Efficient separation and recovery of cobalt(II) and lithium(I) from spent lithium ion batteries (LIBs) by polymer inclusion membrane electrodialysis (PIMED)

Effective and sustainable recycling of valuable metals from spent lithium ion batteries (LIBs) after acid leaching are still facing challenges in hydrometallurgical process. In this study, separation of Co(II) and Li(I) from spent LIBs leaching solution was achieved by using newly developed polymer inclusion membrane electrodialysis (PIMED). Significantly high Co(II) transport flux (145.8 μmol m−2s−1) along with high selectivity was achieved, which was much larger than those of the commercial membranes CJMA-3 and AGU, and those reported PIMs and liquid membranes. Solution purity higher than 99.9 % and 99.1 % for Li(I) and Co(II) was obtained in feed and stripping solutions, respectively. Possible transport mechanism for Co(II) was established as a fixed-site jumping mechanism allowing ions to be transported directly in a continuous pathway manner even with low current density. PIMED system exhibited excellent long-time stability in 10 repeated transport cycles. Moreover, PIMED was an energy-saving method with the lowest green-house gas (GHG) emission of 3.1 kg CO2e kg-1Li(I) in comparison with other electrochemical methods. The realization of scale-up experiments also supplies precondition for the large-scale industrial applications. This technology is a promising candidate for practicable recycling of valuable metals from LIBs with high separation performance and environmental benefits.