Flowerlike Vanadium Sesquioxide: Solvothermal Preparation and Electrochemical Properties

A novel 3D hierarchical flowerlike vanadium sesquioxide (V2O3) nano/microarchitecture consisting of numerous nanoflakes is prepared via,a solvothermal approach followed by an appropriate heating treatment. The as-obtained nanostructured V2O3 flower is characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) analysis, and transmission electron microscopy (TEM) (or/and high-resolution TEM, HRTEM), and it is found that the V2O3 flower is constructed by single-crystalline nanoflakes. Furthermore, it is demonstrated that the surface of the flowerlike V2O3 material is composed of nanostructured pores, which derive from the adsorption/desorption of nitrogen, and that the pore-size distribution depends on the unique three-dimensional interconnection between nanoflakes and on their intrinsic properties. The electrochemical behavior of the V2O3 flower for lithium-ion insertion/extraction in non-aqueous solution as well as the faradaic capacitance for pesudocapacitors in a neutral aqueous solution are also investigated. A reversible discharge capacity as high as 325 mA hg(-1) is obtained at a current density of 0.02 A g(-1) from a LiClO4/EC:DEC electrolyte solution (i.e. LiClO4 in ethyl carbonate and diethyl carbonate). When used as the cathode material of pesudocapacitors in Li2SO4, the flowerlike oxide displayed a very high initial capacitance of 218 F g-1 at a current density of 0.05 A g(-1). We believe that the good performance of the flowerlike V2O3 electrode is most probably due to its unique 3D hierarchical nano/microarchitecture, which shows that the electrochemical properties of a cathodic material do not only depend on the oxidation state of that material but also to a large extent on its crystalline structure and morphology. The aforementioned properties suggest that the present V2O3 flower materials may have a great potential to be employed as electrode materials in rechargeable lithium batteries and pesudocapacitors.