Emulsion and suspension polymerization processes, and improved electrochemical performance for carbon derived from same
The present application is directed to methods for preparation of polymer particles in gel form and carbon materials made therefrom. The carbon materials comprise enhanced electrochemical properties and find utility in any number of electrical devices, for example, as electrode material in ultracapacitors or batteries. The methods herein can also be employed generally to improve emulsion and/or suspension polymerization processes by improved control of diffusion of acidic and basic species between the polymer and secondary phases.
1. A process for making a carbon material, comprising:
mixing a carrier fluid and a monomer component containing one or more phenolic compounds and one or more crosslinking compounds to produce a reactant mixture; and
polymerizing the monomer component in the reactant mixture to produce polymer particles in gel form, wherein:
the carrier fluid contains less than 50 wt % cyclohexane, based on a total weight of the carrier fluid,
the carrier fluid is free of surfactant or contains a surfactant at a concentration less than a critical micelle concentration,
the carrier fluid comprises an acid, a base, a catalyst, or a combination thereof, at a concentration for each species of at least 50% of the saturation limit, and
the polymer particles in gel form have a volume average particle size (Dv,50) of greater than or equal to 1 mm;
heating the polymer particles in gel form to produce pyrolyzed carbon particles; and
activating the pyrolyzed carbon particles to produce activated carbon particles, wherein:
the activated carbon particles have a specific surface area of greater than 1,700 m 2 /g and a pore volume of greater than 0.7 cm 3 /g,
greater than 95% of the total number of pores in the activated carbon particles have a size of 20 angstroms or less,
the activated carbon particles have a gravimetric capacitance of greater than 120 F/g to about 130 F/g, as measured at a constant current discharge from 2.7 V to 0.1 V with a 5-second time constant and employing a 1.8 M solution of tetraethylammonium-tetrafluroroborate in acetonitrile electrolyte and a current density of 0.5 A/g, and
the activated carbon particles have a maximum theoretical volumetric capacitance of greater than 26 F/cm 3 to about 30 F/cm 3 , as calculated at a constant current discharge from 2.7 V to 0.1 V with a 5-second time constant and employing a 1.8 M solution of tetraethylammonium-tetrafluroroborate in acetonitrile electrolyte and a current density of 0.5 A/g.
2. The process of claim 1 , wherein the carrier fluid comprises one or more vegetable oils, one or more mineral oils, one or more chlorinated hydrocarbons, one or more paraffinic oils, or a mixture thereof.
3. The process of claim 1 , wherein the volume average particle size (Dv,50) of the polymer particles in gel form is 1 mm to about 6 mm.
4. The process of claim 1 , wherein the carrier fluid comprises the catalyst, and wherein the catalyst comprises acetic acid, hydrochloric acid, sulfuric acid, phosphoric acid, phosphorous acid, a sulfonic acid, gallic acid, oxalic acid, picric acid, ammonium carbonate, ammonium bicarbonate, ammonium acetate, ammonium hydroxide, sodium hydroxide, sodium carbonate, sodium bicarbonate, potassium hydroxide, potassium carbonate, potassium bicarbonate, hexamethylenetetramine, or any mixture thereof.
5. The process of claim 1 , wherein:
the one or more phenolic compounds comprise phenol, resorcinol, catechol, hydroquinone, phloroglucinol, or a mixture thereof,
the one or more crosslinking compounds comprise formaldehyde, paraformaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, furfuraldehyde, benzaldehyde, glutaraldehyde, glyoxal, glyoxylic acid, a glyoxylic acid ester, a glyoxylic acid amide, 5-(hydroxymethyl)furfural, or a mixture thereof,
the carrier fluid comprises one or more vegetable oils, one or more mineral oils, one or more chlorinated hydrocarbons, one or more paraffinic oils, or a mixture thereof,
the carrier fluid comprises the catalyst,
the catalyst comprises acetic acid, hydrochloric acid, sulfuric acid, phosphoric acid, phosphorous acid, a sulfonic acid, gallic acid, oxalic acid, picric acid, ammonium carbonate, ammonium bicarbonate, ammonium acetate, ammonium hydroxide, sodium hydroxide, sodium carbonate, sodium bicarbonate, potassium hydroxide, potassium carbonate, potassium bicarbonate, hexamethylenetetramine, or a mixture thereof, and
the volume average particle size (Dv,50) of the polymer particles in gel form is 1 mm to about 6 mm.
6. The process of claim 1 , wherein the one or more phenolic compounds and the one or more crosslinking compounds are prepolymerized with one another to form a prepolymer prior to making the polymer particles in gel form.
7. The process of claim 1 , wherein the one or more phenolic compounds and the one or more crosslinking compounds are prepolymerized with one another to form a liquid prepolymer having a refractive index ranging from about 1.2000 to about 1.6000 prior to making the polymer particles in gel form via the emulsion or suspension process.
