187results about How to "High tap density" patented technology

The invention provides a preparation method of an isotropic Ti2AlNb / TiAl-based interpenetrating composite material, and belongs to the technical field of intermetallic compound-based composite materials. The method comprises the following steps: firstly, designing a Ti2AlNb reinforcement framework of various TPMS configurations by utilizing implicit function modeling; then, carrying out anisotropy research on the TPMS configuration by utilizing finite element simulation; secondly, a Ti2AlNb reinforcement framework of a TPMS configuration is prepared through a selective laser melting (SLM) technology; and finally, the TPMS configuration Ti2AlNb / TiAl-based interpenetrating composite material is prepared through vacuum hot pressing sintering of HPS. Therefore, strong anisotropy of a traditional fiber reinforced composite material in mechanical property is avoided, good matching of strength, plasticity and toughness of the composite material is achieved, and a new thought and a new solution are provided for breaking through the application bottleneck of TiAl in spaceflight power system hot end components.

The invention belongs to but not limited to the technical field of electrode materials, and particularly relates to a high-tap-density lithium nickel manganese oxide positive electrode material, a preparation method and a lithium ion battery, the chemical general formula of the high-tap-density lithium nickel manganese oxide positive electrode material is LiNi < 0.5-x > Mn < 1.5-y > M < x > N < y > O < 4 >, 0.1, 0 < = y < lt >; 0.1, M and N are doping elements and comprise one or more of Mg, Co, Al, Zr, W, Sb, Ta and Ti; the material is micron-sized spherical secondary particles formed by stacking and aggregating nano-sized octahedral primary particles, and is uniformly dispersed without agglomeration; the spherical secondary particles are formed by mixing spherical secondary particles with large and small particle size distribution, and the average particle size range of the large particles is 3lt; d < 50lt >; the average particle size range of the small particles is 1lt; d < 50lt >; 2 [mu] m.

The invention belongs to the technical field of new energy materials, and particularly relates to a low-sulfur metal cation doped ammonium manganese ferric phosphate precursor, carbon-coated modified sodium manganese ferric pyrophosphate and a preparation method and application thereof. According to the invention, the low-sulfur metal cation doped ammonium manganese ferric phosphate precursor is successfully prepared. A proper amount of phosphoric acid source is added into the prepared metal cation doped ammonium manganese ferric phosphate precursor for treatment, so that the sulfur content of the precursor is remarkably reduced, and the molar ratio of manganese, iron, doped elements and phosphorus elements is regulated and controlled to be slightly smaller than 1. The atomic-scale distribution of elements in the precursor is realized, the tap density is also improved, and the subsequent preparation of a high-performance carbon-coated modified manganese ferric sodium phosphate pyrophosphate material is facilitated. The sodium ion battery constructed based on the material has excellent charge-discharge capacity, capacity retention ratio and cycling stability. In addition, the preparation method of the precursor is simple and convenient to operate and easy to control, and has the advantage of wide application.

The invention belongs to the technical field of preparation of electrode materials, and particularly relates to a high-tap-density spherical ferric sodium pyrophosphate electrode material and a preparation method thereof. According to the preparation method, a uniform precursor is prepared by utilizing solution gel, and a strategy of combining spray drying with secondary sintering is adopted, so that uniform carbon coating and doping modification of ferric sodium pyrophosphate can be successfully realized, and the strategy provides an important experimental basis for an industrialization process of a sodium ion battery. And the method has great potential of large-scale preparation.

The invention discloses a nanometer silicon filled microcrystalline graphite negative electrode material and a preparation method and application thereof. The preparation method of the nano-silicon filled microcrystalline graphite negative electrode material comprises the following steps: by taking microcrystalline graphite as a base material, depositing silane between sheet layers of the microcrystalline graphite by adopting a gradient heating method to obtain a nano-silicon filled microcrystalline graphite composite material; and finally, forming the nano-silicon filled microcrystalline graphite negative electrode material with a porous structure on the surface of the nano-silicon filled microcrystalline graphite composite material through carbon source coating carbonization. According to the nano-silicon-filled microcrystalline graphite negative electrode material with the core-shell structure provided by the invention, an inner core is a silicon-graphite composite material formed by nano-silicon-filled microcrystalline graphite, nano-silicon particles are filled in the surfaces and gaps of crystalline grains of the microcrystalline graphite, volume expansion of the nano-silicon in the charging and discharging process is inhibited by a microcrystalline graphite matrix material, and particularly, the volume expansion of the nano-silicon in the charging and discharging process is inhibited by the microcrystalline graphite matrix material. And due to different structural orientations of the microcrystalline graphite, the stress effect can be counteracted, and the volume expansion of the material is further inhibited.

