49 results about "Multiwalled carbon" patented technology

The application relates to the technical field of composite materials, and particularly discloses a carbon fiber / epoxy electromagnetic shielding composite material with strong interface bonding and a preparation method thereof, which comprises the following steps: hydrothermal reaction of oxidized carbon fibers O-CF, an organic ligand and an iron source in a solvent, washing and drying of the fibers to obtain MIL-loaded carbon fibers, carbonization treatment to obtain iron-based oxide-loaded carbon fibers dF@CF, vacuum-assisted introduction of epoxy resin into the multilayer carbon fibers dF@CF, and curing to obtain the carbon fiber / epoxy electromagnetic shielding composite material. The organic ligand and trivalent iron ions are used to synthesize a large number of rhombic MILs on the active sites on the surface of the carbon fibers, the MILs are reduced into iron-based oxide nanoparticles after carbonization, the iron-based oxide nanoparticles are closely loaded on the surface of the carbon fibers, the interface bonding performance is improved, the electromagnetic shielding efficiency is increased, and the carbon fiber / epoxy composite material with both the interface and the electromagnetic shielding efficiency is realized.

The invention discloses a high-performance silicon-carbon negative electrode material and a preparation method thereof, and relates to the technical field of lithium ion battery materials, the high-performance silicon-carbon negative electrode material comprises a porous carbon material, the surface of the porous carbon material is successively deposited with a carbon nanotube network and nano silicon, the porous carbon material on which the carbon nanotube network and the nano silicon are deposited is also provided with a secondary outer layer carbon shell and an outer layer carbon shell from inside to outside; according to the invention, double optimization of the silicon-carbon negative electrode material is realized through a unique structural design: (1) the volume expansion effect of nano silicon is relieved through cooperation of the carbon nanotube network and the multi-layer carbon shell; and (2) the migration rate of lithium ions is accelerated by the carbon nanotubes and the multi-layer carbon coated structure, and the prepared silicon-carbon negative electrode material has excellent cycling stability and rate capability.

The invention discloses a low-noise and low-rolling-resistance tire tread and a preparation method thereof, and relates to the technical field of tire production, the low-noise and low-rolling-resistance tire tread comprises a supporting layer and multiphase composite tread rubber; the multiphase composite tread rubber comprises a continuous phase matrix, white carbon black with a two-phase structure, functionalized multiwalled carbon nanotubes, a disilane coupling agent, dynamic crosslinking thermoplastic elastomer particles, zinc oxide, stearic acid, an anti-aging agent, an accelerant and sulfur, and good wear resistance and mechanical strength are kept while the rolling resistance and driving noise of a tire are remarkably reduced.

This application discloses an impact buffer structure, which includes an inner support, a buffer layer, and a paint layer. The buffer layer is disposed on the outer surface of the inner support, and the paint layer is disposed on the outer surface of the buffer layer. The buffer layer contains a mesh and multiple layers of carbon fiber balls. This application can improve the buffering capacity of the impact buffer structure and increase its service life.

A device (1) for rapidly transferring thermal energy from a thermal energy source (A) to a destination point (B) at a rate higher than the convection and heat transfer capacity of adjacent means 2 and for capturing said thermal energy point or surface, wherein a thermoelectric conversion means located at the destination point B can convert the thermal energy into electrical energy with zero emissions harmful to the environment and living things. The thermal energy is transferred by a coating 4 composed of a plurality of nanometric layers with atoms forming a regular geometric structure (Figure 1). The present invention also relates to a device for the transfer of thermal energy having multiple layers of carbonaceous material on a planar or non-planar (three-dimensional shape), opaque, transparent or translucent, rigid or semi-rigid substrate of fabric, metallic or non-metallic or flexible material, having flexible but not opaque, transparent or translucent natural or synthetic fibers. The present invention also includes a method for manufacturing a device (10 or 10a) for the rapid transfer of thermal energy. The method comprises at least one deposition step of at least one layer (12, 12a-12b-12c-12d, etc.) of a carbonaceous material having a regular geometric structure on a support substrate (11 or 11a) in an environment (110) of a deposition machine (100), the environment being vacuum-packed under controlled temperature and pressure conditions and isolated from the external environment, the deposition being performed along a direction perpendicular or locally radial to a plane or shape substantially defined by the support substrate (11 or 11a). The present invention also relates to an integrated system for generating electrical energy using said device coupled to a possible generator other than a renewable energy source of thermoelectric generator, photovoltaic and / or thermoelectric-photovoltaic and / or motive power type, all used jointly for the supply of an electrical load.

