Recycling the cathode materials of spent Li-ion batteries in a H-Shaped neutral water electrolysis cell

Abstract

• A large pH gradient is generated in a neutral water electrolysis cell. • The pH gradient allows concurrent LiCoO 2 leaching and Co(OH) 2 precipitation. • The use of external acid and base is avoided. • The Co(OH) 2 and Li 2 CO 3 recovered were calcined to resynthesize new LiCoO 2 . • The treatment of LiMn 2 O 4 and NCM with this process was also investigated. The recycling of Li-ion batteries is becoming increasingly urgent due to the rapid accumulation of spent Li-ion batteries from aging portable electronics and electric vehicles. The lack of environmentally and economically feasible recycling technologies will not only cause material losses and environmental contamination, but also poses a serious limit for the penetration of more Li-ion batteries in electric vehicles and grid-scale energy storage applications. Here, we present a proof-of-concept demonstration of an innovative process for recycling cathode materials of Li-ion batteries in a neutral water electrolysis cell. During electrolysis, an electrochemical pH gradient was generated, which enables the leaching of waste LiCoO 2 at low pH in the anode chamber and the precipitation of solid Co(OH) 2 at high pH in the cathode chamber. The Co(OH) 2 precipitates can be readily filtered and separated from the electrolysis cell. In addition, the Li + is recovered in the form of Li 2 CO 3 . Unlike conventional hydrometallurgical processes and other aqueous electrochemical processes, this work harnesses the in-situ electrochemical pH gradient generated by neutral water electrolysis. This allows concurrent LiCoO 2 leaching and Co(OH) 2 precipitation at separate chambers and avoids the use of external acid and base, extractant or ion-selective polymer electrolyte membrane. This method is also extended to recycling waste LiMn 2 O 4 and LiNi 0.5 Co 0.2 Mn 0.3 O 2 . Therefore, this new process represents a green advance for recycling the waste cathode materials of the Li-ion batteries.