The invention belongs to the technical field of lithium ion battery positive electrode materials, and provides a high-specific-energy lithium manganese iron phosphate positive electrode material and a preparation method thereof.The preparation method comprises the following steps that 1, carbon nanotubes are added into deionized water to be subjected to ultrasonic dispersion, modified xanthan gum, ammonia water and hydrazine hydrate are added to be stirred, the mixture is heated to continue to be stirred, suction filtration and washing are conducted, and carbon nanotubes are obtained; drying to obtain a carbon source; step 2, adding the lithium hydroxide solution into the phosphoric acid solution, stirring and dispersing, adjusting the pH value, adding the manganese sulfate solution and the ferrous sulfate solution, and carrying out hydrothermal synthesis reaction to obtain a hydrothermal reaction product; step 3, centrifuging, washing and drying the hydrothermal reaction product, and mixing the dried product with a carbon source to obtain a mixture; step 4, carrying out ball milling on the mixture to obtain powder; and step 5, calcining the powder, and cooling to obtain the product. The obtained lithium manganese iron phosphate positive electrode material has the advantages of uniform thickness of a carbon coating layer, excellent electrochemical performance, stable cycle performance and the like.

The invention belongs to the technical field of lithium ion battery materials, and particularly relates to a ternary precursor material, a ternary positive electrode material and a preparation method and application of the ternary precursor material and the ternary positive electrode material. The ternary precursor material comprises a matrix and a coating layer on the surface of the matrix, the matrix is an active metal hydroxide, and the coating layer is an active metal oxalate. The preparation method of the ternary precursor material comprises the following steps: adding an oxalic acid solution into a dispersion liquid of an active metal hydroxide, and carrying out an in-situ coating reaction to obtain the ternary precursor material. The surface of the active metal hydroxide is coated with a layer of active metal oxalate in situ, after the active metal hydroxide is subsequently mixed with a lithium source, the oxalate on the surface of a precursor can be decomposed to generate gas in the sintering process to form pore structures, and the pore structures can increase pores among primary particles and inhibit the agglomeration of the primary particles; primary particles can be effectively dispersed in the crushing process, and the electrochemical performance of the single-crystal ternary positive electrode material is further improved.

The invention provides micron blocky and submicron spherical mixed silver powder and a preparation method thereof. The preparation method comprises the steps that firstly, a silver salt solution is prepared, a reducing agent, a dispersing agent and pure water are mixed to obtain a reducing agent solution, and nano-silver crystal suspension liquid and the dispersing agent are mixed to obtain a base solution; synchronously dropwise adding the silver salt solution and the reducing agent solution into the base solution to obtain a solution containing the mixed silver powder; and finally, the solution is subjected to washing, solid-liquid separation and drying and shaping treatment, and then the micron blocky and submicron spherical mixed silver powder is obtained. According to the preparation method, polyvinylpyrrolidone with low molecular weight is selected as a dispersing agent, and the adding process of the dispersing agent is controlled, so that nano-silver crystals and the dispersing agent play a synergistic role, the micron blocky and submicron spherical mixed silver powder with good dispersion uniformity and high tap density is obtained, and the mixed silver powder is better in stacking structure and high in conductivity after being formed into slurry; the preparation method provided by the invention simplifies the process steps, shortens the preparation time, and has industrial application prospects.

