88 results about "Cobalt compounds" patented technology

The invention belongs to the technical field of electrochemical energy storage, and relates to a nitrogen-doped MXene loaded VCo double-monatomic catalyst as well as a preparation method and application thereof. The preparation method comprises the following steps: adding a nitrogen-containing precursor into at least one layer of MXene suspension, and uniformly stirring to obtain a suspension; respectively dissolving a cobalt-containing compound and a vanadium-containing compound in water to prepare a cobalt-containing compound solution and a vanadium-containing compound solution, adding the cobalt-containing compound solution and the vanadium-containing compound solution into the suspension, and performing stirring, ultrasonic treatment and crushing to obtain a mixed solution; freeze-drying the mixed solution to obtain a precursor; and carrying out heat treatment on the precursor, and washing, centrifuging and drying the obtained powder to obtain the nitrogen-doped MXene loaded VCo double-monatomic catalyst. According to the invention, VCo double monatomic atoms are anchored on the surface of the few-layer MXene, so that the MXene serving as a sulfur carrier of the room-temperature sodium-sulfur battery can effectively adsorb and catalyze conversion of sodium polysulfide, and the room-temperature sodium-sulfur battery with excellent cycle life and capacity is obtained.

The invention belongs to the technical field of chemical catalysis, and particularly relates to a preparation method of an alkali metal cation modified cobalt-nitrogen-carbon monatomic catalyst and application of the catalyst in electrosynthesis of hydrogen peroxide. The Co-N-C / X catalyst is obtained by taking a cobalt-containing compound as a metal source, mixing the metal source with a nitrogen-containing organic matter and a carbon material, performing rotary evaporation, grinding and high-temperature pyrolysis in an inert atmosphere, performing acid washing with strong acid to construct surface defects, and finally performing stirring adsorption with an alkali metal salt solution, suction filtration and drying. Alkali metal cations are physically adsorbed and anchored on the surface and interface of the Co-N-C catalyst instead of being dissolved in a solution, so that the electronic structure of Co active sites and the adsorption energy of the * OOH intermediate are optimized, and the problem of separation of alkali metal and a product is solved. When the catalyst is used for electro-catalytic oxygen reduction reaction, the H2O2 selectivity reaches up to 98%, the preparation process is simple, the cost is low, large-scale production can be realized, and the problems that the traditional method is high in energy consumption and large in pollution and the existing catalyst is insufficient in selectivity are solved.

The invention provides a ternary composite nanofiber capable of being used for marine metal corrosion prevention and electromagnetic wave absorption and a preparation method and application of the ternary composite nanofiber. The preparation method of the ternary composite nanofiber comprises the following steps: (1) preparation of a precursor solution: dispersing a copper salt and a cobalt compound in a first solvent, stirring until the copper salt and the cobalt compound are fully dissolved, adding a polymer, and uniformly mixing to obtain the precursor solution; (2) preparation of a nanofiber membrane: performing electrostatic spinning on the precursor solution to obtain the nanofiber membrane loaded with copper and cobalt metal ions; and (3) carbonization: drying the nanofiber membrane, and performing high-temperature treatment after drying to obtain the ternary composite nanofiber capable of being used for marine metal corrosion prevention and electromagnetic wave absorption. The preparation method of the ternary composite nanofiber is simple and low in cost, and the prepared ternary composite nanofiber has a huge application prospect when being used for electromagnetic wave shielding in corrosion environments such as ocean.

The method comprises the following steps: a) introducing a composite transition metal hydroxide precursor and a first cobalt compound into a reactor, and forming a second cobalt compound on the particle surface of the composite transition metal hydroxide precursor; and b) a step of mixing the composite transition metal hydroxide precursor with a sodium compound in which a second cobalt compound is formed on the surfaces of the particles, and then heat-treating the mixture to prepare a cobalt (Co)-doped sodium manganese-based oxide; wherein the sodium-manganese-based oxide contains at least nickel (Ni), manganese (Mn), and cobalt (Co), and the content of manganese is 55 mol% or more among all metals other than sodium. The invention provides a method for preparing a positive electrode active material for a sodium secondary battery, a positive electrode comprising the positive electrode active material, and a sodium secondary battery.

