102results about How to "The number of layers is controllable" patented technology

The invention discloses a method for preparing large-size high-quality graphene with controllable number of layers, wherein graphite powder or flake graphite is mainly adopted as a raw material. The method specifically comprises the steps of intercalating the graphite raw material by virtue of an intercalating agent to initially weaken the intercalation interaction force and obtain different orders of graphite intercalation compounds (GICs); soaking the GICs in an appropriate expander, and then under the case that an auxiliary agent is added or not, enabling the intercalation materials to be quickly reacted with the expander to release a gases to obtain highly expanded wormlike graphene aggregate and further to cause the distances among graphene lamellar layers to be increased; and after certain processing, peeling, and then repeatedly centrifuging and dispersing to obtain a graphene dispersion with different numbers of layers. According to the method disclosed by the invention, the intercalation-expansion-peeling process is involved, raw materials are cheap, the reaction process is simple and easily controlled, and the number of layers of graphene is precisely controlled; the obtained graphene lamellar layers have the advantages of few defects, large size, high conductivity, high yield and the like, the large-scale industrial production is easily implemented, and the problems of high cost, low productivity, poor quality, small size, uncontrollable number of layers and the like in an existing graphene preparation technology are solved.

The invention discovers and proposes a characteristic that interior species of phenolic resin are nonuniform in distribution in a polymerization process, and discloses a method for preparing a hollow carbon sphere by utilizing the characteristic of phenolic resin. The method comprises: (1) putting phenol into water or a solvent, adjusting the pH, then adding aldehyde and stirring at a certain temperature for a period of time; (2) adding a corrosive agent in a reaction system, stirring at a certain temperature, and selectively removing a part with a relatively low polymerization degree inside a polymer by utilizing a solubility difference of interior species for different solvents, to obtain an intermediate product, that is, a hollow sphere of phenolic resin polymer; and (3) calcining the intermediate product that is obtained in step (2) in an inertia or reducing atmosphere, naturally cooling to room temperature, and thus completing preparation of the hollow carbon sphere. The method is simple and practicable, and the prepared hollow carbon sphere is uniform in shape and controllable in dimension. Moreover, by utilizing a characteristic that the phenolic resin can be in-situ polymerized on surfaces of different nanometer particles, on one hand, a multi-layer hollow structure can be prepared in a multi-cladding and layer-by-layer corrosion manner, and on the other hand, the different nanometer particles can also be packaged in a cavity in an in-situ mode, so as to prepare a nuclear shell or egg yolk-nuclear structure. The prepared hollow carbon sphere has a potential application value in aspects of silicon-carbon negative electrode material, Li-S battery, supercapacitor, heavy metal ion adsorption, and the like.

The invention relates to technology for preparing graphene, in particular to a method for massively preparing high-quality graphene with a controllable layer number, which is suitable for massively preparing the high-quality graphene with the controllable layer number. In the method, graphite with different sizes and crystallinities is used as the raw material. The method comprises the following steps of: oxidizing the graphite by an Hummer method; swelling and splitting the oxidized graphite by a rapid heating method to obtain stripped graphite; reducing the stripped graphite at a high temperature; uniformly dispersing the reduced graphite in solution of a surfactant by an ultrasonic method; and removing the graphite which is not totally stripped and thick graphite sheets with large sizes by a high-speed centrifugation method so as to obtain the high-quality graphene with the controllable layer number. In the method, the layer number of the graphene is controlled according to different oxidization and splitting degrees of the graphite with different sizes and crystallinities, mixed gas of hydrogen and argon is used for reducing and stripping the graphite to further remove oxygenic functional groups in the graphene and improve the electrical conductivity of the graphene so as to prepare the high-quality graphene with the controllable layer number.

