# US 10,504,662 B2 · Supercapacitor using porous activated carbon cow dung

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- Number: US 10,504,662 B2
- Document ID: US10504662B2
- Status: Granted
- Kind: B2
- Application number: 16/184,523
- Filed: 2018-11-08
- Published: 2019-10-24
- Granted: 2019-12-10
- Earliest claimed: 2018-04-23
- Assignees: King Saud University
- Applicants: King Saud University
- Inventors: Jothi Ramalingam Rajabathar; Hamad Abdullah Al-Lohedan; Judith J. Vijaya; M. Sivachidambaram
- Web page: https://patentgrep.com/patent/US10504662B2

## CPC

- H01G 11/34: characterised by carbonisation or activation of carbon
- C01B 32/324: from waste materials, e.g. tyres or spent sulfite pulp liquor
- H01G 4/38: Multiple capacitors, i.e. structural combinations of fixed capacitors
- H01G 9/0032: {formation of the dielectric layer}
- H01G 9/022: Electrolytes; Absorbents
- H01G 9/04: Electrodes {or formation of dielectric layers thereon}
- H01G 11/26: characterised by their structure, e.g. multi-layered, porosity or surface features
- H01G 11/28: arranged or disposed on a current collector; Layers or phases between electrodes and current collectors, e.g. adhesives
- H01G 11/44: Raw materials therefor, e.g. resins or coal
- H01G 11/52: Separators
- H01G 11/58: Liquid electrolytes
- H01G 11/74: Terminals, e.g. extensions of current collectors
- H01G 11/86: specially adapted for electrodes (carbonisation or activation of carbon for the manufacture of electrodes H01G11/34)
- H01G 9/145: Liquid electrolytic capacitors (H01G11/00 takes precedence)
- H01G 11/62: characterised by the solute, e.g. salts, anions or cations therein
- H01G 11/68: characterised by their material
- Y02E 60/13: Energy storage using capacitors
- H01G: CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE (selection of specified materials as dielectric H01B3/00; capacitors having potential barriers H10D1/62, H10K10/10)
- C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C}
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

The method of making a supercapacitor using porous activated carbon from cow dung includes converting cow dung to porous activated carbon by, in a first step, preparing the dung waste by washing and drying the dung waste, and heating the dung waste in a vacuum environment to form pre-carbonized carbon. In a second step, the pre-carbonized carbon is impregnated with phosphoric acid to form a slurry, which is dried, ground, and heated in a vacuum to between 600-900° C. to form porous activated carbon. The porous activated carbon is mixed with a binder, acetylene black, and an organic solvent to form a paste, which is dried on a conductive metal foil to form an electrode. Two such electrodes (an anode and cathode) to are coated with an electrolyte gel (e.g., aqueous potassium hydroxide) and separated by a polymer (e.g., PTFE) membrane to form the supercapacitor.

## Claims

### Claim 1

A supercapacitor, comprising:
an anode and a cathode, the anode and a cathode each having:
a conductive metal foil having an inner side and an outer side;
a terminal attached to the outer side;
a layer of porous activated carbon made from cow dung disposed on the inner side, wherein the layer of porous activated carbon has a specific BET surface area of 2457 m2/g with a total pore volume of 1.965 cm3/g with a micropore volume of 0.985 cm3/g and a mesopore volume of 0.980 cm3/g and a specific capacitance of 347 F/g at a small scan rate (5 mV/s); and
an aqueous electrolyte in contact with the layer of porous activated carbon;
a separator disposed between the anode and the cathode, wherein the separator comprises a polymer membrane and the aqueous electrolyte is disposed on the opposite sides of the polymer membrane.

### Claim 2 (depends on 1)

The supercapacitor according to claim 1, wherein said aqueous electrolyte comprises aqueous potassium hydroxide.

### Claim 3 (depends on 1)

The supercapacitor according to claim 1, wherein said aqueous electrolyte comprises an electrolytic gel disposed on the separator.

### Claim 4 (depends on 1)

The supercapacitor according to claim 1, wherein the polymer membrane comprises a membrane made of polytetrafluoroethylene.

### Claim 5 (depends on 1)

The supercapacitor according to claim 1, wherein the conductive metal foil comprises foil made of nickel.