Pulse ultrasonication leaching approach for selective Li leaching from spent LFP cathode material

Lithium-iron-phosphate (LFP) batteries are a type of battery whose usage is increasingly expanding due to their features and low production costs. The recovery of precious metals from discarded LFP batteries, resulting from their growing utilization, holds significance from both environmental and economic perspectives. Hydrometallurgical recycling of LFP has gained attention due to its cost-effectiveness and environmental considerations. This study explores the application of ultrasound-assisted leaching as an alternative to conventional hydrometallurgical leaching processes, yielding promising results. The utilization of ultrasound facilitates efficient Li solubility within a short duration of 15 min, eliminating the need for prolonged leaching times. Moreover, selective Li solubility was achieved without the use of additional oxidizing agents through the calcination of the LFP cathode powders. In the ultrasonic leaching of uncalcined powders, a Li dissolution efficiency of 98.60% was obtained, while the Fe dissolution efficiency remained at 32.46%. However, in the ultrasonic leaching of calcined powders, the Li dissolution efficiency was 90.66% within 15 min, while the Fe leaching efficiency remained at 4.88%. Thermodynamic models were employed to elucidate all leaching processes, and the influential parameters were discussed. Furthermore, Al current collectors were successfully recycled, resulting in the production of amorphous Al₂O₃ powders.