Non-Destructive, Non-Invasive Noise Measurements for Metallic Lithium Anodes for Lithium Ion Batteries

Abstract

Electrochemical Noise measurements have been in the spotlight of electrochemical analysis for measurements on stochastic modes of corrosion since the days of Dawson (Hladky and Dawson Corrosion Science 21(4), (1981),317-322). More recently, electrochemical noise measurements for fuel cells and batteries came up as non-invasive and non-perturbing testing methods that can be used for research(Journal of The Electrochemical Society, 165 (11) A2557-A2562 (2018)) and a potential real-time monitoring tool (Denisov et.al. Fuel Cells 17,(2017),225-237).Metallic lithium anodes are currently commercially employed for non-rechargeable batteries (e.g LiSOCl2 or LiMnO2). The main hurdle along the way of implementation in rechargeable batteries is the dendrite formation during the charging process (Cheng, et.al. Chem. Rev. 2017, 117, 10403−10473). The formation of dendrites during charging can lead to catastrophic failure of the batteries including thermal runaway. Though studies on avoiding such failures through either modifying the surface of the electrode and/or the kinetics of deposition are underway, however, as indicated by the review: “more smartly designed in situ or operando techniques are urgently needed to track the process in a working cell”.We have been working on battery noise measurements for the past number of years (Turkish Journal of Chemistry, 42, (2018), 859-868). We have recently shown that the noise of primary Li/MnO2 batteries increase to measurable levels upon suffering a short circuit (Journal of the Electrochemical Society 165(11),(2018),A2557-A2562) and that this is due to the uneven discharge of the metallic lithium anode(Journal of the Electrochemical Society, submitted).In this contribution, we are going to be reporting electrochemical noise as a truly operando method to study dendrite formation. As the measurement requires no modification to the cell (i.e. no windows in the case or the current collectors, no geometry change, not a half cell) and no perturbation in the applied current or the voltage, it is the ultimate non-invasive and non-perturbing method that has the potential to be used as not only a research tool, but also a real-time implementable sensor that can be commercially deployed.As shown in the figure below, using a metallic lithium anode, the noise after a charging attempt with a high current does show an increased noise level due to the uneven formation of dendrites. Figure 1