65 results about "Iron phosphide" patented technology

The invention relates to the technical field of battery positive electrode materials, and provides a lithium iron phosphate positive electrode material and a preparation method thereof. The lithium iron phosphate positive electrode material has the characteristic of high energy density, the proportion of iron phosphide impurities in the total mass of the lithium iron phosphate positive electrode material is 0.001-0.008 PPM, the compaction density under the pressure of 3T is 2.68-2.8 g / cm < 3 >, the powder resistivity is 8-15 omega.cm, the 0.1 C discharge capacity is 161-163 mAh / g, the 0.1 C charge-discharge efficiency is 98.5-100%, and the 1C discharge capacity is 145-148 mAh / g. The preparation process is simple and safe, low in cost and high in stability. The content of iron phosphide impurities in a final lithium iron phosphate product can be regulated and controlled by regulating and controlling the phosphorus-iron ratio of the iron phosphate precursor and the ratio of the carbon source to the iron phosphate precursor in two-time burdening and controlling the sintering temperature in cooperation with secondary sintering, and the high-energy-density lithium iron phosphate positive electrode material is obtained.

The invention relates to the technical field of preparation of positive electrode materials, in particular to a preparation method and application of a lithium iron phosphate material. The preparation method at least comprises a process of sintering a precursor material under a reduction condition to obtain the lithium iron phosphate material, wherein the precursor material at least comprises an iron source, a lithium source, a phosphorus source and a metal dopant, the mass ratio of the metal dopant is larger than or equal to 0, and the molar ratio of the iron element to the total phosphorus and the molar ratio of the doped metal to the total phosphorus are 0.96-0.97. According to the preparation method, generation of the iron phosphide (Fe3P, Fe2P, FeP and the like) impure phase is controlled from the burdening end by regulating and controlling the proportion of specific elements in the raw materials, so that preparation of the lithium iron phosphate material with high compaction and low iron phosphide impure phase is realized, and subsequent complicated impurity removal operation is avoided.

The invention belongs to the technical field of energy and electrochemical catalysis, and discloses a titanium nitride / transition metal phosphide heterojunction electrode with a nano array structure, a preparation method of the titanium nitride / transition metal phosphide heterojunction electrode and application of the titanium nitride / transition metal phosphide heterojunction electrode to seawater electrolysis for hydrogen production. The electrode comprises titanium nitride grown on a conductive substrate and transition metal phosphides (such as cobalt phosphides, nickel phosphides, iron phosphides or a combination thereof) loaded on the surface of the titanium nitride. According to the composite electrode, a titanium dioxide nano array is synthesized on a conductive substrate through seed crystal assisted solvothermal, and a titanium nitride electrode is obtained through high-temperature nitridation; and then carrying out hydrothermal loading on a transition metal precursor and carrying out low-temperature phosphating treatment to obtain the titanium nitride / transition metal phosphide composite electrode. By combining high conductivity and corrosion resistance of titanium nitride and high catalytic activity and electrochemical stability of transition metal phosphide, the technical problems that a traditional electrode is easy to corrode and poor in catalytic stability in a seawater environment are solved; the synthesized titanium nitride / transition metal phosphide composite electrode is of a multi-scale graded nano array structure, and the micro-nano composite morphology of the composite electrode can be used for inducing the turbulence effect of an electrolyte, so that hydrogen evolution bubble separation is accelerated, and interface adsorption of precipitates such as magnesium hydroxide / calcium hydroxide is inhibited. Through the innovative hierarchical heterostructure design, an efficient, low-cost and long-life electrode solution is provided for direct hydrogen production from seawater, and the method has a wide industrial application prospect.

A composite lithium manganese iron phosphate positive electrode material, and a preparation method therefor and a use thereof. The composite lithium manganese iron phosphate positive electrode material comprises a lithium iron phosphate core (1), and an iron phosphide intermediate layer (2) and a composite coating layer sequentially stacked on the surface of the lithium iron phosphate core (1), the composite coating layer comprising a lithium manganese iron phosphate material (3) coated with a carbon material (4). A unique structural design enables the positive electrode material to have excellent electrochemical performance.