The invention belongs to the technical field of new energy materials, and discloses a method for preparing special high-purity manganous-manganic oxide for high-end lithium manganate from manganese sulfate, which is characterized in that manganese sulfate is used as a raw material, seed crystals are prepared firstly and then subjected to oxidative synthesis to enable the seed crystals to grow slowly, any additive is not needed, complex procedures such as roasting, crushing and the like are removed, and the method is suitable for industrial production. The manganous-manganic oxide particles with different particle sizes can be prepared, the prepared manganous-manganic oxide product is high in sphericity degree, controllable in particle size distribution, high in tap density and low in specific surface area, and the process has the advantages of being high in automation degree, improving the physical and chemical properties of manganous-manganic oxide, reducing the impurity content in the product and the like.

The invention relates to the technical field of batteries, in particular to a sodion positive electrode precursor material and a preparation method and application thereof. The chemical formula of the sodium ion positive electrode precursor material is Ni F Mn < c > M < d > (O < H >) < 2 > (at) Ni < a-x > F Mn < c > M < d + x > (O < H >) < 2 >, and M is an element doped according to a preset gradient concentration and comprises one of Zn, Cu and Mg; 0.2 < = a < = 0.8, 0lt; b < = 0.5, 0lt; c < = 0.5, 0 < = d < = 0.1, and a + b + c + d = 1, 0lt; x is less than or equal to 0.2, and the morphology is a sphere-like morphology; the invention also provides a preparation method of the sodion positive electrode precursor material, and the prepared sodion positive electrode precursor material has the structural characteristics of uniform phase, high tap density and gradient concentration increase of doped elements from the inner core to the shell, so that the inner core has high specific capacitance, and the shell has high stability; and the preparation process is simple and easy for large-scale production.

The invention provides a preparation method of spherical iron phosphate, and relates to the technical field of lithium ion batteries, and the preparation method comprises the following steps: S1, one-step reaction: carrying out parallel flow on an iron salt solution, a phosphorus salt solution and ammonia water according to a molar ratio of 1: (0.8-1.2): (0.8-1.1) to generate amorphous iron phosphate slurry; adding ammonia water into the iron phosphate slurry to adjust the pH value to 1.5-2.5; s2, membrane washing; s3, a second-step reaction: adding pure water into the washed iron phosphate slurry, adjusting the iron concentration to 0.5-1.2 mol / L, adding a phosphoric acid solution, heating to 90-120 DEG C, and controlling the heat preservation time for 30-90 minutes after the material is converted into a white material, so as to obtain white slurry; s4, washing: taking a filter cake; s5, drying: generating iron phosphate dihydrate; s6, calcining: spherical iron phosphate is generated, and the iron phosphate is successfully converted from a traditional olive type, peanut type or honeycomb type to a spherical type through the preparation method provided by the invention.

The invention discloses a lithium iron manganese phosphate precursor and a preparation method and application thereof, and belongs to the technical field of lithium iron manganese phosphate precursors, and the preparation method comprises the following steps: S1, mixing a lithium hydroxide solution, a phosphoric acid solution, a manganese sulfate solution and a ferrous sulfate solution to obtain a first solution; s2, carrying out a hydrothermal reaction on the first solution, adding an MOF mixture to obtain a second solution, and carrying out a secondary hydrothermal reaction on the second solution to obtain a lithium manganese iron phosphate precursor; the MOF mixture comprises an iron-based MOF, a zinc-based MOF and sodium poly (p-styrenesulfonate). According to the preparation method, the micron-sized lithium manganese iron phosphate precursor with relatively high tap density is prepared through the hydrothermal reaction.

The invention relates to a negative active material and a preparation method thereof, a negative pole piece, a battery and an electric device. The negative electrode active material comprises: an inner core, which comprises porous graphite and a sulfur-doped hard carbon-metal oxide material, and the sulfur-doped hard carbon-metal oxide material is arranged in a pore channel of the porous graphite; the shell layer coats at least part of the surface of the inner core, and the shell layer comprises a polyaniline material. According to the negative electrode active material provided by the invention, through the synergistic effect among the porous structure of the graphite, the sulfur-doped hard carbon-metal oxide material and the shell layer containing the polyaniline material, the capacity performance, the rate performance and the cycle performance of the battery are improved at the same time, and the comprehensive improvement of the material performance is realized.

