Recycling of lithium-ion batteries: a novel method to separate coating and foil of electrodes

Lithium-ion batteries will play a crucial role in the development of mobile consumer devices, stationary energy storage systems, and electric mobility. The growth in these fields will bring about a surge in the lithium-ion battery market. This leads experts to agree that more effective recycling processes are needed in conjunction with the recycling of lithium. This calls for an entirely revolutionary recycling process which we here have attempted to develop. Our approach uses thermal decomposition of the polyvinylidene fluoride binder to lessen the cohesion of coated active material particles and weaken the adhesion between coating and foil. Then, an air-jet-separator is able to detach the coating powder from the current collector foils while stressing remaining particulate agglomerates. This separation process named ANVIIL (Adhesion Neutralization via Incineration and Impact Liberation) was tested on a laboratory scale with electrode rejects. We compared this to the widely used mechanical recycling process that utilizes a cutting mill to separate the current collector and coating. Intermediates and products were characterized using thermogravimetric analysis, tape adhesion tests, atomic absorption spectroscopy, particle size analysis, and gravimetric sieve analysis. We found that 97.1% w/w of the electrode coating can be regained with aluminum impurities of only 0.1% w/w, 30 times purer than the comparative process. This demonstrates a more effective recycling process than is currently available that also enables the recapture of lithium from the electrode coating.