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O: Fachverband Oberflächenphysik

O 45: Poster: Solid-Liquid Interfaces - Structure, Spectroscopy, Reactions and Electrochemistry

O 45.5: Poster

Tuesday, March 13, 2018, 18:15–20:30, Poster A

The Influence of Li-Imide Salt Additives in Li-Ion Battery Electrolytes on the Solid Electrolyte Interphase Formation on Graphite Electrodes — •Thomas Diemant¹, Varvara Sharova^2,3, Arianna Moretti^2,3, Alberto Varzi^2,3, R. Jürgen Behm^1,2, and Stefano Passerini^2,3 — ¹Institute of Surface Chemistry and Catalysis, Ulm University, Albert-Einstein-Allee 47, D-89069 Ulm — ²Helmholtz Institute Ulm (HIU) Electrochemic Energy Storage, Helmholtzstr. 11, D-89077 Ulm — ³Karlsruhe Institute of Technology (KIT), P.O. Box 3640, D-76021 Karlsruhe

The solid electrolyte interphase (SEI), a passivating layer which is formed by electrolyte decomposition during the first electrochemical cycles on the electrodes of Li-ion batteries (LIBs), is one of the main factors influencing the battery performance. In order to ensure the formation of a SEI with well-balanced physico-chemical characteristics, additives are often included into the electrolyte formulation. These additives either decompose prior to the electrolyte main components during the first charge or incorporate into the passive layer, leading to the formation of a more compact, stable and ion conducting SEI.

Herein, we report results of a detailed study on the effect of various Li imide salts (LiTFSI, LiFTFSI, and LiFSI) as electrolyte additives in LIBs, in which the chemical composition and thickness of the SEI layer on graphite anodes is characterized by ex-situ XPS. This is complemented by characterization of the SEI resistance via electrochemical impedance spectroscopy (EIS). Finally, the implications for the cycling performance in half and full cells are discussed.