Cyclohexanehexone-assisted one-step ball-milling of graphite to graphene composites as cathodes for lithium-ion batteries

Abstract

Organic molecules are promising electrode materials for green and sustainable energy-storage fields due to their abundant resources, tunable theoretical capacity, and environmental friendliness. However, the high solubility and inherently poor conductivity of organic electrode materials have impeded their further application. Herein, a series of cyclohexanehexone/graphene composites (C6O6/Gr) were successfully fabricated by facile ball-milling exfoliation of graphite and in-situ immobilization of cyclohexanehexone (C6O6) molecules onto as-made graphene (Gr) surfaces. The resultant C6O6/Gr composites were used as cathodes in lithium-ion batteries which exhibited large specific capacity (550 mA h g−1 at 50 mA g−1), high cycling stability (237 mA h g−1 at the 200th cycle at 50 mA g−1 and 126 mA h g−1 at the 3000th cycle at 2 A g−1) and superior rate capability (318 mA h g−1 at 500 mA g−1), significantly outperforming its C6O6 counterpart and previously reported carbonyl-based cathodes. In particular, the influence of ball-milling speed and graphene content on the morphology, structure, and electrochemical performance of the composites was also investigated. Such a universal and green approach to preparing graphene-based composites is suitable for the low-cost, high-efficiency and large-scale production of organic electrode materials to fulfill requirements in diverse energy-storage systems.