Supercapacitor with gel electrolyte for electrochemical double-layer energy storage

Patent metadata

Field	Value
Publication number	US-12142425-B2
Application number	US-202217709713-A
Country	US
Kind code	B2
Filing date	Mar 31, 2022
Priority date	Mar 31, 2022
Publication date	Nov 12, 2024
Grant date	Nov 12, 2024

Abstract

A supercapacitor including a gel electrode and two electrodes is described. Each of the two electrodes include a second mixture of 5-10 wt. % conductive additive, 5-10 wt. % binding compound, and 80-90 wt. % activated carbon. Further, the second mixture is at least partially coated on an inner surface of a substrate, and where the inner surfaces of the two electrodes are separated by and in physical contact with the gel electrolyte to form the supercapacitor. The gel electrolyte includes a polyol compound, a base with a molarity (M) of 1-5 in the polyol compound, and 1-10 wt. % of boric acid relative to the weight of the polyol compound. The boric acid intercalates with a first mixture of the polyol compound and the base, creating a gel.

First claim

The invention claimed is:

1. A supercapacitor, comprising:
two electrodes; and
a gel electrolyte;
wherein the gel electrolyte comprises:
a polyol compound that is selected from the group consisting of glycerol and ethylene glycol;
a base with a molarity (M) of 1-5 in the polyol compound; and
1-10 wt % of boric acid relative to the weight of the polyol compound;
wherein the boric acid intercalates with a first mixture of the polyol compound and the base, creating a gel;
wherein
the base is selected from a group consisting of lithium hydroxide, sodium hydroxide, and potassium hydroxide;

wherein the two electrodes each comprise:
a second mixture comprising 5-10 wt % of a conductive additive, 5-10 wt % of a binding compound, and 80-90 wt % of an activated carbon, based on the total weight of the conductive additive, the binding compound, and the activated carbon; and
wherein the second mixture is at least partially coated on an inner surface of a substrate;
wherein an outer surface of the substrate is not coated with the second mixture; and
wherein the inner surfaces of the two electrode substrates are separated by and in physical contact with the gel electrolyte to form the supercapacitor.

2. The supercapacitor of claim 1 , wherein
the polyol compound is glycerol; and
the base is potassium hydroxide.

3. The supercapacitor of claim 1 , wherein the gel electrolyte has
a glass transition temperature of −90 to −60° C.;
wherein the gel electrolyte comprises 2-4 wt % boric acid.

4. The supercapacitor of claim 1 , wherein the gel electrolyte has
an ionic conductivity of 2×10 −3 -4×10 −3 S/cm.

5. The supercapacitor of claim 1 , wherein
the gel electrolyte produces no fire after treatment with a flame.

6. The supercapacitor of claim 1 , wherein the gel electrolyte is made by a method comprising:
mixing the base and the polyol compound at a temperature of 40-60° C. to form a mixture;
cooling the mixture to 23-26° C. and adding the boric acid to form the gel electrolyte.

7. The supercapacitor of claim 1 , wherein:
the binding compound is at least one selected from the group consisting of polyvinylidene fluoride and n-methylpyrrolidone;
the conductive additive is at least one selected from the group consisting of graphite, activated carbon, reduced graphene oxide, carbon nanotubes, carbon nanofibers, and carbon black; and
the substrate is formed from at least one material selected from the group consisting of copper, aluminum, nickel, iron, and steel.

8. The supercapacitor of claim 1 , wherein:
the binding compound is polyvinylidene fluoride;
the conductive additive is carbon black; and
the substrate is an aluminum current collector.

9. The supercapacitor of claim 1 , wherein:
the inner surface is precoated with at least one boronic acid-containing polymer selected from the group consisting of poly(styreneboronic acid)-b-polystyrene, and poly(ethylene glycol)-b-poly(styrene boronic acid).

10. The supercapacitor of claim 1 , wherein the first mixture further comprises:
1-15 wt. % of at least one boronic acid-containing polymer selected from the group consisting of poly(styreneboronic acid)-b-polystyrene, and poly(ethylene glycol)-b-poly(styrene boronic acid), based on the total weight of the polyol compound and the boronic acid-containing polymer.

11. The supercapacitor of claim 1 , wherein the second mixture further comprises:
1-10 wt % of at least one boronic acid-containing polymer selected from the group consisting of poly(styreneboronic acid)-b-polystyrene, and poly(ethylene glycol)-b-poly(styrene boronic acid), based on the total weight of the conductive additive, the binding compound, the activated carbon, and the boronic acid-containing polymer.

12. The supercapacitor of claim 1 , having:
a specific capacitance of 300-350 F/g at 1 A/g;
wherein the gel electrolyte comprises 2-4 wt % of the boric acid.

13. The supercapacitor of claim 12 , wherein
at least 90% of the initial capacitance is maintained up to 10,000 cycles.

14. The supercapacitor of claim 12 , wherein
at least 90% of the initial capacitance is maintained after at least 30 days under ambient conditions.

15. The supercapacitor of claim 12 , having
a specific energy of 40-55 Wh/kg at a power of 900-950 W/kg.

16. The supercapacitor of claim 12 , having
having an equivalent series resistance of 4-8 Ω.

17. The supercapacitor of claim 1 , having
an open voltage window of 0-3 V.

18. The supercapacitor of claim 1 , having:
a specific capacitance of 150-200 F/g at 1 A/g;
wherein the gel electrolyte comprises 5-7 wt % of the boric acid and 1 M base.

19. A wearable device comprising the supercapacitor of claim 1 , wherein:
the supercapacitor is electrically connected to a sensor; and
the supercapacitor functions as a battery.

20. The supercapacitor of claim 1 , comprising:
2-10 of the supercapacitors connected in parallel and/or series.

Assignees

• Univ Imam Abdulrahman Bin Faisal

Inventors

• Bozkurt Ayhan
• Cevik Emre
• Anil Seyda Tugba Gunday

Classifications

• Y02E60/13

  Energy storage using capacitors · CPC title

• H01G11/56 Primary

  Solid electrolytes, e.g. gels; Additives therein · CPC title

• H01G11/48

  Conductive polymers · CPC title

• H01G11/32

  Carbon-based · CPC title

• H01G11/24 Primary

  characterised by structural features of the materials making up or comprised in the electrodes, e.g. form, surface area or porosity; characterised by the structural features of powders or particles used therefor · CPC title