Dresden 2014 – scientific programme
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MM: Fachverband Metall- und Materialphysik
MM 14: Functional Materials III - Li ion batteries
MM 14.4: Talk
Monday, March 31, 2014, 16:30–16:45, IFW A
Diffusion and Interface Transport in LCO Thin-Films — •Frank Berkemeier, Tobias Stockhoff, and Guido Schmitz — Universität Münster, Institut für Materialphysik, Wilhelm-Klemm-Str. 10, 48149 Münster
Lithium cobalt oxide (LCO) thin-films are prepared by ion-beam sputter deposition. The capability of the films to reversibly store and release lithium ions is proven by cyclic voltammetry and chronopotentiometry. It is demonstrated that the lithium concentration of the films can be reliably determined by electrochromic absorbtion technique using visible light, which even allows to measure the time-dependence of the lithiation/delithiation reaction. Using this electrochromic absorbtion technique, the intercalation of lithium into LCO is studied in case of films between 10 and 400 nm in thickness. To describe the intercalation reation in a proper way, it is found that – apart from the volume diffusion – the interface transport of lithium has to be taken into account. Therefore, we suggest a diffusion model which includes an interface transport coefficient that consideres the transfer of lithium ions from the liquid electrolyte into the LCO. Using this model, we are able to accurately describe the experimental data, and deterime the interface transport coefficient to ≈ 10−7 cm/s.