CN113611862A - Preparation method of lithium niobate-coated positive electrode material, lithium niobate-coated positive electrode material and application - Google Patents

Preparation method of lithium niobate-coated positive electrode material, lithium niobate-coated positive electrode material and application Download PDF

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CN113611862A
CN113611862A CN202110869214.2A CN202110869214A CN113611862A CN 113611862 A CN113611862 A CN 113611862A CN 202110869214 A CN202110869214 A CN 202110869214A CN 113611862 A CN113611862 A CN 113611862A
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lithium
positive electrode
electrode material
lnmo
niobate
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杨伟
方凯斌
谢谦
丘秀莲
陈家俊
庞晓贤
陈胜洲
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Guangzhou University
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
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    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/628—Inhibitors, e.g. gassing inhibitors, corrosion inhibitors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/04—Construction or manufacture in general
    • H01M10/0422—Cells or battery with cylindrical casing
    • H01M10/0427—Button cells
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
    • H01M4/505—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
    • H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
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    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
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    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
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    • H—ELECTRICITY
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    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
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    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
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    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/028—Positive electrodes
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Abstract

The invention provides a preparation method of a lithium niobate-coated positive electrode material, the lithium niobate-coated positive electrode material and application, and relates to the technical field of battery materials.

Description

Preparation method of lithium niobate-coated positive electrode material, lithium niobate-coated positive electrode material and application
Technical Field
The invention relates to the technical field of battery materials, in particular to a preparation method of a lithium niobate-coated positive electrode material, the lithium niobate-coated positive electrode material and application.
Background
Modern portable electronic products and electric vehicles urgently need lithium ion batteries having high power, high energy density and high cycle performance. However, many lithium ion positive electrode materials, especially spinel LiMn2O4(LNMO), spinel LiNi0.5Mn1.5O4(LNMO) and layered Li2MnO3-LiMO2(M ═ Ni, Co, Mn, etc.) shows severe specific capacity fading at high voltage or high temperature cycling. The cycle performance decay is mainly attributed to structural distortion of the positive electrode material and side reactions occurring between the positive electrode and the electrolyte. Because the working voltage of the anode material is very high, the organic solvent in the electrolyte is very easy to be oxidized to form an insulating solid electrolyte interface film (SEI) accumulated on the surface of the active material, and the SEI film can not only aggravate Li+Also causes the electrolyte (such as LiPF) in the electrolyte6) Is more easily decomposed and has LiPF6The decomposition products of (2) are combined with residual water molecules in the electrolyte to form HF, and the HF has corrosiveness on the anode material, so that the electrochemical performance of the material is reduced.
In view of the above, the present invention is particularly proposed.
Disclosure of Invention
One of the objectives of the present invention is to provide a method for preparing a lithium niobate-coated positive electrode material, so as to prepare the lithium niobate-coated positive electrode material, avoid direct contact between the positive electrode material and an electrolyte, reduce dissolution of transition metal ions caused by side reactions, alleviate oxidative decomposition of the electrolyte during charging and discharging of the material, maintain stability of the material, and ensure electrical properties of the material.
The preparation method of the lithium niobate-coated cathode material provided by the invention comprises the following steps:
(a) dispersing a positive electrode material in a regulator solution to obtain a suspension;
(b) adding ammonium niobate oxalate hydrate solution into the suspension, uniformly mixing, and carrying out solid-liquid separation to obtain a niobium compound coated positive electrode material;
(c) adding the niobium compound coated positive electrode material into a lithium source solution, uniformly mixing, evaporating the solvent to dryness, drying, and calcining to obtain a lithium niobate coated positive electrode material;
wherein the regulator is a cationic surfactant.
Further, the regulator is a quaternary ammonium salt cationic surfactant, preferably polyoxyethylene alkyl quaternary ammonium salt.
Further, the alkyl group of the polyoxyethylene alkyl quaternary ammonium salt is C10-C20 alkyl group, preferably C14-C18 alkyl group;
preferably, the conditioning agent comprises at least one of octadecylamine polyoxyethylene ether diquaternary ammonium salt, hexadecanol polyoxyethylene ether dimethyloctane ammonium chloride, tetradecanol polyoxyethylene ether dimethylhexadecyl ammonium bromide, octadecanol polyoxyethylene ether dimethyltetradecyl ammonium bromide, octadecanol polyoxyethylene ether dimethyloctyl ammonium bromide, octadecanol polyoxyethylene ether dimethylmethyl ammonium bromide, hexadecanol polyoxyethylene ether dimethyloctadecyl ammonium bromide, hexadecanol polyoxyethylene ether dimethylhexadecyl ammonium bromide, hexadecanol polyoxyethylene ether dimethyltetradecyl ammonium bromide, or hexadecanol polyoxyethylene ether dimethyldodecyl ammonium bromide.
Further, the mass concentration of the regulator solution is 0.5-5%, preferably 1-3%.
Further, the calcining temperature is 650-850 ℃, and the time is 5-8 h;
preferably, the temperature for evaporating the solvent is 70-90 ℃;
preferably, the temperature for drying is 100-.
Further, the mass concentration of the ammonium niobate oxalate hydrate solution is 1-10 per mill;
preferably, the solvent of the ammonium niobate oxalate hydrate solution is a mixed solution consisting of absolute ethyl alcohol and deionized water;
further preferably, in the solvent composed of the anhydrous ethanol and the deionized water, the volume ratio of the anhydrous ethanol to the deionized water is 1-3:1, preferably 2: 1.
Further, the lithium source includes at least one of lithium acetate, lithium carbonate, lithium oxalate, or lithium hydroxide.
Further, the positive electrode material includes at least one of lithium nickel manganese oxide, lithium cobaltate, lithium nickel oxide, lithium manganese oxide, lithium iron phosphate or lithium iron manganese phosphate, preferably lithium nickel manganese oxide.
The second purpose of the invention is to provide a lithium niobate-coated positive electrode material, which is obtained by the preparation method of the lithium niobate-coated positive electrode material provided by the first purpose of the invention.
The invention also aims to provide the application of the lithium niobate-coated positive electrode material in a lithium battery.
According to the niobium niobate-coated positive electrode material provided by the invention, the positive electrode material is dispersed in the regulator solution, so that the regulator is uniformly adsorbed on the surface of the positive electrode material, the ammonium niobate oxalate hydrate is uniformly adsorbed on the surface of the positive electrode material through the positive electricity of the regulator, and then the positive electrode material is mixed with a lithium source and calcined to prepare the lithium niobate-coated positive electrode material, wherein the lithium niobate is uniformly coated on the surface of the positive electrode material to form a uniform and compact lithium niobate layer, so that the lithium niobate-coated positive electrode material, which is uniformly and compactly coated on the surface of the positive electrode material, is prepared by adding the regulator.
