A Fe(III)-driven strategy for efficient closed-loop recovery of critical metals from spent LiNixCoyMnzO2 powder

Abstract

With the concepts of carbon peaking and carbon neutrality taking hold, the demand for recycling of spent lithium-ion batteries (LIBs) is increasing rapidly. However, current recycling methods are mostly faced with the dilemma of high cost and low efficiency and unable to meet the demand for energy conservation and consumption reduction. Here, inspired by the formation of acid mine drainage (AMD), we propose a Fe(III)-driven recovery approach, in which the leaching of valuable metals is enhanced by the addition of solid reagents Fe2(SO4)3 and pyrite (FeS2) to create an acidic reducing atmosphere. Under optimal conditions, the leaching efficiency of Ni/Co/Mn/Li reached 99.9%. In addition, NH3·H2O-NaOH was employed to adjust the pH of the leachate for stepwise precipitation of Fe and Ni/Co/Mn. Li was finally collected as Li2CO3 and Fe(III) could be recycled. We have also made attempts on Ni/Co/Mn co-precipitation and Li2CO3 resynthesis of regenerated LiNixCoyMnzO2 (NCM). It is predicted that this process can provide a green, efficient and economical closed-loop approach for cathode recovery of LIBs, with far-reaching implications for the entire battery recycling industry.