Abstract: A supercapacitor electrode comprises a mixture of graphene sheets and humic acid. The humic acid occupies 0.1% to 99% by weight of the mixture and the graphene sheets are selected from a pristine graphene material having essentially zero % of non-carbon elements, or a non-pristine graphene material having 0.001% to 5% by weight of non-carbon elements. The non-pristine graphene is selected from graphene oxide, reduced graphene oxide, graphene fluoride, graphene chloride, graphene bromide, graphene iodide, hydrogenated graphene, nitrogenated graphene, chemically functionalized graphene, or a combination thereof. The mixture has a specific surface area greater than 500 m2/g.

Abstract: Provided is a powder mass of multiple porous graphene balls, wherein at least one of the porous graphene balls comprises multiple graphene sheets having a catalyst, in a form of nanoparticles or coating having a diameter or thickness from 0.3 nm to 10 nm, bonded to or supported by graphene sheet surfaces, wherein the porous graphene balls have a density from 0.01 to 1.7 g/cm3 (preferably and typically from 0.1 to 1.5 g/cm3), and a specific surface area from 50 to 3,000 m2/g (preferably and typically from 200 to 2,630 m2/g). A method of producing such porous graphene balls is provided as well. Also provided is a gas storage device containing the invented powder mass as a gas-absorbing, gas-adsorbing, gas-capturing, or gas-storing medium to store a gas species therein.

Abstract: Provided is a process for producing a graphene-based supercapacitor electrode from a supply of coke or coal powder, comprising: (a) exposing this powder to a supercritical fluid for a period of time in a pressure vessel to enable penetration of the supercritical fluid into internal structure of the coke or coal; wherein the powder is selected from petroleum coke, coal-derived coke, meso-phase coke, synthetic coke, leonardite, anthracite, lignite coal, bituminous coal, or natural coal mineral powder, or a combination thereof; (b) rapidly depressurizing the supercritical fluid at a fluid release rate sufficient for effecting exfoliation and separation of the coke or coal powder to produce isolated graphene sheets, which are dispersed in a liquid medium to produce a graphene suspension; and (c) shaping and drying the graphene suspension to form the supercapacitor electrode having a specific surface area greater than 200 m2/g.

Abstract: A process for producing a supercapacitor cell, comprising (a) Assembling a porous cell framework composed of a first conductive foam structure, a second conductive foam structure, and a porous separator, wherein the first and/or second conductive foam structure has a thickness no less than 200 ?m and at least 80% by volume of pores; (b) Preparing a first suspension of an anode active material dispersed in a liquid electrolyte and a second suspension of a cathode active material (e.g. graphene sheets) dispersed in a liquid electrolyte; and (c) Injecting the first suspension into pores of the first conductive foam structure to form an anode and injecting second suspension into pores of the second conductive foam structure to form a cathode, wherein the anode active material or the cathode active material constitutes an electrode active material loading >10 mg/cm2, preferably >15 mg/cm2, more preferably >20 mg/cm2.

Abstract: A graphene-enabled hybrid particulate for use as an anode active material in a hybrid supercapacitor or lithium-ion capacitor, wherein the hybrid particulate is formed of a single or a plurality of graphene sheets and a single or a plurality of fine primary particles of a niobium-containing composite metal oxide, having a size from 1 nm to 10 ?m, and the graphene sheets and the primary particles are mutually bonded or agglomerated into the hybrid particulate containing an exterior graphene sheet or multiple exterior graphene sheets embracing the primary particles, and wherein the hybrid particulate has an electrical conductivity no less than 10?4 S/cm and said graphene is in an amount of from 0.01% to 30% by weight based on the total weight of graphene and the niobium-containing composite metal oxide combined.

Abstract: Provided is a supercapacitor comprising an anode, a cathode, an ion-permeable separator disposed between the anode and the cathode, and an electrolyte in ionic contact with the anode and the cathode, wherein at least one of the anode and the cathode contains multiple graphene sheets spaced by cellulosic nanofibers and has a specific surface area from 50 to 3,300 m2/g. Also provided is a process for producing an electrode for such a supercapacitor having a large electrode thickness, high active mass loading, high tap density, and exceptional energy density.

