Improving the Volumetric Energy Densities of Nanostructured V[sub 2]O[sub 5] Electrodes Prepared Using the Template Method

Abstract

Membrane-based template synthesis was used to prepare nanostructured V2O5 electrodes with high Li-insertion rate capabilities and improved volumetric charge capacities. Two methods were used to increase volumetric capacity. The first entailed chemically etching the template membrane prior to template-synthesis of the V2O5 within the pores of the membrane. Chemical etching increased both the pore diameter and porosity of the membrane. Nanostructured electrodes were prepared by depositing an alkoxide V2O5 precursor within the pores of the etched template membranes. The resulting electrodes consisted of V2O5 nanofibrils protruding from a Pt current collector surface like the bristles of a brush. The second approach for increasing volumetric capacity entailed applying additional V2O5 to the nanostructured electrodes prepared from the etched membranes. Results of investigations of the volumetric and geometric rate capabilities and the cycling performance of these electrodes are presented here. © 2001 The Electrochemical Society. All rights reserved.

Flame spray-pyrolyzed vanadium oxide nanoparticles for lithium battery cathodes

“…17 As lithium ions are inserted into the layers of V2O5, the phase transformation occurs consecutively from α-V2O5 to ε-Li0.5V2O5 (3.35 V), δ-LiV2O5 (3.15 V), γ-Li2V2O5 (2.26 V), and ω-Li3V2O5 (1.87 V). 19,20,40 Among the various phases of LixV2O5, δ-LiV2O5 can be restored to pristine V2O5 through lithium deintercalation, while γ-Li2V2O5 and ω3-Li2V2O5 (rock-salt type structure) are formed irreversibly. In the following anodic scanning, two broad peaks were observed at around 2.67 and 3.26 V vs. Li/Li + , respectively, corresponding to the lithium extraction processes.…”

“…17 This γ-phase can only be reversibly cycled in the stoichiometric range 0 < x < 2 without changing the γ-type structure. 17,20 Upon further lithiation (up to x = 3), the γ-phase will be irreversibly transformed to the ω-phase with a rock-salt type structure. The Li + intercalation and deintercalation process can be expressed by the following overall equation: [16][17] …”

High rate capability of carbon nanofilaments with platelet structure as anode materials for lithium ion batteries

“…Thus, increasing interest is directed toward nanostructured electrode materials since the nanostructure reduces clearly the distance that lithium ions must diffuse. Martin and his co-workers demonstrated the improved rate capabilities of nanostructured SnO 2 and V 2 O 5 electrodes, prepared by a template method, relative to the corresponding thin film controlled electrodes [2][3][4][5][6][7]. They have also reported 2 that nanostructured honeycomb carbon anode delivers 50 times the capacity of the thin film-controlled anode that does not have honeycomb nanopores [8].…”

Cathodes for lithium ion batteries: the benefits of using nanostructured materials

“…59,60 To improve the performance of cells employing vanadium pentoxide as cathode several tricks have been tested, including the use of aerogels, 61-63 xerogels, [64][65][66] nanocomposites of LiV 2 O 5 with electronically conducting organic polymers 17,60,[67][68][69][70][71][72][73][74][75][76][77][78] and nanostructured materials (nanotubes, nanorods and nanoparticles). [79][80][81] In general, nanotubes of V 2 O 5 are prepared by sol-gel method from the hydrolysis of vanadium (V) triisopropoxide. [82][83][84] Some authors have used hexadecylamine 82,83 as templating molecule while others microporous polycarbonate filtration membranes.…”