Novel closed-loop process for simultaneous recovery of valuable metals and iron from mixed type of spent lithium-ion batteries

It might be of practical significance to recover different metals from the already complicated waste spent lithium-ion batteries (LIBs) stream by simplified recycling processes. This study is, therefore, focused on exploration of simplified process for simultaneous recovery of different metals from waste cathode materials of mixed types of spent LIBs. It is discovered that leaching agent of phosphoric acid demonstrates natural repulsion for Fe, while valuable metals of Ni, Co, Mn and Li can be completely dissolved under optimized leaching conditions, indicating a coupling reaction of selective leaching and precipitating for valuable metals ad iron, respectively. Characterization results indicate valuable metals enriched solution and pure FePO4 in leaching solution and residue, respectively. Kinetics and dynamics studies suggest that the leaching of valuable metals are co-controlled by chemical reaction and internal diffusion, accompanying a spontaneous formation of FePO4. Then new cathode materials of LiFePO4 and LiNi1/3Co1/3Mn1/3O2 with sound electrochemical performances can be re-fabricated from leaching residues and lixivium, respectively. And phosphoric acid can be regenerated during the co-precipitating of valuable metals. This whole recycling process can be a highly selective, closed-loop and simplified alternative for different metals recycling from current most complicated waste LIBs stream.