According to the lithium niobate-coated cathode material provided by the invention, the uniform and compact lithium niobate layer is coated on the surface of the cathode material, so that the cathode material can be effectively prevented from being in direct contact with an electrolyte, the dissolution of transition metal ions caused by side reactions is reduced, the oxidative decomposition of the electrolyte in the charge and discharge processes of the material is relieved, the stability of the material is maintained, and the electrical property of the material is ensured.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.
FIG. 1 is an XRD pattern of LNO-LNMO prepared in examples 1-3 and LNMO provided in a comparative example;
FIG. 2 is an SEM image of LNO-LNMO prepared in examples 1-3 and LNMO provided in a comparative example;
FIG. 3 is a HETEM image of LNO-LNMO prepared in examples 1-3 and LNMO provided in a comparative example;
FIG. 4 is an XPS survey of LNO-LNMO prepared in examples 1-3 and LNMO provided in a comparative example;
FIG. 5 is a 3d XPS plot of LNO-LNMO prepared as described in examples 1-3 and LNMO provided as a comparative example;
FIG. 6 is a CV curve of a CR2032 button cell prepared from LNO-LNMO prepared in examples 1-3 and LNMO provided in a comparative example;
fig. 7 is a first constant current discharge curve of the CR2032 type button cell prepared by using the LNO-LNMO provided in examples 1 to 3 and the LNMO provided in the comparative example as the positive electrode material at a 1C rate;
fig. 8 is a graph of cycle life of CR2032 button cells prepared with LNO-LNMO provided in examples 1-3 and LNMO provided in comparative example as positive electrode materials;
fig. 9 is a graph of the rate performance of CR2032 button cells prepared using LNO-LNMO provided in examples 1-3 and LNMO provided in a comparative example as the positive electrode material.
Detailed Description
The technical solutions of the present invention will be described clearly and completely with reference to the following embodiments, and it should be understood that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Currently, the positive electrode materials of lithium ion batteries mainly include lithium cobaltate and lithium nickelate with layered structures, lithium manganate and derivatives with crystal structure, lithium iron phosphate with olivine structure, ternary layered materials, lithium-rich ternary materials and derivatives, and the like. The cycle performance decay is mainly due to the structural distortion of the positive electrode material and the side reaction of the positive electrode and the electrolyte.
The coating layer is coated on the surface of the anode material, so that the direct contact between the anode material and electrolyte can be avoided, the dissolution of transition metal ions caused by side reactions is reduced, the oxidative decomposition of the material to the electrolyte in the charge and discharge process is relieved, and the structural stability of the material is maintained. Lithium niobate (LiNbO)3Abbreviated as LNO) is an attractive cladding material, which is a solid electrolyte with a rhombohedral crystal structure, high ionic conductivity, Li at room temperature+Ion diffusion rate of 10-5S·cm-1The interface resistance can be effectively reduced, and the rate capability of the material is improved.
At present, common lithium niobate-coated cathode materials are obtained by mixing and sintering niobium compounds, cathode materials and lithium sources, and lithium niobate coatings prepared by the method cannot be uniformly distributed on the surfaces of the cathode materials, so that uniform and compact lithium niobate coatings cannot be formed, partial surfaces of the cathode materials can still be in contact with electrolyte to generate side reactions, and the electrochemical performance of the materials is reduced.
In view of this, the invention provides a method for preparing a lithium niobate-coated cathode material, which can coat a uniform and dense lithium niobate layer on the surface of the cathode material.
According to one aspect of the invention, the invention provides a preparation method of a lithium niobate-coated cathode material, which comprises the following steps:
(a) dispersing a positive electrode material in a regulator solution to obtain a suspension;
(b) adding ammonium niobate oxalate hydrate solution into the suspension, uniformly mixing, and carrying out solid-liquid separation to obtain a niobium compound coated positive electrode material;
(c) adding the niobium compound coated positive electrode material into a lithium source solution, uniformly mixing, evaporating the solvent to dryness, drying, and calcining to obtain a lithium niobate coated positive electrode material;
wherein the regulator is a cationic surfactant.
In the present invention, the cationic surfactant refers to a surfactant which is dissolved in water and ionized, and the hydrophilic group linked to the hydrophobic group is a positively charged surfactant.
In the step (a), the anode material is dispersed in the regulator solution, so that the regulator is uniformly adsorbed on the surface of the anode material through a hydrophobic group, in the step (b), the ammonium niobate oxalate hydrate solution is added into the suspension and uniformly mixed, so that the ammonium niobate oxalate can be uniformly adsorbed on the surface of the anode material by the positive charge on the surface of the regulator, and then in the step (c), the anode material uniformly adsorbed with the ammonium niobate oxalate on the surface is uniformly mixed with a lithium source and then sintered, so that the lithium niobate coated anode material uniformly coated on the surface of the anode material to form a uniform and compact lithium niobate layer is obtained, and the lithium niobate coated anode material uniformly coated on the surface of the anode material by uniformly coating the lithium niobate is obtained by adding the regulator.
In a preferred scheme of the invention, the regulator is a quaternary ammonium salt cationic surfactant which can be dissolved in alkaline and acidic media and dissociated into surface active ions with positive charges, and particularly when the regulator is polyoxyethylene alkyl quaternary ammonium salt, the regulator is more favorable for uniform adsorption on the surface of the positive electrode material and is also favorable for uniformly adsorbing ammonium niobate oxalate on the surface of the positive electrode material, thereby being more favorable for preparing the lithium niobate-coated positive electrode material with a uniform and compact lithium niobate layer formed on the surface of the positive electrode material.
Preferably, the alkyl group of the polyoxyethylene alkyl quaternary ammonium salt is the alkyl group of C10-C20, so that the regulator has excellent solubility while having a hydrophobic group, and is more favorably and uniformly adsorbed on the surface of the cathode material, and particularly, when the alkyl group of the polyoxyethylene alkyl quaternary ammonium salt is the alkyl group of C14-C18, the regulator has excellent solubility while having the performance of being uniformly adsorbed on the cathode material.
Typically, but not limitatively, the alkyl group of the polyoxyethylene alkyl quaternary ammonium salt is, for example, a linear or branched alkyl group of C10, C11, C12, C13, C14, C15, C16, C17, C18, C19 or C20.
In one embodiment of the present invention, the modifier is selected from one or more of octadecyl polyoxyethylene ether bis-quaternary ammonium salt, hexadecyl polyoxyethylene ether dimethyl octane ammonium chloride, tetradecanol polyoxyethylene ether dimethyl hexadecyl ammonium bromide, octadecyl polyoxyethylene ether dimethyl tetradecyl ammonium bromide, octadecyl polyoxyethylene ether dimethyl octyl ammonium bromide, octadecyl polyoxyethylene ether dimethyl methyl ammonium bromide, hexadecyl polyoxyethylene ether dimethyl octadecyl ammonium bromide, hexadecyl polyoxyethylene ether dimethyl hexadecyl ammonium bromide, hexadecyl polyoxyethylene ether dimethyl tetradecyl ammonium bromide or hexadecyl polyoxyethylene ether dimethyl dodecyl ammonium bromide.
