87results about How to "Crystal structure intact" patented technology

The invention relates to a method for preparing graphene, characterized by carrying out explosion treatment for one or more times on carbonaceous materials by using fluids under supercritical state. By using the fluids under supercritical state to penetrate and dissolve the carbonaceous materials and having the aid of sudden release of high pressure hot steam, the shearing and peeling between layers of the carbonaceous materials are promoted to realize the preparation of graphene. Compared with using ball milling, mechanical peeling, high temperature and high pressure to prepare graphene in the prior art, the invention has the advantages of mild process conditions (low pressure), short process time, large area of prepared graphene, and complete preserved crystal structure. According to the invention, the content of graphene which comprises less than 5 layers is higher than 90 %, and the batch production of graphene powder products can be really realized.

The production process of silicon chip for solar cell with waste integrated circuit chips includes the following steps: treating waste integrated circuit chips with HCl and H2SO4 to eliminate Mg, Al, Mn, Zn, Cr, Fe, Ni, Sn, Pb and other metals with activity higher than hydrogen; treating with HNO3 to eliminate Cu, Hg, Ag and other transition metals; treating with mixed acid of HF and HNO3 to eliminate metal silicide, silicon oxide and silicon nitride; single-side thinning and double-side thinning to eliminate active area and silicon chip with original resistivity; cleaning, classifying, detecting and grading to obtain silicon chip for solar cell. The process can obtain silicon chip with less impurity and intact crystal structure for producing solar device with high photoelectronic conversion efficiency.

The invention discloses graphene and a preparation method thereof. The preparation method comprises the following steps: (1) providing a metal substrate, cleaning the metal substrate, putting the metal substrate into the reaction chamber of chemical vapor deposition equipment, introducing protective gas into the reaction chamber after sealing, stopping introduction of protective gas and carrying out vacuum-pumping so as to allow the reaction chamber to be in a vacuum state; (2) heating the metal substrate to 400 to 500 DEG C, starting an ultraviolet source, allowing the ultraviolet source to irradiate the surface of the metal substrate, introducing a carbon-containing fluid, carrying out a heat-preserved reaction for 10 to 100 min, stopping introduction of the carbon-containing fluid and stopping heating after completion of the reaction, carrying out cooling to room temperature, opening the chemical vapor deposition equipment and taking the metal substrate out so as to obtain the metal substrate with grown graphene on its surface; and (3) soaking the metal substrate with grown graphene on its surface in a corrosive liquid, removing the metal substrate, carrying out filtering, taking a filter residue and carrying out cleaning and drying so as to obtain graphene. The method adopts a chemical vapor phase process for deposition preparation of graphene on the substrate, guarantees the lamellar structure of graphene, simplifies preparation steps and has small energy consumption and low cost.

A process for preparing cerium oxide nanoparticles includes such steps as proportionally dissolving cerium nitrate and hexamethylenetetraamine (HMT) respectively in alcohol and distilled water, mixing, stirring, sealing, heating at 70-90 deg.C for 1-2 hr, cooling, ageing for 1-2 hr, filter, washing deposit, and drying at 60-80 deg.C for 6-10 hr. The obtained CeO2 nanoparticles can be used to prepare the polishing liquid for polishing the semiconductor wafer of gallium arsenide.

The invention discloses a Ta-Zr-C ternary ceramic and a preparation method thereof. The Ta-Zr-C ternary ceramic provided by the invention is of Ta-Zr-C continuous single-phase solid solution ceramic powder. The preparation method comprising the following steps of (1) proportioning precursor solution; (2) preparing sol; (3) aging; (4) drying; and (5) calcining the dried material at a high temperature and in steps. The Ta-Zr-C ternary ceramic provided by the invention has the characteristics that the grain size is small, the components are uniform, the purity is high and the like, and the preparation method provided by the invention has the excellent advantages that the requirement of the process equipment is simple, the temperature requirement is low, the cost is low and the like.

