Regensburg 2019 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 20: Poster session II

MM 20.22: Poster

Tuesday, April 2, 2019, 18:30–20:00, Poster C

Electrochromism in Thin Film Lithium Ion Battery Electrodes — •Yug Joshi, Efi Hadjixenophontos, Juliane Mürter, Robert Lawitzki, and Guido Schmitz — Chair of Materials Physics, Institute of Material Science, University of Stuttgart, Stuttgart, Germany

Numerous lithium-ion battery electrodes have been studied for their electrochemical cyclabilty, reversibility, capacity. An interesting aspect of these electrodes, which has not gained much attention, is the change of optical properties upon dis-/charging (or electrochromism). In this study, we show the optical response of some well-known battery electrodes namely lithium manganese oxide (LMO), lithium iron phosphate (LFP), lithium cobalt oxide (LCO) and lithium titanate (LTO). The primary focus of this study is on the in-situ electrochromic characterization of the mentioned electrodes. The LMO and the LTO are further characterized ex-situ to calculate the refractive indices of the materials using the Clausius-Mossotti equation. This equation gives the electronic resonance wavelengths which are closely related to the band structure of the material. A particularly clear change in the resonance wavelength is observed upon de-/intercalation in LMO. For the LTO, since it is a phase-transformation based electrode, the optical constants in the dual phase region are represented as a combination of the pure phases, which yields information about the phase transformation mechanism. Finally, we consider options of utilizing these materials in optical integration based on silicon-based waveguides.