Cécile Courrèges oral presentation (OA3-Tue2-3-5)
ToF-SIMS in battery science
1 IPREM, UMR 5254 CNRS/UPPA, 2 avenue du Président Pierre Angot, 64000 Pau, France
2 SAFT, 111-113 Boulevard Alfred Daney, 33000 Bordeaux, France
The fast-growing demand of portable electronic devices and the development of electric and hybrid cars have induced big improvements in the design of batteries, especially for Li-ion batteries, which present high electrochemical performances . However, the formation of passivation layers at the electrode/electrolyte interfaces during cycling, which come from the degradation of electrolyte solvents and salts, can limit the batteries performances . In this study, we show that Time-of-Flight Secondary Ion Mass Spectrometry can provide new relevant information on electrode/electrolyte interfaces, complementary to the ones obtained by X-ray Photoelectron Spectroscopy (XPS) and Scanning Auger Spectroscopy (SAM), which are the techniques commonly used nowadays. Cells composed of LiMn2O4 (LMO) facing Li4Ti5O12 (LTO) have been considered due to their low cost, liability and high rate capabilities. The formation of surface layers on both electrodes during cycling has been evidenced by XPS and ToF-SIMS . The chemical composition of these layers is quite similar with mainly LiF, organic and (fluoro)phosphates compounds; however, the layer formed on the LTO electrode is thicker than the one formed on the LMO electrode and manganese compounds have been detected on the upper part of the LTO surface layer, as revealed by ToF-SIMS depth-profile analysis (figure 1). This manganese deposition on the LTO electrode, originated from the manganese dissolution at the LMO electrode side, shows the interactions between the two electrodes during cycling. FIB (Focused Ion Beam)-ToF analysis as well as sputtering analysis with C60 clusters are currently in progress to go further in the characterization of these electrode/electrolyte interfaces, in order to relate their chemistry to the electrochemical performances of cells, in agreement with XPS and SAM results.