8. The process of claim 1 , wherein the reactant mixture further comprises a nitrogen-containing electrochemical modifier.
9. The process of claim 1 , wherein the polymer particles in gel form are heated in an inert atmosphere at a temperature of about 500° C. to about 2,400° C. to produce the pyrolyzed carbon particles.
10. The process of claim 1 , wherein:
the polymer particles in gel form are heated in an inert atmosphere at a temperature of about 500° C. to about 2,400° C. to produce the pyrolyzed carbon particles; and
the pyrolyzed carbon particles are heated in an atmosphere comprising carbon dioxide, carbon monoxide, steam, oxygen, or any mixture thereof at a temperature of about 500° C. to about 1,300° C. to produce the activated carbon particles.
11. A carbon material having a specific surface area of greater than 1,700 m 2 /g and a pore volume of greater than 0.7 cm 3 /g, wherein:
greater than 95% of the total number of pores in the carbon material has a size of 20 angstroms or less,
the carbon material has a gravimetric capacitance of greater than 120 F/g to about 130 F/g, as measured at a constant current discharge from 2.7 V to 0.1 V with a 5-second time constant and employing a 1.8 M solution of tetraethylammonium-tetrafluroroborate in acetonitrile electrolyte and a current density of 0.5 A/g, and
the carbon material has a maximum theoretical volumetric capacitance of greater than 26 F/cm 3 to about 30 F/cm 3 , as calculated at a constant current discharge from 2.7 V to 0.1 V with a 5-second time constant and employing a 1.8 M solution of tetraethylammonium-tetrafluroroborate in acetonitrile electrolyte and a current density of 0.5 A/g.
12. The carbon material of claim 11 , wherein the carbon material has a specific surface area of greater than 1,700 m 2 /g to about 3,000 m 2 /g and a pore volume of greater than 0.7 g/cm 3 to about 7 g/cm 3 .
13. The carbon material of claim 11 , wherein the carbon material has a gravimetric capacitance of about 125 F/g to about 130 F/g.
14. The carbon material of claim 11 , wherein the carbon material comprises less than 200 ppm of all atoms having an atomic number between 11 and 92, as measured by photon induced x-ray emissions.
15. The carbon material of claim 11 , wherein the carbon material has a particle size distribution of less than 3, wherein the particle size distribution is equal to:
Dv
,
90
-
Dv
,
10
Dv
,
50
and wherein the Dv,10, Dv,50, and Dv,90 are the volume particle sizes measured at 10%, 50% and 90%, respectively, of the particle size distribution.
16. The carbon material of claim 11 , wherein:
the carbon material has a specific surface area of greater than 1,700 m 2 /g to about 3,000 m 2 /g and a pore volume of greater than 0.7 g/cm 3 to about 7 g/cm 3 ,
the carbon material has gravimetric capacitance of about 125 F/g to about 130 F/g,
the carbon material comprises less than 200 ppm of all atoms having an atomic number between 11 and 92, as measured by photon induced x-ray emissions, and
the carbon material has a particle size distribution of less than 3, wherein the particle size distribution is equal to:
Dv
,
90
-
Dv
,
10
)
Dv
,
50
and wherein the Dv,10, the Dv,50, and the Dv,90 are the volume particle sizes measured at 10%, 50% and 90%, respectively, of the particle size distribution.
17. The carbon material of claim 11 , wherein the carbon material has a specific surface area of greater than 1,700 m 2 /g to about 2,000 m 2 /g and a pore volume of greater than 0.7 g/cm 3 to about 2 g/cm 3 .
18. A carbon material having a specific surface area of greater than 1,700 m 2 /g and a pore volume of greater than 0.7 cm 3 /g, wherein:
greater than 98% of the total number of pores in the carbon material has a size of 20 angstroms or less,
the carbon material has a gravimetric capacitance of greater than 125 F/g to about 130 F/g, as measured at a constant current discharge from 2.7 V to 0.1 V with a 5-second time constant and employing a 1.8 M solution of tetraethylammonium-tetrafluroroborate in acetonitrile electrolyte and a current density of 0.5 A/g, and
the carbon material has a maximum theoretical volumetric capacitance of greater than 27 F/cm 3 to about 30 F/cm 3 , as calculated at a constant current discharge from 2.7 V to 0.1 V with a 5-second time constant and employing a 1.8 M solution of tetraethylammonium-tetrafluroroborate in acetonitrile electrolyte and a current density of 0.5 A/g.
19. The carbon material of claim 18 , wherein the carbon material has a specific surface area of greater than 1,700 m 2 /g to about 3,000 m 2 /g and a pore volume of greater than 0.7 g/cm 3 to about 7 g/cm 3 .
20. The carbon material of claim 18 , wherein the carbon material comprises less than 200 ppm of all atoms having an atomic number between 11 and 92, as measured by photon induced x-ray emissions.