664 results about "Ferromanganese" patented technology

The invention discloses a modified carbon-coated sodium manganese ferric phosphate pyrophosphate / sodium ferric phosphate pyrophosphate positive electrode material as well as a preparation method and application thereof, and relates to the technical field of new energy materials. The preparation method comprises the following steps: preparing MnFe-MOF from a manganese source, a first iron source and a first organic ligand under a hydrothermal reaction; a second iron source, the MnFe-MOF and a second organic ligand are subjected to a hydrothermal reaction, and MnFe-MOF / Fe-MOF is obtained; uniformly mixing with a sodium source and a phosphorus source, and sintering to obtain a positive electrode material; and carrying out high-temperature gas-phase etching treatment to obtain the fluorine-doped carbon-coated modified sodium manganese ferric phosphate pyrophosphate / sodium ferric phosphate pyrophosphate positive electrode material. The material disclosed by the invention has a coating modified structure, so that an interface side reaction caused by direct contact between sodium ferromanganese phosphate and an electrolyte can be effectively avoided, a manganese dissolution phenomenon is reduced, and the structural stability of the material is improved; and meanwhile, the material has high conductivity, excellent structural stability, excellent long cycle life and excellent rate capability.

The invention discloses a direct-current hollow electrode hydrogen plasma furnace mineral powder smelting system and method and application, and belongs to the technical field of hydrogen metallurgy. The system comprises a hollow electrode gas powder injection hydrogen plasma gun system, a direct current bottom electrode ore-smelting electric furnace system, a fine ore and hydrogen supply system and the like. The hollow electrode and the furnace bottom electrode form a direct-current arc, hydrogen carrying mineral powder is sprayed into an arc area to generate high-temperature hydrogen plasma, mineral powder reduction is achieved, and metal and slag are separated. According to the method, hydrogen serves as a reducing agent, carbon emission is reduced, the reaction efficiency is high, energy consumption is low, and the method can be used for steelmaking, smelting of micro-carbon ferromanganese and titanium slag and recovery of valuable metal in nonferrous smelting waste slag and has good green metallurgy application prospects.

A preparation method for a lithium manganese iron phosphate positive electrode material, comprising the following steps: (1) uniformly stirring an iron source, a phosphorus source, a lithium source and a dispersing agent in water, adding a manganese source, and uniformly mixing same to obtain a precursor pre-slurry; and (2) adjusting the solid content of the precursor pre-slurry to reach a target solid content A, the target solid content A satisfying 30 wt% ≤ A ≤ 60 wt%; (3) carrying out primary grinding treatment on the precursor slurry obtained in step (2); and (4) adding an organic phosphine scale and corrosion inhibitor to the precursor slurry, dissolving same, then drying the obtained slurry, and performing sintering and crushing to obtain the lithium manganese iron phosphate positive electrode material. Also provided is a positive electrode material prepared by the method.

The invention provides a lithium manganese iron phosphate precursor hydrate which comprises a mixture of manganese phosphorus ore phase manganese manganese phosphate and ammonium manganese iron phosphate, and the molar ratio of the manganese phosphorus ore phase manganese manganese phosphate to the ammonium manganese iron phosphate is (1: 9)-(1: 1). A precursor material obtained by roasting the precursor hydrate is uniform in manganese and iron element distribution and good in processability, and lithium manganese iron phosphate with relatively high compaction density, relatively high capacity and better comprehensive performance can be prepared. The invention also provides a preparation method of the lithium iron manganese phosphate precursor hydrate, a lithium iron manganese phosphate precursor, lithium iron manganese phosphate and a secondary battery.

