Described are processes for making graphene pellet (GP) with a three-dimensional structure. The process includes forming a nickel pellet from nickel powder to function as a catalyst for graphene growth, exposing the nickel pellet to a hydrocarbon under conditions sufficient to grow graphene, and etching nickel from graphene with an acid resulting in a graphene pellet. Also described is a process for making a graphene paper from the graphene pellet comprising applying a compression force to the graphene pellet sufficient to compress the pellet. Also described is a method for forming a graphene pellet composite useful as an electrode.

Provided is a production method that enables the production of a composite body of lithium titanate particles and a carbonaceous material, the composite body having excellent electrical characteristics and so on, and the composite body of lithium titanate particles and a carbonaceous material. A method for producing a composite body of lithium titanate particles and a carbonaceous material includes the steps of: preparing a raw material mixture using a titanium compound, a lithium compound, and an oligomer and/or raw material monomer of an alkali-soluble resin; and subjecting the raw material mixture to heat treatment under a non-oxidizing atmosphere to produce the composite body.

Provided is a production method that enables the production of a composite body of lithium titanate particles and a carbonaceous material, the composite body having excellent electrical characteristics and so on, and the composite body of lithium titanate particles and a carbonaceous material. A method for producing a composite body of lithium titanate particles and a carbonaceous material includes the steps of: preparing a raw material mixture using a titanium compound, a lithium compound, and an oligomer and/or raw material monomer of an alkali-soluble resin; and subjecting the raw material mixture to heat treatment under a non-oxidizing atmosphere to produce the composite body.

The present invention relates to an additive for an electrochemical element positive electrode comprising an activated carbon, wherein the activated carbon has a specific surface area in accordance with BET method of 1300-2500 m.sup.2/g, a pore volume of pores having a diameter of 2 nm or more of 0.35 cm.sup.3/g or less, a pore volume of pores having a diameter less than 2 nm of 0.5 cm.sup.3/g or more, and an ash content of 0.5% by weight or less.

The present invention relates to an additive for an electrochemical element positive electrode comprising an activated carbon, wherein the activated carbon has a specific surface area in accordance with BET method of 1300-2500 m.sup.2/g, a pore volume of pores having a diameter of 2 nm or more of 0.35 cm.sup.3/g or less, a pore volume of pores having a diameter less than 2 nm of 0.5 cm.sup.3/g or more, and an ash content of 0.5% by weight or less.

A carbon porous body has a micropore volume, calculated from an α.sub.s plot analysis of a nitrogen adsorption isotherm at a temperature of 77 K, of 0.1 cm.sup.3/g or less, the micropore volume being smaller than a mesopore volume calculated by subtracting the micropore volume from a nitrogen adsorption amount at a nitrogen relative pressure P/P.sub.0 of 0.97 on the nitrogen adsorption isotherm, wherein a nitrogen adsorption amount at a nitrogen relative pressure P/P.sub.0 of 0.5 on the nitrogen adsorption isotherm is within a range of 500 cm.sup.3 (STP)/g or less, and a nitrogen adsorption amount at a nitrogen relative pressure P/P.sub.0 of 0.85 on the nitrogen adsorption isotherm is within a range of 600 cm.sup.3 (STP)/g or more and 1100 cm.sup.3 (STP)/g or less.

Provided are a method for preparing a vertical branched graphene comprising treating a pristine vertical graphene with an inert plasma in the absence of an introduced carbon source to develop a vertical branched graphene. The method may also include pre-treating a substrate surface with an inert plasma; depositing a pristine vertical graphene onto the substrate surface by contacting the substrate surface with a deposition plasma comprising a carbon source gas for a deposition period. Also provided are a vertical branched graphene attached to a substrate surface, the vertical branched graphene having a trunk portion extending from the substrate surface, said trunk possessing an increased degree of branching as the distance from the substrate surface increases; and a freestanding branched graphene with a proximal end and a distal end, the proximal end comprising a trunk portion, the trunk portion possessing and increased degree of branching as the distance from the proximal end increases and the distance to the distal end decreases.

An electric double layer capacitor electrode, including: an activated carbon having: a pore volume utilization efficiency (PVUE) of from about 200 to 290 F/cm.sup.3, wherein PVUE is the ratio of the activated carbon gravimetric capacitance (F/g) to the pore volume (cm.sup.3/g) of the activated carbon; a low non-linearity value of from 0.1 to 5%; and a total pore volume of from 0.32 to 0.56 cm.sup.3/g. Also disclosed is a method of making an electric double layer capacitor electrode, and a method of characterizing the performance of activated carbon, and the electrode, in an electric double layer capacitor (EDLC) device, as defined, herein.

An electric double layer capacitor electrode, including: an activated carbon having: a pore volume utilization efficiency (PVUE) of from about 200 to 290 F/cm.sup.3, wherein PVUE is the ratio of the activated carbon gravimetric capacitance (F/g) to the pore volume (cm.sup.3/g) of the activated carbon; a low non-linearity value of from 0.1 to 5%; and a total pore volume of from 0.32 to 0.56 cm.sup.3/g. Also disclosed is a method of making an electric double layer capacitor electrode, and a method of characterizing the performance of activated carbon, and the electrode, in an electric double layer capacitor (EDLC) device, as defined, herein.

Disclosed herein is a high-capacity slurry electrode for use in a flow energy storage system, comprising: an electrolyte; electrode active particles, distributed in the electrolyte, functioning as an electrode active material in an electrochemical flow capacitor storage system; and a redox active material, dissolved in the electrolyte, behaving as a pseudo-capacitor through a redox reaction on a surface of the electrode active material, wherein the high-capacity slurry electrode exhibits both capacitor properties based on the electrode active particles and pseudo-capacitor properties based on the redox active material.