160results about How to "Shorten the diffusion path" patented technology

The invention provides carbon-coated lithium iron phosphate and a preparation method thereof, a positive plate and a lithium ion battery. The preparation method comprises the following steps: S1, mixing raw materials including a lithium source, a phosphorus source, an iron source and a first solvent to obtain slurry; s2, sequentially carrying out spray drying and crushing treatment on the slurry to obtain a lithium iron phosphate precursor; s3, carrying out polymerization reaction on raw materials of the lithium iron phosphate precursor, styrene, an initiator and a second solvent in an inert atmosphere, and adding a cationic monomer in the polymerization reaction process to obtain a cationic polystyrene coated lithium iron phosphate precursor; and S4, calcining the cationic polystyrene coated lithium iron phosphate precursor in an inert atmosphere to obtain the carbon coated lithium iron phosphate. According to the preparation method disclosed by the invention, lithium iron phosphate is coated with a layer of porous carbon while being controlled to be nano-sized, so that the electrochemical impedance of the lithium iron phosphate material is reduced, and the rate capability of the lithium iron phosphate material is improved.

The invention provides an ultrahigh-nickel single-crystal positive electrode material and a preparation method and application thereof.The ultrahigh-nickel single-crystal positive electrode material comprises fluxing agent doping elements and high-valence doping elements, the fluxing agent doping elements comprise Zr, Ce, Sr, Y, La, Sn or Na, and the high-valence doping elements comprise Sb, W, Nb, Ta, Mo, Ti or P; the doping amount of the fluxing agent doping element is omega A, the doping amount of the high-valence doping element is omega B, and omega A and omega B meet the following relational expression: 0.5 < 0.746 * exp [-omega B / (0.891 * omega A)] + 0.556 < 1.0. Omega A and Omega B meet a specific relational expression, two doping elements are effectively promoted to play a role, a small-particle-size and uniformly-dispersed single crystal is formed, the material has high stability and safety of the single crystal, a Li < + > diffusion path can be shortened, dynamics can be improved, and the advantage of high capacity can be achieved.

The invention discloses a graphite composite material with a functional coating layer, and a preparation method and application thereof, and belongs to the technical field of lithium ion batteries. The graphite composite material with the functional coating layer is a secondary particle formed by bonding single graphite particles with a core-shell structure, wherein the single graphite particles comprise graphite particles and the functional coating layer coating the surfaces of the graphite particles; the functional coating layer comprises a fast ion conductor and a doped element carbon layer. According to the graphite composite material with the functional coating layer disclosed by the invention, secondary particles are formed by coating the surface of the graphite particles with an elemental carbon layer and a fast ion conductor layer, so that the Li < + > diffusion path and the interface diffusion resistance can be shortened, and a surface SEI layer is stabilized; therefore, the high-rate capacity exertion and the long cycle stability of the graphite composite material are remarkably improved.

The invention discloses a preparation method of a defective graphene negative electrode for a lithium battery, which comprises the following steps: grinding natural graphite into powder, carrying out graphite modification by irradiation of a high-current pulse electron beam, mixing with a conductive agent and a binder to prepare slurry, and coating the slurry on a metal foil to prepare the defective graphene negative electrode for the lithium battery. Natural graphite is modified through high-current pulse electron beam irradiation, obvious expansion deformation occurs on the surface of the natural graphite, defects are generated on a graphite structure, mutual stripping between graphite layers is achieved, the whole surface of the graphite is in a hairy wrinkle form, the structure is almost transparent, and the storage capacity and the cycling stability are obviously improved; the obtained defective graphene negative electrode material provides more channels for lithium ion diffusion, the ion diffusion path is effectively shortened by internal gaps, and a physical method is adopted, a specific reducing agent, an oxidizing agent or other intermediate media do not need to be used, and introduction of impurities is avoided.