The invention relates to a method for recovering nickel and cobalt from a mixture of compounds of these metals from the recycling of spent lithium-ion batteries, comprising the following steps: a) digestion of a mixture of nickel and cobalt compounds in a solution containing hydrochloric acid having a concentration of more than 25 mass %, in case the mixture of nickel and cobalt compounds is solid; or bringing the mixture of nickel and cobalt compounds to a hydrochloric acid concentration of more than 25 mass %, in case the mixture of nickel and cobalt compounds is a solution; b) activation of ion-exchange resin in a column using hydrochloric acid; c) passing the solution from step a) through the column filled with the ion-exchange resin activated in step b); d) washing the column with hydrochloric acid having a concentration of more than 25 mass % in order to wash out the remaining solution containing nickel ions; e) washing the column with hydrochloric acid having a concentration of less than 10 mass % in order to wash out cobalt ions; f) extraction distillation of the nickel ion solution obtained in step d) in hydrochloric acid using sulfuric(VI) acid; phase separation in a spent liquid; recycling of a filtrate to distillation; dissolution of nickel sulfate(VI) and electrolysis in order to recover metallic nickel; g) extraction distillation of the cobalt ion solution obtained in step e) in hydrochloric acid using sulfuric(VI) acid; phase separation in a spent liquid; recycling of a filtrate to distillation; dissolution of cobalt sulfate(VI) and electrolysis in order to recover metallic cobalt; h) extraction distillation of the solution of diluted hydrochloric acid with nickel and cobalt ions obtained after the activation of the ion-exchange resin in step b), using sulfuric(VI) acid; phase separation in a spent liquid; recycling of a filtrate to distillation; recycling of a mixture of the formed cobalt sulfate(VI) and nickel sulfate(VI) to digestion in step a); i) rectification of diluted hydrochloric acid having a concentration below the azeotropic concentration (approx. 20.2 mass % at atmospheric pressure) formed in extraction distillation processes in steps f)-h) in order to concentrate hydrochloric acid and recover and recycle of water; recycling of concentrated hydrochloric acid to extraction distillation in steps f)-h).

The invention relates to a preparation method of a photocatalytic full-decomposition water film based on electrostatic spinning, and the preparation method comprises the following steps: S1, taking a carbon nitride precursor as a raw material, and carrying out secondary calcination to obtain an ultrathin g-C3N4 nanosheet; and carrying out electrostatic self-assembly on Co-coated BCN obtained by carrying out boron doping and cobalt compounding on the g-C3N4 and acidized Pt-coated CN obtained by carrying out platinum loading and acidizing treatment on the Co-coated BCN and the g-C3N4, so as to obtain the Co-coated BCN / Pt-coated CN photocatalyst. And S2, placing the Co-coated BCN / Pt-coated CN photocatalyst in an organic solvent, carrying out ultrasonic treatment, adding PAN, continuously carrying out ultrasonic treatment to obtain an electrostatic spinning solution, and carrying out an electrostatic spinning technology to obtain the photocatalytic full-decomposition water film. A carbon nitride precursor is used as a raw material, a carbon nitride-based photocatalyst Co (at) BCN / Pt (at) CN is obtained through modification means such as boron doping, cobalt compounding and platinum loading, the carbon nitride-based photocatalytic full-decomposition water film with high photocatalytic activity is prepared by combining an electrostatic spinning technology, and the carbon nitride-based photocatalytic full-decomposition water film can directly drive a water decomposition reaction under visible light to achieve efficient hydrogen production and oxygen production.