The invention discloses a metal composite lithium iron phosphate solid-phase deposition coated lithium manganese iron phosphate positive electrode material and a preparation method thereof, and belongs to the technical field of lithium ion battery positive electrode materials. The preparation method of the metal composite lithium iron phosphate solid-phase deposition coated lithium iron manganese phosphate positive electrode material comprises the following steps: S1, preparing a lithium iron manganese phosphate material and sintering; s2, grinding lithium iron phosphate into nano particles, and mixing the nano particles with a sugar source to form lithium iron phosphate nano slurry; s3, transferring into a CVD (Chemical Vapor Deposition) fluidized bed in the lithium manganese iron phosphate cooling and sintering stage, spraying lithium iron phosphate nano slurry, gasifying and drying the lithium iron phosphate material, and coating the surface of the lithium manganese iron phosphate with the lithium iron phosphate material through solid-phase deposition; and S4, carrying out composite coating of carbon and metal oxide on the lithium manganese iron phosphate coated with the lithium iron phosphate to obtain the lithium manganese iron phosphate coated with the lithium iron phosphate. According to the invention, the problem of poor uniformity of lithium iron phosphate coated lithium iron manganese phosphate is solved, the electrical property of lithium iron manganese phosphate is improved, the ferromanganese dissolution is improved, and the cycle performance is improved.

The invention discloses a carbon-loaded high-entropy oxide and a preparation method thereof, the carbon-loaded high-entropy oxide is of a core-shell structure formed by coating carbon with a high-entropy oxide, and the high-entropy oxide comprises at least five metal elements of chromium, manganese, iron, cobalt, nickel and copper. The carbon-loaded high-entropy oxide has the advantages of low density, high dielectric loss and excellent wave-absorbing performance, and is expected to be widely applied to electromagnetic absorption and elimination in the fields of electronics, communication civil affairs and aerospace military.

The invention belongs to the technical field of magnetite beneficiation, and particularly relates to a method for removing iron impurities in minerals through manual and automatic three-stage combination in magnet beneficiation, a three-stage iron removal system is arranged, the iron impurities and ferromanganese are detected step by step according to the size of the iron impurities and the property of magnets or ferromanganese, and a detected magnetic field is cooperatively calibrated step by step; and iron impurities in the ores are removed in a classified manner. Compared with the prior art, the system has the beneficial effects that a manual and automatic three-stage combined iron removal solution is adopted, large magnetic iron impurities, small magnetic iron impurities and ferromanganese impurities in the process are efficiently classified and removed in a targeted manner, damage of the iron impurities to equipment such as an ore crusher and a belt conveyor is avoided, the operation efficiency of the process is improved, and the production cost is reduced. And the problem of removing iron impurities in magnet beneficiation is solved.

The present invention discloses a method for producing manganese monohydrogen phosphate trihydrate, a method for recycling Mn-containing mother liquor, and a cathode material, relating to the technical field of lithium-ion batteries. In the present invention, a solid manganese carbonate slurry is used as a bottom liquid to synthesize manganese monohydrogen phosphate. Through precipitation solid-phase transformation, an octahedral morphology feature is constructed, which has a larger specific surface area. During the subsequent synthesis of lithium iron manganese phosphate, it helps to improve the reactivity of Mn and form a more uniform lithium iron manganese phosphate cathode material, thereby improving the compaction capacity and electrochemical performance of the cathode material.

The invention relates to the technical field of electrode materials, and discloses a preparation method of a lithium iron manganese phosphate material and a lithium ion battery. The lithium iron manganese phosphate material is prepared by the following steps: performing in-situ growth in a cavity of polyethylene glycol-sucrose hybrid aerogel with a three-dimensional porous network structure to form a manganese iron phosphate precursor; the hybrid aerogel can control excessive agglomeration and disordered growth of ferromanganese phosphate precursor particles and avoid particle agglomeration, so that the finally formed lithium ferromanganese phosphate material particles are finer and more uniformly distributed, and an amorphous carbon-aluminum layer is formed during later calcination, so that the performance of the material is improved. The surface of lithium manganese iron phosphate particles is tightly coated with the composite material, electron transmission can be accelerated, particle pulverization can be reduced, meanwhile, corrosion of corrosive components in electrolyte can be inhibited, interface side reactions such as transition metal ion dissolution can be reduced, and finally the conductivity and cycling stability of the lithium ion battery are remarkably improved.

