Exploring the degradation pathways of a nickel-rich cathode during high-temperature storage in high-energy lithium-ion batteries

Abstract

The degradation of nickel-based cathodes under high temperature is challenging for expanding their application to electric vehicles (EVs) and stationary energy storages. While a majority of the research focuses on the improving performances and degradation mechanisms for long-term cycling, relatively less studies are published regarding the long-term storage conditions. Herein, we discuss a high-temperature calendar life of Ni-rich cathode using systematic protocols with high-energy lithium-ion cell. Although the final capacity retention after the calendar life test is the same with ∼70% compared to the original cell capacity, Ni-rich cathode showed diverse degradation behavior depending on the calendar temperature of 45 °C and 60 °C. The major degradation factor for cells stored at 60 °C is the loss of lithium inventory; however, there was a severe loss of the active material in the cells stored at 45 °C as well as lithium inventory loss.