Graphene and Its Composites as Cathodes for Lithium Ion Batteries

This chapter summarizes many innovative methods for synthesizing graphene-based cathode materials as well as various modifications that have been made to improve electrode performance. There have been attempts to use pure graphene or graphene oxide (GO) as cathode materials, but the majority of the research has involved the use of composite materials. Among the cathode materials produced, Lithium iron phosphate (LiFePO₄), Lithium cobalt oxide, Lithium manganese oxide, and Vanadium oxide are the most interesting cathodes for lithium ion batteries (LIBs). LiFePO₄ with its olivine structure is one of the most promising cathode materials for LIBs, owing to its high theoretical capacity, flat operating voltage, and so on. Functionalized/doped graphene or reduced graphene nanosheet have been studied as high-performance cathodes for future LIBs. GO is reduced using ethylene glycole as both reducing agent and solvent, by thermal reduction, and by N-doping. There has been a renewed interest in “green” cathode materials for LIBs.