The present disclosure belongs to the technical field of lithium battery cathode materials, and discloses a preparation method of multiple carbon-coated high-compaction lithium iron manganese phosphate, comprising the following steps: (1) synthesizing a carbon and vanadium co-doped ferromanganese phosphate precursor through a co-precipitation method, sintering, and removing crystal water to obtain an anhydrous ferromanganese phosphate precursor; (2) adding lithium phosphate, a supplemental phosphorus source, an organic carbon source, a dopant and deionized water, and performing ball milling, wet sanding, spray drying and sintering to obtain an intermediate material; and (3) adding deionized water and the organic carbon source, then performing ball milling, sanding, spray drying, sintering and air jet pulverization to obtain multiple carbon-coated high-compaction lithium iron manganese phosphate.

The invention relates to a polypropylene composition as well as a preparation method and application thereof. The polypropylene composition comprises the following components in parts by weight: 58-86 parts of polypropylene, 5-17 parts of conductive carbon black, 3-9 parts of multiwalled carbon nanotubes and 0.5-2 parts of an antioxidant. The surface of the multi-walled carbon nanotube is modified with carboxyl; the mass ratio of the conductive carbon black to the multi-walled carbon nanotubes is (1.5-3): 1. According to the invention, the polypropylene is used as a resin matrix and added into the multi-walled carbon nanotube with the surface modified with carboxyl, and the mass ratio of the conductive carbon black to the multi-walled carbon nanotube is controlled within a specific range, so that the prepared polypropylene composition not only has high electromagnetic shielding effectiveness, but also has high tensile strength retention rate after thermal aging treatment, and the electromagnetic shielding performance of the polypropylene composition is improved. And the thin-wall injection molding requirement can be met.

The utility model discloses a shock-resistant cable protection pipe connector, which relates to the technical field of protection pipe connectors and comprises a connector, two groups of fixing sheets are fixedly connected to the front end and the rear end of the top of the connector, and a shock-resistant component is fixedly connected to the periphery of the connector. According to the shock-resistant cable protection pipe connector, by arranging the Y-shaped reinforcing ribs, the multiple layers of carbon fiber honeycomb pieces and the carbon fiber arched plates, when the shock-resistant cable protection pipe connector is used, firstly, the interior is protected through the steel shell, internal and external deformation caused by impact force is prevented, meanwhile, after the impact force is inwards transmitted into the pressure bearing layer, external pressure and impact are effectively resisted through the Y-shaped reinforcing ribs, and the service life of the cable protection pipe connector is prolonged. Stress is dispersed, after the carbon fiber arched plates in the supporting layers bear pressure, the pressure is downwards and outwards transmitted to the adjacent multi-layer carbon fiber honeycomb pieces and finally enters the retarding layers, the springs buffer and weaken the pressure, finally, the pressure is transmitted to the high-density sponge, additional impact resistance is provided, and the problem that the impact resistance of the device is poor is solved.

