Regeneration of graphite anode from spent lithium-ion batteries via microwave calcination

Abstract

• Microwave calcination is applied to regenerate spent anode graphite. • Microwave calcination consumes less energy than conventional calcination. • The charge specific capacity of regenerated graphite is 354.1 mAh·g −1 at 0.1 C. • The capacity retention rate of regenerated graphite is 98.3% after 60 cycles at 0.1 C. An efficient and economical recycling method for spent anode graphite via microwave has been proposed in this study. The spent graphite (SG) was firstly treated by sulfuric acid curing-acid leaching, and then regenerated by microwave calcination. The effects of microwave calcination temperature and time on electrochemical performance were systematically studied. The morphology and structure of graphite were analyzed by SEM, FT-IR and XRD. The results show that compared with the SG, regenerated graphite (RG) obtained by microwave calcination has a neat graphite surface and a significantly improved electrochemical performance, such as the initial coulombic efficiency and the charge specific capacity at 0.1 C are 83.4% and 354.1 mAh·g −1 , and the capacity retention rate after 60 cycles at 0.1 C increases to 98.3%. In addition, microwave calcination has the advantages of selective heating and fast heating rate. Therefore, this method can realize efficient regeneration of spent anode graphite with low-energy consumption, which provides new light on the recycling of spent graphite.