The invention discloses a vanadium-doped lithium manganese iron phosphate positive electrode material as well as a preparation method and application thereof. Secondary hydrothermal treatment is adopted, so that the particle size and the size of the material can be obviously controlled, short nanorod particles of lithium manganese iron phosphate grow into nanoparticles with the length smaller than 100 nm and the width smaller than 20 nm in an oriented mode, the diffusion size of Li < + > in the [010] direction is reduced, the diffusion path of Li < + > is shortened, meanwhile, ammonium metavanadate serves as a vanadium source to carry out Fe / Mn site substitution on the lithium manganese iron phosphate positive electrode material, and the lithium manganese iron phosphate positive electrode material is obtained. The preparation method has the advantages of reducing the dissolution behavior of manganese, increasing lattice defects, improving the lattice constant, carrying out double-layer modification of morphology and structure, ensuring the migration rate of Li < + > in the charge-discharge process, and realizing the improvement of the electrochemical performance of the lithium manganese iron phosphate positive electrode material.

The invention belongs to the field of silicon carbide powder synthesis, and particularly relates to a silicon carbide powder synthesis crucible and a use method. The silicon carbide powder synthetic crucible is formed by vertically stacking single-layer crucibles with the same structure along the central axis of a graphite crucible; the single-layer crucible comprises a crucible upper cover, a graphite sheet and a crucible main body; the crucible upper cover and the crucible main body are nested; the bottom of the inner cavity of the crucible main body is used for placing silicon powder and graphite powder; and the graphite flake is clamped between the crucible upper cover and the crucible main body. By designing the height of the single-layer crucible and the structure of the multi-layer crucible, a proper temperature gradient is favorably constructed, and by controlling parameters such as heat preservation time and pressure, batch production of large-particle-size and high-uniformity silicon carbide powder is realized, and an ideal raw material is provided for growth of high-quality silicon carbide crystals.

The invention discloses a preparation method and application of a lithium manganese iron phosphate secondary microsphere with a porous structure, and belongs to the technical field of a lithium ion battery positive electrode material. The chemical formula of the lithium manganese iron phosphate secondary microspheres is LiMn < 0.5 > Fe < 0.5 > PO4, and the lithium manganese iron phosphate secondary microspheres are prepared by spray drying of a plurality of sheet-shaped lithium manganese iron phosphate primary nanoparticles; according to the preparation method, a surfactant is added in the preparation process to induce generation of sheet-shaped lithium manganese iron phosphate nanoparticles, then primary nanoparticles are assembled into lithium manganese iron phosphate secondary microspheres through spray drying, and the formed lithium manganese iron phosphate secondary microspheres are regular in morphology and have a porous structure; electrolyte infiltration and a shorter ion transmission path are facilitated, and the rate capability of the material as a positive electrode material can be effectively improved.

The invention relates to the field of sodium ion batteries, and discloses a sodium vanadium phosphate composite positive electrode active material, a preparation method thereof and a sodium ion battery. The sodium vanadium phosphate composite positive electrode active material comprises a sodium vanadium phosphate inner core and a carbon coating layer coating at least part of the surface of the sodium vanadium phosphate inner core; and the compaction density of the sodium vanadium phosphate composite positive active material is greater than 1.8 g / cm < 3 >. When the positive electrode active material with relatively high compaction density is applied to the sodium ion battery, the diffusion path of sodium ions can be reduced, the energy density of the battery is improved, the discharge capacity of the battery is increased, the internal resistance of the battery is reduced, the polarization loss is reduced, the voltage platform of the battery is improved, and the rate capability and the cycle performance of the battery are ensured.

The invention discloses a high-entropy ferric pyrophosphate sodium ion battery positive electrode material and a preparation method thereof, and belongs to the field of battery positive electrode materials. The chemical formula of the positive electrode material is Na4Fe3-aMa (PO4) 2P2O7 (0.05 < = a < = 0.5), M is a metal element and comprises at least five of cobalt, magnesium, zirconium, zinc, aluminum, molybdenum, copper, manganese, nickel, calcium and chromium, the high-entropy ferric sodium phosphate pyrophosphate battery positive electrode material is spherical, and the surface of the high-entropy ferric sodium phosphate pyrophosphate battery positive electrode material is coated with an amorphous carbon layer. The preparation method adopts a sol-gel method and comprises the following steps: mixing an iron source, a doped metal source, sodium pyrophosphate, ammonium dihydrogen phosphate and citric acid monohydrate according to a stoichiometric ratio, stirring, gelatinizing and drying to obtain xerogel, and calcining through a two-stage hydrogen-argon mixed gas to obtain the iron-doped metal-doped sodium pyrophosphate / citric acid composite material. The crystal structure is optimized by means of the high-entropy synergistic effect, the electron conductivity and the Na < + > diffusion rate are improved, and the industrial adaptability of the spherical morphology and the structural stability of carbon coating are combined.

