Methods and applications for conductive graphene inks
The present disclosure provides for an exemplary energy storage device and methods of forming thereof, comprising an exemplary conductive graphene ink on exemplary substrates to form durable, flexible, and facile graphene films and energy storage devices for use with and within a variety of electronics and devices.
1. A conductive graphene ink comprising:
a) 20% to about 70% by mass of a binder solution comprising a binder and a first solvent; and
b) a reduced graphene oxide dispersion comprising reduced graphene oxide, and a second solvent;
wherein the conductive graphene ink has a viscosity of at least about 1,000 centipoise.
2. The conductive graphene ink of claim 1 , wherein at least one of the first solvent and the second solvent comprises water, ethanol, isopropyl alcohol, N-methyl-2-pyrrolidone, cyclohexanone, terpineol, 3-methoxy-3-methyl-1-butanol, 4-hydroxyl-4-methyl-pentan-2-one, methyl isobutyl ketone, or any combination thereof.
3. The conductive graphene ink of claim 1 , wherein the binder comprises carboxymethyl cellulose, polyvinylidene fluoride, poly(vinyl alcohol), poly(vinyl pyrrolidone), poly(ethylene oxide), ethyl cellulose, or any combination thereof.
4. The conductive graphene ink of claim 1 , wherein the conductive graphene ink has a viscosity of at most about 10,000 centipoise.
5. The conductive graphene ink of claim 1 , wherein the conductive graphene ink has a C:O mass ratio of about 2:1 to about 40:1.
6. A method of forming a conductive graphene ink comprising:
forming a binder solution comprising:
heating a first solvent;
adding a binder to the first solvent;
mixing the binder and the first solvent; and
cooling the binder and the first solvent;
forming a reduced graphene oxide dispersion comprising a second solvent and reduced graphene oxide;
forming a graphene solution comprising the binder solution and the reduced graphene oxide dispersion; and
mixing the graphene solution under a vacuum degree of about −0.05 MPa to about −0.2 MPa to form a conductive graphene ink.
7. The method of claim 6 , wherein at least one of the first solvent and the second solvent comprises water, ethanol, isopropyl alcohol, N-methyl-2-pyrrolidone, cyclohexanone, terpineol, 3-methoxy-3-methyl-1-butanol, 4-hydroxyl-4-methyl-pentan-2-one, methyl isobutyl ketone, or any combination thereof.
8. The method of claim 6 , wherein the binder comprises carboxymethyl cellulose, polyvinylidene fluoride, poly(vinyl alcohol), poly(vinyl pyrrolidone), poly(ethylene oxide), ethyl cellulose, or any combination thereof.
9. The method of claim 6 , wherein the first solvent is heated to a temperature of about 35° C. to about 125° C.
10. The method of claim 6 , wherein the binder is added to the first solvent during the mixing of the binder and the first solvent, over a period of time of about 45 minutes to about 240 minutes.
11. The method of claim 6 , wherein, after the binder is fully added to the first solvent, the binder and the first solvent are mixed for a period of time of about 7 minutes to about 30 minutes.
12. The method of claim 6 , wherein the mixing of the graphene solution is performed with at least one of a stirring speed of about 15 rpm to about 125 rpm, and a dispersing speed of about 50 rpm to about 4,500 rpm.
13. The method of claim 6 , wherein the graphene solution is mixed during one or more intervals, wherein each interval comprises a period of time of about 0.5 minutes to about 30 minutes.
14. The method of claim 6 , wherein the binder and the first solvent are cooled to a temperature of about 10° C. to about 40° C.