1718 results about "Pore diameter" patented technology

One aspect is a method for producing a first intermediate product. A feedstock is provided that comprises a first polyester. The first polyester is contacted with a further organic compound in a volume section V3 to obtain a further initial mixture. A weight average molar mass of the first polyester is reduced in the volume section V3 to obtain a first intermediate mixture. The first intermediate mixture comprises a first intermediate product and the further organic compound. First particulated material is added to the first intermediate mixture in a volume section V4. A filtering means is pre-coated with the first particulated material. At least one impurity is at least partially removed from the first intermediate mixture using the filtering means. The first particulated material has a median pore diameter in the range of 5 mm to 20 mm.

A silicon-carbon material, a preparation method therefor, a secondary battery, and an electric device. The silicon-carbon material comprises silicon-carbon composite particles; the silicon-carbon composite particles comprise a porous carbon material, nano-silicon grains and a silicon carbide material layer; the porous carbon material is provided with through pores, the nano-silicon grains are located in the through pores, and the silicon carbide material layer is partially located on through pore walls; the grain size of the nano-silicon grains is not smaller than the average pore diameter of the porous carbon material. The silicon-carbon material is used as an active material of a negative electrode sheet, thereby improving the cycle performance of batteries.

The invention discloses a charcoal nano lanthanum material capable of synchronously removing organic phosphorus and inorganic phosphorus, and belongs to the field of environmental functional materials. The adsorbent comprises biochar and nano lanthanum loaded on the biochar, wherein the biochar is bamboo biochar; the nano lanthanum is in a La (OH) 3 form, the particle size of the nano lanthanum is 1-250nm, and the loading capacity of the nano lanthanum is 3-20wt%; the pore diameter of the biochar nano lanthanum material is 1-30nm, and the specific surface area is 100-250m < 2 > / g. Compared with a biochar-loaded nano lanthanum composite material in the prior art, the composite material has the inorganic phosphorus adsorption performance and also has the organic phosphorus adsorption effect, and inorganic phosphorus and organic phosphorus can be synchronously removed. According to the charcoal nano lanthanum material, organic phosphorus is adsorbed and removed by regulating and controlling the defect form of lanthanum, especially organic phosphonate can be hydrolyzed and removed, meanwhile, large pore channels of bamboo charcoal are beneficial to diffusion of macromolecular organic phosphorus to action sites of lanthanum, and the adsorption and hydrolysis effects of lanthanum on the organic phosphorus are further enhanced.

The present application discloses a composite separator, a preparation method therefor and a use thereof. The composite separator comprises a polyolefin separator, an adhesive layer coated on one or both sides of the polyolefin separator, and a cellulose film covering the surface of the adhesive layer, wherein the pore diameter of the cellulose film is greater than that of the polyolefin separator. According to the composite separator, the strength and thermal stability of a traditional separator can be improved, and the requirements of liquid absorption and retention are met, so that the performance and the cycle life of an energy storage device are improved.

The invention discloses a microporous diaphragm for a low-electrical-impedance lithium battery and a preparation method of the microporous diaphragm. The diaphragm comprises: a base film layer, wherein the base film layer is of a microporous structure formed by biaxially stretching polypropylene and / or polyethylene; the surface of the base film layer is coated with the functional coating, and the functional coating contains mixed slurry of inorganic nanoparticles and a binder; the surface modification layer is formed by introducing a hydrophilic electrolyte group on the surface of the functional coating through plasma treatment or chemical grafting. The base membrane layer forms a uniform micropore structure through a two-way stretching process, the functional coating is formed by compounding nano silicon dioxide or aluminum oxide and polyvinylidene fluoride according to a specific proportion, a porous layer with gradient pore diameter is formed, the pore size of the porous layer is smaller than that of the base membrane layer, and efficient permeation of electrolyte is ensured. Electrolyte-philic groups such as sulfonic groups are introduced into the surface modification layer, so that the wettability of the diaphragm to an electrolyte is remarkably improved. During preparation, the base membrane is formed through melt blending, two-way stretching and pore-forming agent extraction, and then the functional layer is constructed through slurry coating and a low-temperature plasma treatment or sulfonation process. The diaphragm combines gradient aperture design, inorganic filler enhancement and surface chemical modification, and realizes low impedance, high thermal stability and excellent mechanical strength.