The invention relates to the technical field of electrochemical energy storage materials, in particular to a high-performance nitrogen-doped hard carbon negative electrode material prepared on the basis of waste graphite and a preparation method and application of the high-performance nitrogen-doped hard carbon negative electrode material. The preparation method comprises the following steps: crushing and screening graphite, mixing graphite powder with glucose, adding ammonia water, stirring, then adding urea as a nitrogen source, and preserving heat at 1000 + / -50 DEG C to obtain the high-performance nitrogen-doped hard carbon negative electrode material. According to the preparation method provided by the invention, the interlayer spacing of the hard carbon material can be increased, the nitrogen content is increased, the quick charge performance of the material is improved, and the preparation method has relatively high practical value and application prospect.

The invention discloses a GaN-based photoelectric refractive index sensor integrated with a guided-mode resonant grating and a preparation method of the GaN-based photoelectric refractive index sensor, and relates to the technical field of semiconductor photoelectric sensors. The LED light source comprises a substrate layer, a silicon dioxide bonding layer is formed above the substrate layer, an LED structure and a light detector structure are formed on the upper portion of the silicon dioxide layer, and an electric isolation area is arranged between the LED structure and the light detector structure. The gallium nitride buffer layer and the undoped gallium nitride layer are removed by adopting the inductive coupling plasma etching technology, the n-type gallium nitride layer is further etched and thinned, and finally the grating structure is formed by etching, so that the integration of the thinning process and the grating optimizes the light propagation path, improves the light extraction efficiency, enhances the coupling effect between the light and the medium to be detected, and improves the detection accuracy. In addition, monolithic integration of the light emission function and the light detection function is achieved, a system-level sensor chip can be achieved by combining the driving circuit and the signal processing circuit, and the integration level of the system is improved.

The invention provides a method for preparing a non-porous metal catalyst through a photodeposition method and application of the catalyst, and relates to the technical field of catalysts. The preparation method of the non-porous metal catalyst comprises the following steps: preparing carbon quantum dots, pickling a carrier material, blocking the carrier material with the carbon quantum dots to prepare a non-porous carrier, and loading a metal active component onto the non-porous carrier through a photodeposition method to prepare the non-porous metal catalyst. And the catalyst can be applied to a nitro compound hydrogenation reaction in a fixed bed. According to the invention, the defects in the prior art are overcome, the metal catalyst is prepared by using the surface non-porous carrier and the photodeposition technology, the dispersity of metal on the surface of the carrier can be improved, the aggregation and accumulation of metal particles can be effectively prevented, the surface smoothness of the non-porous carrier is high, the diffusion path between the metal and reactants is reduced, and the reaction efficiency is improved.

This invention belongs to the field of wet electronic chemicals technology, specifically relating to a method for preparing electronic-grade hydrogen peroxide. The method includes the following steps: adjusting the concentration of raw hydrogen peroxide, and then filtering it sequentially through a reverse osmosis membrane, a modified cation exchange resin, an anion exchange resin, and a mixed ion exchange resin to obtain electronic-grade hydrogen peroxide. The modified cation exchange resin used is modified based on conventional cation exchange resin through pore expansion and grafting, optimizing the spatial matching of pore structure and functional sites. This achieves passivation of metal ions, enhanced adsorption capacity, and improved oxidation resistance, as well as a deep synergistic effect of these three effects. Ultimately, it achieves the dual goals of efficient purification and stable operation of the resin in the hydrogen peroxide system. The resulting electronic-grade hydrogen peroxide can reduce the content of single impurity metal ions to below 5 ppt, meeting the requirements of SEMI G5 standards, and can be directly applied to high-end manufacturing fields such as semiconductor wafer cleaning.

