A process for preparing surface-modified carbon, comprising adding carbon material to a solution of a reaction product of primary aromatic amine and excess molar amount of nitrite source, and recovering surface-modified carbon bearing redox-active sites. Surface-modified carbon material, electrodes and capacitors based thereon are also provided.

A graphite-copper composite material that includes a copper layer having an average thickness of 15 μm or less and scaly graphite particles laminated with the copper layer interposed therebetween. The graphite-copper composite material has a copper volume fraction of 3 to 20%. The graphite-copper composite material further has: (A) copper crystal grains of the copper layer having an average grain size of 2.8 μm or less, a mass fraction of Al of less than 0.02%, and a mass fraction of Si of less than 0.04%, or (B) an interfacial gap of the copper layer and the scaly graphite particles of 150 nm or less.

A graphite-copper composite material that includes a copper layer having an average thickness of 15 μm or less and scaly graphite particles laminated with the copper layer interposed therebetween. The graphite-copper composite material has a copper volume fraction of 3 to 20%. The graphite-copper composite material further has: (A) copper crystal grains of the copper layer having an average grain size of 2.8 μm or less, a mass fraction of Al of less than 0.02%, and a mass fraction of Si of less than 0.04%, or (B) an interfacial gap of the copper layer and the scaly graphite particles of 150 nm or less.

Some implementations of the disclosure are directed to a method, comprising: receiving a sheet of graphite comprising a first surface and a second surface opposite the first surface; and perforating the sheet in a first plurality of locations from the first surface through the second surface to form a first plurality of perforations through the sheet and a first plurality of protrusions of the graphite oriented outward from the second surface, the first plurality of protrusions configured to conduct heat away from a plane of the sheet. Further implementations comprise perforating the sheet in a second plurality of locations from the second surface through the first surface to form a second plurality of perforations through the sheet and a second plurality of protrusions of graphite material oriented outward from the first surface, wherein the second plurality of protrusions are configured to conduct heat away from the plane of the sheet.

In an embodiment, a negative electrode active material includes a particulate silicon-carbon nanocomposite (SCN) material composition including SCN particles that each have: a graphite particle core having an irregular morphology; a plurality of silicon nanostructures distributed around the graphite particle core, including silicon nanostructures exhibiting plate-like morphologies and which have an outer layer that includes SiO.sub.x; and an amorphous carbon layer or matrix that encapsulates the silicon nanostructures and at least portions of the irregular morphology graphite particle core, wherein the SCN material composition has a wt % material composition ratio of: (a) 20-60 wt % of graphite particle cores; (b) 35-60 wt % silicon nanostructures; and (c) 15-30 wt % amorphous carbon, wherein the combination of each such wt % totals to 100%. The negative electrode active material can exhibit an oxide content of less than 8 wt % provided by silicon nanostructure SiO.sub.x layers.

In an embodiment, a negative electrode active material includes a particulate silicon-carbon nanocomposite (SCN) material composition including SCN particles that each have: a graphite particle core having an irregular morphology; a plurality of silicon nanostructures distributed around the graphite particle core, including silicon nanostructures exhibiting plate-like morphologies and which have an outer layer that includes SiO.sub.x; and an amorphous carbon layer or matrix that encapsulates the silicon nanostructures and at least portions of the irregular morphology graphite particle core, wherein the SCN material composition has a wt % material composition ratio of: (a) 20-60 wt % of graphite particle cores; (b) 35-60 wt % silicon nanostructures; and (c) 15-30 wt % amorphous carbon, wherein the combination of each such wt % totals to 100%. The negative electrode active material can exhibit an oxide content of less than 8 wt % provided by silicon nanostructure SiO.sub.x layers.

A method of using carbon dioxide and low pH effluent from prior processing batches for synthesizing-carbon particles or hydrochar from carbohydrate/water solution formulations and conversion of aqueous feedstock containing carbohydrate waste. The hydrochar is a precursor material containing biochar solids and an acidic effluent. The hydrochar can be separated into solids (biochar) and liquid where the solids can be used for preparing a variety of carbonaceous products such as activated carbon. The carbohydrate/water formulation is heated in a pressure vessel converting solid waste to hydrochar forming uniform stable carbon nuclei and converting the aqueous carbohydrates in solution to solid spherical carbon particles. Microwave-assisted or inductive heating can be used as a preprocessing step to increase formation of carbon nuclei to accelerate growth of the carbon particles.

A method of using carbon dioxide and low pH effluent from prior processing batches for synthesizing-carbon particles or hydrochar from carbohydrate/water solution formulations and conversion of aqueous feedstock containing carbohydrate waste. The hydrochar is a precursor material containing biochar solids and an acidic effluent. The hydrochar can be separated into solids (biochar) and liquid where the solids can be used for preparing a variety of carbonaceous products such as activated carbon. The carbohydrate/water formulation is heated in a pressure vessel converting solid waste to hydrochar forming uniform stable carbon nuclei and converting the aqueous carbohydrates in solution to solid spherical carbon particles. Microwave-assisted or inductive heating can be used as a preprocessing step to increase formation of carbon nuclei to accelerate growth of the carbon particles.

A negative electrode active material for a lithium secondary battery, a lithium secondary battery including the same, and a method for preparing the negative electrode active material is disclosed. The negative electrode active material includes a porous carbon coating layer self-bound to a surface of a carbonaceous material. The porous carbon coating later contains porous carbon particles, and thus shows reduced resistance during lithium-ion intercalation on the surface of the carbonaceous material and provides improved surface reactivity and structural stability. This provides improved high-rate charge characteristics, while causing no deterioration of charge/discharge efficiency and life characteristics, when being used as a negative electrode active material for a lithium secondary battery. The self-bound amorphous carbon coating layer may optionally have a controlled pore structure through chemical etching.

A composite artificial graphite includes a first graphite and a second graphite. The first graphite includes secondary particles and has a graphite interlayer spacing d.sub.002 of 0.33560 nm to 0.33610 nm. The second graphite includes primary particles and has a graphite interlayer spacing d.sub.002 of 0.33620 nm to 0.33670 nm. A mass percentage of the first graphite in the composite artificial graphite is 40% to 90%.