Solid Electrolyte Interphase Formation on Silicon and Lithium Titanate Anode Materials in Lithium-Ion Batteries

Aiming at an improved knowledge of the formation of the solid electrolyte interphase (SEI), as basis for the safe and efficient use of new anode materials, we investigated the SEI formation on silicon and lithium titanate (LTO) anodes by electrochemical impedance spectroscopy (EIS) and ex situ X-ray photoelectron spectroscopy (XPS) measurements. While the EIS measurements performed at equidistant voltage intervals gained information on the SEI formation process, the ex situ X-ray photoelectron spectroscopy (XPS) measurements gained insight into the chemical composition of the resulting SEI layer. For silicon anodes we observe a reduction of the resistance in the second cycle and thus assume the formation of a stable SEI with SiO2, Li4SiO4, LiF and different carbonates as main components. In contrast, on LTO anodes resistance increases by a factor of two indicating incomplete SEI formation. LiF and different carbonates were identified as main components of the SEI. Submitted: 21.06.2016 *Corresponding author: Tel.: +49 711 6862 8154; fax +49 711 6862 747; E-Mail: [email protected]