layered MNC cathode material for lithium-ion batteries† Mehmet Nurullah Ates, Sanjeev Mukerjee and K.
Abraham* We report a high rate Li-rich layered manganese nickel cobalt (MNC) oxide cathode material of the composition Li 2MnO 3$LiMn Ni Co O 2, termed Li-rich MNC cathode material, with discharge. Report: Metal Oxide Cathodes and High-Conductivity Ionic Liquids for Next-Generation Batteries (59th Annual Report on Research Under Sponsorship of The American Chemical Society Petroleum Research Fund): 59th Annual Report on Research Under Sponsorship of The American Chemical Society Petroleum Research Fund.
Electronic conductivity and TEC of several solid oxide fuel cell cathodes (adapted from Florio et al., and Sun et al., ). In parenthesis are temperatures in o C. Dutta et al., synthesized different perovskites with different dopants (La Sr FeO 3-δ ; La Sr Co Fe O 3-δ and La Sr Co Fe O 3. Molybdenum oxide sputtering targets for the manufacture of highly absorbent functional layers.
Whether it be the reliable separation of subpixels, an elegant way of covering conductor strips or the prevention of unwanted reflections from the ambient light, molybdenum oxide layers, with their low level of optical reflection, have a wide range of.
To improve conductivity, researchers have experimented extensively with placing the cathode’s sulfur within highly conductive carbon host materials, such as hollow porous carbon, graphene, mesoporous carbon, and microporous carbon.
Unfortunately, long-term cycling stability continues to be a problem because of the nonpolar covalent bonds that.
For cathodes thicker than ∼10microns, losses within the ionic conducting network determined performance, resulting in a breakdown of the linear performance dependence on cathode surface area.
The boundary between these regimes varied with ionic conducting cathode arm width, column width, and ionic conductivity. In an H(+) -SOFC system, however, MIEC cathodes limit the electrochemically active sites to the interface between the proton conducting electrolyte and the cathode.
New approaches to the tailoring of cathode materials for H(+) -SOFCs should therefore be considered. The study reported here is a comprehensive investigation of SVPO cathode conductivity measured by the four-point probe method and the associated changes in lithium cell impedance and cell DC resistance as a function of discharge over the complete range of 0 to 4 electrons per formula unit of silver vanadium phosphorous oxide (Ag 2 VO 2 PO 4.ﬁlm MIEC cathodes of SOFCs, which can help facilitate the development of intermediate temperature SOFCs.
We ﬁrst discuss the ORR mechanisms on the cathode of SOFCs. We then cover in detail recent advances in ABO. 3. and RP oxide thin ﬁlm cathodes .