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Bad Münster am Stein-Ebernburg, Germany

Vogl U.S.,University of Munster | Vogl U.S.,Lawrence Berkeley National Laboratory | Lux S.F.,University of Munster | Lux S.F.,Lawrence Berkeley National Laboratory | And 6 more authors.
Journal of the Electrochemical Society | Year: 2015

Subsequent to our previous studies on the SEI formation mechanism on the single crystal silicon (100) surface, here we report on complementary studies of the SEI formation on Si surfaces with the crystal orientations (111) and (110). The differences in electrochemical behavior of the different crystal orientations are discussed - especially with regard to the effect of the SEI forming electrolyte additives fluoroethylene carbonate (FEC) and vinylene carbonate (VC) added to ethylene carbonate (EC)/diethyl carbonate (DEC) based electrolytes. Fourier transform infrared spectroscopy (FTIR) of the SEI during early stages of SEI formation and physico-chemical investigations (wetting behavior) indicate a strong dependence of the chemical composition of the SEI on the surface orientation and the electrolyte composition during the early stages of lithiation of Si. However, at a higher lithiation degree less difference in the chemical composition of the SEI can be observed. These findings are in agreement with those made for the SEI formation on the Si(100) surface. © 2015 The Electrochemical Society.

Pohl B.,University of Munster | Grunebaum M.,University of Munster | Grunebaum M.,Helmholtz Institute Munster HI MS | Drews M.,Helmholtz Institute Ulm | And 7 more authors.
Electrochimica Acta | Year: 2015

3-((Trimethylsilyl) oxy) propionitrile is introduced as non-volatile solvent for lithium-ion battery electrolytes using LiTFSI as lithium salt. The thermal and chemical stability of the electrolytes offer an enhanced safety as compared to conventional volatile carbonate electrolytes. In cell tests, the investigated LiTFSI nitrile silyl ether electrolyte shows compatibility with LiFePO4, LiNi0.33Mn0.33Co0.33O2 and graphite active materials. © 2015 Elsevier Ltd. All rights reserved.

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