The invention belongs to the technical field of sound-absorbing materials, and particularly relates to a composite sound-absorbing material as well as a preparation method and application thereof. The composite sound-absorbing material comprises a foaming base material and sound-absorbing particles, the sound-absorbing particles are dispersed in the foaming base material; the foaming base material is a polyurethane material; the sound-absorbing particles comprise at least one of a metal organic framework compound, activated carbon, aerogel, carbon nanotubes and graphene. The sound-absorbing particles are dispersed in the foaming base material, so that obvious concave-convex structures are formed around foam holes of the sound-absorbing material, and the sound wave transmission resistance can be increased. Besides, the sound-absorbing particles with specific types, specific surface areas and pore diameters and porous structures are adopted, the number of internal pore channels is large, multi-angle collision of airflow in the pore channels can be enhanced, and the composite sound-absorbing material has a good sound-absorbing effect at low and medium frequencies.

The present invention belongs to the technical field of porous materials. Disclosed are a fiber porous carbon material, a porous graphite, and a preparation method therefor and the use thereof. The preparation method for the fiber porous carbon material comprises: subjecting a mixture of carbon fibers and a carbonizable and graphitizable organic precursor substance to cold pressing, controlling the density after cold pressing to be 0.7-1.0 g / cm3 or controlling the pressure intensity of cold pressing forming to be 2-80 MPa, and sequentially carrying out carbonization and graphitization after forming, wherein the average length of the carbon fibers is 50-350 μm. The porous material prepared by means of the method has relatively high air permeability, also has a relatively small pore diameter, a relatively uniform pore diameter distribution, a relatively high bending strength and a relatively low heat conductivity coefficient, and can improve the growth quality of silicon carbide crystals when being applied to the growth of the silicon carbide crystals.

The invention provides a collagen freeze-dried product and a preparation method thereof, and belongs to the technical field of biology. In the formula design, through the synergistic effect of the arginine (salt) and the surfactant, denaturation and aggregation of the collagen freeze-dried product in the production process and the storage period are inhibited, the stability of the product is improved, and the prepared collagen freeze-dried product is high in activity, purity and safety. In the freeze-drying process, pre-freezing parameters are optimized, and the nucleation effect of ice crystals in the freezing process of the collagen mixed solution is controlled by regulating and controlling parameters such as temperature and vacuum degree in the freeze-drying process, so that the shapes and the sizes of the crystals in the collagen freeze-dried product are more uniform, the drying time is shortened, and the production efficiency is improved. And the collagen freeze-dried product with uniform pore diameter and excellent appearance is obtained, and the uniformity and stability of batch and inter-batch products are improved.

The invention belongs to the technical field of biomedical engineering, and particularly relates to a single-base resolution laminated two-dimensional material nanopore structure, a DNA sequencing device and a DNA sequencing method. The two-dimensional material nanopore structure comprises an insulating layer and conducting layers arranged on the upper side and the lower side of the insulating layer, through nanopores are formed in the insulating layer and the conducting layers, and the pore diameter of the nanopores is 2-5 nm; the insulating layer and the conductive layer are made of two-dimensional materials. The conductive layers on the two sides serve as upper and lower electrodes, and a power supply is connected between the upper and lower electrodes to form a phase conductive path which is provided with a longitudinal current detection element. A plurality of groups of two-dimensional material nanopore structures are stacked, and meanwhile, a plurality of groups of base pair signals are obtained. According to the invention, the advantages of small thickness, high physical strength and the like of the two-dimensional material nanopore are kept by using a few layers of two-dimensional material films, the vibration of the films is reduced by increasing the number of layers and improving the mechanical strength, so that the signal-to-noise ratio is improved, and the spatial resolution of the nanopore sensor is improved by designing the upper electrode and the lower electrode.

