Intercalation assembly of Li3VO4 nanoribbons/graphene sandwich-structured composites with enhanced oxygen reduction catalytic performance

Novel sandwich-like nanocomposites of alternative stacked ultrathin Li3VO4 nanoribbons and graphene sheets (LVO-G) were successfully developed by a facile intercalation assembly method with a post heating treatment. The characterization results demonstrate that the average size of the Li3VO4 nanoribbons with a non-layered crystal structure is a few micrometers in length, 50-100 nm in width and a few atomic layers in height. The addition of graphene sheets can modify the preferred orientation of the Li3VO4 nanoribbons from (110) to (011) plane and restrict the growth of impurity phase at the same time. In addition, EIS analysis has also verified the reduced resistance and thus the enhance conductivity of LVO-G nanocomposites compared with bare Li3VO4 nanoribbons. What's more, the electrocatalytic performances of these novel LVO-G nanocomposites for oxygen reduction reaction (ORR) in alkaline solution are further investigated by cyclic voltammetry (CV), rotating disk electrode (RDE) and chronoamperometry test. It is found that the enhanced activity and stability of LVO-G can be attributed to the synergistic effect between the Li3VO4 nanoribbons and graphene sheets with a larger reduction current density and a smaller onset potential value for LVO-G25 compared with LVO-G50 due to the change of components. (C) 2015 Elsevier B.V. All rights reserved.