In a preferable scheme of the invention, the mass concentration of the regulator is 0.5-5% so as to be beneficial to adsorbing a proper amount of the regulator on the surface of the positive electrode material, and then the regulator adsorbed on the surface of the positive electrode material adsorbs a proper amount of lithium niobate oxalate through the positive electricity of the regulator, so that a uniform and compact lithium niobate coating layer with a proper thickness can be formed on the surface of the positive electrode material.
Typically, but not by way of limitation, the mass concentration of the conditioner solution is, for example, 0.5%, 0.8%, 1%, 1.2%, 1.5%, 1.8%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, or 5%.
When the mass concentration of the regulator solution is lower than 0.5%, the positive electrode material is dispersed in the regulator solution and cannot adsorb enough regulator on the surface of the positive electrode material, so that in the subsequent mixing process with the ammonium niobate oxalate hydrate solution, enough ammonium niobate oxalate cannot be adsorbed by positive charges carried by the regulator adsorbed on the surface of the positive electrode material, and thus lithium niobate coated on the surface of the positive electrode material obtained by subsequent preparation cannot form a uniform and compact lithium niobate layer, and when the mass concentration of the regulator solution is higher than 5%, the lithium niobate coated on the surface of the positive electrode material can only adsorb a proper amount of regulator due to the limitation of the surface of the positive electrode material, and the excessive regulator can cause waste, and especially when the mass concentration of the regulator solution is 1-3%, the lithium niobate coated positive electrode material with a coating layer with a proper thickness can be prepared.
In a preferable scheme of the invention, in the step (c), the calcining temperature is 650-.
Typically, but not by way of limitation, the calcination is carried out at a temperature, e.g., 650, 680, 700, 720, 750, 780, 800, 820, or 850 ℃ for a time, e.g., 5, 5.5, 6, 6.5, 7, 7.5, or 8 hours.
In a preferred embodiment of the present invention, in the step (c), the solvent is evaporated at a temperature of 70 to 90 ℃ to facilitate that the lithium source can be uniformly coated on the surface of the niobium compound coated positive electrode material, so that the lithium niobate coated positive electrode material in which the lithium niobate is uniformly and densely coated on the surface of the positive electrode material can be prepared by subsequent calcination.
Typically, but not by way of limitation, the solvent is evaporated to dryness at a temperature of, for example, 70, 72, 75, 78, 80, 82, 85, 88, or 90 ℃.
In a preferable scheme of the invention, in the step (c), after the solvent is evaporated to dryness, the drying is performed by controlling the temperature of the vacuum drying oven to be 100-120 ℃, so that the influence of the existence of moisture on the uniformity and the compactness of the surface coating layer of the lithium niobate-coated cathode material prepared by the subsequent sintering is avoided.
Typically, but not by way of limitation, the drying temperature is, for example, 100, 105, 110, 115 or 120 ℃.
In a preferable scheme of the invention, in the step (b), the mass concentration of the ammonium niobate oxalate hydrate solution is 1-10 per mill, so that a proper amount of ammonium niobate oxalate is favorably adsorbed on the surface of the positive electrode material to form a lithium niobate coating layer with a proper thickness.
Typically, but not by way of limitation, the mass concentration of the ammonium niobate oxalate hydrate solution is, for example, 1%, 2%, 3%, 5%, 8% or 10%.
When the mass concentration of the ammonium niobate oxalate hydrate solution is lower than 1 per thousand, and the ammonium niobate oxalate hydrate solution is added into the suspension to be uniformly mixed, sufficient ammonium niobate oxalate cannot be adsorbed on the surface of the anode material, and when the mass concentration of the ammonium niobate oxalate hydrate solution is higher than 10 per thousand, on one hand, the ammonium niobate oxalate hydrate is too high in concentration to be favorable for the ammonium niobate oxalate hydrate to be adsorbed on the surface of the anode material, and on the other hand, because the surface area of the anode material and the using amount of the adsorbed regulator are limited, the excessive ammonium niobate oxalate cannot be adsorbed, so that the waste of the niobate oxalate hydrate is caused.
Preferably, the ammonium niobate oxalate hydrate solution is prepared by dissolving ammonium niobate oxalate in a solvent, wherein the solvent is a mixed solution composed of absolute ethyl alcohol and deionized water, so that the ammonium niobate oxalate hydrate solution can be prepared and obtained.
Preferably, in the solvent consisting of the absolute ethyl alcohol and the deionized water, the volume ratio of the absolute ethyl alcohol to the deionized water is 1-3:1, so that the ammonium niobate oxalate hydrate is favorably dissolved in the solvent.
Typically, but not by way of limitation, the volume of absolute ethanol and deionized water in the solvent used for the niobate oxalate hydrate solution is, for example, 1:1, 1:2, or 1: 3.
Preferably, the solid-liquid separation in step (b) is centrifugal separation, and after centrifugal analysis, deionized water and absolute ethyl alcohol are respectively adopted to wash for 3-5 times, so that unadsorbed ammonium niobate oxalate is removed, and the niobium compound coated cathode material is obtained.
In a preferred embodiment of the present invention, in step (c), the lithium source includes but is not limited to one or more of lithium acetate, lithium carbonate, lithium oxalate or lithium hydroxide.
Preferably, the lithium source is used in excess, and the amount of the lithium source is determined according to the amount of the amine niobate oxalate.
In a preferred embodiment of the present invention, the positive electrode material includes, but is not limited to, one or more of lithium nickel manganese oxide, lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium iron phosphate, or lithium iron manganese phosphate, and especially when the positive electrode material is lithium nickel manganese oxide, the prepared lithium battery has more excellent electrical properties.
Preferably, the solvent adopted by the lithium source solution is a mixed solvent formed by mixing absolute ethyl alcohol and deionized water, wherein the volume ratio of the absolute ethyl alcohol to the deionized water is (1-3): 1, preferably 2: 1.
in a typical but non-limiting embodiment of the invention, lithium nickel manganese oxide is prepared by the following steps: dissolving nickel salt and manganese salt with stoichiometric ratio (0.5:1.5) in an ethanol-water mixed solvent (V deionized water: V absolute ethyl alcohol is 1: 3), and uniformly stirring to obtain a mixed solution A. Dissolving urea in deionized water, and uniformly stirring to obtain a solution B. Dissolving polyethylene glycol (PEG) in N-methylpyrrolidone (NMP), and stirring uniformly to obtain suspension C. And respectively dripping the solution A and the solution B into the suspension C dropwise. Continuously stirring for 1-2 h, transferring to a stainless steel high-temperature reaction kettle, sealing, and reacting in an oven at the temperature of 150 ℃ and 200 ℃ for 8-12 h. After the reaction is finished and the reaction product is naturally cooled to room temperature, taking out the product for centrifugal separation, washing the product for 3-5 times by using deionized water and absolute ethyl alcohol respectively to obtain light green precipitate, and placing the precipitate in a vacuum drying oven for vacuum drying for 12-24h at the temperature of 80-100 ℃ to obtain dry Ni0.25Mn0.75CO3A precursor material. Ni is weighed according to the molar ratio of 1:1.050.25Mn0.75CO3The precursor material and a lithium source (5% excess) are uniformly mixed, and are placed in a muffle furnace for presintering at 450-600 ℃ for 2-4h, calcining at 800-950 ℃ for 10-15h, and annealing at 500-600 ℃ for 8-12h to obtain the lithium nickel manganese oxide.