The invention relates to a method for preparing a lithium manganese phosphate positive material of a lithium battery by spray pyrolysis and belongs to the technical field of the positive materials of lithium batteries. According to the method, homogeneous nucleation of lithium manganese phosphate is promoted through the high-temperature spray pyrolysis under the condition of an inert atmosphere, so as to reduce the temperature and the time of the follow-up reaction to obtain the lithium manganese phosphate positive material with excellent electrochemical performance. The method disclosed by the invention is simple; and since raw materials are mixed in molecular ion level and the temperature and the time of the follow-up reaction are reduced after the high-temperature spray pyrolysis, the obtained lithium manganese phosphate material has the advantages of high purity, complete crystal structure, fine and uniform particles and the excellent electrochemical performance.

The invention relates to an SCM-3 molecular sieve and a preparation method thereof, which mainly solve the technical problems of the molecular sieve SCM-3 having a new structure not involved in the prior art. The invention provides a technical scheme of a new SCM-3 molecular sieve which comprises the following chemical compositions in mole ratio: XO2:nY2O3, wherein X is silicon or germanium; Y is at least one of elements such as aluminum, boron, gallium, iron and the like; 0.002<=n<=0.25; and the maximum value of an X-ray diffraction peak exists when the interplanar distance of the SCM-3 molecular sieve d=16.70+/-1.7A, d=8.24+/-0.23A, d=7.24+/-0.15A, d=6.22+/-0.12A, d=3.59+/-0.06A, d=3.48+/-0.06A and d=3.38+/-0.06A. Thus, the technical scheme well solves the technical problems. The synthesized SCM-3 molecular sieve has favorable application prospects in the aspects of catalytic cracking of heavy oil and isomerization reaction of organic molecules.

An array of semiconductor nanowires with multi-layer structure features that said nanowire structure is a multi-layer nanowires formed by alternative arrangement of metal/semiconductor or semiconductor/semiconductor, and said multi-layer nanowires are arranged parallelly and perpendicularly to form an array. Its preparing process includes preparing multi-layer metallic nanowire array and sulfurizing or oxidizing gas-solid reaction.

The invention provides a preparation method of graphene, which comprises the following steps: (1) mixing graphite and an ionic liquid in a mass ratio of 1:(0.5-5), and carrying out ultrasonic dispersion for 10-48 hours to obtain intercalation graphite of which the intercalation compound is the ionic liquid, wherein the ionic liquid is an imidazole ionic liquid or pyrrolidine ionic liquid; and (2) putting the intercalation graphite in a reactor in an inert gas protective atmosphere, heating to 700-900 DEG C, keeping for 0.5-1 hour, cooling to room temperature in the inert gas protective atmosphere, and collecting the solid product which is the graphene. The method has the advantages of simple equipment and simple and feasible operation, and can easily implement large-scale industrial production; the prepared graphene has the characteristics of high yield, smaller number of layers, favorable mechanical properties and high conductivity; and compared with the common graphene prepared by a redox process, the graphene prepared by the method provided by the invention has the advantages of fewer defects, complete crystal structure and the like.

The invention is a method for preparing a silicon nanotube, which takes the mixed powder of SiO, Si, etc. as the starting material and a small amount of rare earth elements as an indirect catalyst, evaporates the material under the conditions of high temperature and low air pressure, and causes the silicon atoms to accumulate and nucleate at a proper deposition temperature, thereby preparing the hollow-structured silicon nanotube. The method for preparing the silicon nanotube has the advantages of simple process, low-cost equipment, complete crystal structure of the nanotube, and capability for meeting the industrial requirements. The successful preparation of the nanotube provides a practicality foundation for the nanuotube to be widely applied in nanoelectronic devices in the future, and the theoretical research of the nanotube is verified from the experiment.