This invention belongs to the technical field of lithium battery anode materials, specifically relating to a highly conductive graphite electrode material and its preparation method. The preparation method includes: pre-dissolving sodium carboxymethyl cellulose into a gel solution, then ball-milling and mixing graphite and conductive carbon black, dispersing them together with a cobalt hexacyanorubium(II)-dodecyltungstencobalt(III) salt hybrid material and hafnium diboride nanomaterials in the gel solution, adjusting the acidity, adding styrene-butadiene rubber emulsion to obtain a uniform slurry, and then coating, drying, and compacting to obtain the anode sheet. This invention significantly improves the conductivity and structural stability of the graphite anode through the synergistic effect of the interface modification of the cobalt hexacyanorubium(II)-dodecyltungstencobalt(III) salt hybrid material and the conductive framework of the hafnium diboride nanomaterials. The process is safe and controllable, and suitable for industrial production of lithium-ion batteries.

The present application relates to the technical field of sodium battery materials, in particular to a sodium supplement coating based on a spiral iron-carbon composite material and a preparation method thereof, a spiral polypyrrole template is synthesized by a chiral template method, Fe3C@CNS spiral carbon composite material rich in Fe3C nanocrystals and iron single-atom sites is prepared through iron loading, sulfidation and high-temperature pyrolysis, Na2C2O4@Fe3C@CNS composite material is prepared by highly dispersing sodium oxalate on the surface and in the pores of the spiral carbon composite material through a recrystallization method, finally, a slurry is prepared by mixing the Na2C2O4@Fe3C@CNS composite material with a conductive agent and a binder, and the slurry is coated on the surface of an electrode to form a functional sodium supplement coating. The sodium supplement coating based on the spiral iron-carbon composite material and the preparation method thereof solve the problems of poor interface stability and first-cycle irreversible sodium loss of existing sodium ion batteries, realize efficient sodium pre-activation and interface synergistic regulation, and improve the comprehensive performance of the battery.

The invention relates to the technical field of synthesis of zeolite molecular sieves, in particular to a preparation method of an in-situ metal-loaded hierarchical pore MFI type ZSM-5 zeolite molecular sieve material. The method comprises the following steps: 1, adding a trivalent aluminum source and a hydroxyl ion source into deionized water, and stirring to obtain a clear solution; 2, adding a tetravalent silicon source into the clear solution, stirring, adding a molecular sieve template agent and a boron source, stirring, and adding a metal complex solution to obtain a mixed solution; 3, mixing the mixed solution with commercial sponge in a hydrothermal reaction kettle, and crystallizing through hydrothermal reaction; 4, after crystallization is finished, quenching, filtering, centrifuging, washing and drying the mixture in the reaction kettle to obtain a crystallized product; and 5, calcining the crystallized product. The method has the advantages of simple production process, cheap and easily available raw materials, low energy consumption, high product crystallinity, low production cost and good economic benefit, and is suitable for batch production.

The invention relates to the technical field of new energy materials, and discloses a silicon-containing carbon-based negative electrode material and a preparation method and application thereof. The negative electrode material is prepared by depositing nano-silicon in the pores of a nitrogen / sulfur-doped microporous carbon material using a vapor deposition method, wherein the nitrogen / sulfur-doped microporous carbon material is prepared by using chemically cross-linked dextran aerogel as a carbon precursor and is prepared by carbonization. Since the chemically cross-linked dextran aerogel has a uniform and dense micro-nanoscale pore structure, the prepared nitrogen / sulfur-doped microporous carbon material can have high porosity and a large specific surface area. The material also contains miscellaneous elements doped therein, and the nano-silicon is coated with the aerogel as a coating material. The formed silicon-containing carbon-based negative electrode material has strong conductivity, good cycle stability, and high specific capacity, and can be used as an excellent negative electrode material for lithium-ion batteries.