The invention discloses a composite separation membrane for enriching < 6 > Li isotope and application. The composite separation membrane comprises a functional membrane and at least one supporting membrane; the functional film comprises a plurality of pore channels penetrating through the first surface and the second surface of the functional film, and the pore channel diameter of each pore channel is 0.4-0.7 nm; a lithium ion trapping functional group or a macrocyclic compound and a derivative thereof are modified at an inlet of the first surface of the pore channel. The strength of the lithium isotope separation effect depends on the diameter of a pore channel of the composite separation membrane and functional groups modified at an inlet, does not change along with the migration time and the lithium ion migration proportion, and has long-term continuous stability.

The invention relates to the technical field of batteries, in particular to a porous composite diaphragm, a preparation method thereof and a secondary battery. The porous composite diaphragm comprises a base membrane, a first coating and a second coating, the first coating and the second coating are oppositely arranged on the two surfaces of the base film; the first coating layer and the second coating layer comprise a copolymer containing a first monomer unit and a second monomer unit; the first monomer unit contains a cyano group on a side chain, and the second monomer unit contains a carbonyl group on a side chain; in the copolymer, the molar ratio of the second monomer unit is 1-20%; the first coating and the second coating comprise skeleton structures and first-class pore structures formed between the skeleton structures, and second-class pore structures are formed on bodies of the skeleton structures; and the average pore diameter of the first-type pore structure is greater than that of the second-type pore structure. According to the porous composite diaphragm, the lithium ion conductivity can be improved while the bonding performance with a pole piece is improved.

The present invention relates to the field of battery materials, and provides a lithium manganate cathode material coated with lithium triborate and a preparation method thereof. The cathode material is a porous lithium manganate / lithium triborate composite electrode material, which includes porous lithium manganate with a highly connected directional columnar pore structure and a lithium triborate coating covering the pore surface, with a mass ratio of (86.0~92.0):(8.0~14.0), a coating thickness of 600~800 nm, a pore diameter of 45~95 μm, and a porosity of 65~78%. The preparation method includes: preparing a precursor colloidal solution by the sol-gel method, obtaining porous lithium manganate through low-temperature freezing molding and freeze-drying, and forming a cathode substrate through pre-oxidation and high-temperature sintering; subsequently, using vacuum-assisted impregnation, ultrasound, and nitrogen pressure to promote the penetration of the lithium triborate precursor solution, and forming a uniform coating layer through gradient drying and annealing treatment. The present invention significantly improves the crystal structure stability of the cathode material, inhibits manganese dissolution, improves the cycle life and rate performance, and has wide application value.

The invention relates to the technical field of electrochemical energy storage devices, in particular to a silicon-carbon negative electrode material, a negative electrode plate, an electrochemical device and an electronic device, and mainly comprises a core material and a coating material, the core material comprises silicon particles, the coating material comprises a porous carbon material doped with indium particles, and the coating material comprises a porous carbon material doped with indium particles. The average pore size of the coating material ranges from 10 nm to 20 nm, and the porosity of the coating material ranges from 35% to 45%. According to the silicon-carbon negative electrode material provided by the invention, the coating material has the effects of buffering and inhibiting silicon volume expansion, so that pulverization of the silicon-carbon negative electrode material is inhibited, and the problem of volume expansion of a battery is solved.

The invention discloses a high-air-permeability humidity display film based on optical interference and a preparation process of the high-air-permeability humidity display film. Comprising a substrate layer, a humidity response layer, a middle layer and a hydrophobic layer, wherein the substrate layer is made of a transparent material; a plurality of breathable micropores are formed in the substrate layer; the humidity response layer is a thin film layer which is made of a humidity sensitive material and has the thickness of 50-100 [mu] m, micropores are formed in the humidity response layer, and the pore diameter of the micropores is 0.5-2 [mu] m; the middle layer is a nanofiber membrane, and the fiber diameter of nanofiber is controlled to be 100-300 nm; the density of the middle layers in the length direction is in gradient change so as to control the air permeability of the humidity response layers corresponding to the middle layers with different densities; the hydrophobic layer is made of a transparent and breathable material and provides a good protection effect for the humidity display film. According to the invention, the hydrophilic microporous structure material is adopted, the humidity can be rapidly conducted to the humidity response layer through the multilayer design, instant color change is generated, and the humidity indication effect is more sensitive.