The application relates to a structural health monitoring system and application thereof. A preparation method of a carbon fiber reinforced thermoplastic composite material involved in the system comprises the following steps: providing a plurality of carbon fiber reinforced thermoplastic resin layers; prepositioning a multifunctional sensor unit array between adjacent thermoplastic resin layers, the multifunctional sensor unit array comprising a functional film containing ferroelectric ceramic, an electrode layer, and an insulating protective layer between the functional film and the carbon fiber layer; wherein the functional film comprises ferroelectric ceramic material with dielectric and piezoelectric response characteristics; and performing selective laser solidification on the layer area prepositioned with the multifunctional sensor unit array, so that the layer interface locally melts under the action of laser heating and embeds the multifunctional sensor unit array between adjacent layers; wherein the peak temperature of the laser heating area in the selective laser solidification process is not higher than 200 DEG C.

The utility model discloses an efficient gluing device for carbon fiber prepreg cloth, which belongs to the technical field of carbon fiber prepreg cloth, and adopts the technical scheme that the efficient gluing device comprises a dipping gluing box, a supporting plate is arranged at the top of the dipping gluing box, and clamping mechanisms are arranged on the two sides of the rear side of the top of the dipping gluing box; fixing mechanisms are arranged on the two sides of the rear side of the top of the dipping and gluing box; the clamping mechanism comprises two sliding rods, a plurality of clamping plates, two sliding blocks, a plurality of connecting belts and two springs, the sliding blocks are connected to the surfaces of the sliding rods in a sliding mode, the bottoms of the sliding blocks are fixedly connected with the top of the top clamping plate, the connecting belts are fixedly connected between the rear sides of the adjacent clamping plates, the surfaces of the sliding rods are movably sleeved with the springs, and the springs are fixedly connected with the top of the top clamping plate. The problem that the gluing efficiency of the carbon fiber prepreg cloth is low due to the fact that an existing part of structures for gluing the carbon fiber prepreg cloth are inconvenient to glue multiple layers of carbon fiber prepreg cloth at the same time is solved.

Disclosed is a hybrid composite anode for a lithium ion battery comprising silicon nanoparticles, a multiwalled carbon nanotube (MWCNT) sheet, and a polymeric binder capable of enhancing capacity retention of the hybrid composite anode. Also disclosed is a method of manufacturing an anode for a lithium ion battery, the method comprising the steps of: manufacturing a carbon nanotube (CNT) pad on an anode current collector; dispersing the manufactured CNT pads in a mixture of deionized (DI) water and ethanol using a probe-type ultrasonic generator and a magnetic stirrer; and adding silicon nanoparticles, a multi-walled carbon nanotube (MWCNT) sheet, and a polymeric binder to the mixture, thereby forming a Si-MWCNT nanocomposite (SMC) anode.

The invention discloses a reinforcing and toughening ice material composite foundation for polar region engineering, and particularly relates to the technical field of foundations, the reinforcing and toughening ice material composite foundation comprises a first foundation base, a second foundation base is arranged at the top of the first foundation base, and a supporting assembly is arranged between the first foundation base and the second foundation base; the supporting assembly comprises a first base plate arranged in the middle of the second foundation base, a second base plate is arranged in the middle of the first foundation base, and the first base plate and the second base plate are arranged in a stacked mode. The first base plate and the second base plate are formed by stacking the multiple layers of carbon fiber reinforced ice composite plates, and after basalt fibers and nano zirconium oxide are doped for reinforcement, the defects that pure ice is low in strength and poor in toughness are effectively overcome, so that the second foundation base achieves height fine adjustment within a certain range relative to the first foundation base; height change and ice surface settlement caused by ice layer freezing and thawing can be adapted in real time, it is ensured that the upper structure is always in a horizontal stable state, and the problem that a traditional foundation cannot be dynamically adapted to polar region ice surface deformation is solved.

A nanocomposite proximity-pressure sensor (NPPS), configured to measure one or more human biometrics, the NPPS including a carbon nanotube-paper (CPC) electrode, a multiwalled carbon nanotubes (MWCNTs) foam, and an auxetic MWCNTs-embedded frame, wherein the auxetic MWCNTs-embedded frame is positioned around the MWCNTs foam, wherein when the auxetic frame is compressed, it expands and exerts a pressure onto the MWCNTs foam.

