SURFACE REACTIONS AND SURFACE ANALYSIS OF LITHIUM METAL AND ITS COMPOUNDS STUDIED BY AUGER ELECTRON SPECTROSCOPY, X-RAY PHOTOELECTRON SPECTROSCOPY AND RUTHERFORD BACKSCATTERING SPECTROMETRY (THERMAL BATTERIES).
AuthorBurrow, Bradley James
AdvisorArmstrong, Neal R.
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PublisherThe University of Arizona.
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.
AbstractThe development of analysis techniques necessary for the quantitative, chemical surface analysis of lithium-containing solids important in the construction of high energy density batteries is presented. Electron beam damage is discovered to be the source of apparent lithium metal formation in Li(ls) XPS spectra of lithium salts. Beam Damage thresholds of Li₂O, Li₂CO₃ and Li₂SO₄ are calculated using time-dependent Auger spectra, and possible mechanisms are discussed. The variables which affect Auger quantitation are reviewed with particular emphasis on low energy transitions. Two experimental attempts at measuring the instrument response function for the cylindrical mirror analyzer and electron multiplier are discussed. Background correction techniques proposed in the literature are compared using synthesized Auger data. Auger lineshapes are synthesized by a series of calculations which mimic each step of the Auger electron's path from the atomic core level to the detector. The results indicate that the SIBS (Sequential Inelastic Background Subtraction) method is more applicable to Auger analysis because of its analytical accuracy, speed and ability to handle spectra with poor signal to noise. The special problem of low energy background subtraction is resolved through the use of a new five-parameter function which adequately accounts for the analyzer distortions and secondary cascade in one calculation. Using the above correction techniques, Auger spectra, peak energies, relative intensities and FWHM's of Li₂O, LiOHNH₂O, LiH, Li₃N, Li₂CO₃ and Li₂SO₄NH₂O are presented. Despite special handling techniques, the hydroxide, hydride and nitride reveal extensive oxidation. The oxyanion salts reveal little Li Auger intensity until substantial anion desorption had occurred. The reaction products of lithium with oxygen, water and carbon dioxide are studied by AES. Results indicate the formation of Li₂O, LiOHNH₂O and Li₂O with hydrocarbons, respectively. These results are used to construct a plausible surface structure of the Li-SO₂ interface which explains its stability to self-discharge corrosion and yet maintain electronic conductivity for external discharge. RBS and AES depth profiling are used to analyze potassium-implanted glasses. The results indicate a great deal of ionic migration for glasses which leads to a speculative mechanism for alkali corrosion of glasses.