The invention provides a lithium manganese iron phosphate positive electrode material and a preparation method and application thereof. The method comprises the following steps: mixing manganese metal and iron metal, heating, melting and uniformly mixing in an inert gas atmosphere, and grinding into powder; adding an ammonium salt solution, continuously adding the ground manganese-iron alloy powder under heating to form a suspension, introducing compressed air and stirring, reacting, filtering, washing, drying, crushing and grinding to obtain a manganese-iron oxide precursor, feeding the manganese-iron oxide precursor, a lithium source, a phosphorus source and doped metal elements into pure water, adding a carbon source, mixing to form a suspension, and grinding and drying to obtain the lithium-phosphorus-doped manganese-iron composite material. And carrying out carbon thermal reduction in an inert gas atmosphere, and crushing to obtain the lithium manganese iron phosphate positive electrode material. The ferromanganese oxide precursor prepared by heating the metal manganese and the metal iron to a molten state and mixing the metal manganese and the metal iron realizes uniform dispersion of the manganese and the iron at an atomic level, avoids the problems of nonuniform mixing of the manganese and the iron and dissolution of the manganese, and improves the conductivity and the electrochemical performance of the material.

The application relates to a method for smelting high-manganese steel in a converter, and belongs to the technical field of steelmaking. The technical problem to be solved by the application is that the manganese content of end-point molten steel produced by a converter in the prior art is low. The technical solution provided by the application for solving the above technical problem is that carbon balls and high-carbon ferromanganese are added in stages according to oxygen supply amount in the smelting process of the converter, when the oxygen supply amount is within 0-10% and 10-80%, 30% and 70% of manganese alloy are respectively added; and when the oxygen supply amount is within 0-10%, 10-50%, 50-80% and 80-100%, 20%, 40%, 30% and 10% of carbonaceous raw materials are respectively added. Compared with the current process for producing high-manganese steel in a converter, the application reduces the investment of alloy heating furnaces and other equipment, meets the production requirements of more varieties of high-manganese steel, improves the metal yield of manganese, shortens the production cycle, and reduces the production cost of high-manganese steel.

The invention discloses a high-entropy doped manganese / iron-based layered material and a preparation method thereof, a pole piece and a battery, the material contains six different metal cations of manganese, iron, copper, titanium, lithium and magnesium in a transition metal layer, the material contains two different metal cations of sodium and calcium in a sodium layer, the chemical formula of the layered material is Na < 0.62 > Ca < 0.03 > Mn < 0.58 > Fe < 0.23 > Cu < 0.085 > Mg < 0.01 > Ti < 0.015 > Li < 0.08 > O < 2 >, the problem that the specific capacity is reduced and unstable in the prior art is solved.

The invention relates to the field of material science and mechanical engineering, in particular to a high-strength aluminum-magnesium-silicon material bolt for a new energy automobile and a preparation method of the high-strength aluminum-magnesium-silicon material bolt. The bolt is made of an aluminum-magnesium-silicon alloy, and the alloy contains magnesium, silicon, manganese, iron, chromium, titanium, scandium, rare earth elements and the balance of aluminum. By optimizing the proportion of rare earth elements (yttrium, lanthanum and cerium) and scandium, grains are effectively refined, the tensile strength, the yield strength and the ductility are improved, and meanwhile the corrosion resistance and the fatigue resistance are enhanced. The preparation method comprises the steps that vacuum melting is combined with the ultrasonic-assisted technology, alloy elements are evenly distributed, and then the material structure is optimized through solution treatment at the temperature of 540 DEG C for 1.5 h and aging treatment at the temperature of 160 DEG C for 8 h. And the surface of the bolt is subjected to anodic oxidation and coated with a composite coating containing silicon dioxide nanoparticles, so that the wear resistance and the corrosion resistance are improved. Through verification, the bolt has the excellent performance that the tensile strength is larger than or equal to 490 MPa, the yield strength is larger than or equal to 440 MPa, the ductility is larger than or equal to 8.5%, and the salt spray test time is larger than or equal to 1500 hours, and the fastening requirement of the new energy automobile under the complex working condition is met.