The invention discloses a method for preparing a manganese sulfate crystal by using manganese carbonate ore. The preparation method of the manganese sulfate crystal comprises the following steps: leaching manganese carbonate ore by using sulfuric acid to obtain a leaching solution, precipitating the leaching solution by using a heavy removing agent to remove heavy metal ions, neutralizing redundant sulfuric acid in the leaching solution, introducing a precipitating agent, reacting with the precipitating agent to obtain a precipitate, washing the precipitate with water to remove impurities, and dissolving by using sulfuric acid to obtain the manganese sulfate crystal. And after dissolving, precipitating a small amount of residual calcium and magnesium ions by using fluoride, filtering to obtain fluorine-containing manganese sulfate filtrate, finally adding a fluorine removal agent for solid-liquid separation, and evaporating and crystallizing the filtrate to obtain manganese sulfate crystals. The manganese sulfate crystal is suitable for production of a lithium ion battery positive electrode material. According to the preparation method of the manganese sulfate crystal, the impurity removal cost is greatly reduced. The invention also discloses a method for preparing manganous-manganic oxide from manganese carbonate ore. The tap density of the manganous-manganic oxide is greater than 2.3 g / cm < 3 >, the specific surface area is less than 3m < 2 > / g, and the requirement of a battery-grade material is met.

The invention discloses a complex-phase lithium-rich positive electrode material as well as a preparation method and application thereof, belongs to the technical field of battery positive electrode materials, and solves the problem that a material in the prior art cannot meet the requirements of high energy density and long service life at the same time. The complex-phase lithium-rich positive electrode material provided by the invention comprises the following components: a lithium-rich manganese-based positive electrode material and a partially ordered lithium-rich spinel positive electrode material in a mass ratio of (1-20): 1, wherein the particle size of the lithium-rich manganese-based positive electrode material is 1-20 [mu] m, and the particle size of the partially ordered lithium-rich spinel positive electrode material is 50-500 nm. The complex-phase lithium-rich positive electrode material provided by the invention is used as a battery positive electrode active material, and the energy storage density and the service life of the battery are improved in multiple dimensions from the aspects of improving the specific capacity through cooperation of anions and cations, improving the tap density through particle size grading fusion and the like.

The invention discloses a SiOX / microcrystalline graphite negative electrode material and a preparation method and application thereof. Relates to the technical field of lithium battery cathode materials. The preparation method comprises the following steps: by taking microcrystalline graphite as a base material, growing nano silicon oxide particles in situ on the surface of the microcrystalline graphite and in gaps of sheet layers by adopting a hydrothermal reaction method to form a SiOX / microcrystalline graphite composite material, and coating the surface of the SiOX / microcrystalline graphite composite material with a carbon coating layer with a complete carbon layer structure, and finally, the SiOX / microcrystalline graphite negative electrode material with the core-shell structure is formed. By adopting the technical scheme, the stress effect caused by silicon volume expansion in the charging and discharging process is counteracted and inhibited by utilizing the disordered layer structure characteristic that the structure orientation of fine scales of the microcrystalline graphite is different; meanwhile, the nano SiOX particles are filled in the gaps of the microcrystalline graphite flake layer, and the fine flake graphite constructs a three-dimensional conductive network structure, so that the problem of poor conductivity of the SiOX particles is solved.

The invention belongs to the technical field of precious metal materials, and particularly relates to crystal face sphere-like silver powder and a preparation method and application thereof. The preparation method of the crystal face sphere-like silver powder comprises the following steps that a first silver nitrate solution, a first reducing agent solution, a stabilizer and a surfactant are mixed, and a colloidal solution is obtained; mixing the colloidal solution and the neutralizer solution to obtain a reaction base solution; and a second silver nitrate solution and a second reducing agent solution are added into the reaction base solution at the same time and then mixed with a dispersing agent, and the crystal face sphere-like silver powder is obtained. According to the preparation method provided by the invention, the colloidal solution is prepared as the seed crystal, the liquid-phase reduction reaction is carried out in a manner of simultaneously adding the reducing agent solution and the oxidizing agent solution, the crystal face silver powder with a novel structure is obtained, and the prepared silver powder has relatively good dispersity, consistency and crystal face sphericity-like degree and also shows relatively high sintering activity; therefore, the conductive ink has a good printing effect and conductive performance, and has a wide application prospect.

