Title of Invention

ELECTRODE BASED ON TUNGSTEN TRIOXIDE NANORODS FOR SUPERCAPACITOR

Abstract

A method of manufacture of an electrode based on tungsten trioxide nanorods tor a supercapacitor, comprising the steps of preparing n-aucylammonium decatungstate by reacting sodium tungstate and n-alkylammonium bromide; preparing tungsten trioxide nanorods by pyrolysis of n-alkylammonium decatungstate in an inert atmosphere; dispersing the electrode material in water, placing the electrode material from the dispersion obtained on a glassy carbon electrode; drying the electrode material obtained; coating a nation solution as a hinder on the electrode so obtained.

Full Text

This invention relates to an electrode based on tungsten trioxide nanorods, for supercapacitor. Electrochemical supercapacitors are gaining a great deal of interest as energy storage devices due to their higher power density and longer cycle life compared to batteries and higher energy density than conventional dielectric capacitors. These devices occupy the area in the Ragone plot (that is, the plot of volumetric against gravimetric energy density) between batteries and dielectric capacitors. Supercapacitors are of key importance in supporting the voltage of a system during increased loads in everything from portable equipment to electric vehicles. This invention proposes electrode material based on tungsten trioxide nanorods as an aJternative tor high cost ruthenium oxide for supercapacitor applications. This invention also proposes the preparation of tungsten trioxide nanorods from tetrabutylammonium decatungstate. This invention further proposes the manufacture of super capacitor electrodes with highly dispersed tungsten trioxide nanorods. Various other features of this invention will be apparent from its following description. The method of manufacture of an electrode based on tungsten trioxide nanorods for a supercapacitor, according to this invention, comprises the steps of preparing n-alkylammonium decatungstate by reacting sodium tungstate and n-alkylammonium bromide; and preparing tungsten trioxide nanorods by pyrolysis of n-alkylammonium decatungstate in an inert atmosphere; dispersing the electrode material in water, placing the electrode material from the above dispersion obtained on a glassy carbon electrode; drying the electrode material obtained; placing nation solution as a binder on the electrode so prepared. EXAMPLE Tetrabutylammonium decatungstate was prepared by mixing boiling solutions of 16 g of Na2W04.2H20 in 100 ml of water and 33.5 ml of 3M HC1. The obtained clear yellow solution was precipitated by addition of an aqueous solution of tetrabutylammonium bromide (6.4 g/10 ml). Hie obtained white precipitate was filtered, washed with boiling water and ethanol, vacuum dried at 50 °C for 12h and recrystallized in hot DMF (10 ml) to give yellowish crystals. Preparation of WO3 nanorods: 1 g of (( C4H9)N)4W10O32) was taken in an alumina or quartz boat and introduced inside a tubular furnace and heated at 450° C at a heating rate of 25° C per min under N2 atmosphere(99.9 % pure) for 3h at a flow rate of 100 ml min"1. Then it was gradually cooled to room temperature to obtain a blue powder of WO3 nanorods. The morphology of the WO3 nanorods was investigated by a scanning electron microscopy (SEM) (FEI, Model: Quanta 200). Transmission electron microscopy (TEM) and Energy Dispersive X-ray Analysis (EDAX) were performed on a Philips CM12/STEM instrument. High-resolution Transmission Electron Microscopy (HRTEM) was carried out on a JEOL 3010 instrument. A drop of the material dispersed in ethanol was placed on carbon coated copper grids and dried in air atmosphere. TEM images ' show:. rod like morphology. Further, the dimensions of the nanorods calculated from the TEM images vary in the ranges of 130-4&0 nm and 18-56 nm of length and width respectively. The representative high resolution TEM image of a nanorod showed a well resolved lattice. The electrode is fabricated in the following manner. 5 mg of tungsten trioxide nanorods is dispersed by sonication in 100 ul of deionized water for 20 mm. From this dispersion 10 yl has been taken and placed on a glassy carbon electrode (area: 0.07 cm2). The electrode is then placed in an oven at 70 °C to remove water. 5 >JLL of nafion solution is then coated on the electrode as a binder and dried at room temperature to obtain the electrode. We Claim: 1A method of manufacture of an electrode based on tungsten trioxide nanorods for a supercapacitor, comprising the steps of preparing n- alkylammonium decatungstate by reacting sodium tungstate and n-alkylammonium bromide; preparing tungsten trioxide nanorods by pyrolysis of n-alkylammonium decatungstate in an inert atmosphere; dispersing the electrode material in water; placing the electrode material from the dispersion obtained on a glassy carbon electrode; drying the electrode material obtained; coating a nation solution as a binder on the electrode so obtained. 2. A method as claimed in Claim 1 wherein tungsten trioxide nanorods are prepared by pyrolysis of n-alkylammonium decatungstate in an inert atmosphere at 450 °C for 3h. 3. A method as claimed in any one of the preceding Claims wherein the inert atmosphere is composed of nitrogen or argon. 4. A method as claimed in Claim 1 or Claim 2 wherein the electrode material is dispersed in deionized water in the proportion 5 mg of the electrode material in 100 /iL water, 5. A method as claimed in any one of the preceding Claims wherein 20 piL of electrode materia] from the dispersion obtained is placed on a glassy carbon electrode (Area = 0.07 cm2). 6. A method as claimed in any one of the preceding Claims wherein the electrode material obtained is dried at 70 °C in a hot air oven. 7. A method as claimed in any one of the preceding Claims wherein 5 iiL of nation solution (5% solution in methanol) is coated as a binder on the electrode. 8. A method of manufacture of an electrode based on tungsten ttioxide nanorods for a supercapacitor, substantially as herein described with reference to and as illustrated by the Example. 9. An electrode based on tungsten trioxide nanorods for a supercapacitor whenever manufactured in accordance with any one of the preceding Claims.

Documents:

1488-CHE-2007 EXAMINATION REPORT REPLY RECEIVED 07-09-2011.pdf

1488-che-2007-abstract.pdf

1488-che-2007-claims.pdf

1488-che-2007-correspondnece-others.pdf

1488-che-2007-description(complete).pdf

1488-che-2007-form 1.pdf

1488-che-2007-form 18.pdf

1488-che-2007-form 26.pdf