An-Min Cao Jin-Song Hu Han-Pu Liang Li-Jun Wan and Chun-Li Bai

Self-assembled structures with highly specific morphology and novel property are of great interest to chemists and materials scientists. Controlled organization from rod-like building blocks to curved structures remains a challenge. Such a capability is attractive to scientists not only because of its importance in understanding the concept of self-assembly with unnatural building blocks but also for its great application potentials.

Vanadium pentoxide (V₂O₅) has been extensively studied as a well-known transition-metal oxide. The nanostructured V₂O₅ shows great potential applications in the field of lithium-ion batteries actuators catalysis and sensors. A mediated-polyol process is then adopted to synthesize highly ordered superstructure of vanadium pentoxide (V₂O₅) in which nanorods circle around leading to hollow microspheres in various shapes from “nest” to “hedgehog”. The protocol represents a substantial simplification over more conventional methods such as electrostatic spray or thermal evaporation. The state of nanorods on the surface is readily tunable by changing the concentration of V(acac)₃. The formed microspheres can adopt various shapes from a nest to a hedgehog. The prepared V₂O₅ exhibits desirable electrochemical properties in terms of high capacity at remarkable reversibility when it is used as cathode material in lithium-ion battery.

Angew. Chem. Int. Ed. 2005 Vol 44 No. 28 4391－4395

a) SEM image of the prepared vanadium precursor with 6 mM V(acac)₃ and no PVP. The inset is the EDX pattern of the rod. b c d) SEM images of the microspheres synthesized with different concentrations of V(acac)₃ at b) 6 mM c) 18 mM and d) 42 mM while the concentration of PVP was constant at 0.14 mM.

 a) Cyclic Voltammograms of V₂O₅ microspheres obtained at a scan rate of 10 mV/s. First scan is indicated by line A and after 15 cycles by line B. b) The third charge (dash-dot line)-discharge (solid line) curve with the current rate of C/5. The capacity was as high as 286.4 mAh/g while the charge-discharge efficiency was up to the level of 97.2% in the potential range from 2.0 V to 4.0 V.