Disclosed is a preparation method for ammonium manganese iron phosphate. The preparation method comprises: respectively mixing a mixed salt solution of metals and an ammonium dihydrogen phosphate solution with an organic solution to obtain a mixed liquor of metal salts and a mixed liquor of phosphate; concurrently adding the mixed liquor of metal salts, the mixed liquor of phosphate and a first ammonia water into a base solution for reaction; and carrying out solid-liquid separation to obtain ammonium manganese iron phosphate. A mixed metal salt solution of a ferrous source and a manganese source and a phosphorus source are subjected to a coprecipitation reaction in an organic phase, to synthesize large-particle ammonium manganese iron phosphate with high compaction density. After the ammonium manganese iron phosphate is mixed with a lithium source and a carbon source, sintering can be carried out to prepare a lithium manganese iron phosphate cathode material.

The invention relates to low-cost high-toughness super-thick specification 450 MPa-grade marine pipeline steel. A hot-rolled coiled plate comprises the following chemical components in percentage by mass: 0.040-0.080% of C, 1.10-1.30% of Mn, 0.07-0.25% of Si, less than or equal to 0.0020% of S, less than or equal to 0.015% of P, 0.010-0.030% of Ti, 0.025-0.050% of Nb, 0.20-0.30% of Cr, less than or equal to 0.0005% of B, less than or equal to 1.5 ppm of H, less than or equal to 50 ppm of N and the balance of Fe and inevitable impurities. The production method comprises the working procedures of converter smelting, LF + RH refining, continuous casting, heating, rolling, ultra-fast cooling + laminar cooling and coiling. Low-carbon, manganese and niobium composite microalloying is utilized, medium-carbon ferromanganese is adopted to replace metal manganese, the low heating temperature is matched with the low-pressure ultra-fast cooling and layer cooling process, and the material cost is reduced on the premise that the performance of the ultra-thick steel strip is guaranteed.

The invention belongs to the technical field of lithium ion batteries, and relates to a preparation method and application of a lithium manganese iron phosphate positive electrode material with uniformly mixed iron and manganese, and the preparation method comprises the following steps: S1, synthesizing a spherical (Mn < 1-x > Fe < x >) 3 (PO4) 2 * xH2O precursor through a coprecipitation reaction; s2, removing crystal water from (Mn < 1-x > Fe < x >) 3 (PO4) 2 * xH2O in a protective atmosphere to obtain a (Mn < 1-x > Fe < x >) 3 (PO4) 2 precursor; s3, sanding and mixing the (Mn1-xFex) 3 (PO4) 2 precursor, a lithium source, a phosphorus source and water to obtain first slurry; s4, adding a carbon source into the first slurry, uniformly stirring to obtain second slurry, quickly drying, and granulating to obtain dry powder; and S5, roasting the dried powder in a protective atmosphere to obtain the lithium manganese iron phosphate positive electrode material LiMnxFe (1-x) PO4 / C, the lithium manganese iron phosphate secondary particle prepared by the method has a microsphere structure wrapped by nanosheets, the size of the secondary particle is 1-5 microns, the size is uniform, the dispersity is good, the grain size of the primary particle is 50-80 nm, the size of the material is obviously reduced, the path of lithium ions in the transmission process is shortened, and the rate capability of the lithium manganese iron phosphate positive electrode material is improved.

The invention relates to the technical field of battery materials, and discloses a method for producing lithium iron manganese phosphate by using a lithium iron phosphate reclaimed material, and the method comprises the following steps: S1, disassembling a waste lithium iron phosphate battery to obtain a waste pole piece; s2, mixing the pretreated waste pole piece with a manganese source and a lithium source; s3, presintering the mixture in an oxygen atmosphere at 650 DEG C for 4 hours, then heating to 750-800 DEG C, and sintering for 8-12 hours to obtain a lithium manganese iron phosphate material; and S4, crushing the sintered product through airflow, and controlling the frequency of a grading wheel to be 50-60 Hz, so that the particle size D100 of the lithium manganese iron phosphate material is less than 15 microns. According to the method, the positive plate of the waste lithium iron phosphate battery is used as a raw material to replace precursors such as high-purity phosphate, manganese salt and ferric salt required in the traditional process, so that the high cost of extracting or chemically synthesizing the raw material from ore is avoided.

