Research on pretreatment green discharge technology of spent lithium-ion batteries

Spent lithium-ion batteries with a residual voltage need to be discharged. Salt solution discharge is the mainstream discharge method, but there is a lack of systematic evaluation of the discharge effect of different salt solutions. In terms of discharge efficiency and environmental impact, the effects of different salt solutions were evaluated and compared when salt solution was used as discharge media. Qualitative and quantitative analyses of gaseous, liquid and solid pollutants in the discharge process were carried out, while the discharge mechanism was discussed. The results show that the residual pressure of the battery can be reduced to less than 0.5 V within 8 h of discharge time when 5% Na2S solutions are used as the discharge medium. During the discharge process,S2− is transformed into S at the positive electrode, while H2 is produced at the negative electrode,consuming the residual power of the battery. When Na2S solution is used as the discharge medium, the discharge process produces less slag and the concentration of other ions in the solution after discharge is low. The gaseous product comprises N2 and H2O(g) and exhibits low pollutant emissions and excellent discharge efficiency. © 2023 Central South University of Technology. All rights reserved.