Topic Advanced Cell testing: Quantitative, Time Resolved Detection of Lithium Plating on Graphite Anodes in Lithium Ion Batteries

The ability of fast and safe charging is critical for the success of lithium ion batteries for automotive applications. In state of the art lithium ion batteries the charging rate is limited by the onset of lithium plating on the graphite anode. Despite its high importance, so far no analytical technique has been available for directly measuring lithium plating during battery charge. Herein, we introduce in-operando electron paramagnetic resonance (EPR) spectroscopy as the first technique capable of the time resolved and quantitative detection of lithium metal plating in lithium ion batteries. In an exemplary study the C-rate dependence of lithium metal plating during low temperature charging at 20 °C is investigated. It is possible to quantify the amount of dead lithium and observe the chemical re-intercalation of plated lithium metal. The time-resolved and quantitative information accessible with in-operando EPR spectroscopy will be very useful for the optimization of fast charging procedures, testing of electrolyte additives and model validation.

J. Wandt, P. Jakes, J. Granwehr, R.-A. Eichel, H.A. Gasteiger, Materials Today (2017).