Preferably, the nickel salt is one or more of nickel sulfate, nickel acetate, nickel nitrate or nickel chloride.
Preferably, the manganese salt is one or more of manganese sulfate, manganese acetate, manganese nitrate or manganese chloride.
Preferably, the number average molecular weight of the polyethylene glycol is 4000-.
Preferably, the lithium source is one or more of lithium hydroxide, lithium acetate, lithium oxalate or lithium carbonate.
According to a second aspect of the present invention, there is provided a lithium niobate-coated positive electrode material prepared according to the method for preparing a lithium niobate-coated positive electrode material provided in the first aspect of the present invention.
According to the lithium niobate-coated cathode material provided by the invention, the uniform and compact lithium niobate layer is coated on the surface of the cathode material, so that the cathode material can be effectively prevented from being in direct contact with an electrolyte, the dissolution of transition metal ions caused by side reactions is reduced, the oxidative decomposition of the electrolyte in the charge and discharge processes of the material is relieved, the stability of the material is maintained, and the electrical property of the material is ensured.
According to a third aspect of the present invention, the present invention provides the use of a lithium niobate-coated positive electrode material in a lithium battery.
In order to facilitate understanding of those skilled in the art, the technical solutions provided by the present invention will be further described below with reference to examples and comparative examples.
Example 1
The embodiment provides a lithium niobate-coated lithium nickel manganese oxide positive electrode material, which is prepared according to the following steps:
(1) preparing a lithium nickel manganese oxide positive electrode material: 2.043g of nickel acetate and 6.306g of manganese acetate were dissolved in 40mL of a mixed solvent (V deionized water: V absolute ethyl alcohol ═ 1: 3), and the mixture was stirred uniformly to obtain a solution a. Dissolving 7g of urea in 10mL of deionized water, and uniformly stirring to obtain a solution B. 1g of polyethylene glycol (number average molecular weight: 6000) was dissolved in 20mL of N-methylpyrrolidone, and the mixture was stirred uniformly to obtain a suspension C. And respectively dripping the solution A and the solution B into the suspension C dropwise. After continuously stirring for 2h, the mixture was transferred to a 100mL stainless steel high-temperature reaction kettle, sealed and placed in an oven to react for 8h at 200 ℃. After the reaction is completed and naturalCooling to room temperature, taking out the product, performing centrifugal separation, washing with deionized water and absolute ethyl alcohol for 3-5 times respectively to obtain light green precipitate, and placing the precipitate in a vacuum drying oven for vacuum drying at 80 ℃ for 12h to obtain dried Ni0.25Mn0.75CO3A precursor material. According to the mol ratio of 1:1.05 weighing of Ni0.25Mn0.75CO3And mixing the precursor material and lithium acetate (5% excess), grinding for 15min by using an agate mortar, pre-sintering in a muffle furnace at 500 ℃ for 4h, calcining at 850 ℃ for 12h, and annealing at 600 ℃ for 10h to obtain the Lithium Nickel Manganese Oxide (LNMO) cathode material.
(2) Dissolving an octadecyl amine polyoxyethylene ether biquaternary ammonium salt regulator in water to form a uniform solution with the mass concentration of 1%, adding 1g of the nickel LNMO positive electrode material obtained in the step (1) into 25mL of the regulator solution, and stirring at room temperature for 1.5h to obtain a suspension.
(3) And (3) dissolving 0.1025g of ammonium niobate oxalate hydrate in 25mL of a mixed solvent (V absolute ethyl alcohol: V deionized water: 2:1), stirring at room temperature for dissolving, adding into the suspension obtained in the step (2), stirring for 10-30 minutes, performing centrifugal separation, and washing with the deionized water and the absolute ethyl alcohol for 3-5 times respectively to obtain the niobium compound coated lithium nickel manganese oxide material.
(4) And (3) dissolving 0.0245g of lithium acetate in 25mL of mixed solvent (V absolute ethyl alcohol: V deionized water is 2:1), stirring at room temperature for dissolving, adding the niobium compound coated lithium nickel manganese oxide material obtained in the step (3), and stirring at constant temperature of 80 ℃ until the solvent is evaporated. And then transferring the lithium niobate-coated lithium nickel manganese oxide cathode material to a vacuum drying oven for vacuum drying at 120 ℃ for 8h, and calcining the lithium niobate-coated lithium nickel manganese oxide cathode material for 5h by using a muffle furnace at 650 ℃ to obtain the lithium niobate-coated lithium nickel manganese oxide cathode material (abbreviated as LNO-LNMO).
Example 2
The embodiment provides a lithium niobate-coated lithium nickel manganese oxide positive electrode material, which is prepared according to the following steps:
(1) dissolving octadecyl amine polyoxyethylene ether biquaternary ammonium salt regulator in water to form a uniform solution with the mass concentration of 1.5%, adding 1g of lithium nickel manganese oxide material (the lithium nickel manganese oxide material is the same as the lithium nickel manganese oxide material prepared in example 1) into 25mL of the solution, and stirring at room temperature for 1.5h to obtain a suspension.
(2) And (3) dissolving 0.1025g of ammonium niobate oxalate hydrate in 25mL of a mixed solvent (V absolute ethyl alcohol: V deionized water: 2:1), stirring at room temperature for dissolving, adding into the suspension obtained in the step (2), stirring for 10-30 minutes, performing centrifugal separation, and washing with the deionized water and the absolute ethyl alcohol for 3-5 times respectively to obtain the niobium compound coated lithium nickel manganese oxide material.
(3) And (3) dissolving 0.0245g of lithium acetate in 25mL of mixed solvent (V absolute ethyl alcohol: V deionized water is 2:1), stirring at room temperature for dissolving, adding the niobium compound coated lithium nickel manganese oxide material obtained in the step (2), and stirring at constant temperature of 80 ℃ until the solvent is evaporated. And then transferring the lithium niobate-coated lithium nickel manganese oxide cathode material to a vacuum drying oven for vacuum drying at 120 ℃ for 8h, and calcining the lithium niobate-coated lithium nickel manganese oxide cathode material for 5h by using a muffle furnace at 650 ℃ to obtain the lithium niobate-coated lithium nickel manganese oxide cathode material (LNO-LNMO).
