Solution Synthesis and Electrochemical Properties of V2O5 Nanostructures
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Date: 03-24-2006
Start Time:
2:00pm
End Time: 3:00pm
Speaker: Prof. Guozhong Cao
From:
University of Washington
Location: 214 Mudd
Hosted by:
Center for Integrated Science
Abstract:
In this seminar, I will present our recent work on the growth and
electrochemical properties of single crystalline vanadium pentoxide
(V2O5) nanorod, amorphous V2O5 nanotube, and Ni-V2O5 nanocable arrays.
Vanadium pentoxide nanorod arrays were grown by electrochemical
deposition, surface condensation induced by a pH change, and sol
electrophoretic deposition. Uniformly sized vanadium oxide nanorods
with a length of about 10.m and diameters of 100 or 200 nm were grown
over large area with near unidirectional alignment. TEM micrographs and
electron diffraction patterns of V2O5 nanorods clearly show the
single-crystalline nature of nanorods from all three growth routes with
a growth direction of [010]. Electrochemical analysis revealed that
nanorod array electrodes possess significantly improved storage
capacity and charge/discharge rate approximately 5 times higher
applicable current density than that of sol-gel derived films. V2O5
coated Ni nanorods arrays were grown by template-based electrochemical
deposition of Ni, followed by electrophoretic deposition of V2O5 layer.
Each Ni core nanorod is covered completely and uniformly by V2O5 shell
of average thickness of about 40nm. The current density and Li+
insertion capacity of Ni-V2O5 nanocable array electrodes possess
approximately 10 times larger capacitance than single crystal V2O5
nanorod arrays and 40 times larger than sol-gel derived polycrystalline
V2O5 films. The most significant improvement in the electrochemical
supercapacitor performance based on Ni-V2O5 nanocable arrays is on the
simultaneous enhancement of specific power and specific energy with the
enhancement easily above one order of magnitude. Further improvement in
energy storage density and cyclic fatigue resistance with carefully
designed doping and amorphotization will also be briefly discussed.