The invention provides a graphene / activated carbon composite material and a preparation method and application thereof, and belongs to the technical field of nano materials, the graphene / activated carbon composite material comprises a carbon matrix and a two-dimensional sheet material covering the carbon matrix; the carbon matrix is an activated carbon material and is a carbon material prepared by performing high-temperature pyrolysis on magnesium citrate in a high-temperature self-propagating reaction process; the two-dimensional sheet material is a graphene material and is a few-layer carbon material which is prepared by converting CO2 through a high-temperature self-propagating reaction and is formed by arranging carbon atoms according to a honeycomb-shaped two-dimensional lattice. According to the invention, graphene is used as a conductive and structural dual skeleton; and a hierarchical pore structure is constructed by utilizing gas production and template effect in the reaction process, so that the electrochemical performance of the active carbon positive electrode is improved. And a proper amount of graphene can provide more active sites and maintain the structural stability at the same time, so that the specific capacity and the cycle life are remarkably improved and prolonged, and the material has a wide application prospect and is particularly suitable for preparing a high-performance lithium ion capacitor positive electrode material.

The present invention relates to the technical field of oxygen sensors, and in particular to a small-sized limiting current type zirconia oxygen sensor core, which includes a porous Pt electrode anode layer, a YSZ solid electrolyte layer, a porous Pt electrode cathode layer, an insulating layer and a heating electrode layer from top to bottom, and the porous Pt electrode anode layer, the porous Pt electrode cathode layer and the heating electrode layer are all connected with conductive wires. In this way, the number of layers of the YSZ solid electrolyte layer is reduced, the diffusion path of oxygen during oxygen measurement is reduced, and the response time is reduced, so that it responds quickly. At the same time, a corresponding manufacturing method is also provided, which can be used to manufacture a micron-sized core; the total thickness of each functional layer of the core is 1.1μm-24μm, which greatly reduces the thickness of the core, and can reduce power consumption and improve heating unevenness during subsequent heating treatment.

The invention provides a silane deposition silicon-carbon composite material as well as a preparation method and application thereof, and belongs to the technical field of lithium battery materials. The preparation method comprises the following steps: performing in-situ reaction on zinc salt, dimethylimidazole and a pore-forming agent to obtain a first precursor; and after carbonization treatment, alkali activation is carried out, and then vapor deposition is adopted to obtain the silane deposition silicon-carbon composite material. The prepared silane deposition silicon-carbon composite material has good stability and mechanical strength, hierarchical pore structure distribution and high-capacity ultra-long circulation. The method can solve the problems that existing vapor deposition silicon-carbon is poor in structural stability, and pores of a carbon matrix obtained through traditional ZIF-8 carbonization are prone to collapse.

The invention provides a vanadium-doped Co9S8 nanosheet array as well as a preparation method and application thereof. The invention provides a vanadium-doped Co9S8 nanosheet array preparation method, which comprises: dissolving a cobalt salt and 2-methylimidazole in deionized water, adding foamed nickel, and carrying out a reaction at a room temperature to obtain a Co-ZIF nanosheet array precursor; then adding the VCo-ZIF nanosheets into a sodium metavanadate solution, and carrying out hydrothermal reaction to obtain a VCo-ZIF nanosheet array; and finally, adding the VCo-ZIF into a sulfur source solution, and vulcanizing to obtain the vanadium-doped Co9S8 nanosheet array. The formed porous nanosheet structure can provide a larger active specific surface area, the synergistic effect between Co and V ions can improve the charge storage capacity of the material, and sulfur vacancies on the surface of the electrode material can increase the conductivity and the number of active sites. Practice shows that when the material is used as a supercapacitor electrode material, the specific capacity and the rate capability are remarkably improved.

The invention relates to the technical field of battery materials, and discloses a positive electrode active material, a preparation method thereof and a secondary battery, and the positive electrode active material provided by the invention comprises a sodium-containing layered oxide, a selenium-antimony compound and carbon. The Sb element can induce radial orientation primary particles, and effectively reduce internal mechanical stress, so that development and diffusion of micromarks are hindered, intergranular cracking is inhibited, the structural stability of the material is enhanced, and the rate capability and the cycle stability of the material are improved; the Se element covers primary particles and secondary particles in situ in a Se-like compound form, so that side reaction between an electrolyte and a positive electrode is reduced, dehydrogenation of a common electrolyte organic solvent is inhibited, and the cycle performance of the positive electrode material is obviously improved; according to the invention, the carbon material is added, so that the conductivity between particles is enhanced, the battery polarization is reduced, the growth of crystal grains can be inhibited, the effect of refining the crystal grains is achieved, the diffusion path of Na < + > in the particles is shortened, and the rate capability of the material is improved.

