Extending the calendar life of LiNi0.8Co0.1Mn0.1O2-based lithium-ion batteries via low-temperature storage

Abstract

Given the widespread application of lithium-ion batteries (LiBs), additional in-depth aging investigations based on commercial batteries are necessary for safety and economic considerations. However, calendar aging, the loss of capacity caused by cell storage, is always neglected. Herein, the calendar aging patterns of LiNi0.8Co0.1Mn0.1O2 (NCM811)-based full and half cells are discussed. According to the electrochemical tests, the cell capacity decay increases with the storage state of charge (SOC), and storage time, and excellent capacity retention is demonstrated in low-temperature (LT) storage. Furthermore, in situ electrochemical impedance spectroscopy (EIS) reveals that the interfacial impedance of batteries increases significantly at LT and decreases rapidly upon return to room temperature (RT). It is hypothesized that the calendar aging is mainly controlled by the kinetic lithium diffusion impedance and the temperature-determined reaction rate. Finally, no adverse effects are found after LT storage, as revealed by the long-term cycling and electrode characterization results. It is recommended that long-term resting-state batteries should be stored at a suitable LT to prolong the calendar life.