The present application belongs to the technical field of secondary batteries, and specifically relates to a lithium iron phosphate composite cathode active material, and further discloses a preparation method thereof, as well as an application thereof for use in the preparation of battery plates and secondary batteries. The lithium iron phosphate composite cathode active material of the present application comprises a core containing a lithium iron phosphate material and iron phosphide particles, as well as a carbon coating layer and / or a LiBO2-containing coating layer at least partially coated on the surface of the core.

The invention relates to a carbon-coated lithium iron phosphate material and a preparation method thereof, a positive plate and a battery. The carbon-coated lithium iron phosphate material comprises a lithium iron phosphate matrix and a carbon coating layer at least partially coating the lithium iron phosphate matrix, and the carbon coating layer comprises a carbon material doped with a silicon element and a boron element. According to the carbon-coated lithium iron phosphate material, the surface of the lithium iron phosphate matrix is coated with the carbon coating layer, and the carbon material in the carbon coating layer is doped with the silicon element and the boron element, so that the electronic conductivity of the lithium iron phosphate material can be improved; in addition, doping sources of the silicon element and the boron element can react with magnetic substances such as iron phosphide in the coating process to be converted into non-magnetic inert substances, then the content of magnetic foreign matter impurities in the carbon-coated lithium iron phosphate material is reduced, the overcharge problem is solved, the carbon-coated lithium iron phosphate material has good overcharge prevention performance, and the safety performance is improved.

The invention belongs to the technical field of catalyst preparation, and provides an iron-nickel-phosphorus catalyst, a preparation method and application thereof, and a method for producing an aqueous hydrogen peroxide solution through electro-catalysis. The preparation method comprises the following steps: mixing nickel chloride, ferric chloride, elemental phosphorus and alcohol amine, and carrying out solvothermal reaction to obtain the iron-nickel-phosphorus catalyst. The iron-nickel-phosphorus catalyst containing iron phosphide, nickel phosphide and iron-doped nickel phosphide is obtained by taking a nickel salt, an iron salt, a phosphorus simple substance and a reducing solvent as raw materials and carrying out solvothermal reaction. The iron-nickel-phosphorus catalyst obtained by the invention can efficiently generate hydrogen peroxide through electro-catalysis in an electrolyte with the pH value of 5-9, so that the pH value range of the prepared hydrogen peroxide aqueous solution is wide, and the application range and field are wider; compared with selenium-doped cobalt phosphide in the prior art, the prepared hydrogen peroxide aqueous solution is wider in application.

The invention discloses an integrated nano-enzyme with multiple response mechanism synergism, and a preparation method and application thereof. A Z-type heterojunction based on boron nanosheets (B NSs) and rare earth doped iron phosphide (Nd < 0.02 > Fe < 1.98 > P) is constructed for the first time, and CTAB is used for surface modification to obtain a ternary composite nano-enzyme (BFC); according to the present invention, the material is endowed with the multi-response ability (POD / GSHOx enzyme activity synergistic activation) on the bacterial infection microenvironment (low pH and high H2O2), and the nano-enzyme has excellent acoustic-magnetic responsiveness, can break through the depth limitation, and can achieve the precise and controllable generation of the reactive oxygen species (ROS). Under the acidic microenvironment of pulmonary infection, the activity of peroxidase (POD) and glutathione oxidase (GSHOx) is activated, so that efficient and controllable synergistic killing is performed on bacteria.

