651results about How to "Improve electronic conductivity" patented technology

The invention discloses a carbon-silicon negative electrode material and a preparation method and application thereof, and the preparation method comprises the following steps: S1, carrying out mixed reaction on a lithium source compound, a lanthanum source compound and a titanium source compound to obtain a mixed reactant; mixing the mixed reactant with a carbon source compound, and dispersing and emulsifying to obtain element-doped microspheres; s2, carbonizing the element-doped microspheres in the step S1 to obtain carbides, and activating the carbides to obtain a porous carbon material; and S3, performing silicon deposition on the porous carbon material in the S2 to obtain silicon deposition porous carbon, and performing carbon deposition on the silicon deposition porous carbon to obtain the carbon-silicon negative electrode material. The carbon-silicon negative electrode material disclosed by the invention is high in lithium ion transmission rate, the problem of poor electronic conductivity of silicon is solved, and the electrical property of a battery can be effectively improved.

The invention belongs to the field of sodium ion batteries, and particularly discloses a positive electrode material and a preparation method and application thereof. The positive electrode material is carbon nitride coated fluorine-doped pyrophosphate sodium manganese iron phosphate, the chemical formula of the positive electrode material is NaaFe3-bMnb (PO4-x) 2F4xP2O7 / C3N4, a is larger than or equal to 3.95 and smaller than or equal to 4.1, b is larger than or equal to 0.3 and smaller than or equal to 2.4, and x is larger than or equal to 0.005 and smaller than or equal to 0.05. The sodium ferromanganese pyrophosphate is subjected to fluorine doping and carbon nitride coating, so that the electronic conductivity and the structural stability of the sodium ferromanganese pyrophosphate can be improved, the capacity of the sodium ferromanganese pyrophosphate can be well exerted, and the capacity and the voltage platform of the sodium-ion battery are improved.

The invention provides a modified lithium iron manganese phosphate positive electrode material and a preparation method thereof, a positive plate and a lithium ion battery. The modified lithium manganese iron phosphate positive electrode material comprises transition metal element-doped lithium manganese iron phosphate and a silicon hydroxyl-containing carbon coating layer, wherein the surface of the transition metal element-doped lithium manganese iron phosphate is coated with the silicon hydroxyl-containing carbon coating layer. And the transition metal element replaces the position of an iron element in the lithium manganese iron phosphate, so that the ion diffusion coefficient of the lithium manganese iron phosphate and the compaction density of the modified lithium manganese iron phosphate positive electrode material can be improved. The existence of the silicon hydroxyl-containing carbon coating layer is beneficial for improving the electronic conductivity and the structural stability of the lithium manganese iron phosphate positive electrode material, so that the manganese dissolution rate of the lithium manganese iron phosphate positive electrode material in the high-temperature cycle process of the battery is reduced. Therefore, the modified lithium manganese iron phosphate positive electrode material disclosed by the invention has relatively high ion diffusion coefficient, electronic conductivity, compaction density, rate capability, energy density and cycling stability.

The invention discloses a method for preparing a composite iron-based polyanion positive electrode material. The structural formula of the positive electrode material is represented as Na4Fe3 (PO4) 2 (P2O7) (at) Camp, mXenes are sodium ferric pyrophosphate compositely coated by an MXenes material and a carbonaceous precursor, and the preparation method comprises the following steps: weighing a sodium source, a ferrous source, a phosphorus source and a carbon source according to a stoichiometric ratio, uniformly mixing, grinding, spray-drying and sintering at high temperature to obtain the composite iron-based polyanion positive electrode material, and the carbon source comprises iron-nickel doped polyethylene glycol. The composite iron-based polyanion positive electrode material provided by the invention is remarkably improved in the aspects of energy density, rate capability and cycle life, and the preparation process is simple to operate, reliable in flow, quick in preparation process and easy for industrial production, so that an ideal scheme is provided for commercialized sodium ion battery positive electrode materials.

