Abstract
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•Battery capacity and thermal stability degradation are more serious at 0 °C.•Long-term CC charging at low temperature causes low thermal stability depositions.•The CC charging ratio decrease indicates an increase in internal depositions.•A mount of depositions significantly reduces the battery self-heating temperature.•The capacity loss of the battery at −20 °C is reversible after recovery to 25 °C.
This study investigates the aging behavior of lithium-ion batteries (LIBs) subjected to low-temperature cycling. Soft pouch batteries were aged for 100 cycles at 25 °C, 0 °C, and –20 °C, followed by capacity tests, internal resistance (IR) measurements, material characterization, and thermal stability evaluation using an accelerating rate calorimeter (ARC). Results show that long-term cycling at 0 °C leads to the most severe degradation, with significant lithium deposition, increased separator contamination, and a marked reduction in thermal stability. In contrast, batteries aged at –20 °C exhibit large capacity losses during cycling, but most of the loss is reversible upon returning to 25 °C, due to limited lithium deposition under high polarization resistance. At 25 °C, capacity fading remains relatively small and thermal stability is well maintained. The findings highlight that 0 °C represents a temperature-sensitive point where lithium-ion intercalation kinetics and current density become mismatched, leading to excessive side reactions and irreversible active lithium loss. These results provide insights into the mechanisms of low-temperature aging and underline the need for improved anode kinetics and charging strategies to mitigate safety risks in cold environments.