The invention discloses a nickel-cobalt-loaded nitrogen-sulfur-doped graphene aerogel microsphere and a preparation method and application thereof.The preparation method comprises the following steps that S1, a graphene oxide water-phase dispersion liquid is prepared, L-cysteine is added into the graphene oxide water-phase dispersion liquid, the mixture is stirred to be uniform, and a first mixed dispersion liquid is obtained; s2, performing electrostatic spraying, obtaining ice microspheres by combining an ice template method, and performing freeze drying to obtain nitrogen and sulfur doped graphene oxide aerogel microspheres; s3, reduction is carried out, and nitrogen and sulfur doped reduced graphene oxide aerogel microspheres are obtained; s4, preparing a nickel-cobalt compound mixed dispersion liquid, adding nitrogen and sulfur doped reduced graphene oxide aerogel microspheres into the nickel-cobalt compound mixed dispersion liquid, and uniformly stirring to obtain a mixed dispersion liquid II; and S5, carrying out hydrothermal reduction, washing and freeze drying to obtain the nickel-cobalt-loaded nitrogen-sulfur-doped graphene aerogel microspheres. The nickel-cobalt-loaded nitrogen-sulfur-doped graphene aerogel microspheres with high catalytic activity can be provided, and technical support is provided for catalyzing propylene cracking to grow carbon nanotubes.

The invention discloses a method for preparing a self-supporting Co / MoN composite three-dimensional graphene-like carbon material, which specifically comprises the following steps: soaking the self-supporting three-dimensional graphene-like carbon material in a solution containing a molybdenum compound and a cobalt compound, taking out the self-supporting three-dimensional graphene-like carbon material after soaking, drying the self-supporting three-dimensional graphene-like carbon material, and calcining the self-supporting three-dimensional graphene-like carbon material in an ammonia / inert gas atmosphere to obtain the self-supporting Co / MoN composite three-dimensional graphene-like carbon material. Based on high activity provided by the Co / MoN nanoparticles and high conductivity provided by the three-dimensional graphene-like carbon material, high capacity, high-rate discharge capacity and good cycle stability of the lithium-sulfur battery can be realized.

According to the lithium cobalt oxide and the preparation method of the lithium cobalt oxide provided by the invention, by utilizing the characteristics that a molten state reaction is more uniform than a pure solid state reaction and the particle size of a product is easier to control, two raw materials are distributed and molten in a grading and zoning manner, and when a lithium-containing compound is in a molten state, the lithium cobalt oxide is prepared; distributing the cobalt-containing compound in a solid state, a semi-molten state or a molten state into the lithium-containing compound material in the molten state; distributing the solid, semi-molten or molten cobalt-containing compound into a molten lithium-containing compound material layer, uniformly diffusing the cobalt-containing compound to each part of the material layer, and carrying out chemical reaction to generate lithium cobalt oxide; according to the method, the molten reaction is more uniform than the pure solid-phase reaction, the particle size of the product is easier to control, and the lithium cobalt oxide prepared by the method is good in uniformity and high in tap density.

The invention relates to the technical field of catalyst preparation, and provides a Co-loaded ferronickel-based three-way catalyst, a preparation method and application, and the preparation method of the Co-loaded ferronickel-based three-way catalyst comprises the following steps: S1, adding a divalent cobalt compound solution into a liner of a hydrothermal kettle; s2, a foamed ferronickel substrate is added into the divalent cobalt compound solution for a hydrothermal reaction, washing and drying are carried out after the reaction is finished, and a Co / NiFe (at) INF electrode is obtained; and S3, oxidizing and calcining the Co / NiFe (at) INF electrode to obtain the Co / NiFeO (at) INF electrode. Compared with the prior art, the preparation method of the Co-loaded nickel-iron-based three-way catalyst, disclosed by the invention, shows excellent HER activity and excellent stability under a high-current-density alkaline condition.

A positive electrode active material having both higher capacity and safety is provided. Provided is a method for manufacturing a positive electrode active material, including forming a mixed solution containing a cobalt compound and a nickel compound dissolved; making the mixed solution react with an alkaline aqueous solution to obtain a suspension in which a cobalt nickel hydroxide is precipitated; performing first suction filtration of the suspension with use of water; and after the first suction filtration, performing second suction filtration with use of an organic solvent. In the cobalt nickel hydroxide, an atomic ratio of nickel in the sum of an atomic ratio of cobalt and the atomic ratio of nickel is greater than 0 and less than or equal to 0.01.