The invention relates to a composite positive active material and a preparation method thereof, a positive pole piece and a secondary battery. The composite positive electrode active material comprises a positive electrode active material substrate, a porous metal oxide coating layer arranged on the surface of the positive electrode active material substrate and a conductive polymer coating layer arranged on the surface of the porous metal oxide coating layer. In the composite positive electrode active material, the electrochemical inert porous metal oxide coating layer has good thermal stability and is beneficial to stabilization of a crystal structure and inhibition of surface side reaction, and in addition, the porous structure is beneficial to transmission of lithium ions and storage of oxygen free radicals separated out due to structural collapse of a positive electrode active material matrix in the overcharge process; severe reaction with electrolyte is relieved, and overcharge failure of the positive electrode active material is slowed down. The conductive polymer coating layer can make up the electrochemical inertness of the metal oxide and improve the electronic conductivity of the positive electrode active material.

The invention relates to the field of batteries, in particular to a negative plate and a battery comprising the negative plate. The negative plate comprises a negative current collector, a bottom coating and a negative active material layer, the bottom coating and the negative active material layer are positioned on one side or two sides of the negative current collector, the bottom coating is positioned between the negative current collector and the negative active material layer, the bottom coating comprises a three-dimensional structure formed by a first conductive binder, the first conductive binder comprises a first carbon nano tube, and the first carbon nano tube comprises a second carbon nano tube. The negative plate meets the following relational expression: 1.2 < = B / K < = 3.4, B is the length-diameter ratio of the first carbon nanotube, and K is the tensile strength of the negative current collector. According to the negative plate, the thickness of the priming coat can be greatly reduced, and the energy density of the battery is increased; the binding power between the negative electrode current collector and the negative electrode active material layer can be enhanced, the structural stability of the active material layer can be improved, the pole piece deformation and powder falling in pole piece processing and battery circulation can be improved, and the circulation expansion can be inhibited; the conductivity of the pole piece is improved and the fast charging performance of the battery is improved.

The invention relates to a silicon-carbon composite material, a preparation method thereof and a lithium ion battery. The preparation method comprises the following steps: adding porous carbon into a fluidized bed, heating and introducing alkaline mixed gas to obtain amino porous carbon; transferring the amino porous carbon into fluidized bed equipment, vacuumizing, heating, and introducing hydroxyl silane gas for nano silicon deposition; after deposition, introducing ultraviolet light for polymerization and oxidation to obtain a modified silicon-carbon precursor material; transferring the modified silicon-carbon precursor material into a tubular furnace, introducing inert gas to discharge air in the tube, and performing first carbonization to obtain a silicon-carbon material; and adding the resin into an organic solvent, adding the fast ion conductor and the silicon carbon material to be uniformly dispersed, performing spray drying, and performing secondary carbonization to obtain the fast ion conductor coated silicon carbon composite material. The preparation method provided by the invention is simple and efficient, and the prepared silicon-carbon composite material can improve the fast charging performance and is suitable for a negative electrode material of a high-energy-density lithium ion battery.

The invention belongs to the field of lithium ion batteries, and discloses a carbon-coated nanotube lithium titanate / carbon composite negative electrode material, a preparation method and a lithium ion battery. The lithium titanate / carbon composite negative electrode material is of a unique nanotube structure, the structure is composed of nanoparticles which are connected with one another and are covered with carbon layers on the surfaces, and certain gaps are formed among the nanoparticles. The preparation method comprises the following steps: dissolving a carbon source and hexadecyl trimethyl ammonium bromide in an organic solvent, then respectively adding the carbon source and a lithium source according to the proportion, and carrying out solvothermal reaction after fully stirring; and washing, drying and calcining the precipitate obtained after the reaction at high temperature to obtain the lithium titanate / carbon compound. Benefited from the synergistic interaction mechanism of the lithium titanate and the carbon material, the electron / ion transmission kinetics in the charge-discharge process of the lithium titanate / carbon compound is greatly improved, so that the lithium titanate / carbon compound has excellent rate capability and cycle performance. The method has the characteristics of simple process, environment friendliness, low cost, high efficiency and the like.

