Recovery of cathode materials and Al from spent lithium-ion batteries by cleaning

Cathode materials are difficult to separate from Al-foil substrates during the recycling of spent lithiumion batteries (LIBs), because of the strong bonding force present. In this study, ultrasonic cleaning was used to separate and recycle these cathode materials. The mechanism of separation was ascribed to the dissolution of polyvinylidene fluoride (PVDF) and the cavitation caused by ultrasound. Based on this mechanism, the key parameters affecting the peel-off efficiency of cathode materials from Al foil was identified as solvent nature, temperature, ultrasonic power, and ultrasonic time. The peel-off efficiency of cathode materials achieved, similar to 99% under the optimized conditions of N-methyl-2-pyrrolidone (NMP) cleaning fluid, 70 degrees C process temperature, 240 W ultrasonic power, and 90 mm of ultrasonication. The cathode materials separated from Al foil displayed a low agglomeration degree, which is beneficial to the subsequent leaching process. Finally, a new, environmentally-sound process was proposed to efficiently recycle cathode materials and Al from spent LIBs, consisting of manual dismantling, ultrasonic cleaning, and picking. (C) 2015 Elsevier Ltd. All rights reserved.