The invention discloses a piezoelectric interface modified piezoelectric ion sensor and a preparation method and application thereof, and belongs to the field of flexible piezoelectric ion sensors, multiwalled carbon nanotubes are dispersed in NMP to form a suspension, and vacuum filtration and drying are performed to obtain a multiwalled carbon nanotube film; the BPNA powder is dissolved in a DMF / ethanol solution, and BPNA crystals are obtained through a liquid-liquid diffusion method; dissolving PEO in deionized water to obtain a PEO solution; adding the BPNA crystal into the PEO solution to obtain a PEO / BPNA dispersion liquid; adding ionic liquid into the PEO solution to obtain PEO / IL dispersion liquid; pouring the PEO / BPNA dispersion liquid on a glass plate to obtain a PEO / BPNA layer; a PEO / IL dispersion liquid is poured on the PEO / IL layer to form a PEO / IL middle layer; and pouring a PEO / BPNA layer on the multi-walled carbon nanotube electrode film layer to obtain an electrolyte, and laminating two multi-walled carbon nanotube electrode film layers on two sides of the electrolyte to obtain the assembled sensor.

The invention discloses a stretchable elastic carbon nanofiber membrane material and a preparation method thereof. The preparation method comprises the following steps: respectively dissolving polystyrene and a carbon precursor polymer to prepare a spinning solution, spinning according to a certain combination sequence to obtain a multi-layer carbon precursor nanofiber membrane, and inducing the construction of a micro-buckling structure of the carbon precursor nanofiber membrane by utilizing a thermal shrinkage effect of a polystyrene layer to obtain the multi-layer carbon precursor nanofiber membrane. Polystyrene is dissolved and removed through ethyl acetate, a nanofiber membrane only retaining a pure carbon precursor is obtained, and finally the stretchable elastic carbon nanofiber membrane is obtained through pre-oxidation and carbonization. The elastic carbon nanofiber membrane prepared by the invention has excellent tensile resilience, high conductivity and high specific surface area, and can be applied to the application fields of national defense and military industry, energy environmental protection, aerospace, flexible electronics and the like.

The application discloses a kind of resistance stable stretchable conductive fiber and its continuous preparation method, comprising the following steps: S1, with elastic fiber as baseline, through feeding roller pay-off, after wetting, coating carbon nanotube, solvent bath, drying, through collection roller take-up;The linear velocity of collection roller is greater than the linear velocity of feeding roller;S2, the fiber obtained in the previous step is payed-off by feeding roller, after wetting, coating carbon nanotube, solvent bath, drying, through collection roller take-up;The linear velocity of feeding roller and collection roller is the same as step S1;S3, repeat step S2 to coat multiple layers of carbon nanotube, and obtain resistance stable stretchable conductive carbon fiber.The application uses elastic fiber as baseline, realizes the elongation of elastic fiber to preset multiple by the speed difference of feeding roller and collection roller, and obtains resistance stable stretchable conductive fiber by wetting and coating carbon nanotube multiple times, and the preparation method is simple, low in cost, and continuous production can be realized.

The application discloses a method for preparing gradient multistage multilayer carbon film on the surface of fluoroether rubber by Cr / Ti co-doping, wherein the substrate is washed, dried, and then placed into a magnetron sputtering cavity; Ar gas is introduced to clean the substrate under high vacuum condition; and then modified metal micro-doped carbon film is obtained by adopting cathode arc magnetic filtering technology. The obtained co-doped carbon film obviously improves the friction performance, the hydrogenated amorphous carbon film composition in the film is increased, and meanwhile, the film itself density and hardness are maintained; the cathode arc magnetic filtering technology makes the doping elements uniformly disperse in the film, so that the film performance is improved by a small amount of doping elements; the order degree of the friction interface of the film is obviously improved during the friction process, the film has low friction coefficient and low wear rate, and the tribological performance of the film is improved.

