Lithium-Chelating Resins Functionalized with Oligoethylene Glycols toward Lithium-Ion Battery Recycling

Recycling spent lithium-ion batteries (LIBs) is an important consideration both to preserve metal resources and to reduce hazardous waste. One recycling method is to extract lithium and cobalt ions using organic solvents that contain battery components. However, it is hard to achieve the complete separation of metal ions and this also requires multiple steps. Herein, functionalized polymeric resins are reported, that can capture both lithium and cobalt ions from organic solutions and separate them chromatographically. Specifically, Merrifield resin is functionalized with oligoethylene glycol derivatives, which are structurally similar to crown-ethers. To test the lithium-ion depletion, these resins are incubated with bulk solutions of lithium cations at approximate to 50 ppm in acetonitrile. The results showed 30-45% depletion after filtration in optimal cases. To test this polymer support for chromatographic separation and check the potential for LIB recycling, a column is packed with the functionalized resin beads, and a mixture of lithium (approximate to 200 ppm) and cobalt (approximate to 200 ppm) ions is loaded. The column can achieve baseline separation of these ions and can be used multiple times without degradation. These results suggest that the current solvent extraction steps during recycling processes can be greatly simplified.

Automated summary

Using functionalized polymeric resins can capture and separate lithium and cobalt ions from organic solutions, simplifying the solvent extraction steps in the recycling of LIBs.