Direct Recycling of Li_xNi_0.5Mn_0.3Co_0.2O₂ from Production Scrap and End‐Of‐Life Batteries, Using Solid‐State Relithiation

Abstract

Direct recycling of Li‐ion battery cathodes offers a sustainable and potentially cost‐effective alternative to conventional methods, often involving complex chemical processes and significant material losses. This study focuses on the relithiation of cathode materials from quality control reject (QCR) and end‐of‐life (EoL) Li‐ion cells to restore their physical structure, morphology, and electrochemical performance. Two NMC532/graphite pouch cells from the same manufacturer were studied. QCR cells, stored under ambient conditions, experienced corrosion and degradation before recycling, while EoL cells were cycled to the end of life. The cells were disassembled, and the cathode materials were delaminated using NaOH solution, then relithiated with LiOH at 700°C for 15 hours in the air. Extensive characterization analyzed elemental composition, structural properties, thermal stability, and particle size distribution. Results indicated that relithiation successfully restored lithium content and improved the structural ordering and morphology of the cathode materials. The electrochemical performance of the relithiated cathodes exhibited good stability over 100 charge‐discharge cycles. The relithiated QCR samples achieved a capacity of 155.57 mAh g⁻¹, while EoL samples reached 152.53 mAh g⁻¹, comparable to pristine materials. This study highlights relithiation's potential to extend the lifecycle of Li‐ion cathodes, contributing to a more sustainable circular economy for battery materials.