Regeneration of spent NCM622 into high performance cathode materials with exposed {010} planes via an efficient closed-loop recycling strategy.

Abstract

The recycling of the spent cathode materials of lithium-ion batteries is crucial to address the resource shortage and environmental pollution issues. In this article, the spent LiNi_0.6Co_0.2Mn_0.2O₂ polycrystal cathode materials were regenerated to the monodispersed rod-shaped cathode materials with exposed {010} planes by a recycling method that combines the selective extraction and solid-state calcination. Such a selective extraction involves the treatment of spent cathode materials in an oxalic-urea mixed solution under hydrothermal reaction, which ensures the complete decomposition and reduction of spent cathode materials, further promoting the uniform precipitation of Ni, Co and Mn elements. The regenerated LiNi_0.6Co_0.2Mn_0.2O₂ cathode materials are obtained by the subsequent calcination that exhibit excellent electrochemical performance in terms of Li⁺ ions diffusivity, rate capability and long-term cycling performance. This deconstructive and remanufacturing recycling method could provide a guidance for the upcycling of spent ternary cathode materials.