| In recent year,considerable interests have been focused on one-dimensional nanostructures of vanadium oxides due to their novel electrochemical properties.Nowadays,the synthesis and doping of vanadium oxides nanostructures have become the forefront and hotspots in the research of nanomaterials.In this paper,we have synthesized the silver vanadate and copper vanadate nanostructures by various methods.The influences of experiment conditions on the morphologies,crystal structures and discharge-charge properties of the resulting products experiment conditions such as reaction time,reaction temperature have been investigated.The main results are concluded as follows:(1)Ag0.33V2O5/V2O5 core-shell nanobelts have been synthesized by a facile homogeneous reaction between peroxovanadic acid and AgNO3 under hydrothermal conditions.The influences of reaction time on the morphologies and crystal structures of the resulting products have been investigated.It is found that the formation of Ag0.33V2O5/V2O5 core-shell nanobelts is time dependent:Ag0.33V2O5 nanobelts are formed firstly,and then V2O5 grows on the Ag0.33V2O5 surfaces.When used as the cathode material in rechargeable lithium batteries,the core-shell nanobelts exhibit stable lithium-ion intercalation/deintercalation reversibility and deliver specific discharge capacities of around 276.4 mAhg-1 after 50 cycles at a rate of 0.25 Ag-1.The value is lowered to 228 mAhg-1 at 0.5 Ag-1,and 147.2 mAhg-1 at 0.75 Ag-1.The Ag+ addition and nanostructures are likely to be responsible for the preservation of the good electrochemical properties.The good electrochemical properties of Ag0.33V2O5/V2O5 core-shell nanobelts make them a promising candidate as a cathode material for rechargeable lithium batteries.(2)Ultra-long CuV2O6 nanobelts have been successfully synthesized via a facile homogeneous reaction between peroxovanadic acid and cupric acetate in the absence of any templates and surfactants.The reaction parameters,such as reaction time,and with or without H2O2,have profound influences on the crystal structures and morphologies of the resulting products.The time-dependent experiments reveal that the formation of ultra-long CuV2O6 nanobelts is related to the disassembly of urchin-like Cu3(OH)2V2O7·2H2O nanostructures composed of radially aligned nanobelts,and the growth of CuV2O6 along the direction of[010].Without the addition of H2O2 aqueous solution,wide and short CuV2O6 nanobelts coexist with some irregular particles and microrods in the products.Upon aging the solution composed of V2O5,H2O2,and Cu(Ac)2 for 12 h before reaction,oxygen-deficient Cu,V2O5·nH2O nanobelts are obtained.When used as the cathode material in rechargeable lithium batteries,the charge-discharge circulation and cyclic voltammograms show that the ultra-long CuV2O6 nanobelts exhibit good electrochemical properties.(3)The silver vanadate of different crystalline phase have been successfully synthesized via changing the mole ratio of Ag and V when use the silver oxide and peroxynitrite acid as the reactant.The Ag2V4O11/V2O5·nH2O,AgVO3 and AgVO3/Ag4V2O7 nanobelts have been synthesized by changing the mole ratio of Ag and V as 1:2,1:1 and 2:1.The size of nanobelts increase gradually.Ag/Ag2V4O11·H2O nanobelts have been synthesized by aging AgN03 and peroxovanadic acid for 48 h.When keep the Ag/Ag2V4011·H2O nanobelts at 180?for different times,the Ag2V4011·H2O nanobelts were got.The morphology of the products were nanobelts with some protuberance at the surface at first,then it changed into nanobelts with a smooth surface.The size of the nanobelts were also increased with the extension of time.The silver vanadate nanobelts were synthesized by calcining the Ag//Ag2V4011·H2O at different times for 10 h.The silver vanadate nanobelts were used as the cathode material in rechargeable lithium batteries,the initial specific discharge capacity of silver vanadate nanobelts calcined at different temperature(200?,300?,400?)were 168.3 mAh/g,231.9 mAh/g,298.7 mAh/g respectively. |
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