The invention discloses a preparation method for hollow carbon nanospheres, comprising: 1) placing a phenol in water, adjusting the pH value, adding an aldehyde, and stirring the solution at a certain temperature for a period of time; 2) adding an etchant to the reaction system and performing stirring at a certain temperature to obtain an intermediate product through selective removal of parts with low polymeric properties in the polymer by using the solubility difference between internal substances for different solvents; 3) calcining, in an inert or a reducing atmosphere, the intermediate product obtained in Step 2), and cooling the substance, thereby completing preparation of the hollow carbon nanospheres. In addition, by using the property that the phenolic resin is capable of in-situ polymerization on different nanoparticle surface, on one hand, a multi-layer hollow structure can be made through multiple times of coating and layer-by-layer corrosion; and on the other hand, different nanoparticles can be in-situ packaged in a cavity, thereby making a core-shell or yolk-core structure.

The invention relates to the field of graphene materials, particularly relates to preparation methods for graphene micro-sheets and particularly relates to a method for preparing the graphene micro-sheets by using a counter-jet jet mill. According to the method, the graphene sheets are obtained through enabling melted ferric chloride and potassium chloride to enter an interlayer of graphite, enabling the powder materials to be in collision through high-speed airflow in the counter-jet jet mill by using the characteristic of brittleness of ferric chloride and potassium chloride crystal grains and the characteristics of good fluidity and difficulty in agglomeration of talcum powder, delaminating the graphite and the talcum powder by generated impact force, shearing force and frictional force, carrying out further separation by a grading room, refluxing unqualified powder material to a crushing chamber, and yielding delaminated graphite and talcum powder as well as gas together. The continuous and large-scale production of the graphene micro-sheets, which are uniform in layer number dispersion and good in fluidity and are not prone to agglomeration, is achieved, the yield is high, the cost is low, no pollution is caused, and the layer thickness meets the requirements of use in the fields of rubber reinforcing, plastic reinforcing, coating material anticorrosion, lubrication and sewage treatment, so that the promotion of the large-scale application of graphene is facilitated.

The invention belongs to the technical field of carbon material manufacturing technology, and in particular relates to a method for preparing graphene by using lignin as a raw material. The method is as follows: a layered or powdered material is used as a substrate, the lignin and a catalyst precursor are alternately assembled on the surface of the substrate by a layer-by-layer electrostatic self-assembly method, then a lignin / catalyst precursor / substrate composite is put into a double-temperature-zone tubular furnace, a H2 / Ar mixed gas is introduced into the double-temperature-zone tubular furnace at a certain speed, at the same time the double-temperature-zone tubular furnace is heated by a certain procedure, after the double-temperature-zone tubular furnace is heated to target temperature, the temperature of the double-temperature-zone tubular furnace is held for a certain time, when the double-temperature-zone tubular furnace is cooled to room temperature, the sample is taken out, and is soaked in an acid for catalyst removal, and after a plurality of times of washing and vacuum drying, the graphene is obtained. The method has the advantages of simple process and convenient operation, and the prepared graphene is good in growth, controllable in layer number and considerable in yield.

The invention discloses a multilayer membrane lithium ion battery negative electrode comprising a substrate, a silicon base layer and a carbon layer, the silicon base layer and the carbon layer are laminated alternately, the silicon base layer comprises silicon, silicon dioxide and carbon filled between the silicon and the silicon dioxide. The invention also discloses a preparation method using the microwave plasma enhanced chemical vapor deposition (MPECVD) for preparing the multilayer membrane lithium ion battery negative electrode, the multilayer membrane lithium ion battery negative electrode is controllable in the number of electrode layer and thickness, due to the advantages of the structure, the electrode has good conductivity and mechanical adhesion strength, so that the loading capacity of active substances of the electrode is allowed to be improved by increasing of the number of layer, and the energy density of the electrode is improved. The SiO2&Si / C membrane electrode with a 12-layer sandwich structure can achieve good capacity holding rate, and under the current density of 1 / 8C, the reversible capacity reaches 0.46mAh / cm<2> specific capacity per unit area. The material structure strategy can also be applied to other materials, and excellent performances are also expected to be achieved.