The invention belongs to the field of chemical energy materials, and discloses a modified lithium iron phosphate positive electrode material and a preparation method thereof.The preparation method comprises the steps that a lithium source, an iron source and a zinc source are added into water to be stirred and dissolved, then a phosphorus source, a network gelling agent and an initiator are added, stirring reaction is conducted, and wet gel is obtained; and pre-decomposing the wet gel, grinding and sintering to obtain the modified lithium iron phosphate positive electrode material. According to the invention, Zn is introduced into the lithium iron phosphate positive electrode material, so that the olivine structure of the positive electrode material and the purity and consistency of the lithium iron phosphate positive electrode material are ensured; and Zn is oxidized into Zn < 2 + > to be doped into a lithium iron phosphate structure, so that vacancies are formed, the lithium ion diffusion rate and conductivity of the lithium iron phosphate positive electrode material are improved, the rate cycle performance of the prepared modified lithium iron phosphate positive electrode material is stable, and excellent discharge performance and stable rate cycle performance can be kept at low temperature.

The invention provides a quick-charge and quick-discharge type lithium battery and a preparation method thereof, and belongs to the technical field of lithium battery preparation. The preparation process comprises the following steps: preparing a fluorinated carbon nanotube based on biomass carbon; preparing a positive electrode plate; preparing the dendritic mesoporous silicon dioxide nano particles; preparing a cerium oxide-loaded two-dimensional hierarchical porous composite material; preparing a negative electrode plate; and assembling the lithium battery. According to the preparation method, the eutectic and the carbon fluoride nanotubes are added in the preparation of the positive electrode plate, and the cerium oxide-loaded two-dimensional hierarchical porous composite material and the carbon fluoride nanotubes are added in the preparation of the negative electrode plate, so that the prepared positive electrode plate and the prepared negative electrode plate have relatively high conductivity; and moreover, the ion transmission efficiency is improved, the rapid ion transmission is beneficial to reducing the polarization phenomenon of the battery, improving the charging and discharging rate and the power performance of the battery, enhancing the structural stability of the electrode, improving the performance and the safety of the battery, and being more beneficial to rapid charging and rapid discharging.

The invention discloses a lithium salt doped porous carbon coated graphite composite material for an energy storage battery and a preparation method thereof, the composite material has a core-shell structure, the core is graphite, and the shell is a lithium salt doped porous carbon complex. The preparation method comprises the following steps: uniformly mixing amino resin, a pore-forming agent and a heteroatom compound of the pore-forming agent, curing, activating to obtain porous carbon, adding the porous carbon into an inorganic lithium salt, uniformly mixing, and carrying out spray drying to obtain lithium salt doped porous carbon; the preparation method comprises the following steps: adding lithium salt doped porous carbon into a carboxymethyl cellulose lithium solution, uniformly dispersing, then adding into a graphite material, uniformly dispersing, spray-drying, and carbonizing to obtain the lithium salt doped porous carbon coated graphite composite material. According to the obtained material, the coating layer lithium salt is doped with porous carbon, so that the liquid absorption and retention capacity of the material is improved, the diffusion rate of lithium ions is increased, and the rate capability is improved; meanwhile, the expansion of the composite material in the charging and discharging process is reduced by utilizing the low expansion of the porous carbon, and the cycle performance is improved.

The invention provides a method for preparing porous iron phosphate through an emulsion reaction. The method comprises the following steps: (1) reacting an iron source and a phosphorus source according to a certain proportion to prepare an iron phosphate precursor; (2) reacting the iron phosphate precursor with a foaming agent to obtain emulsified iron phosphate dihydrate; (3) adding a cross-linking agent for further emulsification and dispersion, and adding a curing agent to obtain cured iron phosphate dihydrate; and (4) drying, calcining and crushing the iron phosphate dihydrate to obtain the porous iron phosphate. The method is specifically characterized in that the porous iron phosphate with the three-dimensional foam structure is finally obtained through the processes of emulsification foaming, curing reaction, calcination pore-forming and the like in sequence in the iron phosphate preparation process. The iron phosphate material prepared by the method has rich three-dimensional reticular porous structures, high specific surface area and high porosity. The lithium iron phosphate material prepared from the precursor material is high in electronic conductivity and can adapt to a high-rate lithium iron phosphate process. In addition, the raw materials used in the preparation process are cheap and easy to obtain, the preparation process is stable and controllable, and the iron phosphate prepared by the process has better application value and economic value.

