Author: Paul Kitz
Title: SEI formation in Li-ion batteries studied by EIS/EQCM-D
Affiliation: Eidgenössische Technische Hochschule Zürich, ETH
Considering the complex dynamics of the interphase formation process in Li-ion batteries, the SEI nm-sized dimension, as well as the intermediacy and instability of many interphase species, operando analysis methods of high surface sensitivity are of interest. Operando electrochemical quartz crystal microbalance with dissipation monitoring (EQCM D) coupled with simultaneous electrochemical impedance spectroscopy (EIS) was developed for this purpose to accurately measure the mechanical and electrochemical electrode-electrolyte interphase properties. The new technique was applied to study the SEI formation process on carbon based anodes. Indeed, combined EIS/EQCM-D provides unique pieces of information for understanding the highly dynamic structure-function relationships of electrode interphases in Li-ion batteries.