(2021) Journal of CO₂ Utilization_Valorization of a spent lithium-ion battery electrolyte through syngas formation using CO₂-assisted catalytic thermolysis over a battery cathode material

Jung S., Kwon D., Park S., Kwon K., Tsang Y.F., Kwon E.E.

(Elsevier Ltd) Journal of CO2 Utilization ISSN: 22129820 Vol.50 Issue. Article No.101591 DOI: 10.1016/j.jcou.2021.101591

Development of rechargeable batteries in energy storage systems and electric/electronic devices has been rapidly progressed as an effort to amplify the utilization renewable and sustainable energies since the past few decades. However, increasing demand of the rechargeable batteries results in significant accumulation of battery waste materials. In the current battery recycling process, the recovery of cathode metal(oxide)s has been mainly focused, but other organic compartments were not properly recycled. In this study, the valorization of battery electrolyte was investigated. To this end, CO₂-assisted thermolysis of a broadly used battery electrolyte, LiPF₆ in carbonate solvents, was performed. First part examined liquid (carbonates, cyclic and aliphatic hydrocarbons) and gaseous products (H₂, CO, CH₄, C₂H₄, and CO₂) from thermolysis of battery electrolyte at different conditions. The complicated mixture of pyrogenic products needs additional separation processes to recover each compound. To convert the complicated mixture samples into value-added chemicals (i.e., syngas), catalytic thermolysis was done in the second part. Considering that the practical pyrolysis condition of battery electrolyte includes a cathode material during the thermolysis, a conventional cathode material (NCM 811: LiNi_0.8Co_0.1Mn_0.1O₂) was used as a catalyst. It was highly active to convert entire liquid compounds into syngas at ≤ 500 °C, and synergistic effects of catalyst and CO₂ resulted in enhanced CO formation. Given that the metallurgy process for battery operates at near 1300 °C, thermolysis of battery electrolyte could be incorporated into the metallurgy process to maximize recovery of organic and metallic compounds in spent batteries. © 2021 Elsevier Ltd.

This work was also supported by the National Research Foundation of Korea (NRF) grants funded by the Korea government (MSIT) ( NRF-2019R1A4A1027795 ). This work was supported by Brain Pool Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science and ICT ( NRF-2019H1D3A1A01070644 ).