The formation of surface films on lithium ion electrodes is a crucial factor for the performance and durability of the respective battery. Especially the formation of the solid electrolyte interphase (SEI) on the anodes of these cells widely determines the stability and functionality of the electrode. Therefore, a precise insight into the formation process of this layer is required. Based on temperature‐dependent electrochemical impedance spectroscopy a new approach to monitor the formation of the SEI was developed. This way the kinetics of the interphase could be described using its activation energy. Comparison of these values with the respective resistances regarding the charge turnover during the initial charging of the cell provided additional information about the course of the SEI formation. It could be shown that these findings are in good agreement with the descriptions of the mechanism of the SEI formation provided by the literature.

Localized electrochemical techniques, which have been developed for the last few decades, are useful tools for the examination of surface properties and processes in many different fields of research. Especially localized electrochemical impedance spectroscopy (LEIS) is a promising technique for many applications, as it combines the advantages of conventional electrochemical impedance spectroscopy (EIS) and localized techniques. In this study, requirements and difficulties regarding the application of LEIS to lithium ion electrodes are illustrated and different aspects of a useful experimental setup are introduced. Furthermore, some basic observations regarding the development of the system's Ohmic and charge transfer resistances during the electrode's charging process are presented.

Electrical resistivity is an important measure to qualify electrodes for lithium‐ion batteries. A reliable determination of conductivity is of high practical importance with regard to, for example, electrode production improvements and quality control. To complement state‐of‐the‐art measuring techniques, a new method has been developed based on a new “micron‐powder probe”. Following a simple measuring procedure, the system allows nondestructive, highly reproducible, and rapid data acquisition. In this paper, we describe the new concept thoroughly and present experimental results. These results demonstrate that an initial determination of resistance values in battery electrodes is beneficial especially if it is combined with an electrical postmortem analysis of cycled cathode disks. The outcome of our investigation is validated with regard to the electrochemical performance of cathodes in half‐cells.

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