A Novel Reclamation Process For Spent Lithium-ion Batteries

Spent lithium-ion batteries (LIBs) contain lots of strategic resources such as cobalt and lithium together with other hazardous materials such as organic electrolyte and binder, which are considered as both an attractive resource and environmental contaminant. The highly efficiency recovery of spent LIBs meets the need of sustainable development.In this work, vacuum pyrolysis was proposed as an alternative pretreatment method of processing the cathode from the spent LIBs. The cathode material peeled completely from aluminum foils and the organic binder removed completely after vacuum pyrolysis under the following experimental conditions:temperature of600℃, vacuum evaporation time of30min and the residual gas pressure of1.0kPa. Moreover, the aluminum foil was excellent without damage. The typical XRD patterns of the peeled material showed that the main compositions were LiCoO2and CoO. The aluminum foils were intact without any scraping processes and could be recovered in their metallic forms. The FT-IR analysis indicated that the main components of pyrolysis products are organic fluorocarbon compounds. Most of the fluorinated compounds can be enriched and recovered to prevent environmental pollution and resource waste.The cathode material separated from aluminum foils was leached in different acid solutions to recover valuable metals. Over99%of cobalt and lithium could be recovered from peeled cobalt lithium oxides with2.0M sulfuric acid leaching solution and5vol.%H2O2at80℃and solid/liquid ratio of50g/L for60min. Furthermore, the concentration of H2SO4and H2O2showed significant influence on the leaching rate. The reaction efficiency of LiCoO2was more than98%with1.0M oxalate solution at80℃and solid/liquid ratio of50g/L for120min. However, the variable amounts of H2O2had little influence on the leaching LiCoO2with oxalate. During the oxalate leaching process, cobalt from LiCoO2was leached and precipitated directly as CoC2O4. Moreover, cobalt and lithium could be separated efficiently during the oxalate leaching process. The combined process is simple, environmentally friendly and adequate for the recovery of valuable metals from spent LIBs. The obtained product after oxalate leaching was confirmed to be CoC2O4·2H2O by XRD and FT-IR.