The invention relates to a halide intercalated porous graphene material. The halide intercalated porous graphene material contains porous graphene sheets and a halide; the halide is intercalated between the porous graphene sheets; the particles of the halide are evenly spread between the porous graphene sheets at one single layer. The preparation method of the halide intercalated porous graphene material comprises the steps of taking a halide intercalated graphite compound as the raw materials and performing ultrasonic stripping on the raw material in a solvent to prepare the halide intercalated porous graphene material. The method is simple; the raw material is cheap and the equipment is easy to obtain; the production cost of the graphene is greatly reduced; in short, the method can be widely applied to the field of preparation of lithium-ion reversible battery electrode materials, energy source materials, conductive materials, heat-conducting materials and the like.

The invention relates to a lithium cell cathode material and a method for preparing the same, which belong to the technical field of micron and nanometer material. The prior transition metal oxide lithium cell cathode material is a monolayer and has low space utilization rate. The provided cathode material is a multilayer spherical metal oxide; the layer number of the sphere is between 1 and 4; the particle diameter of the outermost layer is between 1.5 and 5 mu m; the metal oxide is cobaltosic oxide, ferroferric oxide, ferric oxide, nickel oxide or zinc oxide. PVP and soluble salt of cobalt, iron or nickel are dissolved in organic alcohol according to mass ratio of between 0.02-0.5:1 and react in a hydrothermal kettle for 12 to 24 hours at a temperature of between 180 and 200 DEG C to obtain a precursor; and the precursor is calcined for 0.5 to 3 hours at a temperature of between 350 and 450 DEG C to obtain the lithium cell cathode material. The layer number and the particle diameter of the cathode material are controllable; and the lithium cell has high performance and simple preparation.

The invention relates to ZrB2-SiC complex phase ultrahigh temperature ceramic, in particular to a process for preparing multilayer ZrB2-SiC complex phase ultrahigh temperature ceramic material by tape casting. The process for preparing multilayer ZrB2-SiC complex phase ultrahigh temperature ceramic material by tape casting is realized by the following steps: preparation of SiC ceramic biological membrane, preparation of ZrB2-SiC complex phase ceramic biological membrane, multilayer membrane stacking and laminating, binder removing and sintering; fracture toughness of the acquired multilayer ZrB2-SiC complex phase ultrahigh temperature ceramic material reaches 7-12Mpa.m1/2, flexural strength is 600-800MPa. The two indexes are obviously higher than those of ZrB2-SiC complex phase ceramic prepared by conventional method.

The invention belongs to the technical field of chemical materials, and particularly relates to a preparation method of a graphene oxide film or composite film capable of presenting different colors in different gas environments. The graphene oxide film can be applied in preparing gas sensors for detecting humidity and harmful gas. The preparation method specifically includes: preparing a grapheneoxide solution and a macromolecular solution, sequentially spin-coating the solutions on a modified silicon wafer substrate through a spin coater, and drying to obtain a color-changing graphene oxide/macromolecular composite film. Dispersity and selectivity of a graphene gas-sensitive material are improved; functionalized macromolecules are introduced, so that graphene lamellar structure is stabilized while gas-sensitive selection is improved, and a graphene/macromolecular schemochrome thin film which is flat and controllable in number of layer is prepared; a characteristic that conventionalgraphene gas-sensitive materials depend on electrochemical detection is broken through, an organic small molecule visual detection assembly array based on interference light response is built, and real-time, quick, accurate and visual detection of humidity and harmful gas is realized.

