It is highly desirable to develop high-performance and cost-effective cathode materials for lithium-ion batteries (LIBs). In this work, functionalized graphene nanosheets (FGNS) were facilely synthesized utilizing ethylene glycol as both reducing agent and solvent. When employed as cathode materials for LIBs, FGNS were demonstrated to exhibit superior electrochemical performance when compared with traditional metal oxide-based cathodes. For instance, FGNS deliver outstanding cycle stability and high specific discharge capacity of 280mAhg−1 at 0.05Ag−1 without obvious capacity fading after 300 cycles. Furthermore, FGNS reveal high rate capacity of 152mAhg−1 at a high current density of 0.4Ag−1. The excellent electrochemical performance is attributed to the oxygen-containing functional groups and specific poriferous structure of FGNS. The proposed FGNS are expected to be a simple, low-cost, efficient, and large-scale production of cathode materials for LIBs.