The invention provides a phosphorus-carbon composite material with a core-shell structure as well as a preparation method and application of the phosphorus-carbon composite material. The phosphorus-carbon composite material with the core-shell structure comprises a pre-sodium-modified phosphorus-carbon core material and a shell coating the surface of the pre-sodium-modified phosphorus-carbon core material, and the material of the shell comprises amorphous carbon and organic sulfonate. By regulating and controlling the structure and composition of the phosphorus-carbon composite material, the specific capacity, the first coulombic efficiency and the fast charging performance of the hard carbon material are improved.

The invention provides a lithium-mixed coated modified ternary positive electrode material as well as a preparation method and application thereof, and relates to the technical field of lithium battery raw materials. Various lithium sources are mixed according to a certain proportion to prepare a ternary positive electrode, co-doping modification is carried out through cooperation of Li3PO4 and a W / Al / Zr / Y / B-containing compound, double-layer coating modification is carried out through cooperation of the Li3PO4 and a Ti / Al-containing compound for primary coating and cooperation of an anhydrous Li compound and TiP2O7 or Ti3 (PO4) 4 for secondary coating, and a double-gradient fast ion conductor coating layer is constructed. The structural stability, the thermal stability, the first discharge capacity and efficiency, the multiplying power, the circulation and storage performance and the like of the single-crystal or polycrystal ternary positive electrode material under different voltage and power conditions are improved; the lithium-mixed multi-element composite ternary positive electrode provided by the invention has the advantages of more stable layered structure, higher safety, higher electronic conductivity, better multiplying power, high specific capacity and long cycle performance.

The invention provides a preparation method of an electron-ion mixed conductor sulfide electrolyte material, which is characterized by comprising the following steps: taking a sulfide solid electrolyte as an inner core, taking a two-dimensional transition metal layered material MXene as a surface coating layer, and coating the surface of the inner core with the two-dimensional transition metal layered material MXene, and carrying out ball milling and calcining to obtain the electron-ion mixed conductor sulfide electrolyte material. The two-dimensional transition metal layered material MXene is used as a surface coating layer, the air stability of the sulfide solid electrolyte is improved, calcination treatment is carried out, S in the sulfide solid electrolyte is combined with metal ions in MXene, the sulfide solid electrolyte has high electronic conductivity, the appearance of a space charge layer can be inhibited, and the performance of the sulfide solid electrolyte is improved. The electronic conductivity of the positive electrode is improved, the multiplying power of a battery cell is improved, the content of conductive carbon is reduced, and the intrinsic ion conductivity of sulfide electrolyte can be kept to the maximum extent.

The invention provides a negative pole piece and a preparation method thereof, a sodium ion battery and electric equipment, and relates to the technical field of sodium ion batteries. The negative pole piece comprises a current collector, a first coating and a second coating, the first coating is arranged between the current collector and the second coating; the raw materials of the first coating comprise hard carbon, first soft carbon, a first conductive agent, a first dispersant and a first binder; the second coating is prepared from the following raw materials: second soft carbon, a second conductive agent, a second dispersing agent and a second binding agent. The negative pole piece has relatively high flexibility, compaction density, electronic conductivity, cycle performance and rate capability, and can also reduce the risk of sodium precipitation and the probability of powder falling.

The invention provides a vapor deposition silicon-carbon composite material for in-situ growth of interconnected carbon nanotubes and a preparation method of the vapor deposition silicon-carbon composite material, and belongs to the technical field of lithium ion battery negative electrode materials. The preparation method comprises the following steps: firstly, complexing and neutralizing a metal salt catalyst solution, then blending the metal salt catalyst solution with a vapor deposition silicon-carbon material, placing a catalyst on the surface and inside the silicon-carbon material, and growing carbon nanotubes in situ under proper conditions to obtain the vapor deposition silicon-carbon composite negative electrode material interconnected with the in-situ grown carbon nanotubes. The prepared vapor deposition silicon-carbon negative electrode material of the in-situ growth interconnection carbon nano tube has the advantages of high conductivity, good mechanical property, high initial coulombic efficiency, long cycle life and the like, the preparation process route is clear, industrial production is easy, and the vapor deposition silicon-carbon negative electrode material has important significance and value for developing a novel negative electrode material of a high-performance lithium ion battery.