The invention provides a preparation method of graphene. According to the method, a nano-scale metal and/or metal oxide catalyst is attached on a rotatable reaction deposition part, a carbon source which can be decomposed into carbon and hydrogen is introduced, and the carbon source is cracked into the graphene under the action of the nano-scale catalyst; as the reaction deposition part is rotatable, the carbon source is in three-dimensional and dynamic contact with the catalyst, and more graphene can be deposited; in addition, the catalytic efficiency of the nano-scale catalyst to the carbon source is higher, and the preparation of the high-quality graphene even in thickness and controllable in number of layers can be effectively realized. The method is simple in process; the problems of less deposited graphene, large catalyst scale and low catalytic efficiency due to the static placement of the catalyst in the existing chemical vapor deposition technology are solved. The invention also provides a graphene; the layers of the graphene are bent to form a hollow cloth bag shape; the graphene of the structure has excellent hydrogen storage and lithium storage functions.

The invention relates to the field of graphene materials, in particular to a method for preparing graphene nanoplatelets with a pulsed high pressure water jet mill.According to the method, a plugging layer is pressurized, Van der Waals' force among graphite powder layers is reduced, so that the graphite layers are easy to strip, then graphite powder is crushed and stripped under the action of water jet and turbulent flow and cavitation through pulsed high pressure water jet of the pulsed high pressure water jet mill, the evenly-dispersed graphene nanoplatelets with the number of layers ranging from 100 to 200 are obtained.Continuous and large-scale production of the graphene nanoplatelets with the number of layers being even is achieved, the yield is high, the cost is low, no pollution is caused, the layer thickness meets the use requirements in the fields of rubber enhancement, plastic enhancement, coating corrosion prevention, lubrication and sewage treatment, and it is convenient to promote large-scale application of graphene.

The invention relates to a passive mode-locking laser based on graphite alkene having an epitaxial growth on a SiC substrate and is directed to the fields of laser technology and nonlinear optics. The passive mode-locking laser mainly comprises a SiC substrate, graphite alkene having an epitaxial growth on the SiC substrate, a doped fiber, a gain medium, a pumped source, a wavelength division multiplexing device, a laser beam splitter, a single-mode fiber, an annular device, a polarization controller and the like. A mode-locking laser output having high stability and high impulse energy is realized through utilizing the characteristic of saturable absorption of graphite alkene. Graphite alkene having an epitaxial growth on the SiC substrate is characterized by high repeatability, good thermal conductivity and strong operationality. Therefore, graphite alkene having an epitaxial growth on the SiC substrate is easier to be applied into the passive mode-locking laser at a low cost and a large scale.

The invention relates to a method for rapidly preparing a transition metal chalcogenide composite optical fiber material. The preparation method comprises the following steps: infiltrating the opticalfiber by adopting molybdic acid or sodium tungstate/potassium salt solution, and then directly depositing high-quality single-layer or few-layer transition metal chalcogenide on the inner wall of anair duct in the center of the optical fiber or on the inner walls of a cladding air hole and a fiber core air duct of the photonic crystal fiber under the conditions of low pressure and high temperature. The optical fiber is made of quartz or quartz polymer. The excellent optical and electrical properties of the transition metal chalcogenide composite and the characteristics of the photonic structure of the optical fiber are combined to realize the multifunctional integration of the two-dimensional TMDC material and the optical fiber. The method has the characteristics of low cost, simple preparation method, short growth period and controllable layer number of the transition metal chalcogenide. The prepared transition metal chalcogenide composite optical fiber has potential application inthe fields of optical communication, sensing and novel optical devices.

The invention provides a method for preparing a reverse osmosis composite membrane containing azobenzene polyamide. The method comprises the following steps: through the instruction of series of azobenzene photoresponse groups and hydrophilic functional groups such as carboxyl and sulfonic acid groups, synthesizing azo-type anion/cation polyamide-function self-assembled molecules with ultraviolet photoresponse and a hydrophilic performance; then through the integration and coupling of electrostatic self-assembly and in situ photochemical reaction between layers, combining a layer-by-layer self-assembly technique with an ultraviolet curing technology science, and preparing the reverse osmosis composite membrane containing azobenzene polyamide, wherein the layer number is controllable, covalent bonds between the layers are firmly cross-linked, and the membrane body is charged, and high in mechanical strength, salt removing rate, water flux, and pollution resistance.