The application relates to the technical field of lithium ion batteries, in particular to a coated ternary positive electrode material and a preparation method and application thereof. The coated ternary positive electrode material comprises a ternary positive electrode material and a coating layer on the surface of the ternary positive electrode material, and the coating layer comprises an aluminum oxide chemically modified cobalt compound layer; in the coating layer, the molar ratio of aluminum oxide and the cobalt compound is (0.001-2):100. The provided coated ternary positive electrode material can improve the specific capacity and cycle performance of a battery.

This invention discloses a method for synthesizing acetate-promoted amidine cobalt complexes. Specifically, when an N,N'-dialkyl-substituted amidine alkali metal salt reacts with a cobalt precursor, acetate is added as a promoter. The chelating effect of acetate regulates the reaction activity and selectivity, enabling the efficient preparation of amidine cobalt compounds. The reaction yield can reach up to 95%, with a product purity >98%. This invention features readily available raw materials, simple operation, mild reaction conditions, good selectivity for the target product, high synthesis efficiency, and convenient post-processing, making it promising for industrial applications.

A particulate cathode active material comprising (A) a base material according to the general formula Li1 + xTM1-xO2, where TM is a combination of Ni with at least one of Mn, Co and Al, and optionally at least another metal selected from the group consisting of Mg, Ti, Zr, Nb, Ta and W, and x is in the range of 0 to 0.2, and (B) crystallites of one or more cobalt compounds, where at least some of the cobalt is in the oxidation state of + III, where the base material (A) is a polycrystalline material, where x is greater than 0 and less than 1. The secondary particles of which consist of primary particles, and crystallites (B) of a cobalt compound are coated on the outer surfaces of these secondary particles, and one or more cobalt compounds are enriched at the surfaces of the primary particles in the voids between adjacent primary particles, and wherein 90% to 99.5% of the secondary particles exhibit such cobalt compound enrichment, all the detection results are determined through EDX and SEM / TEM imaging.

The invention provides a preparation method of an organic carbonyl cobalt compound, which comprises the following steps: preparing an acetonitrile solution taking 1-butyl-3-methylimidazolium hexafluorophosphate as a supporting electrolyte at a cathode of a double-cell electrolytic tank, and adding cobalt salt, metal nickel powder and 3, 3-dimethyl-1-butyne into the cathode; preparing dilute sulphuric acid for an anode; taking a carbon electrode of a copper-zinc catalyst as a working electrode for reduction reaction, a silver wire as a reference electrode and a platinum net as a counter electrode, connecting with an electrochemical workstation, introducing carbon dioxide into a cathode, controlling the flow rate to be 3-5mL / min, and applying constant potential for reaction; filtering after the reaction is finished, and performing post-treatment on the obtained filtrate to obtain a crude product; carbon dioxide is used as an alternative source of carbon monoxide, an electrochemical reduction method is used for replacing a reducing agent, the organic carbonyl cobalt compound is synthesized by a one-pot method under the action of the metal catalyst, the process is novel and simple, the condition is mild, and the synthesis efficiency is high.

The present application relates to the technical fields of catalyst design and ammonia synthesis, and discloses a preparation method of a pyrazole trinuclear cobalt-based catalyst, which comprises the following steps: step 1, dissolving a metal cobalt compound in water to obtain a first mixed solution, dissolving a pyridine molecule in a mixed organic solution to obtain a second mixed solution, mixing and stirring the first mixed solution and the second mixed solution, and then transferring the mixture to a high-vacuum reaction tube, and then placing the high-vacuum reaction tube in an oil bath to perform a solvothermal reaction; step 2, after the solvothermal reaction is completed, washing, centrifuging and drying the obtained substance to obtain a trinuclear cobalt-based compound powder. The present application uses nitrate as a nitrogen source, a pyrazole cobalt-based compound as a catalyst, and a mixture of potassium sulfate and potassium nitrate as an electrolyte, and effectively synthesizes ammonia through electrochemical reduction. The catalyst exhibits high Faraday efficiency and high yield under high-concentration nitrate conditions.