This invention belongs to the field of transmission device technology and discloses a perfectly coupled secure information transmission device based on a multilayer nanofilm structure filled with a dielectric sheet. The device includes an input region, a transmission region, and an output region; the input and output regions are free space; the transmission region consists of a three-layer "sandwich" structure, which is formed by two layers of non-magnetic ENZ dielectric wrapped around a thin dielectric plate. This invention analyzes the effect of the amount of dielectric dopant on the electromagnetic resonant bandwidth of the doped ENZ dielectric when the above structure is equivalent to a lossy EMNZ material. The analysis shows that with the increase of the amount of dopant, the resonant bandwidth of the entire structure is significantly broadened, thereby extending the perfect absorption bandwidth of the above structure. Simultaneously, by using a multilayer Ag / silicon carbide nanofilm structure filled with dopant at a wavelength of 430 nm, an optically perfect absorber based on a lossy EMNZ dielectric with an extended operating bandwidth is designed.

The invention provides a cut-resistant and stab-resistant fabric and a preparation method thereof. The cut-resistant and stab-resistant fabric comprises an outer layer, an interface enhancement layer, a middle layer and an inner layer which are sequentially arranged from outside to inside, the middle layer is prepared from the following raw materials in parts by weight: 20 to 30 parts of EVA (Ethylene-Vinyl Acetate), 15 to 25 parts of TPU (Thermoplastic Polyurethane), 8 to 15 parts of EPDM (Ethylene-Propylene-Diene Monomer), 5 to 12 parts of TPO (Thermoplastic Polyolefin), 6 to 12 parts of ceramic microbeads, 1 to 4 parts of multiwalled carbon nanotubes, 0.3 to 0.8 part of antioxidant, 0.2 to 0.6 part of ultraviolet light absorber and 7 to 14 parts of nano silicon nitride-ethylene propylene diene monomer composite reinforcement. Oxidation and aging of the material can be effectively delayed, and the service life of the middle layer and even the whole fabric is prolonged.

The invention discloses an early warning system for damage of materials in a high-temperature furnace or a graphitization furnace. The early warning system is suitable for the high-temperature furnace provided with an opposite-penetrating type graphite heater and a multi-layer carbonaceous heat preservation layer. According to the system, the center temperature of a hearth is obtained through an optical pyrometer arranged outside a furnace body, temperature sensors are arranged in heat preservation layers with different thicknesses to obtain the temperature of each heat preservation layer, current transformers or Rogowski current loops are arranged at the head and the tail of a graphite heater, and a low-voltage alternating-current voltmeter is connected to a heating loop; collecting the temperature in the furnace, the temperature of each insulating layer and the current, voltage and power data of a heater; the method comprises the following steps: establishing a heat preservation characteristic reference curve corresponding to furnace temperature and different heat preservation thicknesses in the initial heating stage of equipment, comparing real-time data with the reference curve in the operation process, distinguishing abnormal short circuit and normal aging of a heat preservation material by combining head and tail current distribution and resistance change of a graphite heater, and evaluating equivalent loss of a graphite piece. The system records multi-dimensional data for a long time through the PLC and the upper computer, predicts the residual life of the thermal insulation material and the heater, and realizes online diagnosis and early warning of the state of the material in the furnace.

The application discloses a preparation method and application of a multilayer carbon sphere material. Hollow carbon spheres are obtained by a hard template method, silica is used as a core, and phenolic resin (RF) is used as a shell. The multilayer hollow carbon spheres can be obtained by repeatedly and alternately wrapping the silica and the phenolic resin and then carbonizing and removing the core. By adjusting the particle size of the silica, multilayer carbon spheres with different particle sizes can be obtained. By adjusting the number of layers covered by the phenolic resin, the number of layers of the multilayer hollow carbon spheres can be adjusted. The hollow structure of the hollow carbon spheres reflects and scatters electromagnetic waves, and the interface polarization between the multilayer shells makes the multilayer hollow carbon spheres have excellent absorption effect on electromagnetic waves. The application provides a new preparation method for the multilayer hollow carbon spheres, successfully prepares single-layer, double-layer and three-layer carbon spheres with different particle sizes, the synthesis method is simple, raw material prices are low, and the obtained material has a wide application prospect in stealth technology.