The invention discloses a process for separating and recycling scandium, manganese and iron in iron-manganese slag, and belongs to the technical field of metallurgical engineering and comprehensive utilization of secondary resources. The method comprises the following steps: crushing the iron and manganese slag, mixing the crushed iron and manganese slag with a chlorinating agent and a molten salt medium, and carrying out chlorination reaction at 600-850 DEG C, so that iron and manganese are converted into chlorides to volatilize, and scandium is enriched in the slag; the volatile gas is subjected to multi-stage gradient condensation, and manganese and iron concentrates are respectively recovered in different temperature intervals; and leaching-extracting the chlorination residues to obtain a scandium-rich substance. According to the method, source separation and collaborative recovery of iron, manganese and scandium are achieved through pyrogenic process chlorination-condensation, the problems that in a traditional wet process, metal interferes with one another, the process is long, and pollution is heavy are solved, and the method has the advantages of being short in process, small in pollution and high in recycling degree.

The invention relates to the technical field of ferrous metallurgy, in particular to a smelting method for silicon deoxidation of low-carbon low-silicon aluminum killed steel. The method comprises a converter, an alloy fine adjustment station, RH refining and continuous casting. A strong bottom blowing mode is adopted in the later stage of converter blowing, and high-carbon ferromanganese, a ferrosilicon deoxidizing agent and lime are sequentially added during tapping; and after temperature measurement and sampling in the alloy fine tuning station, the steel ladle is transported to RH refining. And the RH executes different treatment modes according to Si and C components of the alloy fine tuning station, such as oxygen blowing decarburization and desilicication, direct aluminum particle addition alloying or vacuum reserved oxygen decarburization and the like. Through cooperation of silicon pre-deoxidation and aluminum final deoxidation, the oxygen content of RH entering molten steel and consumption of an aluminum deoxidizing agent are reduced, and the cleanliness of the molten steel is improved; different treatment modes shorten the treatment period, reduce the final temperature of the converter, meet the low-carbon and low-silicon requirements, reduce the production cost and improve the production efficiency.

The invention relates to the technical field of lithium ion batteries, and discloses a positive electrode material and a preparation method thereof, and a lithium ion battery, the preparation method comprises the following steps: (1) mixing a phosphorus source, a manganese source and water, carrying out primary grinding, and then mixing with an oxidizing agent or a reducing agent for reaction; (2) mixing the product obtained in the step (1) with an iron phosphate solution, controlling the temperature of a mixed system to 70-100 DEG C, washing, drying for the first time and calcining for the first time to obtain an iron phosphate coated manganese iron phosphate precursor; and (3) mixing the iron phosphate coated ferromanganese phosphate precursor obtained in the step (2) with a lithium source, a carbon source and a doping element M source, and then carrying out secondary grinding, secondary drying and secondary calcination. By adopting the preparation method disclosed by the invention, the iron phosphate is better precipitated on the phosphate radical-manganese compound, so that the positive electrode material with better coating effect and better performance parameters is obtained, and meanwhile, the dissolution of Mn < 3 + > can be effectively inhibited by coating.

In one aspect, a lithium manganese iron phosphate material includes a core, and a material of the core is represented by a general formula of LixMgyMnzFeaAlbPO4, where x is ranged from 1.008 to 1.05, y is ranged from 0 to 0.006, z is ranged from 0.4 to 0.6, a is ranged from 0.388 to 0.6, and b is ranged from 0 to 0.012.

