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Author Levi, M. D. ♦ Salitra, G. ♦ Markovsky, B. ♦ Teller, H. ♦ Aurbach, D. ♦ Heider, U. ♦ Heider, L.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword MATERIALS SCIENCE ♦ ENERGY STORAGE ♦ METAL-NONMETAL BATTERIES ♦ LITHIUM ♦ CLATHRATES ♦ LITHIUM OXIDES ♦ COBALT OXIDES ♦ ELECTROCHEMISTRY ♦ CHEMICAL REACTION KINETICS ♦ MATHEMATICAL MODELS ♦ MEASURING METHODS
Abstract The electroanalytical behavior of thin Li{sub 1{minus}x}CoO{sub 2} electrodes is elucidated by the simultaneous application of three electroanalytical techniques: slow-scan-rate cyclic voltammetry (SSCV), potentiostatic intermittent titration technique, and electrochemical impedance spectroscopy. The data were treated within the framework of a simple model expressed by a Frumkin-type sorption isotherm. The experimental SSCV curves were well described by an equation combining such an isotherm with the Butler-Volmer equation for slow interfacial Li-ion transfer. The apparent attraction constant was {minus}4.2, which is characteristic of a quasi-equilibrium, first-order phase transition. Impedance spectra reflected a process with the following steps: Li{sup +} ion migration in solution, Li{sup +} ion migration through surface films, strongly potential-dependent charge-transfer resistance, solid-state Li{sup +} diffusion, and accumulation of the intercalants into the host materials. An excellent fit was found between these spectra and an equivalent circuit, including a Voigt-type analog (Li{sup +} migration through multilayer surface films and charge transfer) in series with a finite-length Warburg-type element (Li{sup +} solid-state diffusion), and a capacitor (Li accumulation). In this paper, the authors compare the solid-state diffusion time constants and the differential intercalation capacities obtained by the three electroanalytical techniques.
ISSN 00134651
Educational Use Research
Learning Resource Type Article
Publisher Date 1999-04-01
Publisher Place United States
Journal Journal of the Electrochemical Society
Volume Number 146
Issue Number 4


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