The invention relates to application of a cobalt compound, a solar cell, slurry of the solar cell and a photovoltaic solder strip. In the application of the cobalt compound in preparation of the photovoltaic module, the cobalt compound comprises anhydrous cobalt chloride and thiocyanide. The cobalt compound is applied to the photovoltaic module, and when water vapor intrudes into the photovoltaic module, anhydrous cobalt chloride in the cobalt compound becomes red when encountering water, so that the area, provided with the cobalt compound, in the photovoltaic module presents conspicuous red which is used as a visual warning signal; maintenance personnel can quickly find and process potential problems of the photovoltaic module; and when the temperature of the photovoltaic module is too high, the anhydrous cobalt chloride reacts with the thiocyanide to present black, so that maintenance personnel can be warned of possible problems of the photovoltaic module in time.

This application relates to a modified high-nickel ternary cathode material, its preparation method, and its applications. The modified high-nickel ternary cathode material includes a substrate and first, second, and third coating layers sequentially coated on the substrate; the substrate includes Li. 1.1‑a M a (Ni b Co c Mn d ) 1‑ e A e O2E f 0.01≤a≤0.2, 0.8≤b≤1, 0.01≤c≤0.2, 0.01≤d≤0.2, 0<e≤0.05, 0≤f≤0.1; M is selected from Na, K, Rb, Cs; A is selected from Al, Mg, Zr, Ti, W, Y, B, Co, Nb, Mo, Sb, Sr; E is selected from F, Cl, Br, and I; the first, second, and third coating layers respectively include Li2SO4, a cobalt-containing compound, and a compound containing M1. This invention can simultaneously improve the battery's capacity, cycle performance, structural stability, and safety, without introducing toxic or harmful products.

The present invention relates to a method for preparing a positive electrode active material, a positive electrode active material prepared using same, and a lithium secondary battery comprising same and, more specifically, to a method for preparing a positive electrode active material, the method comprising: forming a lithium nickel-based composite oxide; and coating the lithium nickel-based composite oxide. Forming the lithium nickel-based composite oxide comprises: forming a first aqueous solution comprising an aluminum compound and a basic compound; forming a mixture including the lithium nickel-based composite oxide and the first aqueous solution; adding a second aqueous solution including a cobalt compound to the mixture; and drying and heat-treating the mixture.

The invention provides a method for enhancing firmness of a coating of a tail gas pollutant treatment catalyst. The method comprises the following steps: S1, drying the tail gas pollutant treatment catalyst of which the coating falls off, and carrying out air pressure purging; s2, nano aluminum oxide is added into deionized water to be dispersed, and nano aluminum sol is obtained; s3, adding the nano aluminum sol into the cerium-containing oxide and dispersing, then adding an organic cobalt compound and dispersing, adding a pH regulator to regulate the pH of the mixed solution to 2-3, and dispersing to obtain composite nano sol; and S4, soaking the tail gas pollutant treatment catalyst into the composite nano sol, fixing one end of the catalyst by using an air seal, and carrying out negative pressure suction, drying and roasting. According to the invention, a layer of porous bonding active film is coated outside the catalyst coating, so that the catalyst coating does not fall off, and the performance is not negatively influenced, thereby avoiding the situations of catalyst scrapping and concession acceptance by customers, reducing the production cost and improving the product percent of pass.

The present invention provides a steel wire for twisting into a steel cord to reinforce rubber products such as tires, hoses and conveyor belts. The steel wire includes a steel substrate coated with a coating comprising brass. The coating differs in that the iron content on its surface is significantly higher than that of the steel wire of the prior art. In a layer extending from the surface to a depth of 3nm below the surface, the average iron content of the coating is 4 atomic percent or more compared to the total amount of iron, zinc and copper atoms. The present invention describes a steel cord made from the steel wire and a rubber product comprising the steel cord. The present invention provides a method for manufacturing a steel wire with an increased surface iron content and an alternative method. The steel wire of the present invention shows improved adhesion retention under hot and wet conditions, which is true in rubbers containing organic cobalt compounds and rubbers that are substantially free of cobalt. The use of the present invention can extend the life of rubber products.