The invention discloses a lithium ion battery negative electrode with low expansion and low impedance. The lithium ion battery negative electrode comprises a composite current collector and a negative electrode active material coating coated on at least one surface of the composite current collector, the negative electrode active material coating comprises a negative electrode active material, graphene and lithium polyacrylate; the mass ratio of the negative electrode active material to the graphene to the lithium polyacrylate is (90-99): (0.5-5): (0.5-5), the negative electrode active material comprises a silicon carbon material and a coating material layer arranged on the outer surface of the silicon carbon material, and the coating material layer comprises a polypyrrole layer and single-walled carbon nanotubes uniformly distributed in the polypyrrole layer. Compared with the prior art, the lithium ion battery negative electrode provided by the invention has the advantages of low expansion and low impedance, and can effectively inhibit the expansion of silicon particles, reduce the internal resistance of the battery and maintain the structural stability of the electrode.

The invention discloses a method for improving the fast charging performance of a silicon-carbon composite material, and the method comprises the following steps: firstly preparing a heteroatom-doped MOF material, then precipitating by a silane cracking method, introducing silane gas and heteroatom gas, and carrying out low-temperature passivation to obtain a silicon-carbon precursor material; the preparation method comprises the following steps: preparing an organic solvent of resin, adding a graphene oxide solution, uniformly dispersing, adding a silicon-carbon precursor, performing spray drying, and introducing hydrogen at 700-1000 DEG C to reduce the obtained material. The obtained material can improve the rate capability and the cycle performance.

The invention relates to the technical field of energy storage nano materials, and provides a ZIF-67-derived CoSe2-atNC hollow nano cubic box material and a preparation method thereof.The preparation method comprises the steps that a solution A is prepared from cobalt nitrate hexahydrate, cetyltrimethylammonium bromide and deionized water, a solution B is prepared from 2-methylimidazole and deionized water, and the ZIF-67-derived CoSe2-atNC hollow nano cubic box material is obtained; adding the solution A into the solution B, stirring to prepare a ZIF-67 precursor solution, and carrying out aging reaction to prepare a ZIF-67 nanocube material; preparing a solution C by adopting a ZIF-67 nanocube material and absolute ethyl alcohol, preparing a solution D by adopting tannic acid, deionized water and absolute ethyl alcohol, and adding the solution C into the solution D for etching reaction to prepare a TA-Co hollow nano cubic box material; carrying out first heat treatment on the TA-Co hollow nano cubic box material, mixing and grinding a product of the first heat treatment and selenium powder, and then carrying out second heat treatment to prepare the ZIF-67 derived CoSe2 (at) NC hollow nano cubic box material. The preparation method can be used for preparing the sodium battery negative electrode material with high specific capacity and high cycling stability.

The invention relates to a high-stability electrode for electrochemical lithium extraction and a preparation method thereof, belongs to the technical field of lithium resource extraction, and is used for solving at least one of the problems of poor cycling stability, low current density, low current efficiency and the like of an electrode prepared by an existing method. According to the electrode, the surface of the active material is coated with the solid electrolyte, the coating layer can effectively avoid direct contact between brine and the active material, side reaction is prevented, and therefore the cycle stability of the electrode is improved. The solid electrolyte layer has the effect of transmitting lithium ions, so that foreign ions can be intercepted, and the selectivity of the electrode to the lithium ions is improved. The active material is also coated with an organic conductive polymer, the electronic conductivity of the active material can be effectively improved by the organic conductive polymer layer, the charge transfer impedance of the active material is reduced, and high-current-density lithium extraction is realized.