The invention discloses a modified lithium-rich manganese-based positive electrode material and a preparation method thereof, and belongs to the technical field of positive electrode materials for lithium-ion batteries. The preparation method comprises the steps of fully mixing a lithium-rich manganese-based precursor, a lithium salt and a doped metal compound, and then burning a mixture to prepare the modified lithium-rich manganese-based positive electrode material; and carrying out pretreatment of heat preservation on a lithium-rich manganese-based precursor at 300-650 DEG C for 2-6 hours before mixing. A pretreatment step of the precursor is added to an existing preparation technology of the lithium-rich manganese-based positive electrode material, a crystal structure of the precursor is more complete and an aluminum element is doped, so that the initial coulomb efficiency of the positive electrode material can be significantly improved and is improved by 15-20% in comparison with that of an un-pretreated material; and the rate capability is also greatly improved.

The invention relates to the field of lithium-ion batteries and particularly relates to a high-nickel ternary positive electrode material with high electrical property consistency, a preparation method thereof and an application thereof. The high-nickel ternary positive electrode material with high electrical property consistency is characterized in that the chemical structural formula is LixNiaCobMcRdO2, wherein R is a doping element, x is larger than 0.95 and smaller than 1.15, a is larger than 0.60 and smaller than 0.85, b is larger than 0 and smaller than 0.2, c is larger than 0 and smaller than 0.2, the sum of a, b and c is larger than or equal to 0.98 and smaller than or equal to 1.00, d is larger than or equal to 0 and smaller than or equal to 0.1, and M is Mn or Al. The high-nickelternary positive electrode material has high particle size consistency, and the physical performance and electrochemical performance of a high-nickel lithium-ion secondary battery can be effectivelyimproved.

Disclosed is a method for preparing graphene. In particular, the method comprises: using n-hexane or propane as a supercritical solvent, filling graphite powder or graphite powder and a cosolvent into an autoclave, sealing the autoclave by selecting an appropriate rupture disk, adding n-hexane or propane after the autoclave is vacuumized, keeping in a supercritical state for a period of time at a temperature and a pressure, then increasing the temperature and the pressure slightly or increasing the pressure alone,, and a collector collecting rushed-out materials instantly for treatment to prepare a graphene product after the rupture disk bursts when the pressure exceeds the pressure which the rupture disk can bear. In the present method, pressure relief occurs in milliseconds, and thereby efficient strip of graphite can be achieved. The method belongs to a physical process, does not cause large damage on the structure of graphene, is simple in the preparation process, does not require a large quantity of inorganic acids and oxidants, and is free of "three wastes". The prepared graphene crystal is intact in structure, good in quality, and capable of achieving large-scale industrial production of graphene.

The invention belongs to the field of graphene, and discloses a preparation method of graphene, which comprises the following steps: introducing protective gas into a reactor of plasma equipment; starting the plasma equipment to generate plasma in the reactor; and adding organic acid intercalated graphite into a reactor, and carrying out pyrolysis reaction under the action of plasma to obtain the graphene. By using the method for preparing the graphene by quickly pyrolyzing organic acid intercalated graphite, the prepared graphene has the advantages of fewer defects and complete crystal structure, and is free of sulfur, chlorine and other corrosive elements; and meanwhile, the invention has the advantages of favorable stripping effect, centralized number of layers, simple equipment, and simple and feasible operation, and can easily implement automatic and industrial production.

The invention provides a preparation method of blue titanium dioxide particles. The method comprises the following steps: 1) removing surface impurities of TiO2 particles; 2) tabletting the TiO2 particles treated in the step 1), so that the surfaces of the tabletted TiO2 particles are flat; 3) irradiating the TiO2 particles treated in the step 2) for 3-10 seconds by using rapid laser with a pulsewidth of picoseconds or nanoseconds to obtain TiO2 particles with TiO films growing on the surfaces in situ; and 4) uniformly mixing the TiO2 particles treated in the step 3) again, and repeating thestep 2) and the step 3) until the whole TiO2 particles are uniform in blue color. According to the method, the preparation process is clean and free of pollution, the required single reaction time isextremely short and is only 3-10 seconds, and the preparation efficiency is high; the prepared blue titanium dioxide particles have good color stability in natural air and show good electrical transport performance, the photocurrent density is improved by about 3 times compared with that of the raw material TiO2, and the current impedance is obviously reduced.

