P-toluenesulfonate doped polypyrrole/carbon composite electrode and a process for the preparation thereof

Patent metadata

Field	Value
Publication number	US-10074453-B2
Application number	US-201414464845-A
Country	US
Kind code	B2
Filing date	Aug 21, 2014
Priority date	Aug 21, 2014
Publication date	Sep 11, 2018
Grant date	Sep 11, 2018

Abstract

Polypyrrole/carbon (PPy/C) composite doped with organic anion p-toluenesulfonate (pTS) is utilized as an electrode in supercapacitor for energy storage application. The surface initiated in-situ chemical oxidative polymerization yields a composite material PPy/C in the presence of varying concentrations of pTS. The novelty of the present invention lies in the doping of PPy/C composite with organic anion pTS and consequent enhancement of its electrochemical activity and stability. The conjugation length and electrical conductivity of pTS doped PPy/C composites increase with the increase in dopant concentration. The pTS doped PPy/C composite synthesized using equimolar concentration (0.1 M) of pTS to pyrrole shows the maximum specific capacitance of ˜395 F/g in 0.5 M Na 2 SO 4 aqueous solution with significant stability ˜95% capacitance retention after ˜500 cycles.

First claim

We claim:

1. A process for preparing a p-toluenesulfonate (pTS) doped conducting polypyrrole/acid-treated carbon black composite comprising the steps of:
i) treating carbon black with 6 M HNO 3 for 2-4 h;
ii) ultrasonic dispersion of treated carbon black as obtained in step (i) in water for 50 to 70 min to form a uniform suspension;
iii) adding 0.1 M distilled pyrrole monomer to the suspension as obtained in step (ii) followed by adding 0.06-0.1 M pTS at temperature in the range of 273-280 K to obtain a solution;
iv) constantly stirring the solution of step (iii) under inert atmosphere for 30-45 min at 273-280 K to obtain a stirred solution;
v) adding 10-30 ml of ammonium persulfate (APS) solution comprising a molar ratio of ammonium persulfate to pyrrole of 1:1 dropwise to the stirred solution of (iv) with constant stirring for period in the range of 8-12 h to obtain a precipitate;
vi) filtering and washing of the precipitate obtained from (v) and keeping it in an oven at 313-353 K for 10-14 h to obtain a p-toluenesulfonate (pTS) doped conducting polypyrrole/acid-treated carbon black composite.

2. The process for preparing a p-toluenesulfonate (pTS) doped conducting polypyrrole/acid-treated carbon black composite according to claim 1 , wherein the washing of the precipitate obtained from (v) comprises washing with methanol and water.

3. The process for preparing a p-toluenesulfonate (pTS) doped conducting polypyrrole/acid-treated carbon black composite according to claim 1 , wherein the inert atmosphere comprises a gas selected from the group consisting of nitrogen, argon and helium.

4. A process for preparing an electrode for a supercapacitor comprising the steps of:
i) treating carbon black with 6 M HNO 3 for 2-4 h;
ii) ultrasonic dispersion of treated carbon black as obtained in step (i) in water for 50 to 70 min to form a uniform suspension;
iii) adding 0.1 M distilled pyrrole monomer to the suspension as obtained in step (ii) followed by adding 0.06-0.1 M pTS at temperature in the range of 273-280 K to obtain a solution;
iv) constantly stirring the solution of step (iii) under inert atmosphere for 30-45 min at 273-280 K to obtain a stirred solution;
v) adding 10-30 ml of ammonium persulfate (APS) solution comprising a molar ratio of ammonium persulfate to pyrrole of 1:1 dropwise to the stirred solution of (iv) with constant stirring for period in the range of 8-12 h to obtain a precipitate;
vi) filtering and washing of the precipitate obtained from (v) and keeping it in an oven at 313-353 K for 10-14 h to obtain a p-toluenesulfonate (pTS) doped conducting polypyrrole/acid-treated carbon black composite,
a) adding 80-90 wt. % of the p-toluenesulfonate (pTS) doped conducting polypyrrole/acid-treated carbon black composite and 10-20 wt. % of a polyvinylidene fluoride (PVDF) in N,N-dimethylformamide (DMF) followed by ultrasonicating for 50 to 60 min to form a uniform slurry;
b) coating a platinum (Pt) disk working electrode with the slurry obtained in step a to cover only a top active surface of the electrode;
c) drying the electrode in an oven at 313-353 K for 30-45 min to obtain the electrode.

5. The process for preparing an electrode according to claim 4 , wherein specific capacitance of the electrode is 395 F/g in 0.5 M Na 2 SO 4 aqueous solution with 95% capacitance retention after 500 cycles.

Assignees

• Council Scient Ind Res

Inventors

• Kumar Amit
• Singh Hari Krishna
• Singh Rajiv Kumar
• Singh Ramadhar
• Srivastava Pankaj

Classifications

• Y02E60/13

  Energy storage using capacitors · CPC title

• H01G11/38

  Carbon pastes or blends; Binders or additives therein · CPC title

• H01B1/127 Primary

  comprising five-membered aromatic rings in the main chain, e.g. polypyrroles, polythiophenes · CPC title

• H01G11/86

  specially adapted for electrodes (carbonisation or activation of carbon for the manufacture of electrodes H01G11/34) · CPC title

• H01G11/34

  characterised by carbonisation or activation of carbon · CPC title