The present invention relates to the technical field of gas treatment, and particularly relates to a multi-stage adsorption recovery method for organic gases by means of biological nano composite activated carbon. The method comprises the following steps: preparing an activated carbon composite, i.e. nFeOOH@AC, of nano-hydroxyl iron modified corn husk and bamboo shoot skin by using an ethanol dispersion method, which composite can be used for the adsorption of organic gases; and introducing a mixed gas containing a target organic matter into a system comprising at least two biological nano composite activated carbon adsorbers, which are connected in series, at a preset flow rate Q (m3 / h), wherein each adsorber is filled with the biological nano composite activated carbon with a density ρ (kg / m3), the specific surface area thereof is S (m2 / g), and the average pore diameter is d (nm), thereby achieving multi-stage adsorption. The beneficial effects comprise: utilizing the high specific surface area and excellent adsorption performance of the biological nano composite activated carbon, and combining the multi-stage adsorption system, such that efficient recovery of organic gases can be achieved, thereby significantly improving the recovery efficiency. Compared with a traditional treatment method, this method is low in energy consumption, extra fuel is not needed, and the adsorption material can be recycled, thereby reducing resource consumption and waste generation, and conforming to the environmentally friendly development concept.

The invention discloses a polytetrafluoroethylene ceramic membrane and a preparation method and application thereof, and the preparation method comprises the following steps: (1) adding polytetrafluoroethylene and a binder into water, and carrying out first mixing to obtain polytetrafluoroethylene slurry; adding a carbon nanotube and a dispersing agent into water, and carrying out secondary mixing, so as to obtain a carbon nanotube dispersion liquid; (2) carrying out third mixing on the carbon nanotube dispersion liquid and the polytetrafluoroethylene slurry to obtain a membrane preparation liquid; and (3) coating the surface of a ceramic support with the membrane preparation liquid, drying, and carrying out microwave sintering. The PTFE / ceramic composite membrane is prepared by microwave sintering, so that the sintering time and the production period are obviously shortened, and the production efficiency and the energy utilization rate of the product are obviously improved; the prepared PTFE / ceramic composite membrane is narrow in pore diameter and uniform in pore diameter distribution, has good hydrophobicity and oil-water separation performance, can effectively intercept 30-200nm nanoparticles, and has excellent anti-pollution capacity and stable separation performance for water-in-oil emulsions with different concentrations.

A negative electrode material, a negative electrode sheet and a battery. The negative electrode material comprises a carbon matrix and an active substance, wherein the carbon matrix is provided with pores, and the active substance is at least partially distributed in the pores. The area proportion of the pores having a pore diameter larger than 50 nm in any section of the negative electrode material is α, which satisfies: α≤10%, wherein α is obtained by means of the following test method: in an image as shown by the SEM section treatment of a single negative electrode material particle, any a×b region is selected, where a=1-10 μm and b=1-10 μm, the sum of the sectional areas of pores having a pore diameter larger than 50 nm in the region of the section of the single negative electrode material particle is denoted as S0, the sectional area of the single negative electrode material particle in the region is denoted as S, the area proportion of the pores having a pore diameter larger than 50 nm in the section of the single negative electrode material particle is defined as α', where α'=S0 / S, and α is the arithmetic mean value of α' values of at least 10 negative electrode material particles.

The invention discloses a self-adaptive floating type aeration device for natural water aeration, and particularly relates to the technical field of water quality treatment.The water to be aerated firstly enters from an outer filter screen and then enters a supporting seat through four inner filter screens, and due to the fact that the pore diameter of the inner filter screens is smaller than that of the outer filter screen, the filtering grade is higher, and the aeration effect is better. Meanwhile, the submersible electric pump synchronously drives the eccentric wheel to rotate, that is, when the eccentric wheel rotates by a circle, the eccentric wheel is in contact with the adjacent sliding plates in sequence, the sliding plates directionally slide along the inner cavity of the supporting seat at the moment, and the folding part is in an extended (opened) state at the moment; the sliding plate drives the ejector pins on the outer sides of the vertical rods to face the outer filter screen, impurities attached to the outer filter screen are pushed out through the ejector pins, the overall collaboration with the secondary sewage interception assembly is higher, the water inlet effect affected by the impurities is avoided, the enough water inlet amount is guaranteed, and the aeration efficiency of the device is improved.