The invention belongs to the technical field of battery materials, and particularly relates to an MXene material composite nickel-iron-manganese-based positive electrode material and a preparation method and application thereof. The chemical formula of the MXene material composite nickel-iron-manganese-based positive electrode material is NaNiaFebMncTMdO2 (at) MXene, TM is one or more of Mg, Al, Ti, Zn, Zr, Cu, Nb, W and Mo, values of a, b, c and d depend on charge balance, M in MXene is one or more of Ti, Nb, V, Mo, Ta, Cr and Hf, X is C or N, and ene represents a structural unit of graphene. MXene is compounded with the nickel-iron-manganese-based positive electrode material, so that the situation that the nickel-iron-manganese-based positive electrode material is in contact with water and CO2 in air to inhibit the interface side reaction between electrolyte and the nickel-iron-manganese-based material can be reduced, and excellent cycling stability is shown under high voltage.

The invention discloses a doped iron manganese phosphate precursor, a preparation method and a lithium iron manganese phosphate positive electrode material, and belongs to the technical field of lithium ion batteries. The doped iron manganese phosphate precursor and the lithium iron manganese phosphate positive electrode material are prepared by adopting a hydrothermal method, and the grain size is refined by doping vanadium ions; the diffusion rate and the conductivity of lithium ions are improved, and the rate capability and the electronic conductivity of the positive electrode material are enhanced. And in the preparation process, quaternization modified sodium lignin sulfonate is used as a dispersing agent, so that the dispersity among particles is improved, and the problem that the electrochemical performance of the positive electrode material is reduced due to the fact that the particle size is too small and the particles are agglomerated due to vanadium doping is solved. The molecular chain of the quaternization modified sodium lignin sulfonate also contains dithio-carboxyl, so that manganese ions can be reduced and fixed while the dispersing performance of the dispersing agent is improved, the structural stability is improved, and the dissolution of manganese is reduced.

The preparation method comprises the following steps: 1) dispersing an unmodified Prussian white positive electrode material and sodium ferrocyanide in deionized water according to a ratio to obtain a manganese-based Prussian white material mixed solution; 2) adding an acid substance into the manganese-based Prussian white positive electrode material mixed solution, and forming an iron-based Prussian blue coating layer on the surface of the manganese-based Prussian white positive electrode material through ion exchange to obtain a solid material; 3) carrying out separation treatment on the solid material; and 4) drying the separated solid material to obtain the iron-based Prussian blue coated Prussian white positive electrode material. The problems of metal ion dissolution and structural distortion caused by the ginger Taylor effect are effectively inhibited, the structural stability, the rate capability, the long cycle performance, the overall electronic conductivity and the ion diffusion rate of the material are remarkably improved, and the preparation method is simple in process, low in equipment requirement, low in cost and suitable for large-scale production.

The invention discloses an iron manganese phosphate precursor and a preparation method thereof, and belongs to the technical field of lithium ion batteries, the iron manganese phosphate precursor is prepared from a phosphoric acid solution, iron powder, manganese carbonate, a surfactant and a UiO-66-NH2 / Nb2CTx composite material through chemical reaction and solid-phase reaction, the iron powder is used as an iron source, the manganese carbonate is used as a manganese source, phosphoric acid is used as phosphoric acid, and the UiO-66-NH2 / Nb2CTx composite material is used as a framework; according to the preparation method, the molar ratio of iron, manganese and phosphorus is accurately controlled, and a surfactant is used, so that the manganese iron phosphate precursor with uniform granularity, good morphology and a porous structure is obtained, the contact area between the prepared lithium manganese iron phosphate positive electrode material and an electrolyte is relatively large, and the lithium manganese iron phosphate positive electrode material has relatively high ion and electron transmission performance; and finally, the prepared lithium battery has the characteristics of high capacity and good cycle performance.

The invention discloses a lithium-free negative electrode for a lithium metal battery, a preparation method of the lithium-free negative electrode and the lithium metal battery. The lithium-free negative electrode comprises a current collector, the metal layer is arranged on at least one side of the current collector, and the material of the metal layer is one or more of tin, magnesium, zinc, bismuth, lead, silver and aluminum; and the graphene oxide layer is arranged on one side, far away from the current collector, of the metal layer. According to the invention, the deposition uniformity of lithium at the negative electrode is improved to inhibit the growth of lithium dendrites, and the coulombic efficiency and the capacity retention ratio of the battery are improved.