The invention belongs to the technical field of battery materials, and particularly relates to a method for determining iron phosphide in a phosphate positive electrode material, the positive electrode material and application. Comprising the following steps: preparing standard solutions of a series of phosphate positive electrode materials with different iron phosphide contents; respectively collecting and purifying magnetic substances in the standard solutions, and adding a quimocilidone reagent to determine the corresponding quinoline phosphomolybdate precipitate; drawing a standard curve according to the mass of the iron phosphide and the mass of the quinoline phosphomolybdate precipitate in the standard solutions with different iron phosphide contents; preparing a to-be-detected solution, collecting and purifying magnetic substances in the to-be-detected solution, adding a quinmolybdenum citronone reagent to determine the mass of the quinoline phosphomolybdate precipitate, and calculating the content of iron phosphide in the to-be-detected phosphate positive electrode material. By means of the method, the content of trace iron phosphide in the phosphate positive electrode material can be efficiently, accurately and quantitatively analyzed, the content of iron phosphide in the phosphate positive electrode material can be quantitatively regulated and reduced, and the electrochemical performance of the phosphate positive electrode material is improved.

A catalytic electrode includes a nickel-based porous base material, and a plurality of catalytic alloy balls of nickel and another metal doped with elements, in which the another metal includes iron, the elements include C, F, and S, and the catalytic alloy balls are dispersed on the surface of the nickel-based porous base material. The catalytic electrode also includes a plurality of metal phosphide particles covering the nickel-based porous base material and the catalytic alloy balls, and the metal phosphide particle includes nickel phosphide, nickel iron phosphide, nickel cobalt phosphide, nickel copper phosphide, or nickel zinc phosphide.

The invention discloses an iron phosphide catalyst for separating hydrogen isotopes from PEM electrolyzed water and a preparation method of the iron phosphide catalyst, and the preparation method of the iron phosphide catalyst comprises the following steps: step 1, adding ferric salt and carbon black into a solvent according to a certain proportion, dispersing, and evaporating the solvent to obtain a uniform mixture of the ferric salt and the carbon black; 2, heating the mixture obtained in the step 1 at a high temperature, and introducing hydrogen-argon mixed gas to obtain an intermediate product Fe / C; and 3, carrying out high-temperature phosphorization on Fe / C and red phosphorus under the protection of argon to obtain the iron phosphide catalyst. The non-noble metal iron phosphide catalyst is synthesized to replace a traditional noble metal platinum carbon catalyst, the cost is reduced, and the hydrogen isotope separation factor is remarkably increased to 6-8; the cathode iron phosphide catalyst disclosed by the invention is high in stability, the performance of the cathode iron phosphide catalyst is almost not attenuated after long-time electrolytic reaction, an electric pile can stably run for about more than 2000 hours under the condition that the current density is 0.5 A / cm < 2 >, and the cathode iron phosphide catalyst has a very high industrial application value.

The application discloses a kind of foam nickel load iron nickel bimetallic phosphide heterojunction catalyst and its preparation method and application, belong to electrocatalytic material technical field.The application is in situ grown by hydrothermal deposition in combination with low-temperature phosphorization process, and is prepared on foam nickel base Phosphide iron / Phosphide nickel heterojunction catalyst (Fe2P / Ni2P@NF).The prepared catalyst shows excellent performance in the electrocatalytic reduction of nitrate synthesis ammonia and high nitrate wastewater degradation.The preparation process of the catalyst of the application is simple, low in cost, and little to environmental pollution, and the self-supporting electrode prepared by integration can be directly applied to proton exchange membrane electrolytic cell, and has wide application prospect.

The invention relates to an N-FeP / IF-coated Au material and a preparation method and application thereof.The preparation method comprises the steps that foam iron IF is placed in surface treatment liquid to be subjected to surface treatment, and foam iron subjected to surface treatment is obtained; the method comprises the following steps: putting foam iron which is cut into round sheets and is subjected to surface treatment into a porcelain boat, putting the porcelain boat into a tubular furnace filled with protective gas, putting a porcelain boat filled with sodium hypophosphite in the tubular furnace according to the ventilation direction of the protective gas and the ventilation upstream direction, heating the tubular furnace to enable the foam iron to be subjected to phosphating reaction, and then cleaning and drying a product, so as to obtain a phosphating product. The foam iron loaded with iron phosphide is obtained and marked as FeP / IF; under the mixed atmosphere of ammonia gas and inert gas, nitrogen doping is conducted on FeP / IF, and foam iron loaded with nitrogen-doped iron phosphide is obtained and marked as N-FeP / IF; in a magnetron sputtering vacuum bin, gold is used as a target material, N-FeP / IF is used as a substrate, gold deposition is carried out on the substrate, and nitrogen-doped iron phosphide foam iron with gold deposition is obtained and is recorded as N-FeP / IF at Au.

