Probing pyrolysis conversion of separator from spent lithium-ion batteries: Thermal behavior, kinetics, evolved gas analysis and aspen plus modeling
Zhitong Yao, Pietro Romano, Weilin Fan, Shina Gautam, Nakorn Tippayawong, Chawannat Jaroenkhasemmeesuk, Jie Liu, Xiaobo Wang, Wei Qi
Abstract
The exponential growth in the consumption of lithium-ion batteries (LIBs) has resulted in a concomitant increase in the spent LIBs. Multi-component recycling is a highly desirable and beneficial process, yet the separator component remains overlooked. This study examined the thermal behavior, kinetics, thermodynamics, and evolved products of separator pyrolysis in N 2 and CO 2 atmospheres. Furthermore, the conversion was modeled using Aspen Plus and a sensitivity analysis was conducted to investigate the impact of varying operating conditions. The findings indicated that the whole degradation process could be divided into three stages: below 200 °C, 200–550 °C and 550–900 °C. The evolved products at peak temperatures of 485 °C in N 2 and 500 °C in CO 2 were composed of olefins and alkanes. The average apparent activation energy values were determined to be 222.78 kJ mol −1 and 159.36 kJ mol −1 in the N 2 and CO 2 atmospheres, respectively. Thermodynamic analysis indicated that the separator decomposition was an endothermic and non-spontaneous process. Aspen Plus modeling results were in agreement with the experimental data. The sensitivity analysis revealed that an increase in temperature lead to an increased content of lighter compounds (≤C9) and a decrease in the proportion of heavier compounds (>C10) in the pyrolysis products.