An environmentally friendly hydrometallurgy process for the recovery and reuse of metals from spent lithium-ion batteries, using organic acid

Abstract

The increasing use of lithium-ion batteries (LIBs) presents a serious environmental problem. These spent LIBs are suitable sources of metals for the production of LIB cathode active material. This study successfully recovered nickel, cobalt, and aluminum from spent LIB nickel cobalt aluminum oxide (NCA) and regenerated NCA cathode. The effect of the spent anode as a reducing agent was also investigated. The spent anode alone did not reduce the metals Ni and Co sufficiently. The leaching efficiency was only 34.8, 47.15, and 86.75% for Ni, Co, and Al, respectively, and these values did not increase with increasing citric acid concentration or the addition of ascorbic acid as a reducing agent. However, it increased significantly to 85, 90.12, and 100%, for Ni, Co, and Al, respectively, with the addition of 2% v/v H2O2. The ternary metal oxalate (TMO) precipitation of the leaching solution confirmed the synthesis of TMO from the precursor. The regenerated NCA synthesized from TMO had better electrochemical performances than those of new commercial NCA. It had a specific discharge capacity of 137 mA h/g and a retention capacity of 85.4% at 2 C after 50 cycles, whereas the new commercial had a specific discharge capacity of 133.4 mA h/g and a retention capacity of 82.6% at 1 C after 50 cycles.