Recycling of end-of-life lithium-ion batteries

Abstract

The growing demand for lithium-ion batteries (LIBs) in electric vehicles has intensified the need for efficient recycling technologies. This study builds upon a
previously developed LIBs recycling process that used dry milling and attrition scrubbing for material liberation. Three major challenges in this process were addressed: the lack of well-defined discharge conditions to ensure safe mechanical processing, the impact of discharge parameters on the selective liberation of critical metals, and the limited separation efficiency between positive and negative electrode active materials. A series of controlled-discharge protocols was introduced, with different discharge terminal voltages and discharge rates. Battery safety under these conditions was assessed using
penetration tests combined with surface temperature monitoring. The results identified that discharging below 2.0 V at a rate of less than 0.5 C reduces thermal risk and may serve as a practical guideline for safer handling during mechanical processing. Next, selective liberation of critical metals was performed through dry milling and attrition scrubbing on samples discharged at different rates. In the dry milling process, a low discharge rate (0.01 C) resulted in up to 5.22 wt% higher metal recovery compared to a high discharge rate (1 C). In contrast, discharge rate had minimal effect on the efficiency of attrition scrubbing. Furthermore, froth flotation employed in previous studies was replaced by dense media separation to enhance the separation efficiency of positive and negative electrode active materials in the attrition product. Target metals were successfully recovered in the sink materials with a recovery rate of up to 92.66 wt%. The proposed methodology, including constant current discharge,
penetration test, dry milling, attrition scrubbing, and dense media separation, provides practical guidance for developing safer, more efficient processes for the
liberation and separation of battery materials. Future work will focus on evaluating the performance and scalability of these methods in industrial applications.

Date of Award	18 Jul 2026
Original language	English
Awarding Institution	University of Nottingham
Supervisor	Zheng Wang (Supervisor) & Philip Hall (Supervisor)