The invention belongs to the crossing field of biomedical engineering and additive manufacturing, and particularly relates to a 3D printing metamaterial piezoelectric bone defect repair scaffold, and the pore structure of the scaffold is formed by compounding three extremely small curved surface units, namely Gyandroid, SchwarzP and Diamond, which are defined by mathematical expressions; the porosity of the stent is 30%-70%, and the pore diameter range is 0.1-1 mm; the stent is made of a piezoelectric composite material composed of polyvinylidene fluoride (PVDF), polylactic acid and barium titanate, the piezoelectric composite material comprises the following components in percentage by mass: 30%-55% of polyvinylidene fluoride (PVDF), 20%-45% of polylactic acid (PLA) and 10%-25% of barium titanate (BaTiO3), and the sum of the mass percentages of all the components is 100%. Precise regulation and control of a macrostructure and a microstructure are achieved through a multi-material 3D printing technology, and the system has the mechanical adaptability, degradation controllability and the function of actively promoting bone regeneration and is suitable for large-section bone defect repair scenes such as craniomaxillofacial and long bones of four limbs.

The invention relates to the technical field of metal materials, and discloses a composite metal material based on micro-nano porous copper powder, which is composed of the following components: a matrix is micro-nano porous copper powder with the particle size of 50-500 nanometers, the porosity is 30-80%, and the pore diameter is 20-200 nanometers; the metal additive comprises 5-20 wt% of aluminum powder and 3-15 wt% of nickel powder; the functional additive comprises 1 to 8 weight percent of titanium powder, 0.5 to 5 weight percent of graphene and 0.3 to 3 weight percent of a carbon nano tube; a nickel-titanium alloy coating with the thickness of 50-500 nanometers is formed on the surface of the micro-nano porous copper powder through electrochemical deposition. Through the graded hole design of the micro-nano porous copper powder, a main hole channel provides a rapid electron transmission path, the powder gap stress is eliminated in the low-temperature pre-pressing stage, and atom diffusion and densification are promoted in the high-temperature and high-pressure stage, so that the resistance can be effectively reduced, the loss of energy in the transmission process is reduced, and the energy transmission efficiency of the whole system is improved.

The invention discloses a silicon-carbon negative electrode material, a preparation method thereof and a battery, and belongs to the technical field of negative electrode materials. The compaction density of the silicon-carbon negative electrode material is greater than or equal to 1.1 g / cm < 3 >, and the NLDFT total pore volume is less than or equal to 0.005 cm < 3 > / g; and in the NLDFT total pore volume of the silicon-carbon negative electrode material, the pore volume not exceeding 10% is provided by pores with the pore diameter not less than 50nm. The silicon-carbon negative electrode material has relatively high compaction density and first efficiency, and is beneficial to improving the volume energy density of the battery. The preparation method comprises the following steps: carrying out silicon deposition on a porous carbon raw material, carrying out high-pressure impregnation on a precursor obtained after primary carbon deposition by using an organic carbon source, and then carrying out secondary carbon deposition. The method is simple to operate, the silicon-carbon negative electrode material with relatively high compaction density can be prepared, and the prepared silicon-carbon negative electrode material can be further used for preparing a battery, so that the volume energy density of the battery is improved.

The invention discloses a battery packaging shell, a preparation method thereof and a secondary battery. The battery packaging shell comprises a protective layer, a barrier layer, an aerogel nano coating and a heat sealing layer which are sequentially stacked from outside to inside, the aperture of the aerogel nano-coating is smaller than the particle size of air molecules, the aperture of the aerogel nano-coating is M, the porosity of the aerogel nano-coating is N, the proportion of the coating area of the aerogel nano-coating to the forward projection area of the barrier layer is S, and the average thickness of the aerogel nano-coating is H; wherein M, N, S and H meet the relation that MS / NH is larger than or equal to 0.33 and smaller than or equal to 0.83. According to the method, the pore diameter, the porosity coating ratio and the coating thickness parameter of the aerogel nano coating are set to meet the specific relational expression, so that the thermal stability of the battery is improved, and the comprehensive performance is guaranteed while the cycle is not deteriorated.

