One-step selective separation and efficient recovery of valuable metals from spent lithium batteries by phosphoric acid-based deep eutectic solvent

Abstract

With more and more lithium-ion batteries (LIBs) being put into production and application, precious metals such as lithium and cobalt are scarce, so it is imminent to recover various strategic metal resources from spent LIBs. Meanwhile, the complex and difficult problem of separating and recovering metals from leaching solutions has been an urgent question that needs to be resolved. In this work, a phosphoric acid-based deep eutectic solvent (DES) was developed for extracting metals from spent LIBs and one-step selectively separating and efficiently recovering transition metal. The prepared DES shows excellent extraction performance for Li (100%) and Co (92.8%) at 100 °C. In addition, the extraction system can effectively separate and precipitate Co through its own components, avoiding the introduction of new precipitants and the destruction of the original composition structure of DES. This also contributes to the good cycle stability of the extraction system with excellent extraction performance for Li (94.3%) and Co (80.8%) after 5 cycles. This work proposes a green method for one-step selectively separating and recovering valuable metals from spent LIBs.