The application relates to the technical field of battery materials, and discloses a sodium-philic carbon-based material, a negative-electrode-free current collector, a preparation method of the sodium-philic carbon-based material and a sodium metal battery. The preparation method of the sodium-philic carbon-based material comprises the following steps: providing a mixed solution, wherein the mixed solution comprises carbon source powder, an iron source and a solvent; fully reacting the mixed solution in a protective atmosphere at 160-240 DEG C; obtaining a carbon-loaded sodium-philic material after solid-liquid separation; fully calcining the carbon-loaded sodium-philic material in an inert atmosphere at 700-900 DEG C to obtain a porous sodium-philic precursor; and treating the porous sodium-philic precursor in a reaction gas atmosphere at 400-700 DEG C for 1-3 hours to obtain the sodium-philic carbon-based material. The reaction gas atmosphere is an ammonia gas and inert gas mixed atmosphere or an ammonia gas atmosphere. The material is coated on the surface of the negative-electrode-free sodium metal battery current collector, and can enhance the electrochemical performance of the battery.

This invention relates to a core-shell structured sodium iron phosphate pyrophosphate cathode material, its preparation method, electrode sheet, and battery, belonging to the technical field of methods or devices for directly converting chemical energy into electrical energy. The core-shell structured sodium iron phosphate pyrophosphate cathode material of this invention comprises primary particles, each primary particle including: a core, a sodium iron phosphate pyrophosphate shell layer disposed on at least a portion of the surface of the core, and a carbon coating layer located within the pores and on the surface of the sodium iron phosphate pyrophosphate shell layer; the core includes a NASICON-type sodium-ion inorganic solid electrolyte with an average particle size ≤50nm; the average thickness of the sodium iron phosphate pyrophosphate shell layer is ≤500nm; the chemical formula of the sodium iron phosphate pyrophosphate shell layer is Na₄Fe₂O₃. 3‑ x M x (PO4)2P2O7, 0≤x≤0.9, M is a doped metal element. The core-shell structured sodium iron phosphate pyrophosphate cathode material of this invention combines high solid density, high conductivity and good electrochemical performance.

This invention discloses a modified sodium vanadium fluorophosphate material, its preparation method, and its applications. To address the technical problems of low conductivity and poor rate performance in existing sodium vanadium fluorophosphate materials, this invention employs a sodium hexametaphosphate-assisted hydrothermal method to construct an integrated preparation system of "surfactant regulation-hydrothermal crystallization." Sodium hexametaphosphate stabilizes the system and regulates the crystal nucleation rate by coordinating polyphosphate ions with the metal ions of the sodium vanadium fluorophosphate precursor. Simultaneously, it adsorbs at the crystal growth interface, inhibiting particle agglomeration and adjusting the crystal facet growth rate ratio through steric hindrance. The particle size of sodium vanadium fluorophosphate is continuously adjustable by controlling the amount of sodium hexametaphosphate added. The beneficial effects of this invention are: it effectively improves electrode mass transfer efficiency, synergistically enhances the electrochemical performance of sodium vanadium fluorophosphate materials, establishes a simple and efficient "one-step synthesis-performance optimization" technical solution, and provides a theoretical basis and experimental reference for the preparation and application of high-performance sodium vanadium fluorophosphate materials.

