Green recycling and regeneration of LiNi0.5Co0.2Mn0.3O2 from spent Lithium-ion batteries assisted by sodium sulfate electrolysis

• A green recycling for Li-ion battery is proposed based on electrolysis of Na 2 SO 4 . • Leaching efficiencies for Al, Ni, Co, Mn, and Li are all more than 99 %. • Regenerated cathode exhibits comparable performance to the commercial cathode. • Considerable profit can be obtained by recycling spent Li-ion batteries. Considering the necessity of green and sustainable recycling of spent lithium-ion batteries (LIBs). Herein, a green closed-loop leaching process based on electrolysis of sodium sulfate solution for recycling spent LIBs is demonstrated. Electrolysis technology and LIBs recycling technology are combined together in this work. The H 2 SO 4 and NaOH obtained by electrolysis of sodium sulfate solution are used as leachate, and the generated O 2 and H 2 can be recycled due to the high added value. Under the optimal condition, the leaching efficiencies for Al, Ni, Co, Mn, and Li can all reach more than 99%, then high pure Al(OH) 3 , Li 2 CO 3 , and spherical Ni 0.5 Co 0.2 Mn 0.3 CO 3 precursor are obtained from the recycled solution. Moreover, the spherical regenerated LiNi 0.5 Co 0.2 Mn 0.3 O 2 is synthesized by using recycled-Li 2 CO 3 and Ni 0.5 Co 0.2 Mn 0.3 CO 3 precursor, and it has excellent electrochemical performance with the highest discharge specific capacity of 167.04 mAh g −1 , good rate performance and cycle stability (87% capacity retention after 100 cycles). The remained acid-based solution in the recycling process can be neutralized to form sodium sulfate and reused for electrolysis, which constitutes a closed-loop cycling process. Finally, it is calculated that an economic outcome of $6992 is obtained by recycling one ton spent lithium-ion batteries. These results show this closed-loop hydrometallurgical strategy is environment green and industrial valuable, which can be further extended to recycle other transition metal layered oxide cathode batteries.