The invention provides a carbon material, application of the carbon material, a silicon-carbon composite material, a negative electrode and a battery, and particularly relates to the technical field of carbon materials and secondary batteries. The carbon material has the characteristics of a porous structure and graphitization at the same time, and has the following characteristics: i) the N2 adsorption pore volume is 0.4-2.0 cm < 3 > / g; ii) the N2 adsorption average pore size is 1.8 to 5.0 nm; and (iii) partial graphitization is carried out, disordered carbon and graphitized carbon are compounded, a diffraction peak P exists between 2theta = 25-30 degrees in an XRD (X-Ray Diffraction) pattern, and the grain size of P calculated according to a Scherrer formula is 2-40 nm. The invention also provides a silicon-carbon composite material, the silicon-carbon composite material comprises a porous carbon material and silicon nanoparticles, the porous carbon material comprises the carbon material provided by the invention, and the silicon nanoparticles are located in pore channels of the porous carbon material. The silicon-carbon composite material provided by the invention has the advantages of high capacity, high first efficiency and high cycle stability when being applied to the lithium ion secondary battery.

The invention discloses porous activated carbon prepared from a balsa wood material and a preparation method and application of the porous activated carbon, the pore diameter of the porous activated carbon ranges from 0.4 nm to 400 nm, the pore volume ratio of micropores with the pore diameter being 0.4 nm to 2 nm, mesopores with the pore diameter being 2 nm to 50 nm and macropores with the pore diameter being 50 nm to 400 nm is larger than 30%, and the specific surface area of the porous activated carbon is 500 m / g to 700 m / g; the carbon tetrachloride adsorption rate is 130%-145%, and the adsorbent has excellent adsorption performance.

The invention provides a cross-adsorption-temperature industrial organic waste gas adsorbent type selection method and application, two or more model adsorption materials with concentrated pore size distribution are used, and filling type adsorption with high pore volume utilization rate can be formed in pores with a specific size or below due to adsorption of volatile organic compounds (VOCs) on a porous material; and a matching relation equation between the filling type adsorption critical aperture and the adsorption partial pressure and a rule of changing along with the adsorption temperature are explored. According to the method, the partial pressure is normalized relative to the saturated vapor pressure at the respective adsorption temperature, and the parameter saturated vapor pressure related to the adsorption temperature is introduced into an equation as a variable, so that an equation of critical pore diameters suitable for adsorption of VOCs at different temperatures and concentrations is established; and a cross-adsorption-temperature industrial organic waste gas adsorbent type selection method is formed. The method provided by the invention can provide a quantitative reference basis for development of VOCs efficient adsorption materials and technologies suitable for different adsorption temperatures.

The invention provides inter-plant mycorrhiza nutrient transfer culture equipment which comprises a culture box body and an organic glass plate, an inner cavity of the culture box body is divided into a first culture chamber and a second culture chamber through the organic glass plate, the organic glass plate is a porous glass plate, and a white nylon net is pasted on one side of the porous glass plate. And the white nylon net is divided into a white nylon net with the aperture of 0.45 mu m and a white nylon net with the aperture of 37 mu m. The equipment is small in size, small in occupied area, cheap in material, convenient to assemble and suitable for pot culture experiments of large-batch samples, soil ions are allowed to pass through by means of 0.45 microns, ectogenic hyphae and the soil ions are allowed to pass through by means of a white nylon net of 37 microns, the soil ions, the ectogenic hyphae and root systems are allowed to pass through a nylon-free net, and the soil ions, the ectogenic hyphae and the root systems are allowed to pass through. Compared with the prior art, direct and indirect paths of nutrient transfer between plants can be distinguished and quantified, and the method is simple and easy to implement.

