Fast Li Replenishment Channels-Assisted Recycling of Degraded Layered Cathodes with Enhanced Cycling Performance and Thermal Stability.

The direct recycling of cathode materials in lithium-ion batteries is important for environmental protection and resource conservation. The key regeneration processes are composition replenishment and atom rearrangement, both of which depend on the migration and diffusion of atoms. However, for the direct recycling of degraded LiNi 0.5 Co 0.2 Mn 0.3 O 2 (D-NCM523) cathode, the irreversible phase transitions accumulated during the long-term cycles block the Li diffusion channels with a high diffusion energy barrier, resulting in the layered structure difficult to be fully repaired and the capacity decays rapidly. To address the challenge, we rebuild fast Li replenishment channels to regulate the surface phase and effectively assist the regeneration process with a reduced energy barrier. This method reduces the amount of Li supplement by >75% and shortens the sintering time (only 2 hours) to fully regenerate D-NCM523, compared to general direct recycling methods. The regenerated NCM523 (LCMB-NCM523) exhibits a satisfactory repaired specific capacity of 160 mAh g -1 and excellent cycling stability, retaining 78% of its capacity after 300 cycles. In addition, LCMB-NCM523 is recycled with improved thermal decomposition peak temperature and enables 200 cycles even at 60 °C, greatly improving safety. This work proposes a promising way for the large-scale direct regeneration of layered cathodes. This article is protected by copyright. All rights reserved.