Degradation analysis of lithium-ion batteries under ultrahigh-rate discharge profile

Lithium-ion batteries (LIBs) demonstrate significant potential in military applications. While, in application scenarios such as electromagnetic emission, directional energy, LIBs need to be discharged under ultrahigh rates for a long time, which can lead to accelerated performance degradation. To conduct an in-depth study on the degradation behaviour of LIBs under these conditions, this study proposes a peak decomposition method for incremental capacity analysis. This method permits a nuanced quantification of distinct degradation modes within LIBs. The effects of ultrahigh-rate constant-current discharge, ultrahigh-rate pulse discharge, and standard-rate discharge on battery degradation mode are compared. Furthermore, we delve into the fundamental processes potentially underpinning the disparities observed among these degradation modes. The results show that the degradation mode of the batteries aged under ultrahigh-rate discharge profile is dominated by the loss of active material compared with that of the batteries aged under standard-rate discharge profile. Upon reaching 80% state of health, the batteries aged under ultrahigh-rate constant-current discharge and ultrahigh-rate pulse discharge retain 87.3% and 88.51% of their initial active material content, respectively. In addition, lithium plating may have occurred in the charging process of the battery aged under ultrahigh-rate pulse discharge.