The utility model belongs to the technical field of carbon brick production equipment, and particularly relates to a curing device for carbon brick production, which comprises a heating curing chamber and a moving trolley, the heating curing chamber is provided with a sealing door, an air heater is arranged above the heating curing chamber, the air heater is connected with a ventilation pipe, the ventilation pipe penetrates into the heating curing chamber and is connected with a heat conduction pipe, and the heat conduction pipe is connected with the moving trolley. A plurality of air outlets are formed in the heat conduction pipe; the moving trolley comprises a trolley body and a plurality of loading frames, the trolley body comprises a bottom plate and two stand columns, moving wheels are arranged below the bottom plate, the two stand columns are fixed to the bottom plate, a hand push rod is installed on the front sides of the two stand columns, a plurality of supporting rod sets are arranged on the rear sides of the two stand columns, and each supporting rod set comprises two horizontal supporting rods. Each loading frame is placed on the corresponding supporting rod set. According to the device, multiple layers of carbon bricks can be separately stored, the upper surfaces and the lower surfaces of the carbon bricks can make contact with enough hot air flow during curing and heating, heating is more sufficient and even, the curing effect is improved, and the quality of the carbon bricks is guaranteed.

The invention relates to the technical field of alloy pole plates, in particular to an aluminum-magnesium-silicon alloy pole plate with multiple layers of carbon-based coatings and a preparation method thereof.The aluminum-magnesium-silicon alloy pole plate with the multiple layers of carbon-based coatings comprises an aluminum-magnesium-silicon alloy base material layer, and the multiple layers of carbon-based coatings are connected to the surface of the aluminum-magnesium-silicon alloy base material layer; the multi-layer carbon-based coating comprises a CrN layer, a CrNC layer, a CrC layer and an amorphous carbon coating doped with metal atoms and nitrogen atoms which are sequentially arranged in a stacked mode, and the CrN layer is located on the side close to the aluminum-magnesium-silicon alloy base material layer. The bonding force between the multi-layer carbon-based coating and the Al-Mg-Si alloy base material layer of the aluminum-magnesium-silicon alloy pole plate with the multi-layer carbon-based coating is relatively strong, and the aluminum-magnesium-silicon alloy pole plate with the multi-layer carbon-based coating has relatively good conductivity and corrosion resistance, so that the problem that the bonding force, the corrosion resistance and the interface conductivity between the existing coating and the Al-Mg-Si alloy pole plate are difficult to improve at the same time is solved.

A carbon composite channel (10) and method of manufacturing a carbon composite channel. The method entails applying layers of carbon fiber alternatingly in a circumferential and an axial direction, applying liquid carbon, a liquid carbon-containing solution, or a liquid pre-cursor for glassy carbon to one or more layers of carbon fiber before applying the next layer of carbon fiber, and subsequently curing the pre-cursor by exposure to a heat treatment at a temperature below 1200° C.

The application discloses a preparation method of a high-strength flexible self-supporting hydrophobic electromagnetic shielding film, which comprises the following steps: weighing a certain amount of carbon titanium-aluminum, slowly adding the carbon titanium-aluminum into a lithium fluoride / hydrochloric acid etching solution, magnetically stirring in a water bath at a certain temperature for a period of time, obtaining an etched carbon titanium-aluminum dispersion liquid, carrying out acid pickling on the carbon titanium-aluminum dispersion liquid by using dilute hydrochloric acid, and then washing the carbon titanium-aluminum dispersion liquid until neutral, so as to obtain multi-layer titanium carbide; carrying out ultrasonic treatment on the multi-layer titanium carbide, so as to obtain few-layer titanium carbide; mixing the prepared few-layer titanium carbide and bacterial cellulose with nano-iron oxide respectively; alternately performing vacuum filtration on the mixed solutions of bacterial cellulose / nano-iron oxide and few-layer titanium carbide / nano-iron oxide; and naturally airing the obtained film at room temperature. Finally, methyltrimethoxysilane is deposited on the surface of the film to form a hydrophobic network. The film prepared by the method has the characteristics of good flexibility, high electromagnetic shielding performance and high mechanical strength.

