Analysis of failure mechanisms and behavior of LiCoO2-graphite batteries at 0 ℃

A common misconception arises when considering the effects of low temperatures on lithium-ion battery properties, as it is often believed that these effects only manifest significantly at extremely low temperatures. To clarify the battery degradation behaviors and mechanisms, this study conducts an in-depth investigation on commercial LiCoO 2 -graphite batteries with various cycling procedures at 0 ℃. Previous studies usually evaluate performance at −10 ℃ and/or −20 ℃, where failure behaviors mainly occur on the electrode surfaces due to the deposition of metallic lithium. Through the analysis of differential voltage and incremental capacity curves, along with post-mortem analysis after cycling, it is revealed that the desolvation energy of lithium largely determines whether lithium integrates into the active materials or plates on the electrode surface. High current density causes more Li + -solvated molecules to enter graphite layers and deposit on electrode surfaces, leading to graphite expansion and lithium plating. A phase transition at 2 C is observed for the LiCoO 2 cathode, primarily caused by high polarization and overpotential, resulting in structural instability and irreversible loss of active material. The key factors for achieving a moderate desolvation process involve constructing a Li + solvation shell characterized by weak interactions between Li + and the solvents. This study offers an optimal framework for designing batteries with low-temperature properties and aims to facilitate empirical research on mapping abuse intervals of batteries. • The attenuation mechanism of LiCoO 2 -graphite battery under 0 ℃ is analyzed. • The failure behaviors of LiCoO 2 -graphite battery under 0 ℃ is analyzed. • The loss of lithium inventory and loss of active materials at 0 ℃ are identified. • The desolvation energy from electrolytes determines the behavior of lithium ions. • The empirical research on mapping abuse intervals for batteries is first proposed.