Berlin 2018 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 111: Oxides and Insulators: Adsorption II
O 111.5: Vortrag
Freitag, 16. März 2018, 11:30–11:45, MA 041
Interaction of an Ionic Liquid Adlayer with Spinel Li4Ti5O12 and Influence of 1 Post- and Predeposited Lithium — •Jihyun Kim1, Florian Buchner1,2, and R. Jürgen Behm1,2 — 1Ulm University, Institute of Surface Chemistry and Catalysis, D-89069 Ulm, Germany — 2Helmholtz-Institute Ulm (HIU) Electrochemical Energy Storage, D-89081 Ulm, Germany
In this model study, we aimed toward a detailed understanding of the interaction of the battery-relevant ionic liquid 1-butyl-1-methyl-pyrrolidinium bis-(tri-fluoro-methyl-sulfonyl)-imide ([BMP][TFSI]) with well-defined spinel lithium titanate Li4Ti5O12(111), which is a promising anode material for a lithium-ion batteries, employing X-ray photoelectron spectroscopy (XPS) in ultrahigh vacuum (UHV). Furthermore, the influence of pre- and post-deposited Li on the IL adlayer was investigated. First of all, [BMP][TFSI] mainly adsorbs as intact ion pairs on Li4Ti5O12 at 300 K, except a negligible amount of decomposition products (LiF, LixS, LixSOy, SOx and LiN3), which increases moderately after post-deposition of 1 ML of Li, i.e. most of the Li most likely diffuses through the IL adlayer and subsequently into the bulk of Li4Ti5O12. At 80 K, in contrast, a small amount of Li+ remains in the near-surface regime, forming a Li-rich Li4+xTi5O12 (x ∼ 0.3) phase. Due to the remaining Li in the near surface, the subsequent deposition of the IL results in a significant decomposition of the adlayer, which demonstrates the reactive interaction of Li with the IL adlayer even at 80 K.