The invention discloses a porous carbon-sodium ferric phosphate pyrophosphate composite material and a preparation method and application thereof, the composite material comprises porous carbon and sodium ferric phosphate pyrophosphate, and the sodium ferric phosphate pyrophosphate is distributed on the outer surface of the porous carbon and in porous carbon channels. The preparation method of the porous carbon-sodium ferric phosphate pyrophosphate composite material comprises the following steps: (1) preparing a sodium ferric phosphate pyrophosphate precursor solution; (2) uniformly mixing the ferric sodium pyrophosphate precursor solution obtained in the step (1) with porous carbon to obtain a precursor material flow; and (3) drying and roasting the precursor material flow obtained in the step (2) to obtain the porous carbon-phosphoric acid ferric sodium pyrophosphate composite material. According to the method, the composite electrode material with high rate performance can be obtained, and the energy density can be greatly improved when the composite electrode material is applied to a sodium ion capacitor.

The invention relates to the technical field of lithium ion battery negative electrode materials, in particular to a graphite negative electrode material and a preparation method thereof, a negative electrode plate and a lithium ion battery. The graphite negative electrode material comprises composite particles, the composite particles comprise graphite particles and polymer films coating the surfaces of the graphite particles, and the materials of the polymer films comprise polyolefin and / or polyurethane; the weight loss ratio of a TG curve obtained by carrying out a thermal weight loss test on the graphite negative electrode material in an air atmosphere at 200-600 DEG C is 1%-5%. The surfaces of the graphite particles are coated with a small amount of polyolefin and / or polyurethane, so that the specific surface area can be remarkably reduced, and the compaction density can be improved.

The invention discloses a SiO X / Microcrystalline graphite negative electrode material and its preparation method and application; relates to the technical field of lithium battery negative electrode materials. The preparation method comprises using microcrystalline graphite as a matrix material, using a hydrothermal reaction method to in-situ grow nano silicon oxide particles on the surface of microcrystalline graphite and in the gaps between the sheets to form SiO X / microcrystalline graphite composites, and in the SiO X The surface of the microcrystalline graphite composite material is coated with a carbon coating layer with a complete carbon layer structure, and finally a SiO X / Microcrystalline graphite negative electrode material. The technical solution of the present invention uses the structure of microcrystalline graphite flakes with different structural orientations to offset and suppress the stress caused by silicon volume expansion during the charging and discharging process; at the same time, nano-SiO X The particles are filled in the gaps of the microcrystalline graphite flake layers, and the fine flake graphite builds a three-dimensional conductive network structure, improving the SiO X The problem of poor electrical conductivity of particles.

The invention discloses a urea resin doped bamboo parenchyma cell porous carbon electrode material and a preparation method thereof, and belongs to the technical field of electrochemical energy storage materials. The method comprises the following steps: mixing and stirring bamboo parenchyma cells and urea-formaldehyde resin powder, tabletting to obtain a urea-formaldehyde resin doped bamboo parenchyma cell composite material, and calcining to obtain urea-formaldehyde resin doped bamboo parenchyma cell carbon; grinding and mixing the carbonized sample and an activating agent, calcining, taking out, cleaning to be neutral, and drying to obtain the urea-formaldehyde resin doped bamboo parenchyma cell porous carbon. The bamboo parenchyma cells and the urea resin are used as raw materials, and the bamboo parenchyma cells are of a multi-wall-layer cavity structure, so that activation and construction of a pore structure are facilitated; the specific surface area of the porous carbon is increased by heating expansion of the urea-formaldehyde resin in carbonization and activation processes, and meanwhile, the urea-formaldehyde resin doped bamboo parenchyma cell porous carbon prepared by the method is used as an electrode material, has high tap density and high mass specific capacity, and is a positive electrode material which is expected to be industrialized.