The present invention relates to the field of wave absorbing materials. The present invention discloses a method for preparing a p-type doped three-dimensional graphene-wrapped ZIF composite wave absorbing material, comprising: step 1: preparing a graphene oxide dispersion; step 2: mixing ZIF-67 (Co) with the graphene oxide dispersion, adding an excess of Co-containing 2+ Cobalt compound, and then adjust the pH to below 3.5 to obtain three-dimensional graphene-wrapped ZIF powder; step 3: pass borane into high-temperature reduction sintering to obtain p-type doped three-dimensional graphene-wrapped ZIF composite absorbing material. The p-type doped three-dimensional graphene-wrapped ZIF composite absorbing material prepared by the method of the present invention has ZIF stably fixed between three-dimensional graphene sheets, which can effectively prevent graphene from stacking itself, has good structural stability, and can maintain its excellent conductivity. The present invention utilizes high-temperature doping to perform p-type doping on three-dimensional graphene, thereby increasing the carrier concentration, achieving better impedance matching, and making its absorbing performance more excellent.

(A) General formula Li 1+x TM 1-x a core material based on O2, wherein TM is a combination of Ni and at least two of Mn, Co and Al, and optionally at least one further metal selected from Mg, Ti, Zr, Nb, Ta and W, where x is in the range of -0.05 to +0.05, and the nickel content is in the range of 80 to 99 mol% of TM; (B) particles of cobalt compound(s) in which at least some of the cobalt is in the +III oxidation state; (C) a shell containing at least one oxide of B or W 1. A cathode active material comprising: The core material (A) is a polycrystalline material in which secondary particles are composed of primary particles, and particles (B) of a cobalt compound are concentrated on the surfaces of the secondary particles.

The invention provides basic cobalt carbonate with high carbonate content and a preparation method thereof, and belongs to the technical field of cobalt compound preparation. The basic cobalt carbonate can be used as a cobalt source or a cobalt compound precursor for a positive electrode material. The method comprises the following steps: introducing carbon dioxide into a sodium carbonate solution in advance to obtain a pre-carbonized sodium carbonate solution; synchronously dropwise adding the pre-carbonized sodium carbonate solution and the cobaltous sulfate solution for reaction under the condition of partial pressure of carbon dioxide, and controlling the pH value of the reaction solution to obtain reaction slurry; aging the reaction slurry under a carbon dioxide pressurization condition, regulating the pH value, and filtering to obtain a wet filter cake; the wet filter cake is sequentially subjected to sodium bicarbonate solution replacement washing and carbon dioxide saturated deionized water washing, then dried, smashed and screened, and a product is obtained; the method disclosed by the invention is beneficial to improving the carbonate introduction degree of basic cobalt carbonate and reducing soluble salt entrainment, and few insoluble residues are generated in acid medium dissolution evaluation.

The invention relates to a method for producing a Fischer-Tropsch synthesis catalyst. The present invention relates to a method for conveniently preparing a supported cobalt-containing Fischer-Tropsch synthesis catalyst having improved activity and selectivity for C5 + hydrocarbons. In one aspect, the present invention provides a process for preparing a supported cobalt-containing Fischer-Tropsch synthesis catalyst, the process comprising the steps of: (a) impregnating a support material with i) a cobalt-containing compound and ii) acetic acid or a manganese salt of acetic acid in a single impregnation step to form an impregnated support material; and (b) drying and calcining the impregnated support material; wherein the support material impregnated in step (a) is not previously modified with a metal source other than cobalt; and wherein when the cobalt-containing compound is cobalt hydroxide, a manganese salt of acetic acid is not used in step (a) of the process.

The application provides a ternary composite nanofiber for marine metal corrosion prevention and electromagnetic wave absorption, and a preparation method and application thereof. The preparation method of the ternary composite nanofiber comprises the following steps: (1) preparation of a precursor solution: dispersing copper salt and a cobalt compound in a first solvent, stirring until fully dissolved, adding a polymer, and uniformly mixing to obtain the precursor solution; (2) preparation of a nanofiber membrane: electrospinning the precursor solution to obtain a nanofiber membrane loaded with copper and cobalt metal ions; (3) carbonization: drying the nanofiber membrane, and performing high-temperature treatment after drying, so that the ternary composite nanofiber for marine metal corrosion prevention and electromagnetic wave absorption is obtained. The preparation method of the ternary composite nanofiber is simple, low in cost, and has great application prospect in electromagnetic wave shielding in marine and other corrosive environments.

