title: Hierarchical nanocomposites of vanadium oxide thin film anchored on graphene as high-performance cathodes in li-ion batteries.
abstract: Hierarchical nanocomposites of V2O5 thin film anchored on graphene sheets were prepared by slow hydrolysis of vanadyl triisobutoxide on graphene oxide followed by thermal treatment. The nanocomposite possessed a hierarchical structure of thin V2O5 film uniformly grown on graphene, leading to a high specific surface area and a good electronic/ionic conducting path. When used as the cathode material, the graphene/V2O5 nanosheet nanocomposites exhibit higher specific capacity, better rate performance, and longer cycle life, as compared to the pure V2O5. The nanocomposite cathode was able to deliver a specific capacity of 243 mAh/g, 191 mAh/g, and 86 mAh/g at a current density of 50 mA/g, 500 mA/g, and 15 A/g, respectively. Even after 300 cycles at 500 mA/g, the composite electrode still exhibited a specific capacity of ∼ 122 mAh/g, which corresponds to ∼ 64% of its initial capacity. This enhanced electrochemical performance can be attributed to facile electron transport between graphene and V2O5, fast Li-ion diffusion within the electrode, the high surface area of the composites, and a pore structure that can accommodate the volume change during lithiation/delithiation, which results from the unique hierarchical nanostructure of the V2O5 anchored on graphene.
authors.affiliation: Department of Mechanical Engineering, Indiana University-Purdue University Indianapolis , Indianapolis, Indiana 46202, United States.
authors.forename: Zhe-Fei
authors.initials: ZF
authors.lastname: Li
authors.forename: Hangyu
authors.initials: H
authors.lastname: Zhang
authors.forename: Qi
authors.initials: Q
authors.lastname: Liu
authors.forename: Yadong
authors.initials: Y
authors.lastname: Liu
authors.forename: Lia
authors.initials: L
authors.lastname: Stanciu
authors.forename: Jian
authors.initials: J
authors.lastname: Xie
keywords: Li-ion battery; V2O5; cathode; graphene; hierarchical; nanosheets