A preparation method of a carbon black-based composite conductive agent for an automobile lithium battery belongs to the technical field of new energy automobile lithium batteries, and comprises the following steps: depositing conductive carbon black on the surface and gaps of MOF-Ni3 (HITP) 2 by adopting a vapor deposition method to obtain MOF-Ni3 (HITP) 2 loaded carbon black, and then carrying out surface modification on the MOF-Ni3 (HITP) 2 loaded carbon black by adopting a spraying agent to obtain the carbon black-based composite conductive agent for the automobile lithium battery. The carbon black-based composite conductive agent is obtained. The spraying agent is prepared from water, polyvinyl alcohol, waterborne polyurethane, behenamidopropyl dimethylamine and fatty alcohol-polyoxyethylene ether. The carbon black-based composite conductive agent prepared by the invention can greatly improve the dispersibility of the conductive agent, improve the conductivity and the conductive stability in long-term use, has very good high-rate charge-discharge efficiency, and improves the rate capability of a lithium iron phosphate battery.

The invention relates to the technical field of batteries, in particular to a diaphragm for a battery, a preparation method of the diaphragm and an aqueous sodium-ion battery. The battery diaphragm comprises a diaphragm substrate and a coating arranged on the diaphragm substrate, wherein the coating comprises carbon-coated sodium ferrocyanide, a conductive agent and a binder. The preparation method of the battery diaphragm comprises the following steps: mixing the carbon-coated sodium ferrocyanide, the conductive agent, the binder and the solvent to prepare slurry, coating the slurry on the diaphragm substrate, and drying to obtain the battery diaphragm. The high-performance battery diaphragm is obtained by arranging the modified coating containing the carbon-coated sodium ferrocyanide, the conductive agent and the binder on the conventional diaphragm substrate, and the diaphragm can improve the long cycle stability, the capacity, the coulombic efficiency and the energy density of the battery when being used for the water-based sodium ion battery.

The invention relates to the technical field of batteries, in particular to a negative active material, a negative plate comprising the negative active material and a battery. The negative electrode active material comprises silicon-carbon composite particles; the silicon-carbon composite particles have closed pores, and the volume ratio of the closed pores is 4-50%; the silicon-carbon composite particle has a core-shell structure, and the shell thickness of the core-shell structure is t, 0 lt; t < = 10 nm; the cross section of each silicon-carbon composite particle is provided with a first region and a second region, the content of a silicon element in the first region is c1, the content of a silicon element in the second region is c2, and 0.15 < = c2 / c1 < = 1.4; wherein the size of a vertical line of a tangent line of any point on the edge of the cross section on the cross section is L, on the vertical line, an area which is 0.001 L-0. 1L away from the edge of the cross section forms a first area, and an area which is 0.1 L-0. 5L away from the edge of the cross section forms a second area. The battery provided by the invention can give consideration to relatively high energy density, first coulombic efficiency, rate capability and cycling stability.

The invention provides a vanadium dioxide composite electrode material and a preparation method and application thereof. The method comprises the following steps: taking vanadium leachate as a raw material, reacting with a reducing agent under the condition that the pH value is 2-6, mixing the obtained tetravalent vanadium solution with a precipitator, carrying out precipitation reaction, filtering, washing and drying the precipitate to obtain vanadium dioxide precursor particles, grafting a silane coupling agent with sulfydryl onto the surface of the vanadium dioxide precursor through coupling reaction, and carrying out vacuum drying to obtain the vanadium dioxide precursor. Silver ions are chelated under the action of sulfydryl, and silver elementary substances are deposited on the surfaces of vanadium dioxide precursor particles through reduction. And coating the composite slurry of the vanadium dioxide precursor and the carbon nanotube on the surface of a substrate, and calcining to obtain the vanadium dioxide composite electrode material. The vanadium dioxide composite electrode material is used as a negative electrode material of a battery, and the obtained battery is found to have excellent stability and reaction dynamic characteristics.