Self-assembling Carbon-based Anode Materials For Lithium Ion Battery And The Investigation Of Their Properties

The advancement of electric vehicle industry demanded lithium ion batteries with an increasingly high performance including energy density and power density. It was significant to research and develop electrode materials with a large specific capacity and a high rate performance for the technology progress of lithium ion battery. This paper was financially supported by National Natural Science Foundation of China (51274240), investigating carbon-based composites as anode materials for high-performance lithium ion batteries via self-assembled technique. In this paper, carbon nanotube/graphene (CNT/GNS) composite as anode materials was fabricated via self-assembled technique and its microstructure and lithium ion stored performance were investigated. Aiming at solving the problems of poor electric conductivity and poor cycling performance of tin oxide (SnO2) when used as anode materials, self-assembled technique was exploited to synthesize tin oxide/carbon nanotube (SnO2/CNT) and tin oxide/graphene (SnO2/GNS), and their corresponding electrochemical lithium ion stored properties were studied. The conclusions were shown as follows:(1) CNT/GNS composite could be directly fabricated by using the static interaction between aminated carbon nanotubes and carboxylic graphene. The combination of carbon nanotubes and graphene oxide was intensive, which exhibited a layer structure. The relationship between layers and thicknesses was linear growth and the lithium ion storage capacity of the electrode could be well controlled by its layer. Under the voltage window of0.01～3V and the testing current density of0.01mA/cm2, the CNT/GNS composite electrode with80layers exhibited a reversible capacity of0.265mAh/cm. Even though at a high current density of0.4mA/cm, the electrode could still deliver a reversible capacity of0.030mAh/cm2.(2) SnO2/CNT composite could be fabricated via electrostatic interaction between the surface oxide group of CNTs and Sn2+. Under the voltage window of0.01～2V and the current density of100mA/g, the SnO2/CNT electrode exhibited a reversible capacity of898.4mAh/g. After100cycles, its reversible capacity was489.7mAh/g, corresponding to a retention rate of54.5%. When the current density was elevated to500mA/g, it could still deliver a reversible capacity of340mAh/g.(3) SnO2/GNS sandwiched composite could be fabricated by self-assembled technique. Under the current density of100mA/g, the SnO2/GNS electrode exhibited a reversible capacity of850.9mAh/g. After50cycles, its reversible capacity was502.5mAh/g, corresponding to a retention rate of59.1%. When the current density was elevated to500mA/g, it could still deliver a reversible capacity of355mAh/g.