The invention relates to the technical field of hygienic product manufacturing, and discloses a sanitary napkin core body based on a nano material, functional particles are accurately positioned through flow field directional regulation and control of fiber three-dimensional orientation distribution, pulsed electric field activation free radical gradient polymerization and supercritical CO2 deposition, a surface micropore compact water locking layer with the aperture of 5-20 microns is constructed, and an inner macropore flow guide layer is formed. The pore diameter is 80-150 microns, and a cross-scale synergistic structure is formed. Self-reconstruction of the fiber is excited by sudden change of the flow field rotating speed, and mutual exclusion limitation of the absorption rate and the liquid retention amount of a traditional homogeneous structure is broken through in combination with diffusion kinetics of a terahertz wave resonance reinforced cross-linking agent; a C-O-Ag chemical anchoring point is established by a plasma bonding technology, and the nano-silver particles are physically confined by a graphene oxide sheet layer, so that the problems of particle agglomeration and ion burst release in a traditional spraying process are solved. The dynamic multi-field synergistic process realizes porosity gradient, oriented arrangement of molecular chains and long-acting residence of functional particles, and provides a core solution with high absorptivity, zero reverse osmosis and long-acting bacteriostasis for hygienic products.

The invention discloses a positive plate with gradient pores, a preparation method of the positive plate, a lithium ion battery and an electric device. The positive plate comprises a plurality of coatings which are symmetrically coated on the two sides of a positive current collector, the porosity in the plurality of coatings is increased layer by layer from the coating close to the side of the current collector, and the average pore size of pores is increased layer by layer. The preparation method comprises the following steps: adding a self-sacrifice pore-forming agent into positive electrode slurry, uniformly mixing, coating a carbon-coated aluminum foil with the slurry, drying and rolling, enabling the self-sacrifice pore-forming agent to occupy a certain space, heating a positive electrode plate at a certain temperature, enabling the self-sacrifice pore-forming agent in the positive electrode plate to be decomposed into CO2 and H2O, forming corresponding pores, and forming the positive electrode plate with the pores. According to the invention, gradient gaps are designed on the electrode plate by utilizing the self-sacrifice pore-forming agent, so that the concentration polarization of the thick electrode is relieved, the reaction uniformity and the material utilization rate are improved, the ion transmission performance of the thick electrode is effectively improved, and the dynamic performance of the battery is further greatly improved.

The invention relates to the technical field of pearl wool composite materials, in particular to a pearl wool composite material based on an ethylene polymer and application of the pearl wool composite material in building heat preservation, the pearl wool composite material comprises the ethylene polymer, pearl wool particles and nano aerogel, the ethylene polymer is a mixture of linear low density polyethylene and metallocene polyethylene in a specific proportion, the pearl wool particles are treated by the silane coupling agent, the particle size is 0.5-2 mm, the porosity of the nano aerogel exceeds 90%, the average pore size is 2-20 nm, the components are proportioned according to specific parts by weight, the performance of the composite material is improved through the synergistic effect, and the composite material can be used in the field of building heat preservation. The composite material disclosed by the invention has the advantages of excellent thermal insulation performance, capability of effectively reducing building energy consumption, good mechanical property, high deformation resistance, long service life, good flame retardant property, capability of guaranteeing building safety, simple preparation process, low cost, wide application, capability of being used for multiple parts of a building, convenience in construction and high comprehensive benefit.

The invention relates to the technical field of porous carbon materials, and discloses a preparation method of phenolic resin-based porous carbon based on synergistic activation of water vapor and carbon dioxide. The key point of the method is to construct a multi-dimensional process of'ZIF-8 (at) Ni-MOF derived bifunctional material pore forming-nitrogen / nickel co-doping + dynamic pressure-double-gas synergistic etching + Ti < 3 > C < 2 > T < x > MXene gradient modification '. The MOF derivative material provides regular initial pore channels and active sites, and precise customization of the pore diameter of 0.7-50 nm is realized by combining dual-gas characteristic complementation and dynamic pressure regulation and control; and MXene modification synchronously improves the conductivity and the interface bonding force. The micropore rate is greater than or equal to 88%, the specific surface area is greater than or equal to 2200m < 2 > / g, the total pore volume is greater than or equal to 1.3 cm < 3 > / g, and the process is free of chemical waste liquid pollution. When the material is applied to a lithium battery silicon-carbon negative electrode, the capacity retention rate after 500 cycles is greater than or equal to 85%, and the industrialization value is high.