Example 3
The embodiment provides a lithium niobate-coated lithium nickel manganese oxide positive electrode material, which is prepared according to the following steps:
(1) dissolving octadecyl amine polyoxyethylene ether biquaternary ammonium salt regulator in water to form a uniform solution with the mass concentration of 3%, adding 1g of lithium nickel manganese oxide material (the lithium nickel manganese oxide material is the same as the lithium nickel manganese oxide material prepared in example 1 in batch) into 25mL of the solution, and stirring at room temperature for 1.5h to obtain a suspension.
(2) And (3) dissolving 0.1025g of ammonium niobate oxalate hydrate in 25mL of a mixed solvent (V absolute ethyl alcohol: V deionized water: 2:1), stirring at room temperature for dissolving, adding into the suspension obtained in the step (2), stirring for 10-30 minutes, performing centrifugal separation, and washing with the deionized water and the absolute ethyl alcohol for 3-5 times respectively to obtain the niobium compound coated lithium nickel manganese oxide material.
(3) And (3) dissolving 0.0245g of lithium acetate in 25mL of mixed solvent (V absolute ethyl alcohol: V deionized water is 2:1), stirring at room temperature for dissolving, adding the niobium compound coated lithium nickel manganese oxide material obtained in the step (2), and stirring at constant temperature of 80 ℃ until the solvent is evaporated. And then transferring the lithium niobate-coated lithium nickel manganese oxide cathode material to a vacuum drying oven for vacuum drying at 120 ℃ for 8h, and calcining the lithium niobate-coated lithium nickel manganese oxide cathode material for 5h by using a muffle furnace at 650 ℃ to obtain the lithium niobate-coated lithium nickel manganese oxide cathode material (LNO-LNMO).
Example 4
The embodiment provides a lithium niobate-coated lithium nickel manganese oxide positive electrode material, which is prepared according to the following steps:
(1) dissolving octadecyl amine polyoxyethylene ether biquaternary ammonium salt regulator in water to form a uniform solution with the mass concentration of 3%, adding 1g of lithium nickel manganese oxide material (the lithium nickel manganese oxide material is the same as the lithium nickel manganese oxide material prepared in example 1 in batch) into 25mL of the solution, and stirring at room temperature for 1.5h to obtain a suspension.
(2) And (3) dissolving 0.205g of ammonium niobate oxalate hydrate in 25mL of a mixed solvent (V absolute ethyl alcohol: V deionized water ═ 2:1), stirring at room temperature for dissolving, adding into the suspension obtained in the step (2), stirring for 10-30 minutes, performing centrifugal separation, washing with the deionized water and the absolute ethyl alcohol for 3-5 times respectively, and thus obtaining the niobium compound coated lithium nickel manganese oxide material.
(3) And (3) dissolving 0.049g of lithium acetate in 25mL of mixed solvent (V absolute ethyl alcohol: V deionized water is 2:1), stirring at room temperature for dissolving, adding the niobium compound coated lithium nickel manganese oxide material obtained in the step (2), and stirring at constant temperature of 80 ℃ until the solvent is evaporated. And then transferring the lithium niobate-coated lithium nickel manganese oxide cathode material to a vacuum drying oven for vacuum drying at 120 ℃ for 8h, and calcining the lithium niobate-coated lithium nickel manganese oxide cathode material for 5h by using a muffle furnace at 650 ℃ to obtain the lithium niobate-coated lithium nickel manganese oxide cathode material (LNO-LNMO).
Example 5
The embodiment provides a lithium niobate-coated lithium nickel manganese oxide positive electrode material, which is prepared according to the following steps:
(1) dissolving octadecyl amine polyoxyethylene ether biquaternary ammonium salt regulator in water to form a uniform solution with the mass concentration of 5%, adding 1g of lithium nickel manganese oxide material (the lithium nickel manganese oxide material is the same as the lithium nickel manganese oxide material prepared in example 1 in batch) into 25mL of the solution, and stirring at room temperature for 1.5h to obtain a suspension.
(2) And (3) dissolving 0.205g of ammonium niobate oxalate hydrate in 25mL of a mixed solvent (V absolute ethyl alcohol: V deionized water ═ 2:1), stirring at room temperature for dissolving, adding into the suspension obtained in the step (2), stirring for 10-30 minutes, performing centrifugal separation, washing with the deionized water and the absolute ethyl alcohol for 3-5 times respectively, and thus obtaining the niobium compound coated lithium nickel manganese oxide material.
(3) And (3) dissolving 0.049g of lithium acetate in 25mL of mixed solvent (V absolute ethyl alcohol: V deionized water is 2:1), stirring at room temperature for dissolving, adding the niobium compound coated lithium nickel manganese oxide material obtained in the step (2), and stirring at constant temperature of 80 ℃ until the solvent is evaporated. And then transferring the lithium niobate-coated lithium nickel manganese oxide cathode material to a vacuum drying oven for vacuum drying at 120 ℃ for 8h, and calcining the lithium niobate-coated lithium nickel manganese oxide cathode material for 5h by using a muffle furnace at 650 ℃ to obtain the lithium niobate-coated lithium nickel manganese oxide cathode material (LNO-LNMO).
Example 6
The embodiment provides a lithium niobate-coated lithium nickel manganese oxide positive electrode material, which is prepared according to the following steps:
(1) dissolving octadecyl amine polyoxyethylene ether biquaternary ammonium salt regulator in water to form a uniform solution with the mass concentration of 0.5%, adding 1g of lithium nickel manganese oxide material (the lithium nickel manganese oxide material is the same as the lithium nickel manganese oxide material prepared in example 1) into 25mL of the solution, and stirring at room temperature for 1.5h to obtain a suspension.
(2) And (3) dissolving 0.205g of ammonium niobate oxalate hydrate in 25mL of a mixed solvent (V absolute ethyl alcohol: V deionized water ═ 2:1), stirring at room temperature for dissolving, adding into the suspension obtained in the step (2), stirring for 10-30 minutes, performing centrifugal separation, washing with the deionized water and the absolute ethyl alcohol for 3-5 times respectively, and thus obtaining the niobium compound coated lithium nickel manganese oxide material.
(3) And (3) dissolving 0.049g of lithium acetate in 25mL of mixed solvent (V absolute ethyl alcohol: V deionized water is 2:1), stirring at room temperature for dissolving, adding the niobium compound coated lithium nickel manganese oxide material obtained in the step (2), and stirring at constant temperature of 80 ℃ until the solvent is evaporated. And then transferring the lithium niobate-coated lithium nickel manganese oxide cathode material to a vacuum drying oven for vacuum drying at 120 ℃ for 8h, and calcining the lithium niobate-coated lithium nickel manganese oxide cathode material for 5h by using a muffle furnace at 650 ℃ to obtain the lithium niobate-coated lithium nickel manganese oxide cathode material (LNO-LNMO).
Example 7
The embodiment provides a lithium niobate-coated lithium nickel manganese oxide positive electrode material, which is different from the embodiment 6 in that in the step (1), an octadecyl amine polyoxyethylene ether biquaternary ammonium salt regulator is dissolved in water to form a uniform solution with the mass concentration of 0.1%, and the rest steps are the same as the embodiment 6 and are not repeated herein.
