IPREM ECP, UMR CNRS 5254, Université de Pau et des Pays de l'Adour, Hélioparc Pau-Pyrénées, 2 Avenue du Président Angot, Pau Cedex 9, France, CNRS, ICMCB-UPR 9048, Bordeaux INP, Université de Bordeaux, 87 Avenue du Dr. Schweitzer, Pessac, France, CEA LETI, 17 rue des Martyrs, Grenoble, France, Université Grenoble Alpes, Grenoble, France, ST Microelectronics, 10 rue Thalès de Milet CS 97155, Tours, France

"The current sustained demand for ""smart"" and connected devices has created a need for more miniaturized power sources, hence for microbatteries. Lithium-ion or ""lithium-free"" all-solid-state thin-film batteries are adapted solutions to this issue. The capability to carry out spatially resolved chemical analysis is fundamental for the understanding of the operation in an all-solid-state microbattery. Classically cumbersome and not straightforward techniques as TEM/STEM/EELS and FIB preparation methods could be used to address this issue. The challenge in this work is to make the characterization of Li-based material possible by coupling ion-milling cross section preparation method and AES techniques to characterize the behavior of a LiCoO2 positive electrode in an all solid state microbattery. The surface chemistry of LiCoO2 has been studied before and after LiPON deposition. Modifications of the chemical environments characteristic of the positive electrode have been reported at different steps of the electrochemical process. An original qualitative and a semiquantitative analysis has been used in this work with the peak deconvolution method based on real, certified reference spectra to better understand the lithiation/delithiation process. This original coupling has demonstrated that a full study of the pristine, cycled, and post mortem positive electrode in a microbattery is also possible. The ion-milling preparation method allows access to a large area, and the resolution of Auger analysis is highly resolved in energy to separate the lithium and the cobalt signals in an accurate way. © 2017 American Chemical Society."

all-solid-state thin-film lithium microbatteries, Auger electron spectroscopy, cross-sectional characterization, ion-milling, LiCoO2 positive electrode

Auger electron spectroscopy, Augers, Characterization, Chemical analysis, Chemical modification, Electrochemical electrodes, Electrodes, Electron spectroscopy, Film preparation, Ions, Lithium, Lithium compounds, Lithium-ion batteries, Milling (machining), Miniature batteries, Surface chemistry, Thin films, Chemical characterization, Electrochemical process, Ion milling, Lithiation/delithiation, Lithium microbatteries, Positive electrodes, Semi-quantitative analysis, Straightforward techniques, Thin film lithium ion batteries