The invention discloses a Co9S8 / MoS2 / CNTs ternary composite catalyst and a preparation method and application method thereof, and relates to the technical field of catalysts.The preparation method comprises the following steps that S100, a precursor solution is prepared, specifically, a nitrogen-containing sulfur source compound, a transition metal cobalt compound and a transition metal molybdenum compound are jointly dissolved or dispersed in a first solvent, and a precursor solution is prepared; a uniform metal-sulfur coordination precursor solution is formed; s200, precursor curing: performing cryogenic freezing on the metal-sulfur coordination precursor solution, and then performing freeze drying to obtain a loose solid precursor; and S300, in-situ synthesis and compounding: carrying out one-step high-temperature heat treatment on the solid precursor in a protective gas atmosphere, and then cooling to room temperature to obtain the Co9S8 / MoS2 / CNTs ternary composite catalyst. The catalyst prepared by the preparation method is high in stability, good in catalytic performance, wide in pH application range and capable of being magnetically separated and recycled, and the efficiency of activating peroxymonosulfate to decompose organic pollutants is high.

The invention relates to a high-dispersity medium-high-nickel single-crystal ternary positive electrode material, a preparation method thereof and a lithium ion battery. The medium-high-nickel single-crystal ternary positive electrode material comprises single-crystal matrix particles, a symbiotic structure middle layer enriched on the interface of the single-crystal matrix particles, and a lithium-fluorine-cobalt compound coating layer coating the surface of the symbiotic structure middle layer. The preparation method comprises the following steps: mixing, sintering, cooling, crushing and sieving a nickel-cobalt-manganese hydroxide precursor, a lithium source and a high-valence dopant to obtain a high-dispersion primary sintering material; and mixing the obtained primary sintered material with a coating agent, sintering, crushing and sieving to obtain the high-dispersity medium-high nickel single crystal ternary positive electrode material. According to the method, excessive fusion of a single crystal matrix particle interface can be prevented, the primary sintering material is easy to crush and dissociate, the influence on subsequent coating treatment is avoided, and meanwhile, the problem of wastewater caused by water washing by a molten salt method and the problems of short cycle life and low capacity at high voltage and high temperature caused by degradation of the particle interface are avoided.

The invention provides a method for preparing methyl propionate in one step by taking ethylene, carbon monoxide and methanol as raw materials. According to the method, cobalt salt or a cobalt compound and a pyridyl-containing organic compound form a catalytic system, and ethylene can be effectively catalyzed to be converted into methyl propionate at the temperature of 80-180 DEG C and the pressure of 0.5-8 Mpa. The mechanism for realizing the method is that divalent cobalt is promoted to be converted into key active species Co2 (CO) 8 and HCo (CO) 4 by utilizing the alkalinity and coordination capability of a pyridyl organic matter in a CO atmosphere with enough pressure, and a characteristic peak of a key intermediate HCo (CO) 4 is captured through electrospray ionization mass spectrometry (figure 4). Compared with the prior art, the methyl propionate synthesis method has the advantages that carbonyl esterification of ethylene can be realized under relatively mild conditions without using noble metals and acidic auxiliaries, unreacted gas can be recycled, the catalyst can be recycled through rectification, and the methyl propionate synthesis method is green and economical.

A cathode active material comprising (A) a core material according to the general formula Li1 + xTM1-xO2, where TM is a combination of Ni with at least two of Mn, Co and Al, and optionally at least one plurality of metals selected from the group consisting of Mg, Ti, Zr, Nb, Ta and W, and x is in the range of-0.05 to + 0.05, and where the nickel content is in the range of 80 to 99 mol-% of TM, and (B) particles of one or more cobalt compounds, wherein at least some of the cobalt is in the oxidation state of + III, (C) a shell comprising an oxide of at least one of B or W, and wherein the core material (A) is a polycrystalline material, the secondary particles of which consist of primary particles, and the particles (B) of the cobalt compound are enriched at the surface of said secondary particles.