Example 8
The embodiment provides a lithium niobate-coated lithium nickel manganese oxide positive electrode material, which is different from the embodiment 5 in that in the step (1), an octadecyl amine polyoxyethylene ether biquaternary ammonium salt regulator is dissolved in water to form a uniform solution with the mass concentration of 10%, and the rest steps are the same as the embodiment 5 and are not repeated herein.
Comparative example
The comparative example provides a lithium nickel manganese oxide positive electrode material, which is the same as the Lithium Nickel Manganese Oxide (LNMO) prepared in step (1) in example 1 in batch, and is not described herein again.
Test example 1
The Zeta potential of the suspension prepared in the step (2) in example 1, the Zeta potential of the suspension prepared in the step (1) in example 2 and the Zeta potential of the suspension prepared in the step (1) in example 3 were measured respectively, and the results show that the Zeta potential of the suspension prepared in the step (2) in example 1 is 12mV, the Zeta potential of the suspension prepared in the step (1) in example 2 is 21mV, and the Zeta potential of the suspension prepared in the step (1) in example 3 is 28mV, which proves that the regulator is adsorbed on the surface of the nickel lithium manganate positive electrode material, so that the suspension is electropositive, and ammonium niobate oxalate can be uniformly adsorbed on the surface of the nickel lithium manganate positive electrode material through the electropositive property.
Test example 2
XRD tests were carried out on the LNO-LNMO prepared in examples 1-3 and the LNMO provided in the comparative example, and the results are shown in FIG. 1.
As can be seen from FIG. 1, the samples provided in examples 1 to 3 and comparative example all had good crystallinity, and the diffraction peaks substantially matched those of the standard card, lithium niobate (LiNbO)3LNO for short) no obvious structural change occurs before and after coating. Wherein the main diffraction peaks correspond to LNMO with a spinel structure (space group Fd-3m, PDF #80-2162), which indicates LiNbO3The coating does not alter the crystal structure of the LNMO material.
By observing the XRD pattern of LNO-LNMO provided in example 3, it was found that, in addition to the diffraction peaks of LNMO, weak diffraction peaks were found at 21.9 ° (012), 31.2 ° (104), 34.9 ° (110) and 53.5(116), which were confirmed to be LiNbO of diamond structure3(iv) diffraction peaks (space group R3c, PDF #85-2456), while the LNO-LNMO provided in example 1, the LNO-LNMO provided in example 2, and the LNO-LNMO provided in example 3The intensity of the diffraction peak of LiNbO3 in the supplied LNO-LNMO is sequentially enhanced, which proves that LiNbO3The amount of coating on the surface of the LNMO increases.
Test example 3
SEM tests of the LNO-LNMO prepared in examples 1-3 and the LNMO provided in a comparative example are shown in FIG. 2, wherein (a) is an SEM image of the LNMO provided in the comparative example, and (b) is an SEM image of the LNO-LNMO provided in example 1; (c) FIG. is an SEM image of LNO-LNMO provided in example 2; (d) the figure is an SEM image of LNO-LNMO provided in example 3.
From fig. 2, it can be seen that LNO-LNMO prepared in examples 1 to 3 and LNMO provided in comparative example are hollow microspheres having a diameter of about 4 μm, wherein the surface of LNMO provided in comparative example is very smooth and tidy, while LNO-LNMO provided in example 1, LNO-LNMO provided in example 2 and LNO-LNMO provided in example 3 maintain the micro-morphology and particle size before coating substantially unchanged, but as can be seen from comparison among (b), (c), (d) and (a) in fig. 2, the surfaces of LNO-LNMO provided in example 1, LNO-LNMO provided in example 2 and LNO-LNMO provided in example 3 are rough, and there is adhesion of small LNO particles.
Test example 4
The results of the HETEM tests performed on the LNO-LNMO prepared in examples 1-3 and the LNMO provided by the comparative example are shown in fig. 3, wherein (a) is a HETEM image of the LNMO provided by the comparative example, and (b) is a HETEM image of the LNO-LNMO provided in example 1; (c) FIG. is a HETEM image of LNO-LNMO as provided in example 2; (d) the figure is a HEMEM image of LNO-LNMO provided in example 3.
It is clear from fig. 3 that the lattice stripe of the LNMO provided by the comparative example, which has a lattice spacing of 0.47nm, coincides with the (111) crystal plane in the Fd-3m structure, and it is confirmed that the host is a spinel-structured LNMO cathode material. However, the lattice fringes near the edges of the LNO-LNMO provided in example 1, the LNO-LNMO provided in example 2, and the LNO-LNMO provided in example 3 were all changed, and it can be seen that the outer layer of the LNO-LNMO provided in example 1 has a lattice fringe with a lattice spacing of 0.27nm, and LiNbO3The (104) crystallographic planes in the structure (space group R3c, PDF #85-2456) are matched, the LNO-LNMO provided in example 2 and the example3 the outer layer of the LNO-LNMO provided by the method has lattice stripes with the lattice spacing of 0.25nm and LiNbO3The (110) crystallographic alignment in the structures (space group R3c, PDF #85-2456) further confirmed the LiNbO on LNMO in examples 1-33And (4) coating.
Test example 5
XPS full scan spectra of the LNO-LNMO prepared in examples 1 to 3 and the LNMO provided in the comparative example were performed, and the results are shown in fig. 4, in which (a) shows the XPS full scan spectra of the LNMO provided in the comparative example, and (b) shows the XPS full scan spectra of the LNO-LNMO provided in example 1; (c) FIG. is an XPS survey scan of the LNO-LNMO provided in example 2; (d) the XPS full scan spectrum of the LNO-LNMO provided in example 3 is shown.
As can be seen from fig. 4, characteristic peaks of Nb 3p and Nb 3d were present at about 380eV and 210eV for the LNO-LNMO provided in example 1, the LNO-LNMO provided in example 2, and the LNO-LNMO provided in example 3, respectively, whereas the characteristic peaks were absent for the LNMO provided in comparative example, and the intensities of the characteristic peaks of Nb 3p and Nb 3d increased with the increase in the LNO coating amount, confirming that linoblino in examples 1 to 3 was present3The presence of a coating.
Test example 6
The LNO-LNMO prepared in examples 1 to 3 and the LNMO provided in the comparative example were subjected to a 3d XPS spectrum test, and the results are shown in fig. 5.
As can be seen from FIG. 5, the LNMO provided in the comparative example showed no characteristic peak between 195-215eV, while the LNO-LNMO provided in example 1, the LNO-LNMO provided in example 2, and the LNO-LNMO provided in example 3 all showed Nb at 206.06eV (Nb 3d5/2) and 209.3eV (Nb 3d3/2)5+Characteristic peak of (2). In addition, we can see that the peak intensities of the binding energies of the LNO-LNMO provided in example 1, the LNO-LNMO provided in example 2, and the LNO-LNMO provided in example 3 are gradually enhanced, which indicates that LiNbO in examples 1 to 3 is increased3The coating amount gradually increases.