The invention discloses a manganese iron oxalate precursor, a lithium manganese iron phosphate material and a preparation method and application of the manganese iron oxalate precursor and the lithium manganese iron phosphate material, and belongs to the technical field of battery materials. The lithium manganese iron phosphate material core layer is prepared by taking the oxalate manganese iron precursor with a specific particle size range, particle size distribution uniformity and a specific structure as a raw material, and meanwhile, the shell layer comprising the ionic conductive agent and carbon is introduced outside the core layer, so that the comprehensive performance of the lithium manganese iron phosphate material can be effectively improved; and thus, the capacity, the cycle performance and the first charge-discharge efficiency of the prepared corresponding secondary battery are improved.

To provide a calcined body that is processed easier than a conventional calcined body and where differences in hardness between production lots are suppressed.SOLUTION: A calcined body comprises: at least one first transition metal element selected from the group consisting of manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), molybdenum (Mo), technetium (Tc), ruthenium (Ru), rhodium (Rh), palladium (Pd), and silver (Ag); a coloring element of at least one of a lanthanoid rare earth element and a second transition metal element different in kind from the first transition metal element; and zirconia containing a stabilizing element. A content of the first transition metal element is 100 mass.ppm or more, a content of the second transition metal element is less than 100 mass.ppm, and an absolute value of a difference in hardness relative to a hardness of a calcined body obtained from a commercially available powder is 10 HV or less.SELECTED DRAWING: None

The invention discloses a platinum-based high-entropy intermetallic compound electrocatalyst and a preparation method thereof, the electrocatalyst is carbon material loaded platinum-based high-entropy intermetallic compound nanoparticles, and comprises 1-6 of six metal elements of platinum, manganese, iron, cobalt, nickel, zinc and copper, and 1-3 of three metal elements of gallium, indium and tin; in the nano-particles, platinum atoms account for 40%-60% of atoms, the platinum atoms and other metal atoms are orderly and regularly arranged, and the phase structure is an L10 phase. The preparation method of the platinum-based high-entropy intermetallic compound electrocatalyst is simple in process, and the metal loading capacity can be effectively controlled. Due to the introduction of the low-melting-point gallium / indium / tin metal, the high-entropy intermetallic compound can be prepared at a relatively low temperature, the agglomeration / sintering phenomenon is effectively avoided, and the platinum-based high-entropy intermetallic compound electrocatalyst with uniform size and adjustable components can be obtained. The electrocatalyst can be used for a fuel cell cathode material, and has important significance for improving the performance of a fuel cell.

The invention provides a ferromanganese-based NH3-SCR (selective catalytic reduction) denitration catalyst as well as a preparation method and application thereof. The ferromanganese-based NH3-SCR denitration catalyst is obtained through a reaction of Mn salt, Fe salt and Pr salt. The molar ratio of Mn to Fe is (1: 0.69)-(1: 0.71); and the molar ratio of Mn to Pr is (1: 0.05)-(1: 0.25). The preparation method of the ferromanganese-based NH3-SCR denitration catalyst comprises the following steps: providing Mn salt, Fe salt and Pr salt; wherein the molar ratio of Mn to Fe is (1: 0.69) to (1: 0.71); the molar ratio of Mn to Pr is (1: 0.05)-(1: 0.25); the Mn salt, the Fe salt and the Pr salt are subjected to a reaction, and the ferromanganese-based NH3-SCR denitration catalyst is obtained. In flue gas denitration, the catalyst has good sulfur resistance and water resistance and excellent low-temperature catalytic activity.

The invention discloses a lithium manganese iron phosphate positive electrode material, a preparation method thereof and an electrochemical device, and the preparation method comprises the following steps: mixing a manganese source, an iron source, a phosphorus source, a lithium source and a first carbon source, and carrying out primary grinding to obtain first mixed slurry; performing primary sintering on the first mixed slurry to obtain a base material; mixing the base material with water, and carrying out pressure filtration to obtain a solid material; mixing the solid material and a second carbon source, and performing secondary grinding to obtain second mixed slurry; and performing secondary sintering on the second mixed slurry to form a coating layer on the surface of the base material, the coating layer comprising a carbon layer, thereby obtaining the lithium manganese iron phosphate positive electrode material. The pH and specific surface area of the lithium manganese iron phosphate positive electrode material are effectively reduced by means of water washing and pressure filtration, and the processing performance of the lithium manganese iron phosphate positive electrode material in preparation of a rear-end electrochemical device is improved.

