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, SnO.sub.2, 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 m.sup.2/g which is in direct physical contact with the electrolyte.

An energy storage device, such as a sodium ion capacitor, including an anode and a cathode, at least one of the anode and the cathode including a nitrogen and oxygen functionalized carbon (NOFC). The NOFC has a nitrogen content greater than 4 wt %, such as 13 wt %, an oxygen content greater than 8 wt %, such as 11 wt %, and a surface area greater than 800 m.sup.2g.sup.1, such as 945 m.sup.2g.sup.1. The energy storage device has favorable reversible and rate capability, such as 437 mAhg.sup.1 at 100 mAg.sup.1, and 185 mAhg.sup.1 at 1600 mA g.sup.1.

An energy storage device, such as a sodium ion capacitor, including an anode and a cathode, at least one of the anode and the cathode including a nitrogen and oxygen functionalized carbon (NOFC). The NOFC has a nitrogen content greater than 4 wt %, such as 13 wt %, an oxygen content greater than 8 wt %, such as 11 wt %, and a surface area greater than 800 m.sup.2g.sup.1, such as 945 m.sup.2g.sup.1. The energy storage device has favorable reversible and rate capability, such as 437 mAhg.sup.1 at 100 mAg.sup.1, and 185 mAhg.sup.1 at 1600 mA g.sup.1.

Provided is a method for producing an activated carbon with which calcination and molding can be homogeneously performed and an activated carbon of stable quality can be produced. The method includes a plasticizing and densifying step of plasticizing and densifying a mixture of a wooden material and a phosphoric acid compound in a single-screw or twin-screw extruder-kneader under pressurizing and heating conditions until the loss on heating at 140 C. for 30 minutes becomes between 10 mass % and 25 mass %, exclusive, to thereby obtain a carbonaceous material; an adjustment step of heat-treating the carbonaceous material after the plasticizing and densifying step until the loss on heating at 140 C. for 30 minutes becomes between 3 mass % and 12 mass %, exclusive; and an activation treatment step of activating the carbonaceous material after the plasticizing and densifying step under heating conditions at a temperature between 400 C. and 600 C., inclusive.

An electrode of an energy storage device and methods of fabrication are provided which include: pyrolyzing a carbon-containing precursor to form a stabilized-carbonized material; and annealing the stabilized-carbonized material to form a structurally-modified activated carbon material. The structurally-modified activated carbon material includes a tunable pore size distribution and an electrochemically-active surface area. The electrochemically-active surface area of the structurally-modified activated carbon material is greater than a surface area of graphene having at least one layer, the surface area of the graphene having at least one layer being about 2630 m.sup.2 g.sup.1.

An electrode of an energy storage device and methods of fabrication are provided which include: pyrolyzing a carbon-containing precursor to form a stabilized-carbonized material; and annealing the stabilized-carbonized material to form a structurally-modified activated carbon material. The structurally-modified activated carbon material includes a tunable pore size distribution and an electrochemically-active surface area. The electrochemically-active surface area of the structurally-modified activated carbon material is greater than a surface area of graphene having at least one layer, the surface area of the graphene having at least one layer being about 2630 m.sup.2 g.sup.1.

Carbon nanosheets fabricated by carbonization and activation or by carbonization alone. The nanosheets possess a disordered structure for copious reversible binding of ions at the carbon defects. They are also hierarchically micro-meso-macro porous, allowing facile ion transport at high rates both through the pore-filling electrolyte and in the solid-state. Also, a combined batterysupercapacitor energy storage device using the carbon nanosheets as one or both of the electrodes therein. Tuning the mass-loading ratio of the carbon nanosheets in the two electrodes configures the carbon nanosheets to operate either as a bulk insertion electrode (anode) or a surface adsorption electrode (cathode). The energy storage device may further include a housing with a form factor of a commercial battery.

Carbon nanosheets fabricated by carbonization and activation or by carbonization alone. The nanosheets possess a disordered structure for copious reversible binding of ions at the carbon defects. They are also hierarchically micro-meso-macro porous, allowing facile ion transport at high rates both through the pore-filling electrolyte and in the solid-state. Also, a combined batterysupercapacitor energy storage device using the carbon nanosheets as one or both of the electrodes therein. Tuning the mass-loading ratio of the carbon nanosheets in the two electrodes configures the carbon nanosheets to operate either as a bulk insertion electrode (anode) or a surface adsorption electrode (cathode). The energy storage device may further include a housing with a form factor of a commercial battery.

Disclosed are apparatus and method for preparing carbon black, in which the carbon black may be continuously formed and activated. In one embodiment, carbon black powders formed in a combustion reactor are converted into a slurry which in turn is refluxed to the combustion reactor in a repeated manner, thereby to allow successive activation treatments. In this way, a sufficient residence time for the activation of the carbon black may be secured.

Disclosed are apparatus and method for preparing carbon black, in which the carbon black may be continuously formed and activated. In one embodiment, carbon black powders formed in a combustion reactor are converted into a slurry which in turn is refluxed to the combustion reactor in a repeated manner, thereby to allow successive activation treatments. In this way, a sufficient residence time for the activation of the carbon black may be secured.