The invention provides a high-nickel ternary precursor, a preparation method thereof and an all-solid-state battery. The method comprises the following steps: (1) performing a first coprecipitation reaction on a first nickel-cobalt-manganese ternary metal salt solution, a precipitator and a complexing agent, and collecting a first material after the particle size of particles in the first coprecipitation reaction reaches a required particle size range; (2) adding a second nickel-cobalt-manganese ternary metal salt solution into the system in the step (1) to carry out a second coprecipitation reaction, and collecting a second material after the particle size of the particles in the second coprecipitation reaction reaches the required particle size range; and (3) mixing the first material obtained in the step (1) and the second material obtained in the step (2) to obtain the high-nickel ternary precursor. By regulating and controlling the particle size and composition of the high-nickel ternary precursor, the structural stability and electrochemical performance of the high-nickel ternary positive electrode material are further improved.

The invention discloses silver particles and a preparation method and application thereof, and the preparation method comprises the following steps: S1, dispersing a silver source in an alcohol amine solution, and adding a dispersing agent to form a base solution; the molar ratio of silver ions in the silver source to an alcohol amine compound in the alcohol amine solution is 1: (0.05-5); s2, the base solution and an organic amine solution are subjected to a hydrothermal reaction, and the silver particles are prepared; the molar ratio of silver ions in the silver source to the organic amine compound in the organic amine solution is 1: (0.005-0.15). The proportion of the large-particle-size silver particles and the small-particle-size silver particles is regulated and controlled by controlling the dosage of the alcohol amine solution and the organic amine solution, so that gaps of the large-particle-size silver particles are filled with the small-particle-size silver particles, and the tap density of the silver powder is improved.

The invention provides a spherical graphite material and a preparation method and application thereof, and the spherical graphite material meets the following conditions: the r value of the spherical graphite material is gt; 0.7, the sphericity degree of the spherical graphite material is larger than or equal to 0.75, 10 30 nm * 30 nm areas are randomly selected for any cross section of particles of the spherical graphite material, TEM images are obtained respectively, and graphite lattice layer-amorphous carbon layer-graphite lattice layer crystal form change areas exist in the TEM images of not larger than 3 areas. The prepared lithium-ion battery cathode material has the characteristics of high tap density and small orientation, so that the lithium-ion battery cathode material shows excellent processability, and shows the characteristic of low expansion when being applied to the lithium-ion battery cathode material. The graphite material is high in graphitization degree, and shows the characteristics of high capacity and high first efficiency when being applied to a lithium ion battery negative electrode material.

The invention provides a large-particle narrow-span distribution ternary precursor and a preparation method and application thereof, and belongs to the technical field of batteries, the preparation method comprises the following steps: ammonia concentration in a base solution A is 2.0-5.0 g / L, a nickel-cobalt-manganese metal salt solution, ammonia water and an alkali solution are introduced into the base solution A in a parallel flow manner, a first coprecipitation reaction is carried out, and a nickel-cobalt-manganese ternary precursor seed crystal is prepared; in the first coprecipitation reaction, the stirring rotating speed is 150 to 350rpm; a base solution B is prepared, the ammonia concentration in the base solution B is 5.0-7.0 g / L, a nickel-cobalt-manganese metal salt solution, ammonia water and an alkali solution are introduced into the base solution B in a parallel flow mode, a second coprecipitation reaction is conducted, and a nickel-cobalt-manganese ternary precursor is prepared; in the second coprecipitation reaction, the stirring rotation speed is 150 to 280 rpm. The problems that nickel-cobalt-manganese ternary precursor particles are prone to cracking and agglomeration are solved, and therefore the precursor narrow in particle size distribution and good in sphericity degree is obtained.

The invention discloses a high-tap-density iron phosphate battery precursor which is prepared by the following steps: dispersing a basic ammonium iron phosphate filter cake into an acid solution with the pH value of 0.4-0.6, stirring until the filter cake is completely dissolved, adding an alkali solution to adjust the pH value of a base solution to 0.8-1.2, and adding polyethylene glycol for reaction; after the reaction is finished, alkali liquor continues to be added into the solution to adjust the pH value to 1.8-2.2, the temperature is increased to the aging temperature, iron phosphate dihydrate slurry is prepared, and finally the anhydrous iron phosphate with the high tap density is prepared after suction filtration, water washing, drying and calcination are conducted. According to the iron phosphate battery precursor disclosed by the invention, basic ammonium iron phosphate is firstly subjected to acid leaching and then subjected to recombination crystallization during preparation, the pH value of a system is adjusted step by step, and polyethylene glycol is introduced, so that the tap density is improved, the iron phosphate battery precursor has a large specific surface area, large and small particle grading is formed, and the compaction performance of lithium iron phosphate is improved.

