Electrochemical performance and thermal stability of lithium ion batteries after immersion

Abstract In this work, electrochemical performance, aging mechanisms and thermal stability of LIBs after immersion were analyzed. The results show that corrosion increases with the increasing electric potential, NaCl concentration and immersion time. Moreover, capacity fading occurs after immersion, decreasing the lifespan of the battery. This effect is mainly caused by the loss of active material (LAM). With increasing NaCl concentration, capacity fading increases and battery lifespan decreases. The activation barriers (Ea) and the onset temperature of exothermic reactions (TOER) of cells initially increases and then decreases. The thermal stability of cells dramatically decreases after immersion in highly-concentrated NaCl solutions, which has higher onset temperature of thermal runaway (TOTR) and lower maximum temperature (TMax). With the increasing immersion time, the TOER initially decreases and then increases, TOTR increases, while TMax and Ea decrease.