A process for the production of iron phosphate, comprising the following steps: (1) Mixing an iron phosphide waste, an acidic liquid, an oxidizing agent and an adsorbent with stirring, heating to leaching and subjecting the resulting mixture to solid-liquid separation to obtain a first filtrate and a first filter residue; (2) Adding an alkaline liquid to the first filtrate to adjust the pH of the first filtrate, maintaining a temperature of the resulting mixture, and subjecting the resulting mixture to solid-liquid separation to obtain a second filter residue and a second filtrate; and subjecting the second filter residue to heat treatment to obtain iron oxide; (3) Subjecting the iron oxide to high-energy ball milling and adding a surfactant for activation to obtain a slurry; (4) Adding an extraction agent and an acidic liquid to the second filtrate obtained in step (2), carrying out an extraction and separation on a resulting mixture and subjecting a resulting organic phase to back-extraction to obtain phosphoric acid; and (5) Mixing the slurry obtained in step (3) with the phosphoric acid, heating to enable a reaction, subjecting the resulting mixture to solid-liquid separation to obtain a solid, and washing and sintering the solid to obtain the iron phosphate; where in step (1) the iron phosphide waste comprises a mixture of FeP and Fe2P; in step (1) the acidic liquid contains at least two from the following group: nitric acid, sulfuric acid and hydrochloric acid; In step (1) the oxidizing agent is at least one selected from the group consisting of hydrogen peroxide, oxygen, nitric acid and sodium persulfate; wherein in step (2) the alkaline liquid is at least one selected from the group consisting of a NaOH solution, a KOH solution, ammonia water, a urea solution, NH4Cl, NH4HCO3, Na2CO3 and NaHCO3; In step (2) the pH of the first filtrate is adjusted to 2.5 to 5; and In step (5) the molar ratio of Fe in the slurry to P in the phosphoric acid is 1:1–2; heating to enable a reaction is carried out at a temperature of 50 °C to 80 °C for 20 to 60 min; and the iron phosphate has a D 50 from 2 µm to 6 µm, a tapped density of 0.80 g / cm³ 3 up to 1.30 g / cm³ 3 , and a specific surface area of ​​4 m² 2 / g up to 8 m 2 / g indicates.

The present invention provides an iron phosphide negative electrode material and a preparation method thereof and a lithium battery, relating to the technical field of lithium ion batteries. Specifically, the preparation method comprises the following steps: (1) mixing an iron source, a nitrogen source and a solvent, and preparing a nano-sized N-FeP2 precursor by a solvent thermal reaction; (2) subjecting the N-FeP2 precursor and sodium hypophosphite to a gas-cured phosphating reaction to prepare nano-sized N-FeP2; (3) drying a solution containing a carbon source and the N-FeP2, heating the dried product in a protective gas atmosphere for pre-carbonization and carbonization reaction, and cooling to obtain the iron phosphide negative electrode material N-C@FeP2. The method of the present invention improves the volume expansion and fragmentation of the material through material nano-sizing, nitrogen doping and surface carbon coating, reduces resistance, and effectively improves the electrochemical performance of the product.

The invention relates to a positive active material, a preparation method thereof and a battery, and belongs to the technical field of batteries. V ions in the lithium ferrovanadium phosphate active material enter LFP crystal lattices through doping to replace Fe < 2 + > sites to form lattice defects, and in order to maintain electric neutrality, the system spontaneously generates additional free electrons, so that the electronic conductivity is increased, and the rate performance of the lithium ferrovanadium phosphate active material applied to a battery is facilitated. And meanwhile, on the basis of doping the V element, the mass content of iron phosphide in the lithium ferrovanadium phosphate active material is controlled to be less than or equal to 800ppb, so that the probability of side reaction with an electrolyte when the lithium ferrovanadium phosphate active material is applied to a battery can be reduced, and the cycle performance is facilitated. And the lithium iron vanadium phosphate active material has two particles with specific volume median particle sizes, so that a relatively good particle size grading relationship can be formed, the lithium iron vanadium phosphate active material has relatively high compaction density, and the volume energy density of the lithium iron vanadium phosphate active material when the lithium iron vanadium phosphate active material is applied to a battery is facilitated.

