Recycling the waste LiMn2O4 of spent Li-ion batteries by pH gradient in neutral water electrolyser

The rapid development of electric vehicles powered by Li-ion batteries poses a challenge for the supply of raw materials , will also generate significant battery waste. Recycling the spent Li-ion batteries not only mitigates the pressure on resource supply but also reduces environmental pollution. Herein, we present a comprehensive study on using pH gradient generated in neutral water electrolyser for recycling waste LiMn2O4 cathodes without addition of external acid, base or chemical reductant. Li+ and Mn2+ thorn are leached from LiMn2O4 at low pH in the anode chamber, and manganese oxide is precipitated at high pH in the cathode chamber. H-2 and O-2 are also valuable byproducts of the process. Li thorn can be recovered in the form of LiMn2O4. Finally, the LiMn(2)O(4 )is re-synthesized, closing the loop. The exact roles of multiple variables on the leaching of LiMn(2)O(4 )as well as the associated phase evolution are carefully examined. In addition, gamma-MnO2 is deposited on the anode during the process, and it is characterized to be a stable and relatively effective catalyst for oxygen evolution reaction in acid. The process demonstrated represents a promising approach for recovering waste LiMn(2)O(4 )of waste Li-ion batteries in an environmentally friendly way.(c) 2022 Elsevier Ltd. All rights reserved.