Biopolymer hydrogel supercapacitor

Patent metadata

Field	Value
Publication number	US-2025285815-A1
Application number	US-202519220193-A
Country	US
Kind code	A1
Filing date	May 28, 2025
Priority date	Aug 2, 2022
Publication date	Sep 11, 2025
Grant date	—

Abstract

A hydrogel electrolyte for a supercapacitor includes sodium carboxymethyl cellulose (C), water, citric acid (CA); and an aqueous extract of Hibiscus sabdariffa. The sodium carboxymethyl cellulose (C) and the citric acid (CA) form a citric acid cross-linked cellulose-based polymer hydrogel (C-CA-C). An organic acid from the aqueous extract of Hibiscus sabdariffa is intercalated to the citric acid cross-linked cellulose-based polymer hydrogel (C-CA-C) via hydrogen bonds. A method of preparation of the hydrogel electrolyte is also discussed.

First claim

1 : A biopolymer hydrogel supercapacitor, comprising:
an anode; a cathode; and a biopolymer hydrogel electrolyte disposed between the anode and cathode; wherein the anode and the cathode have a surface of a conductive carbonaceous material in contact with the biopolymer hydrogel electrolyte; wherein the biopolymer hydrogel electrolyte comprises:
sodium carboxymethyl cellulose (C) having an average molar mass Mw of 250 kDa;
water;
citric acid (CA); and
an aqueous extract of Hibiscus sabdariffa;
wherein the sodium carboxymethyl cellulose (C) and the citric acid (CA) form a citric acid crosslinked cellulose-based polymer hydrogel (C-CA-C); and
wherein an organic acid from the aqueous extract of Hibiscus sabdariffa is intercalated to the citric acid crosslinked cellulose-based polymer hydrogel (C-CA-C) via hydrogen bonds.

2 : The biopolymer hydrogel supercapacitor of claim 1 , wherein the organic acid is at least one selected from a group consisting of a phenolic acid, hydroxycitric acid, a hibiscus acid, tartaric acid, malic acid, and ascorbic acid.

3 : The biopolymer hydrogel supercapacitor of claim 1 , wherein the sodium carboxymethyl cellulose and citric acid have a weight ratio of 1:4 to 4:1.

4 : The biopolymer hydrogel supercapacitor of claim 1 , wherein the biopolymer hydrogel electrolyte comprises 50 to 99 wt % of water relative to the total weight of the biopolymer hydrogel electrolyte.

5 : The biopolymer hydrogel supercapacitor of claim 1 , wherein the biopolymer hydrogel electrolyte has a weight loss of less than 10% when heated to a temperature of up to 200° C. for at least 15 minutes.

6 : The biopolymer hydrogel supercapacitor of claim 1 , wherein the biopolymer hydrogel electrolyte has an ion conductivity of 0.005 to 0.05 S cm −1 at 20 to 30° C.

7 : The biopolymer hydrogel supercapacitor of claim 1 , wherein the aqueous extract of Hibiscus sabdariffa is made by contacting Hibiscus sabdariffa with water at a mass ratio of the Hibiscus sabdariffa to water of 1:25 to 1:5.

8 : The biopolymer hydrogel supercapacitor of claim 7 , wherein the contacting is done for 12 to 96 h at 20 to 30° C.

9 : The biopolymer hydrogel supercapacitor of claim 7 , wherein Hibiscus sabdariffa is ground, blended, or cut.

10 : The biopolymer hydrogel supercapacitor of claim 7 , wherein the Hibiscus sabdariffa is a flower of Hibiscus sabdariffa.

11 : A method of making the biopolymer hydrogel supercapacitor of claim 1 , comprising:
mixing sodium carboxymethyl cellulose powder and water to form a first mixture; mixing citric acid with the first mixture to form a second mixture; and mixing the aqueous extract of Hibiscus sabdariffa with the second mixture to form the biopolymer hydrogel electrolyte; and disposing the biopolymer hydrogel electrolyte between the anode and cathode.

12 . (canceled)

13 : The biopolymer hydrogel supercapacitor of claim 1 , wherein:
the conductive carbonaceous material is at least one selected from a group consisting of graphite, activated carbon, reduced graphene oxide, carbon nanotubes, carbon nanofibers, and carbon black.

14 : The biopolymer hydrogel supercapacitor of claim 1 , which has a power density of 200 to 500 W/kg.

15 : The biopolymer hydrogel supercapacitor of claim 1 , which has an energy density of 50 to 120 W·h/kg.

16 : The biopolymer hydrogel supercapacitor of claim 1 , wherein at least 90% of the initial specific capacitance is maintained after 90,000 to 12,000 charge-discharge cycles.

17 : The biopolymer hydrogel supercapacitor of claim 1 , which has a specific capacitance of 380 to 500 F/g at 0.2 to 0.8 mA.

18 : The biopolymer hydrogel supercapacitor of claim 1 , which has an equivalent series resistance of 3 to 11 Ohm.

19 . (canceled)

20 . (canceled)

Assignees

• Univ Imam Abdulrahman Bin Faisal

Inventors

• Cevik Emre
• Bozkurt Ayhan

Classifications

• Y02E60/13

  Energy storage using capacitors · CPC title

• H01G11/34

  characterised by carbonisation or activation of carbon · CPC title

• H01G11/42

  Powders or particles, e.g. composition thereof · CPC title

• H01G11/36

  Nanostructures, e.g. nanofibres, nanotubes or fullerenes · CPC title

• H01G11/38

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