The application discloses nitrogen-doped iron phosphide and a preparation method thereof, a negative electrode material, a secondary battery and an electric equipment, and the preparation method comprises the following steps: S1, dissolving iron salt and urea in an organic solvent to obtain a mixed solution; then, performing a solvothermal reaction on the mixed solution to obtain an iron phosphide precursor; and S2, performing phosphorization treatment on the iron phosphide precursor by using a hypophosphite under a protective atmosphere to obtain the nitrogen-doped iron phosphide. The nitrogen-doped iron phosphide prepared by the method overcomes the problems of large irreversible capacity and low electronic conductivity of the iron phosphide negative electrode material.

The present invention provides: a hydrogenation catalyst which can be used in a hydrogenation reaction of a cyclic aldehyde; and a method for producing an alcohol compound by hydrogenation of a cyclic aldehyde using the hydrogenation catalyst. The present invention pertains to a catalyst for hydrogenation of a cyclic aldehyde, the catalyst containing iron phosphide nanoparticles. It is preferable that the iron phosphide nanoparticles are rod-shaped particles and the maximum length of the rod-shaped particles in the major axis direction is less than 100 nm. It is preferable that the catalyst for hydrogenation of a cyclic aldehyde is a catalyst for hydrogenation of a furfural derivative.

The present invention provides a cathode active material comprising primary particles which include at least one transition metal and further comprise an iron phosphide compound, and thus exhibiting excellent charge / discharge capacity and rate performance on the basis of excellent electronic conductivity.

The invention belongs to the technical field of acyclic compounds, and particularly relates to a preparation method of tert-amyl peroxyacetate. Adding a tert-amyl hydrogen peroxide aqueous solution into a solvent, and stirring to obtain a mixed solution; under the stirring condition, p-toluenesulfonic acid and iron phosphide are sequentially added into the mixed solution, stirring reaction continues after adding is completed, and reaction liquid I is obtained; under the stirring condition, acetic anhydride is added into the reaction liquid I, stirring reaction continues after adding is completed, and reaction liquid II is obtained; adding a washing liquid into the reaction liquid II, stirring, washing, and separating to obtain a tert-amyl peroxyacetate crude product; and washing and drying the tert-amyl peroxyacetate crude product, and removing the solvent to obtain the tert-amyl peroxyacetate. The method avoids the problems of a large amount of hydrochloric acid generated by a traditional acyl chloride method and corrosivity caused by using sulfuric acid as a catalyst; meanwhile, iron phosphide has magnetism, cyclic utilization can be achieved through magnetic separation after the reaction is finished, p-toluenesulfonic acid can be regenerated through ion exchange resin, and the production cost is greatly reduced.

This application provides a lithium iron phosphate cathode material, its preparation method, a cathode sheet, and a secondary battery, relating to the field of secondary battery technology. The preparation method of the lithium iron phosphate cathode material includes the following steps: mixing lithium iron phosphate material containing iron phosphide, an oxidizing lithium source, a phosphorus source, an oxidant, water-soluble organic titanium, and a carbon source to obtain a mixture; mixing the mixture with an aqueous phase and subjecting it to gelatinization treatment to obtain a slurry; and sequentially subjecting the slurry to drying and sintering treatments to obtain the lithium iron phosphate cathode material. The technical solution of this application aims to solve the technical problem that the high iron phosphide content in lithium iron phosphate materials makes it difficult to simultaneously achieve good capacity and charge-discharge performance.