The invention provides a flux-cored wire for marine crack arrest steel and a preparation method and application of the flux-cored wire, and particularly relates to the technical field of welding materials. The flux-cored wire comprises a steel strip and a flux core filled in the steel strip, and the flux core comprises the following components in parts by weight: 10-15 parts of rutile, 5-6 parts of quartz, 2-4 parts of ferrotitanium, 20-40 parts of sodium fluoride, 20-40 parts of potassium feldspar, 6-18 parts of manganese-silicon alloy, 4-8 parts of low-carbon ferromanganese, 1.5-2.5 parts of magnesium powder, 1.5-2 parts of rare earth ferrosilicon, 0.2-0.4 part of ferroboron, 1-2 parts of metallic nickel and 1.5-6 parts of iron powder. The ship crack arrest steel flux-cored wire has the advantages of being high in strength, good in low-temperature toughness, good in crack resistance, high in deposition rate, stable in electric arc, little in splashing, easy in slag removal and attractive in weld joint forming, and is suitable for welding of crack arrest steel at a core structure part of an ultra-large container ship.

The invention provides an amorphous carbon coated lithium manganese iron phosphate positive electrode material and a preparation method and application thereof, the preparation method comprises the following steps: mixing a lithium source, a ferrous source, a manganese source, a phosphorus source, a carbon source and a solvent to obtain mixed slurry; carrying out spray drying treatment on the mixed slurry, and carrying out plasma treatment on the obtained dried material to obtain a precursor material; and mixing the precursor material with a boron source, and sintering to obtain the amorphous carbon coated lithium iron manganese phosphate positive electrode material. The surface of the lithium manganese iron phosphate positive electrode material is coated with the amorphous carbon layer, the bonding strength of the amorphous carbon coating layer and the positive electrode material is high, the problem of electronic conductivity of the lithium manganese iron phosphate positive electrode material is solved, and meanwhile, the ionic conductivity of the material is improved through boron doping.

The invention provides a method for preparing a positive electrode material, the positive electrode material, a positive electrode plate, a battery and an electric device. The method comprises the following steps: mixing a lithium source with a phosphoric acid solution to obtain a first mixture; mixing the first mixture with manganese hydrogen phosphate, an iron source and an optional M element source to obtain a second mixture; and drying and sintering the second mixture to obtain the lithium iron manganese phosphate positive electrode material, wherein the M element comprises one or more of transition metal elements except manganese and iron elements, IIA group metal elements, IIIA group metal elements, IVA group metal elements and VIIA group elements. According to the method, side reaction gas and by-products are reduced, the compaction density of the positive electrode material is improved, the resistivity of the positive electrode material is reduced, and the specific capacity and rate capability of the battery are improved.

The invention discloses a cerium-zirconium-based high-entropy oxide as well as a preparation method and application thereof. According to the cerium-zirconium-based high-entropy oxide, cerium and zirconium serve as main bodies, and meanwhile rare earth elements (lanthanum, praseodymium, neodymium and samarium) and transition metal elements (manganese, iron, cobalt, nickel, copper and zinc) are introduced to form a high-entropy solid solution with the equal molar ratio and containing 3-8 kinds of metal. In the cerium-zirconium-based high-entropy oxide, the cerium element and the zirconium element respectively account for 20%-40% of the total amount, and the other elements are respectively 10%-30% in an equimolar ratio. The cerium-zirconium-based high-entropy oxide catalyst prepared by the invention has excellent oxygen storage and release capacity and CO oxidation capacity, and the CO complete conversion temperature is 181 DEG C. The method adopts a simple coprecipitation process, is mild in condition and low in cost, and is suitable for large-scale application in the field of tail gas purification.