(Digital Presentation) Electrochemical Noise Measurement in Batteries with Metallic Lithium Anode
Authors: Karaoglu Gozde , Ulgut Burak 
Published: July 2022

Electrochemical noise measurements are well known in corrosion literature where the noise that is to be measured is appreciable in amplitude. From the measured noise, it is possible to identify the mode of corrosion and distinguish between localized corrosion types from the uniform ones. This is mainly because localized modes of corrosion are stochastic in nature, typically studied in conjunction with post-mortem studies.

In recent years, the increase in the use of batteries demands that the tests to be performed on the batteries are faster, easier, cheaper and, if possible, non-destructive and non-perturbing. Although some electrochemical noise studies have begun to be carried out on batteries, the literature on this subject is scarce and questionable. Electrochemical noise measurement of Li batteries can be ultimately used as a non-invasive tool to diagnose the battery health and we have already shown that non-rechargeable batteries with Li/MnO2 chemistry shows increase in voltage noise after being exposed to a short circuit. On the other hand, if the battery is properly discharged, voltage noise does not increase. As a result, morphological changes on metallic lithium can be detected by electrochemical noise measurements and this method can be used as non-invasive diagnosis tool.[1]

Lithium metal-based chemistries have a much higher capacity than rechargeable chemistries because of the use of Lithium-aluminum alloy or graphite in rechargeable chemistries, as opposed to metallic Lithium used at the anode. It is known that charging of lithium metal electrode to result in the formation of lithium dendrites and/or mossy structures. These end up creating safety and performance issues. For this reason, pre-detection is both academically interesting and industrially important. Some preliminary studies show that noise level increase drastically after charging. Moreover, the anodes of the charged batteries were also examined with SEM and serious deterioration was observed in the anode of the battery after charging. (Figure 1) Just like noise measurements on non-rechargeable batteries with lithium chemistry exposed to short circuits, it is worthy to study on and develop pre-detection method for in lithium batteries that are prone to form dendrite during charging and discharging cycles by using electrochemical noise measurements. For this reason, we also conduct noise studies with symmetrical and asymmetric cells (Li/Li, Cu/Cu and Li/Cu) prepared in the glove box and examine the details of the noise increase in a controlled and detailed manner.

In this talk, how the electrochemical noise of metallic lithium-based batteries is measured, under what conditions it increases and what are the sources of the noise will be discussed both with noise measurements and imaging with optical microscope in situ and after death with spectroscopic analysis.

References

[1] Karaoglu G; Uzundal CB; Ulgut B; “Uneven Discharge of Metallic Lithium Causes Increased Voltage Noise in Li/MnO2 Primary Batteries upon Shorting, submitted.

Figure 1