AN AUGER ELECTRON SPECTROSCOPIC AND KINETIC STUDY OF THE REACTION OF SULFUR DIOXIDE WITH ATOMICALLY CLEAN LITHIUM SURFACES.

Persistent Link:
http://hdl.handle.net/10150/187833
Title:
AN AUGER ELECTRON SPECTROSCOPIC AND KINETIC STUDY OF THE REACTION OF SULFUR DIOXIDE WITH ATOMICALLY CLEAN LITHIUM SURFACES.
Author:
Nebesny, Kenneth Walter
Issue Date:
1984
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
The growth of the layer formed on atomically clean lithium metal upon exposure to SO₂ gas is sequentially studied by controlling the quantity of gas reacted with the surface in a specially constructed vacuum system. A Fast Fourier Transform algorithm for the removal of instrumental broadening, and quantized and inelastic electron loss processes from the background of an Auger spectrum is presented. The deconvolved peaks for the S(LMM) and O(KKL) valence transitions are used to determine the molecular composition of the layer at each stage of its formation. The associated peak areas give the quantity of SO₂ reacted with the surface and the relative amounts of sulfur and oxygen present in each layer. The results indicate that two distinct layers of different composition are formed. The lower layer is a complete monolayer of Li₂O/Li₂S in a two-to-one ratio. The upper layer is thicker and consists of LiS₂O₄ and LiS₂O₃ in a 50% mixture. The formation of the upper layer is observed only after exposures of the surface to partial pressures of SO₂ greater than one millitorr. A model to explain the formation of the two layers and the observed pressure dependence is given. A flow method is used to study the kinetics of the Li-SO₂ reaction at submonolayer coverages. The pressure in a reaction vessel is monitored as a function of time when a fresh Li surface is exposed. A reaction order between 0.5 and 0.9 results, indicating that the surface of the scraped Li is energetically heterogeneous with respect to sites available for adsorption. An Arrhenius plot of the data indicates that the activation energy for the dissociative chemisorption to form the first monolayer lies between 2 and 5 kcal/mole. The sources for site heterogeneity and the activation energy are discussed. The resulting molecular model is used in combination with preliminary electrochemical results to compare the gas phase layer with the film formed on Li anodes in the Li/SO₂ ambient temperature battery. The model proves to be useful in explaining storage and discharge characteristics of the battery that are due to the presence of the anodic film.
Type:
text; Dissertation-Reproduction (electronic)
Keywords:
Sulfur dioxide -- Reactivity.; Lithium -- Reactivity.
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Chemistry; Graduate College
Degree Grantor:
University of Arizona
Advisor:
Armstrong, Neal R.

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleAN AUGER ELECTRON SPECTROSCOPIC AND KINETIC STUDY OF THE REACTION OF SULFUR DIOXIDE WITH ATOMICALLY CLEAN LITHIUM SURFACES.en_US
dc.creatorNebesny, Kenneth Walteren_US
dc.contributor.authorNebesny, Kenneth Walteren_US
dc.date.issued1984en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractThe growth of the layer formed on atomically clean lithium metal upon exposure to SO₂ gas is sequentially studied by controlling the quantity of gas reacted with the surface in a specially constructed vacuum system. A Fast Fourier Transform algorithm for the removal of instrumental broadening, and quantized and inelastic electron loss processes from the background of an Auger spectrum is presented. The deconvolved peaks for the S(LMM) and O(KKL) valence transitions are used to determine the molecular composition of the layer at each stage of its formation. The associated peak areas give the quantity of SO₂ reacted with the surface and the relative amounts of sulfur and oxygen present in each layer. The results indicate that two distinct layers of different composition are formed. The lower layer is a complete monolayer of Li₂O/Li₂S in a two-to-one ratio. The upper layer is thicker and consists of LiS₂O₄ and LiS₂O₃ in a 50% mixture. The formation of the upper layer is observed only after exposures of the surface to partial pressures of SO₂ greater than one millitorr. A model to explain the formation of the two layers and the observed pressure dependence is given. A flow method is used to study the kinetics of the Li-SO₂ reaction at submonolayer coverages. The pressure in a reaction vessel is monitored as a function of time when a fresh Li surface is exposed. A reaction order between 0.5 and 0.9 results, indicating that the surface of the scraped Li is energetically heterogeneous with respect to sites available for adsorption. An Arrhenius plot of the data indicates that the activation energy for the dissociative chemisorption to form the first monolayer lies between 2 and 5 kcal/mole. The sources for site heterogeneity and the activation energy are discussed. The resulting molecular model is used in combination with preliminary electrochemical results to compare the gas phase layer with the film formed on Li anodes in the Li/SO₂ ambient temperature battery. The model proves to be useful in explaining storage and discharge characteristics of the battery that are due to the presence of the anodic film.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.subjectSulfur dioxide -- Reactivity.en_US
dc.subjectLithium -- Reactivity.en_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineChemistryen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorArmstrong, Neal R.en_US
dc.identifier.proquest8504125en_US
dc.identifier.oclc693400262en_US
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