Resistive memory devices having laser-induced graphene (LIG) composites, and methods of making resistive memory devices having LIG composites.

Inter-allotropic transformations of carbon are provided using moderate conditions including alternating voltage pulses and modest temperature elevation. By controlling the pulse magnitude, small-diameter single-walled carbon nanotubes are transformed into larger-diameter single-walled carbon nanotubes, multi-walled carbon nanotubes of different morphologies, and multi-layered graphene nanoribbons.

A slurry of the graphene oxides comprises the graphene oxides and a solvent. The graphene oxides include a strong graphene oxide and a weak graphene oxide. The slurry can be used to make composite films of graphene oxides and graphene heat-conducting films. The slurry includes two graphene oxides with different degrees of oxidation, which can increase a carbon content in the graphene oxide per unit mass, so that the finally obtained graphene heat-conducting film has more carbon.

Provided is a vapor-based heat transfer apparatus (e.g. a vapor chamber or a heat pipe), comprising: a hollow structure having a hollow chamber enclosed inside a sealed envelope or container made of a thermally conductive material, a wick structure in contact with one or a plurality of walls of the hollow structure, and a working liquid within the hollow structure and in contact with the wick structure, wherein the wick structure comprises a graphene material and the hollow structure walls comprise an evaporator wall having a first surface plane and a condenser wall having a second surface plane, wherein multiple sheets of the graphene material in the wick structure are aligned to be substantially parallel to one another and perpendicular to at least one of the first surface plane and the second surface plane. Also provided is a process for producing this apparatus.

A thermal interface material under a high vacuum condition includes a graphite sheet having a thickness of from 9.6 μm to 50 nm and a thermal conductivity in an a-b surface direction at 25° C. of not less than 1000 W/mK.

A weakly coupled enhanced graphene film includes an enhanced graphene structure based on weak coupling, wherein the enhanced graphene structure based on weak coupling comprises a plurality of graphene units stacked vertically; the graphene unit is a single graphene sheet, or consists of two or more graphene sheets stacked in AB form; two vertically adjacent graphene units are weakly coupled, to promote the hot electron transition and increase the joint density of states, thereby increasing the number of hot electrons in high-energy states; the stacking direction of the graphene units in the graphene structure is in the thickness direction of the graphene film; and the graphene film enhances the accumulation of hot electrons in high-energy states by the enhanced graphene structure based on weak coupling.

The present invention provides a graphite/graphene composite material comprising flat graphite particles and graphene aggregates, wherein the flat graphite particles are stacked using the graphene aggregates as a binder so that the basal surfaces of the graphite particles are overlapped with one another, and the graphene aggregates are composed of deposited single-layer or multi-layer graphenes.

Provided is a laminated graphitic layer as an elastic heat spreader, the layer comprising: (A) a plurality of graphitic or graphene films prepared from (i) graphitization of a polymer film or pitch film, (ii) aggregation or bonding of graphene sheets, or (iii) a combination of (i) and (ii), wherein the graphitic or graphene film has a thermal conductivity of at least 200 W/mK, an electrical conductivity no less than 3,000 S/cm, and a physical density from 1.5 to 2.25 g/cm.sup.3; and (B) a conducting polymer network adhesive that bonds together the graphitic or graphene films to form the laminated graphitic layer; wherein the conductive polymer network adhesive is in an amount from 0.001% to 30% by weight and wherein the laminated graphitic layer preferably has a fully recoverable tensile elastic strain from 1% to 50% and an in-plane thermal conductivity from 100 W/mK to 1,750 W/mK.

The embodiments herein provide a facile four-step process for the preparation of binder-free graphene felts that are free standing and mechanically robust. The step of deagglomeration of graphene material leads to a uniform size distribution which when combined/integrated with an appropriate moulding technique allows an easy fine tuning of various attributes of graphene felts including electrical conductivity, porosity, surface area, surface morphology and surface functionalization depending on the desired application. Since graphene felts obtained from this process do not incorporate any binder, to achieve better electrical conductivity, electrochemical activity and catalytic and sensing properties compared to conventional graphene felts while not compromising with their mechanical properties.

Provided is a laminated graphitic layer as an elastic heat spreader, the layer comprising: (A) a plurality of graphitic or graphene films prepared from (i) graphitization of a polymer film or pitch film, (ii) aggregation or bonding of graphene sheets, or (iii) a combination of (i) and (ii), wherein the graphitic or graphene film has a thermal conductivity of at least 200 W/mK, an electrical conductivity no less than 3,000 S/cm, and a physical density from 1.5 to 2.25 g/cm.sup.3; and (B) a conducting polymer network adhesive that bonds together the graphitic or graphene films to form the laminated graphitic layer; wherein the conductive polymer network adhesive is in an amount from 0.001% to 30% by weight and wherein the laminated graphitic layer preferably has a fully recoverable tensile elastic strain from 1% to 50% and an in-plane thermal conductivity from 100 W/mK to 1,750 W/mK.