Test example 7
Lithium batteries were prepared using the LNO-LNMO provided in examples 1 to 8 and the LNMO provided in the comparative example as the positive electrode materials, respectively, and the specific assembly process was as follows:
lithium nickel manganese oxide powder prepared in each example and comparative example was used as a positive electrode active material, and the ratio by mass of lithium nickel manganese oxide powder to lithium nickel manganese oxide powder was 8: 1:1, weighing a positive electrode material, a binder PVDF and a conductive agent Super P, placing the positive electrode material, the binder PVDF and the conductive agent Super P in a 10mL small beaker, uniformly mixing, then dropwise adding an appropriate amount of NMP (N-methyl pyrrolidone), stirring to form uniform slurry, then coating the uniform slurry on a dried aluminum foil by using a scraper (150mm), firstly placing the uniform slurry in a forced air drying oven for drying at 80 ℃ for 8h, then transferring the uniform slurry into a vacuum drying oven for vacuum drying at 120 ℃ for 12h, weighing and transferring the completely dried pole piece into a glove box for later use after the pole piece is a circular positive pole piece with the diameter of 12mm by using a punching machine.
1 mol. L using the prepared positive plate as a positive electrode and metal lithium as a negative electrode-1LiPF of6Dissolving in mixed solvent of ethylene carbonate, Ethylene Carbonate (EC) and dimethyl carbonate (DMC) (volume ratio of 1: 1) as electrolyte, Celgard 2400 polypropylene microporous membrane as separator, placing all materials in glove box (O) filled with high-purity argon2＜0.1ppm，H2O is less than 0.1ppm), assembling into a CR2032 button cell, and sealing by using a sealing machine. And finally standing and activating the assembled CR2032 button cell for 12h at room temperature for later use.
CV curve measurements were performed on the LNO-LNMO prepared in examples 1-3 and the CR2032 button cell prepared from the LNMO provided in the comparative example, and the results are shown in FIG. 6, wherein the voltage ranges from 3.0V vs. Li to 5.0V vs+PerLi, scan rate 0.1 mV. s-1.
As can be seen from fig. 6, CV curves of the button cell using LNO-LNMO as the positive electrode material prepared in examples 1 to 3 and the button cell using LNMO as the positive electrode material provided in the comparative example both exhibited two pairs of typical redox peaks, which were consistent with the characteristic CV curve of the disordered Fd-3m structure LNMO material. Wherein the oxidation-reduction peak at 4.0V corresponds to Mn3+/Mn4+Couple pair, oxidation reduction peak at 4.7V corresponding to Ni2+/Ni3+And Ni3+/Ni4+And (4) a galvanic couple. No other redox peak was present in FIG. 6, indicating LiNbO3The coating does not produce excessive side reactions. The peak currents at 4.0V of the LNO-LNMO provided in example 1, the LNO-LNMO provided in example 2, and the LNO-LNMO provided in example 3 were all significantly higher than L provided in the comparative examplePeak current of NMO, and peak current at 4.0V with LiNbO for examples 1-33The coating amount increases in turn because of LiNbO3The coating increases Mn in LNMO3+In an amount that promotes Mn at the plateau3+/Mn4+Oxidation-reduction reaction of (1).
Test example 8
The first constant current charge and discharge capacity and the discharge capacity after 100 cycles of CR2032 type button cells prepared by using the LNO-LNMO provided by examples 1 to 8 and the LNMO provided by comparative example as positive electrode materials were respectively tested and the capacity retention ratio was calculated, the results are shown in table 1 below, wherein the test voltage range is 3.0 to 5.0V (vs+/Li), the magnification is 1C.
TABLE 1
Figure BDA0003187601010000191
Fig. 7 shows the first constant current discharge curves at 1C rate of the CR2032 type button cell prepared by using the LNO-LNMO provided by examples 1 to 3 and the LNMO provided by comparative example as the positive electrode material, and as can be seen from fig. 7, the CR2032 type button cell prepared by using the LNMO provided by comparative example and the CR2032 type button cell prepared by using the LNO-LNMO provided by examples 1 to 3 have specific discharge capacities of 123.48, 126.73, 129.43 and 112.81mAh/g, respectively, when the first cycle of charging is performed.
Fig. 8 is a graph of cycle life for lithium batteries prepared from LNMO provided by the comparative example and CR2032 type button cells prepared from LNO-LNMO provided by examples 1-3. As can be seen from fig. 8, the CR2032 type button cell prepared from the LNO-LNMO provided in example 1 shows a specific discharge capacity of 126.2mAh/g at a 1C rate, and the capacity retention rate after 100 cycles is as high as 92.3%, the CR2032 type button cell prepared from the LNO-LNMO provided in example 2 shows a specific discharge capacity of 129.2mAh/g at a 1C rate, and the capacity retention rate after 100 cycles is as high as 93.4%, and the CR2032 type button cell prepared from the LNO-LNMO provided in example 3 shows a specific discharge capacity of 115.9mAh/g at a 1C rate, and the capacity retention rate after 100 cycles is as high as 115.9mAh/g93.89%, all higher than comparative example LNMO (88.5%). The cycle performance of all coated samples was improved relative to the uncoated samples. This is because LiNbO in the coating layer3The stable SEI film can be generated through reaction with an electrolyte, so that the main structure of the LNMO material is protected from being corroded by the electrolyte, the dissolution of Mn in the circulation process is reduced, and the circulation performance of the material is improved.
Test example 9
The CR2032 type button cell batteries prepared in test example 7 were sequentially cycled for 5 cycles at a rate of 0.1C, 0.5C, 1C, 2C, 5C, and 0.5C, respectively, to measure the rate capability of the lithium batteries, respectively, and the results are shown in table 2 below.
TABLE 2
Figure BDA0003187601010000201
Fig. 9 is a graph of the rate performance of the CR2032 button cell prepared from the LNO-LNMO provided in examples 1-3 and the LNMO provided in the comparative example, and it can be seen from fig. 9 that the CR2032 button cell prepared from the LNO-LNMO provided in examples 1-2 has a significant improvement in rate performance compared to the CR2032 button cell prepared from the LNMO provided in the comparative example. Among them, the CR2032 type button cell prepared from the LNO-LNMO provided in example 2 shows the most excellent rate capability, when the charge/discharge rate is increased to 5C, the specific discharge capacity of the CR2032 type button cell prepared from the LNO-LNMO provided in example 2 can still reach 116.0mAh/g, while the specific discharge capacity of the CR2032 type button cell prepared from the LNMO provided in comparative example at 5C is 112.7 mAh/g. The excellent electrochemical performance of CR2032 button cell prepared from LNO-LNMO provided in example 2 under high current can be attributed to the fact that the small amount of doped Nb increases the Mn on the surface of the material during coating3+、Mn3+Provides an additional electron transition orbital (Ni) for electrons2+/3+→Mn4+→Ni3+/4+And Ni2+/3+→Mn4+→Mn3+→Ni3+/4+) To make the charge transfer of the material faster, and to help promote the materialRate capability of the material.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims (10)

1. A preparation method of a lithium niobate-coated cathode material is characterized by comprising the following steps:
(a) dispersing a positive electrode material in a regulator solution to obtain a suspension;
(b) adding ammonium niobate oxalate hydrate solution into the suspension, uniformly mixing, and carrying out solid-liquid separation to obtain a niobium compound coated positive electrode material;
(c) adding the niobium compound coated positive electrode material into a lithium source solution, uniformly mixing, evaporating the solvent to dryness, drying, and calcining to obtain a lithium niobate coated positive electrode material;
wherein the regulator is a cationic surfactant.