Abstract: Provided is rolled supercapacitor comprising an anode, a cathode, a porous separator, and an electrolyte, wherein the anode contains a wound anode roll of an anode active material having an anode roll length, an anode roll width, and an anode roll thickness, wherein the anode active material contains isolated graphene sheets that are oriented substantially parallel to the plane defined by the anode roll length and the anode roll width; and/or the cathode contains a wound cathode roll of a cathode active material having a cathode roll length, a cathode roll width, and a cathode roll thickness, wherein the cathode active material contains isolated graphene sheets that are oriented substantially parallel to the plane defined by the cathode roll length and the cathode roll width; and wherein the anode roll width and/or the cathode roll width is substantially perpendicular to the separator.

Abstract: Provided is a supercapacitor electrode, comprising: (a) preparing a deformable mass of multiple flakes of exfoliated graphite worms or expanded graphite dispersed in or impregnated by a liquid or gel electrolyte; and (b) subjecting the deformable mass to a forced assembling and orientating procedure, forcing the deformable mass to form the electrode, wherein these fakes are spaced by thin electrolyte layers, having an electrolyte layer thickness from 0.4 nm to 10 nm, and the flakes are substantially aligned along a desired direction, and wherein the electrode has a physical density from 0.5 to 1.7 g/cm3 and a specific surface area from 50 to 3,300 m2/g, when measured in a dried state of the flakes without the electrolyte. This supercapacitor has a large electrode thickness, high active mass loading, high tap density, and exceptional energy density.

Abstract: Provided is an internal hybrid electrochemical cell comprising: (A) a pseudocapacitance cathode comprising a cathode active material that contains a conductive carbon material and a porphyrin compound, wherein the porphyrin compound is bonded to or supported by the carbon material to form a redox pair for pseudocapacitance, wherein the carbon material is selected from activated carbon, activated carbon black, expanded graphite flakes, exfoliated graphite worms, carbon nanotube, carbon nanofiber, carbon fiber, a combination thereof; (B) a battery-like anode comprising lithium metal, lithium metal alloy, or a prelithiated anode active material (e.g. prelithiated Si, SiO, Sn, SnO2, etc.), and (C) a lithium-containing electrolyte in physical contact with the anode and the cathode; wherein the cathode active material has a specific surface area no less than 100 m2/g which is in direct physical contact with the electrolyte.

Abstract: Provided is an internal hybrid electrochemical cell comprising: (A) a pseudocapacitance cathode comprising a cathode active material that contains both graphene sheets and a porphyrin complex, wherein said porphyrin complex is bonded to or supported by primary surfaces of said graphene sheets to form a redox pair for pseudocapacitance; (B) a battery-like anode comprising lithium metal, lithium metal alloy, or a prelithiated anode active material (e.g. prelithiated Si, SiO, Sn, SnO2, etc.), and (C) a lithium-containing electrolyte in physical contact with the anode and the cathode; wherein the cathode active material has a specific surface area no less than 100 m2/g which is in direct physical contact with the electrolyte.

Abstract: Provided is an internal hybrid electrochemical cell comprising: (a) a pseudocapacitance-like cathode comprising a cathode active material that contains both graphene sheets and a porphyrin compound, including porphyrin or a porphyrin complex, wherein the porphyrin compound is bonded to or supported by primary surfaces of graphene sheets to form a redox pair for pseudocapacitance; (b) a battery-like anode comprising an anode active material selected from sodium metal, a sodium metal alloy, a sodium intercalation compound, a sodium-containing compound, or a combination thereof, and (c) a sodium-containing electrolyte in physical contact with the anode and the cathode; wherein the cathode active material has a specific surface area no less than 100 m2/g which is in direct physical contact with the electrolyte.

Abstract: Provided is rolled supercapacitor comprising an anode, a cathode, a porous separator, and an electrolyte, wherein the anode contains a wound anode roll of an anode active material having an anode roll length, width, and thickness and the anode active material contains flakes of graphite worms or expanded graphite that are oriented substantially parallel to the plane defined by the anode roll length and width; and/or the cathode contains a wound cathode roll of a cathode active material having a cathode roll length, width, and thickness, wherein the cathode active material contains flakes of graphite worms or expanded graphite that are oriented substantially parallel to the plane defined by the cathode roll length and width; and wherein the anode roll width and/or the cathode roll width is substantially perpendicular to the separator.