Layered carbon brush (20) for an electric motor (100) with at least one first carbon brush part (10) and a second carbon brush part (19), which are electrically insulated from each other by means of an intermediate non-conductive connecting layer (18) for the mechanical connection of the carbon brush parts (10, 19), characterized in that each of the carbon brush parts has its own interface for connection to a connecting line for the electrical supply of current, and that the first carbon brush part (10) is made of a different material than the second carbon brush part (19).

The invention relates to a multilayer carbon fiber reinforced composite hydrogen storage cylinder and a manufacturing method thereof, and belongs to the technical field of hydrogen storage cylinders. The gas cylinder comprises an alloy bottle opening, a plastic lining layer, a rubber self-tightening layer, a carbon fiber woven layer and a carbon fiber winding layer which are sequentially arranged from inside to outside. The alloy bottle opening is manufactured through traditional machining. The plastic lining layer covers the surfaces of the alloy bottle opening and the inner container, is made of polytetrafluoroethylene or high-density polyethylene, and has excellent hydrogen corrosion resistance and gas barrier property; the rubber self-tightening layer covers the outside of the plastic lining layer, and the bottle opening area is properly thickened to enhance the structure; the carbon fiber woven layer is manufactured by adopting a dry three-dimensional weaving process, and is impregnated and cured by resin after being woven; and the carbon fiber winding layer covers the braid layer by adopting a wet winding process and is used as a main bearing layer. Through structural design and process optimization of the multi-layer composite material, the advantages of light weight, high strength, high corrosion resistance, fatigue resistance and the like of the gas cylinder are realized.

This application discloses an anti-collision structure and its preparation method. The anti-collision structure includes an inner support, a buffer layer, and a paint layer. The buffer layer is disposed on the outer surface of the inner support, and the paint layer is disposed on the outer surface of the buffer layer. The buffer layer contains a mesh and multiple layers of carbon fiber balls. This application can improve the buffering capacity of the anti-collision structure and increase its service life.

Provided is a nonaqueous electrolyte secondary battery having high capacity, high output, and good fast charge cycle characteristics. In this nonaqueous electrolyte secondary battery, the positive electrode mixture layer contains a positive electrode active material, single-layer carbon nanotubes, and multi-layer carbon nanotubes, the negative electrode mixture layer contains a silicon-containing material, and the tortuosity of the negative electrode mixture layer during discharge is 2.5 or less. The porosity Vc of the positive electrode mixture layer during discharge and the porosity Va of the negative electrode mixture layer during discharge satisfy the relationship Va-Vc < 13%, and Va is 30% or more.

This invention discloses a surface-modified high-pressure SiO2 x The preparation method of this invention includes the following steps: preparation of a carbon layer precursor by controlling the reaction time to prepare spherical carbon layer precursors of different sizes; thorough mixing of the carbon layer precursor with a silicon source and aging of the mixed solution; filtration and washing of the reaction solution followed by drying in a vacuum drying oven, and then sintering under an inert atmosphere to obtain multilayer carbon-coated SiO2. x Materials; SiO2 prepared by the technical solution of this invention x The material has a higher compaction density, thus reducing matrix pulverization. Meanwhile, the SiO₂ prepared by this invention... x The number of carbon shell layers in the material can be controlled, suppressing volume changes during charging and discharging.