The application provides a composite lithium negative electrode material for a solid-state lithium metal battery and a preparation method and application thereof, the preparation raw material of the composite lithium negative electrode material comprises an additive, lithium metal and a solid-state electrolyte; the additive is selected from one or more of gallium phosphide, indium phosphide, tin phosphide, iron phosphide, cobalt phosphide, nickel phosphide, molybdenum phosphide, manganese phosphide, black phosphorus and red phosphorus. The composite lithium negative electrode material prepared by using the additive has good wettability to the solid-state electrolyte sheet, significantly reduces the interface resistance between the solid-state electrolyte and the lithium metal negative electrode, improves the critical current density and the cycle stability, is very close to the solid-state electrolyte sheet at the interface, has good matching with a commercial lithium iron phosphate positive electrode, and the assembled full battery has excellent rate performance and cycle performance.

The present application relates to a composite cathode active material comprising an iron phosphide compound, and further discloses a preparation method thereof, as well as an application thereof for use in the preparation of battery positive electrode plates and secondary batteries. The composite cathode active material of the present application comprises lithium iron phosphate particles, lithium iron phosphate particles coated with carbon, lithium iron phosphate particles coated with an iron phosphide compound, lithium iron phosphate particles coated with an iron phosphide compound and carbon, and iron phosphide compound particles.

The invention relates to the field of new energy materials, and particularly provides a biomass-derived carbon-supported iron phosphide nano-catalyst and a preparation method and application thereof.The biomass-derived carbon-supported iron phosphide nano-catalyst is prepared by taking waste biomass as a raw material and sodium hypophosphite as a phosphorus source through high-temperature carbonization and activation treatment to obtain a biochar carrier with a high specific surface area and a porous structure; the method is used for loading iron phosphide so as to improve the stability and the conductivity, a traditional high-energy-consumption and high-pollution ammonia synthesis process is replaced with an electro-catalysis technology, and a new way is provided for achieving green and efficient synthesis of ammonia. The invention not only helps to solve the problems of energy and environment, but also opens up a new direction for resource utilization of agricultural wastes.

This invention belongs to the field of acyclic compound technology, specifically relating to a method for preparing tert-amyl peroxide. A tert-amyl hydrogen peroxide aqueous solution is added to a solvent and stirred to obtain a mixed solution. Under stirring conditions, p-toluenesulfonic acid and ferric phosphide are added sequentially to the mixed solution. After the addition is complete, stirring continues to produce reaction solution I. Under stirring conditions, acetic anhydride is added to reaction solution I. After the addition is complete, stirring continues to produce reaction solution II. A washing solution is added to reaction solution II, and the mixture is stirred and washed, then separated to obtain crude tert-amyl peroxide. The crude tert-amyl peroxide is washed, dried, and the solvent is removed to obtain tert-amyl peroxide. This invention avoids the problems of large amounts of hydrochloric acid produced by traditional acyl chloride methods and the corrosiveness caused by using sulfuric acid as a catalyst. Furthermore, ferric phosphide is magnetic, allowing for recycling through magnetic separation after the reaction. p-Toluenesulfonic acid can be regenerated through ion exchange resin, significantly reducing production costs.

This application belongs to the field of electrocatalysis and photoelectrocatalysis materials technology, specifically relating to a nickel phosphide-iron phosphide self-supporting electrode, its preparation method, and its application. This application provides a method for preparing a nickel phosphide-iron phosphide self-supporting electrode, which directly constructs an active layer on a conductive nickel foam substrate through in-situ hydrothermal growth combined with a gas-phase phosphating strategy. The nickel foam not only acts as a conductive current collector but also participates in the growth of the precursor as a reaction substrate, enhancing the bonding force between the active layer and the substrate, completely avoiding the use of binders, and effectively reducing interfacial resistance. The phosphating treatment transforms the nickel-iron precursor into a phosphide with metal-like properties, significantly improving the electrode's conductivity and intrinsic catalytic activity, thereby solving the problem of slow reaction kinetics.

