The Investigation Of The Production And Electrochemical Properties Of Graphene And Graphene Based Carbon Nanotubes Composite Materials

Graphene nanosheets with high quality were successfully synthesized in a Teflon-lined container through a low temperature expansion process. The influences of graphite size, oxide time, expansion quality and reduction time on the morphology and structure of products have been systematically investigated, and an optimum experimental condition for the synthesis of graphene nanosheets has been obtained. The results showed that the Teflon-lined container is an effective apparatus for preparing graphene nanosheets at relative low temperature (<300℃), and that this low temperature synthesize process is simple, inexpensive and easy to scale up in comparison with the traditional method with high termperature (>800℃). The electrochemical properties of the as-products were investigated as anode materials for lithium ion batteries. Carbon nanotube/Graphene nano-sheet (CNTs/GNs) hybird composites were successfully synthesized via in-situ growth from the decomposition of ethanol over Co/GNs at the relatively low temperature of600℃. The optimum experimental condition for ethanol decomposition has been systemically investigated. The CNTs/GNs hybird composite as anode material exhibited a more stable and higher specific capacity in lithium-ion battery compared with GNs. After40cycles, the specific capacity of GNs maintained in about500mAhg-1, the CNTs/GNs hybrid presents a higher specific capacity at about550mAhg-1due to a synergistic effect of GNs and CNTs.