The invention relates to the technical field of sodium-ion batteries, and discloses a sodium-ion battery positive electrode material precursor, a preparation method thereof, a positive electrode material and a battery. The sodium ion battery positive electrode material precursor comprises an inner core, a transition layer and a shell layer, the porosity of the inner core is smaller than that of the transition layer, the transition layer comprises copper oxide, and the shell layer comprises nickel-iron-manganese hydroxide. According to the invention, a segmented coprecipitation method is adopted to synthesize the sodium-ion battery positive electrode material precursor with a core-shell structure and high tap density, so that the energy density of the sodium-ion battery is improved.

The invention provides a negative electrode material, a negative plate and a battery, the negative electrode material comprises a carbon matrix and an active substance, the carbon matrix has holes, the active substance is at least partially distributed in the holes, the area proportion alpha of the holes with the aperture greater than 50nm in any cross section of the negative electrode material is less than or equal to 10%; wherein alpha is obtained by the following test method: the sum of the cross-sectional areas of pores with the pore diameter of more than 50nm in the region of the cross section of the single negative electrode material particle is recorded as S0, and the cross-sectional area of the single negative electrode material particle in the region is recorded as S, the area ratio of pores with the pore diameter larger than 50 nm in the cross section of a single negative electrode material particle is defined as alpha ', alpha' = S0 / S, alpha is the arithmetic average of alpha 'values of at least 10 negative electrode material particles, and the problems that in the prior art, the first efficiency is low, the volume expansion rate is large, and the cycle performance and the processing performance are poor are solved.

The invention belongs to the technical field of new energy materials, and particularly relates to a low-sulfur cation-doped ferromanganese pyrophosphate precursor, carbon-coated modified lithium ferromanganese phosphate as well as a preparation method and application of the low-sulfur cation-doped ferromanganese pyrophosphate precursor and carbon-coated modified lithium ferromanganese phosphate. According to the invention, the low-sulfur cation doped ferromanganese pyrophosphate precursor is successfully prepared. A proper amount of phosphoric acid source is added into the prepared metal cation doped ammonium manganese ferric phosphate precursor for treatment, so that the sulfur content is effectively reduced, the molar ratio of manganese, iron, doped elements and phosphorus elements is regulated and controlled to be slightly smaller than 1, and the tap density of the precursor is effectively improved. The precursor can effectively inhibit generation of gas in the high-temperature sintering process, the hole defect is avoided, the compactness of the structure of the prepared carbon-coated modified lithium manganese iron phosphate material is ensured, and the cycling stability of the material is remarkably improved. The lithium ion battery constructed based on the material shows excellent electrochemical performance. In addition, the precursor is simple in preparation process, high in raw material conversion rate and suitable for industrial production.

The preparation method comprises the following steps that S1, a silver nitrate solution and a reducing agent solution are added into a compound dispersing agent solution at the same time, stirring reaction is conducted, and a nanometer silver powder suspension is obtained; s2, adding a flocculant solution into the nano silver powder suspension, and stirring for reaction to obtain a reaction solution; and S3, carrying out solid-liquid separation on the reaction liquid to obtain a solid component, and then drying and crushing to obtain the nano silver powder for the low-temperature sintering type water-based polyester-based conductive paste. The mass ratio of the silver nitrate to the reducing agent to the compound dispersing agent to the flocculating agent is (1000-1500): (500-1000): (20-60): (3-8); according to the preparation method, the mixed dispersing agent, the silver nitrate solution, the reducing agent solution and the flocculating agent react to obtain the nano silver powder which is good in dispersity, high in yield, smooth in surface, small in particle size and high in apparent density and tap density, and preparation of the low-temperature sintering type waterborne polyester-based conductive paste is facilitated.