The invention discloses a single crystal type IV-VI-VIII group lithium-rich disordered rock salt structure positive electrode material and a preparation method thereof. The general formula of the positive electrode material is Li<1+a>TiW<c>Ni<d>O<2>, wherein a is greater than 0.1 and smaller than 0.3, b is greater than 0.1 and smaller than 0.4, c is greater than 0.1 and smaller than 0.4, d is greater than 0.1 and smaller than 0.4 , and the sum of a+4b+6c+2d is equal to 3. The single crystal type material is composed of IV group elements, VI group elements and VIII group elements, is specifically composed of titanium of the IV group elements, tungsten of the VI group elements and nickel of the VIII group elements, and has a more stable three-dimensional disordered cation skeleton structure, a more complete crystal structure, higher compaction density and a smaller specific surface area compared with a traditional ternary lithium nickel cobalt manganate positive electrode material; and therefore, the material has good rate capability and cycle performance, and can be used in lithium ion batteries.

The invention relates to a high-rate lithium iron phosphate positive electrode material and a preparation method thereof. The preparation method comprises the steps: firstly, weighing an iron source and a lithium source according to a molar ratio of 1:1-1:1.05, then weighing a carbon source accounting for 5-15% of the total mass of the iron source and the lithium source and a metal ion doping agent accounting for 0-1% of the total mass of the iron source and the lithium source, adding water, carrying out ball milling and sanding, controlling sanding D50 to be 100-200 nm, and then spraying to obtain a precursor; and putting the precursor into a sintering furnace, introducing nitrogen for protection at the same time, sintering at 650-700 DEG C, cooling to obtain a sintered material, crushing the sintered material, and screening to remove iron to obtain the lithium iron phosphate. The prepared lithium iron phosphate has good rate capability and cycling stability, the 0.1 C discharge capacity of the lithium iron phosphate reaches 160 mAh/g, the 10 C discharge capacity of the lithium iron phosphate reaches 140 mAh/g, the microstructure of the positive electrode material is spherical-like particles, and the average value of primary particles is 100 nm.

The invention discloses preparation and application of an iron-nitrogen co-doped porous carbon material. Ferrocene, zinc nitrate and 2-methylimidazole are weighed and dissolved in methanol, ferrocene-loaded ZIF-8 metal organic framework powder is prepared at normal temperature, and then high-temperature treatment is performed in a protective atmosphere to obtain the iron-nitrogen co-doped porous carbon material. The iron-nitrogen-carbon material prepared by the preparation method disclosed by the invention has excellent sewage treatment performance.

The invention relates to a high-energy catalytic physical stripping preparation method of graphene, relates to the technical field of graphene materials, and solves the problem that a conventional physical stripping method is high in cost and not easy to be mass-produced. The method specifically comprises the following steps: performing preliminary infiltration on pure water, performing first high-energy ultrasonic preliminary stripping, adding SiC for ball milling, then performing second high-energy catalysis for stripping, classifying graphene flakes by gas flow classification and spray-drying to obtain the graphene; by infiltration, ultrasonic treatment, SiC ball milling, addition of a surfactant and the secondary high-energy ultrasonic treatment, the graphene is stripped layer by layer, the process is mild, and basically no crushing and wear phenomena occur; the prepared graphene crystal lattice structure is complete and processed by a physical stripping method, the graphene flakesare present in a completely powdery form, the storage and use environments are not restricted, and the industrial production cost is relatively low, thereby facilitating the wider application of graphene in various industries.