2. The method of claim 1, wherein the conditioning agent is a quaternary ammonium salt cationic surfactant, preferably a polyoxyethylene alkyl quaternary ammonium salt.
3. The method for preparing according to claim 2, wherein the alkyl group of the polyoxyethylene alkyl quaternary ammonium salt is an alkyl group of C10-C20, preferably an alkyl group of C14-C18;
preferably, the conditioning agent comprises at least one of octadecyl polyoxyethylene ether diquaternary ammonium salt, hexadecyl polyoxyethylene ether dimethyloctane ammonium chloride, tetradecyl polyoxyethylene ether dimethylhexadecyl ammonium bromide, octadecyl polyoxyethylene ether dimethyltetradecyl ammonium bromide, octadecyl polyoxyethylene ether dimethyloctyl ammonium bromide, octadecyl polyoxyethylene ether dimethylmethyl ammonium bromide, hexadecyl polyoxyethylene ether dimethyloctadecyl ammonium bromide, hexadecyl polyoxyethylene ether dimethylhexadecyl ammonium bromide, hexadecyl polyoxyethylene ether dimethyltetradecyl ammonium bromide, or hexadecyl polyoxyethylene ether dimethyldodecyl ammonium bromide.
4. The method according to claim 1, wherein the mass concentration of the regulator solution is 0.5 to 5%, preferably 1 to 3%.
5. The method as claimed in claim 1, wherein in the step (c), the calcination temperature is 650-800 ℃ and the calcination time is 5-8 h;
preferably, the temperature for evaporating the solvent is 70-90 ℃;
preferably, the temperature for drying is 100-.
6. The method according to claim 1, wherein the mass concentration of the ammonium niobate oxalate hydrate solution is 1-10 ‰;
preferably, the solvent of the ammonium niobate oxalate hydrate solution is a mixed solution consisting of absolute ethyl alcohol and deionized water;
further preferably, in the solvent composed of the anhydrous ethanol and the deionized water, the volume ratio of the anhydrous ethanol to the deionized water is 1-3:1, preferably 2: 1.
7. The method of claim 1, wherein the lithium source comprises at least one of lithium acetate, lithium carbonate, lithium oxalate, or lithium hydroxide.
8. The production method according to any one of claims 1 to 7, wherein the positive electrode material includes at least one of lithium nickel manganese oxide, lithium cobaltate, lithium nickel oxide, lithium manganese oxide, lithium iron phosphate, or lithium iron manganese phosphate, preferably lithium nickel manganese oxide.
9. A lithium niobate-coated positive electrode material characterized by being produced by the method for producing a lithium niobate-coated positive electrode material according to any one of claims 1 to 8.
10. The use of the lithium niobate-coated positive electrode material according to claim 9 in a lithium battery.
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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114709412A (en) * 2022-04-25 2022-07-05 浙江锋锂新能源科技有限公司 High-temperature-resistant positive electrode material, electrolyte composition, lithium battery and preparation method
CN116014122A (en) * 2022-12-14 2023-04-25 湖北亿纬动力有限公司 Modified lithium iron manganese phosphate positive electrode material and preparation method and application thereof

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102694165A (en) * 2012-06-08 2012-09-26 天津理工大学 High-capacity lithium-rich layered crystalline structured lithium battery cathode material and preparation thereof
CN104766960A (en) * 2015-04-13 2015-07-08 河北工业大学 Method for modifying lithium nickel manganese oxide positive electrode material for lithium ion battery
CN109980187A (en) * 2017-12-27 2019-07-05 荆门市格林美新材料有限公司 A kind of nickel-cobalt lithium manganate cathode material of coated aluminum oxide and preparation method thereof
CN110148737A (en) * 2019-06-06 2019-08-20 山东省科学院能源研究所 A kind of lithium-rich manganese-based electrode material and preparation method thereof
JP2020035608A (en) * 2018-08-29 2020-03-05 トヨタ自動車株式会社 Manufacturing method of positive electrode layer
CN111115713A (en) * 2019-12-18 2020-05-08 中南大学 LaMnO3Coated lithium-rich manganese-based positive electrode material and preparation method thereof
CN111952554A (en) * 2020-07-03 2020-11-17 江苏可兰素环保科技有限公司 Ternary cathode material of lithium ion battery and preparation method thereof

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102694165A (en) * 2012-06-08 2012-09-26 天津理工大学 High-capacity lithium-rich layered crystalline structured lithium battery cathode material and preparation thereof
CN104766960A (en) * 2015-04-13 2015-07-08 河北工业大学 Method for modifying lithium nickel manganese oxide positive electrode material for lithium ion battery
CN109980187A (en) * 2017-12-27 2019-07-05 荆门市格林美新材料有限公司 A kind of nickel-cobalt lithium manganate cathode material of coated aluminum oxide and preparation method thereof
JP2020035608A (en) * 2018-08-29 2020-03-05 トヨタ自動車株式会社 Manufacturing method of positive electrode layer
CN110148737A (en) * 2019-06-06 2019-08-20 山东省科学院能源研究所 A kind of lithium-rich manganese-based electrode material and preparation method thereof
CN111115713A (en) * 2019-12-18 2020-05-08 中南大学 LaMnO3Coated lithium-rich manganese-based positive electrode material and preparation method thereof
CN111952554A (en) * 2020-07-03 2020-11-17 江苏可兰素环保科技有限公司 Ternary cathode material of lithium ion battery and preparation method thereof

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
JONG HWA KIM ET AL: "Bifunctional Surface Coating of LiNbO3 on High-Ni Layered Cathode Materials for Lithium-Ion Batteries", 《ACS APPL. MATER. INTERFACES》 *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114709412A (en) * 2022-04-25 2022-07-05 浙江锋锂新能源科技有限公司 High-temperature-resistant positive electrode material, electrolyte composition, lithium battery and preparation method
CN116014122A (en) * 2022-12-14 2023-04-25 湖北亿纬动力有限公司 Modified lithium iron manganese phosphate positive electrode material and preparation method and application thereof

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