Upcycling spent graphite in LIBs into battery-grade graphene: Managing the produced waste and environmental impacts analysis

This study focuses on connecting graphite demand to battery materials demand, providing a solution to the identified shortage of battery materials and promoting sustainable development. This research used modified Hummer's method to synthesize graphene from the recycled graphite and compared it with graphene synthesized from purified recycled graphite. The purification of recycled graphite was implemented by acid curing-leaching and calcination. The analysis showed that the reduction reaction effectively removed oxygen-containing functional groups from the graphene, resulting in enhanced quality of the produced graphene. Hummer's waste acid was used as a leaching reagent for different LIBs' cathode types in waste management. The waste acid was found to be a strong reagent for transition metals leaching and obtained almost full recoveries of Li, Co, Mn, and Ni from spent LIB cathodes. The synthesized graphene exhibited higher specific surface areas and conductivity values compared to battery-grade graphite. The electrochemical performance of the graphene sheets in lithium half-cells was evaluated, and it was found that the graphene synthesized from recycled graphite enabled increased lithium insertion at active sites, suggesting its potential for enhanced lithium retention. Furthermore, a life cycle assessment study was conducted to evaluate the environmental impacts of the recycling and synthesis processes. This study demonstrates the potential of recycling graphite from spent battery anodes to produce high-quality graphene with improved electrochemical properties.