Evaluation of cracking damage in electrode materials of a LMO/Al-Lix lithium-ion battery through analysis of acoustic emission signals

Abstract

Damage due to the internal degradation of electrode materials in lithium-ion batteries (LIBs) during charge-discharge cycles can cause capacity fading and safety issues. Therefore, it is essential to assess damage to LIBs using nondestructive methods. In this study, the relationship between the damage mechanism and acoustic emission (AE) activity of a commercial lithium manganese oxide (LMO)/Al-Lix alloy battery is systematically investigated. Microstructural observations of the electrodes revealed that the damage mechanisms of the LMO cathode and Al-Lix anode during accelerated charge-discharge were identical to those of microcracking. Energy, amplitude, duration, rise time, and peak frequency were considered as possible AE parameters for real-time damage detection. The generation of AE hits was prominent during the later stages of the charging and discharging processes. The AE signals produced by damage to the Al-Lix alloy anode during charging had a lower amplitude (0–60 dB) and energy (0–10 aJ). In comparison, those produced by damage to the LMO cathode during charging had a relatively high amplitude (100 dB) and energy (120 aJ). Additionally, the energy levels and amplitudes of the AE signals obtained during discharging decreased with an increasing number of cycles, indicating that they can be used as indicators for evaluating the damage progression of the primary, secondary, and tertiary cracks in LMOs. The AE technique offers the possibility of monitoring and evaluating the damage to the anode and cathode of a commercial full cell separately, as well as predicting the remaining capacity of the battery by monitoring the AE hits.