Electrochemical Noise Investigation in Non-Rechargeable Batteries
Authors: Karaoglu Gozde , Ülgüt Burak 
Published: September 2023

Electrochemical noise measurements are well known in corrosion literature where the measurements can be utilized to identify the mode of corrosion and distinguish between localized corrosion types and the uniform ones when it is analyzed in conjunction with post-mortem studies.

In recent years, the increase in the use of lithium-ion 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. In one of our recent studies, it has been shown that, non-rechargeable batteries with Li/MnO2 chemistry shows increase in voltage noise after being exposed to a short circuit. 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]

In this talk, we will discuss details of electrochemical noise of metallic lithium-based batteries. These details involve measurement methods, reasons for increase and sources of the noise. We will present both noise measurements and imaging with optical microscope in situ and post-mortem with spectroscopic analysis.

Lithium metal-based chemistries have a much higher capacity than rechargeable chemistries since Lithium-aluminum alloy is used in rechargeable batteries, where the anode material is Lithium metal in non-rechargeable batteries. It is known that charging of lithium metal electrode causes the formation of lithium dendrites where disruption of the separator can be seen which exposing the battery to a short circuit or even causing the battery to burn or explode. For this reason, the pre-detection of any potential dendrite formation 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.

Figure
1 Left: The noise measurement of pristine CR2032 (black) and the noise measurement of CR2032 after charged (red), and discharged (blue) Right: The SEM images of anode of charged CR2032

References

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

Figure 1