The invention discloses a resin-based sodium-ion battery hard carbon material and a preparation method thereof, and relates to the technical field of sodium-ion battery material preparation. The preparation method comprises the following steps: carrying out cross-linking reaction on a mixture of resin and a cellulose-based derivative to obtain a cross-linked precursor, and then carrying out pretreatment and high-temperature carbonization on the precursor to obtain the resin-based sodium-ion battery hard carbon material. The adopted resin and cellulose derivative have the advantages of low cost and wide source, have rich functional groups, and can be used as cross-linking agents to improve the cross-linking degree of the precursor, reduce the specific surface area of the hard carbon material and improve the first coulombic efficiency; carbonate generated in the pretreatment process of the cellulose derivative can be used as a salt template to regulate and control the internal pore structure of hard carbon. The rich pore structure is beneficial to permeation of electrolyte, the diffusion path of sodium ions can be shortened, and active sites of hard carbon are fully utilized, so that the cycling stability and the rate capability of the sodium ion battery are improved.

The invention discloses a positive electrode active material and a preparation method thereof, a positive electrode plate, a battery and electric equipment, the BET specific surface area of the positive electrode active material soaked in an acid solution is 1.75 m < 2 > / g-4m < 2 > / g, the porosity of the positive electrode active material soaked in the acid solution is 2.6%-6.5%, the weight ratio of the positive electrode active material to the acid solution is 1: 10, and the BET specific surface area of the positive electrode active material soaked in the acid solution is 1: 10. The pH value of the acidic solution is 5.5, and the soaking time is 2 hours. Therefore, the positive electrode active material provided by the invention has relatively high compaction density and excellent cycle performance.

The invention discloses a graphite composite material as well as a preparation method and application thereof. The material comprises graphite and a composite porous carbon layer coating the graphite, the composite porous carbon layer contains hard carbon and graphitized carbon, the graphite composite material is prepared from the raw materials of the composite porous carbon layer, the graphite and an oxygen-containing pore-forming agent, the raw materials of the composite porous carbon layer comprise a hard carbon precursor and a graphitized carbon precursor, and the oxygen-containing pore-forming agent is prepared from the hard carbon precursor and the graphitized carbon precursor. The mass ratio of the graphite to the total mass of the raw materials of the composite porous carbon layer is less than 28: 1, and the mass ratio of the graphitized carbon precursor to the hard carbon precursor is more than 1: 1; the ratio of the total mass of the raw materials of the composite porous carbon layer to the mass of the oxygen-containing pore-forming agent is more than 10: 1. When the graphite composite material disclosed by the invention is prepared into a negative electrode material of a secondary battery, the graphite composite material has excellent quick charging performance and good cycling stability, and a new possibility is developed for high-performance battery application in multiple fields of electric automobiles, portable electronic equipment, energy storage systems and the like.

The invention relates to the technical field of lithium manganese iron phosphate materials, in particular to modified lithium manganese iron phosphate, a preparation method thereof, a positive electrode material, a battery and application. The modified lithium manganese iron phosphate is prepared from the following raw materials: lithium manganese iron phosphate, C7H7ZnCl and silane; the mass ratio of the lithium manganese iron phosphate to the C7H7ZnCl to the silane is 1: (0.01 to 0.06): (0.01 to 0.08). According to the modified lithium manganese iron phosphate provided by the invention, the raw material contains the silane, and the silicon dioxide obtained by sintering the silane is used as a supporting structure of the LFMP, so that the thermal stability of the LFMP is improved.

The invention relates to the technical field of building materials and ocean engineering protection, in particular to a preparation method of a marine concrete heavy anti-corrosion coating. Comprising the following steps: 1, preparing materials and carrying out dry mixing to obtain an inorganic dry powder base material; step 2, preparing and mixing wet materials, taking polymer emulsion, a silane coupling agent and water, and uniformly mixing the polymer emulsion, the silane coupling agent and the water; in a stirring state, slowly dropwise adding the mixed solution into the inorganic dry powder base material in the step 1; step 3, dispersion and defoaming: stirring is kept in the dropwise adding process, a defoaming agent is added, high-speed dispersion is performed until the slurry is in a uniform flow state and has no obvious bubbles, and heavy-duty cement-based composite coating slurry is obtained; 4, film forming construction is conducted, specifically, a concrete base surface is coated with the slurry obtained in the step 3 through a layered coating technology, and an anti-corrosion coating is formed after standing and curing. According to the invention, the physical compactness of the coating is greatly improved, the water absorption rate of the coating is obviously reduced, and the anti-permeability pressure is improved.