This invention discloses a method for preparing high-compact lithium iron phosphate (LFP) cathode material and the prepared LFP cathode material. Using lithium, iron, phosphorus, and carbon sources as raw materials, the LFP cathode material is prepared via a high-temperature solid-state method. A flux is added to the raw materials, and the flux is selected from one or more of magnesium carbonate, magnesium iodide, and magnesium hydroxide. This invention uses magnesium-containing compounds such as magnesium carbonate, magnesium iodide, and magnesium hydroxide as fluxes, enabling the preparation of LFP cathode material under low-temperature sintering conditions. This significantly reduces energy consumption, effectively avoids the generation of magnetic foreign matter such as iron phosphate, reduces electron transport resistance, and promotes particle densification growth. The compacted density of the prepared LFP cathode material is not less than 2.467 g / cm³. 3 The resistivity is not higher than 32.5 Ω•cm.

The application discloses a kind of detection methods of magnetic metal particles in lithium iron phosphate product, comprising the following steps: (1) the lithium iron phosphate product to be measured is added to nylon bucket, diluted with solvent, then add surfactant, obtain slurry;(2) the magnetic bar with isolation layer is immersed in the slurry in nylon bucket;(3) ball milling;(4) the metal particles adsorbed on the magnetic bar and isolation layer are washed into container;(5) the slurry is transferred to magnetic bed funnel, the collected metal particles are placed in container, and ultrasonic acid washing is carried out;(6) anhydrous ethanol is added in the container, and then ultrasonic treatment is carried out for 10-15min;Then carry out suction filtration, drying to obtain magnetic metal particles;(7) the obtained magnetic metal particles are analyzed and counted.The consumable cost of the isolation layer is saved by more than 20%;The interference of iron phosphide on the equipment during subsequent film scanning is reduced, so that the accuracy of identifying target metal particles is improved;The adsorption rate of magnetic metal particles in the detection method is improved.

The invention provides a preparation method and application of a NiP3 / FeP4 heterojunction carbon composite material, and belongs to the technical field of energy materials. Comprising the following steps: by taking nickel powder, iron powder and red phosphorus powder as raw materials, uniformly mixing and then adding into a ball milling tank for ball milling treatment to obtain a phosphorus-rich phase nickel phosphide / iron phosphide NiP3 / FeP4 heterojunction material; and uniformly mixing the obtained NiP3 / FeP4 heterojunction material with a carbon material, and then carrying out ball milling treatment again to obtain the NiP3 / FeP4 heterojunction carbon composite material. The preparation method provided by the invention adopts a two-step ball milling method for preparation, has the advantages of simplicity in operation, high efficiency, suitability for industrial large-scale production and the like, and the NiP3 / FeP4 heterojunction carbon composite material prepared by adopting the method has good stability, has higher lithium / sodium storage capacity due to the phosphorus-rich phase characteristic, and is suitable for industrial large-scale production. The method has a wide application prospect in the fields of lithium / sodium ion batteries, electro-catalysis, capacitors, photoelectric information and the like.

This invention discloses a lithium iron phosphate and its preparation method. The preparation process uses a conventional carbon source, polyethylene glycol (PEG), and an organic compound containing sulfonic acid groups as a composite carbon source. PEG promotes the uniformity of raw material mixing and carbon coating. SO3, generated from the decomposition of sulfonic acid groups, has a certain oxidizing property and counteracts the reducing atmosphere on the surface of lithium iron phosphate particles, inhibiting the excessive reduction of lithium iron phosphate to iron phosphide. The pyrolysis and carbonization of PEG and the sulfonic acid-containing organic compound compensate for the uneven coating problem of conventional carbon sources, forming a uniform conductive carbon layer on the surface. This significantly improves the electronic conductivity of the finished lithium iron phosphate cathode material, suppresses electrolyte side reactions, and thus improves initial efficiency and rate performance. The sulfonic acid compounds have high chemical stability, ensuring that more sulfonic acid compounds decompose during the high-temperature calcination stage, thereby ensuring the thoroughness and effectiveness of inhibiting the excessive reduction of lithium iron phosphate to iron phosphide.