CN111211320A - Lithium nickel cobalt oxide positive electrode material, preparation method thereof and lithium ion battery - Google Patents

Lithium nickel cobalt oxide positive electrode material, preparation method thereof and lithium ion battery Download PDF

Info

Publication number
CN111211320A
CN111211320A CN202010071076.9A CN202010071076A CN111211320A CN 111211320 A CN111211320 A CN 111211320A CN 202010071076 A CN202010071076 A CN 202010071076A CN 111211320 A CN111211320 A CN 111211320A
Authority
CN
China
Prior art keywords
nickel cobalt
lithium
cobalt oxide
positive electrode
salt
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN202010071076.9A
Other languages
Chinese (zh)
Inventor
江浩
李春忠
胡彦杰
朱华威
余海峰
黄君涛
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
GUANGDONG GUANGHUA SCI-TECH CO LTD
East China University of Science and Technology
Original Assignee
GUANGDONG GUANGHUA SCI-TECH CO LTD
East China University of Science and Technology
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by GUANGDONG GUANGHUA SCI-TECH CO LTD, East China University of Science and Technology filed Critical GUANGDONG GUANGHUA SCI-TECH CO LTD
Priority to CN202010071076.9A priority Critical patent/CN111211320A/en
Publication of CN111211320A publication Critical patent/CN111211320A/en
Pending legal-status Critical Current

Links

Images

Classifications

    • 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
    • H01M4/485—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy
    • 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
    • H01M4/362—Composites
    • 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
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Abstract

The invention discloses a lithium nickel cobalt oxide positive electrode material, a preparation method thereof and a lithium ion battery. The chemical formula of the lithium nickel cobalt oxide positive electrode material is LiNiz‑xCo1‑zMoxO2，0<x≤0.02，0.8<z-x is less than or equal to 0.95. The preparation method of the lithium nickel cobalt oxide cathode material comprises the step of sintering the total mixture of nickel cobalt hydroxide, lithium salt and ammonium molybdate tetrahydrate. The lithium nickel cobalt oxide positive electrode material has higher content of nickel, and is combined with the high valence state and the high bond energy of molybdenum to obtain the molybdenum element doped lithium nickel cobalt oxide positive electrode material which can obviously inhibit H2-H3 phase change, so that the structure of the positive electrode material is more stable and the positive electrode material is circulatedHigh stability, high reversible capacity, simple process and low cost, and can be applied to large-scale industrial production.

Description

Lithium nickel cobalt oxide positive electrode material, preparation method thereof and lithium ion battery
Technical Field
The invention relates to a lithium nickel cobalt oxide positive electrode material, a preparation method thereof and a lithium ion battery.
Background
With the gradual increase (more than or equal to 500Km) of the requirement of people on the endurance mileage of the electric automobile, the high-energy density lithium ion battery is in need. However, there is a limit to low energy density and high cost of the cathode material (e.g., LiCoO)2，LiNi1/3Co1/3Mn1/ 3O2) Currently, the most advanced lithium ion batteries still have difficulty meeting the above requirements. Therefore, the development of high-capacity, low-cost and long-life cathode materials is of great significance for the further development of electric vehicles.
High nickel content LiNizCo(1-z)O2(z>0.8) the anode material has high reversible specific capacity (210 mAh g)-1) Low cost and low toxicity become the most promising cathode material for next-generation lithium ion batteries. But its commercial use is severely hampered by poor structural stability and rapid capacity fade. On one hand, the irreversible H2-H3 phase change occurring at the end of charging can cause severe volume change and lattice stress, which further causes the material to generate micro-cracks and even fracture, accelerates the penetration of electrolyte and parasitic side reactions at the interface, and results in poor structural stability. On the other hand, due to Ni2+(0.069nm) and Li+(0.076nm) has similar ionic radius, and the Li/Ni mixed row which is more easily generated leads to the irreversible transformation of the surface structure of the material, namely, the surface structure is layered → the spinel phase → the salt rock phase, so that the material is formedA rapid decay of capacity.
Currently, high nickel positive electrode materials LiNizCo(1-z)O2The content z of the medium nickel is generally not more than 0.8, for example, chinese patent document CN110571422A discloses a high nickel cathode material, and the value of the nickel content is between 0.8 and 1, but the examples only disclose that the cycle stability of the cathode material can be solved when the nickel content is 0.8. In addition, highly iridescent (LiNi)yM1-yO2(M＝Co,Mn,Ti,0<y<1) Preparation and Performance of 2001.9.10, Power technology) discusses LiNiyCo1-yO2When y is 0.7, 0.8 and 0.9, the electrochemical performance of the material shows that the discharge plateau is high and the discharge is smooth when y is 0.8, and the reversible capacity and the cycle performance of the electrode material are good.
The doping modification is an effective means for solving the problems, relieving the phase change of H2-H3 and stabilizing the structure. At present, many works implement cation doping by wet chemical coating of doping source and subsequent two high temperature calcinations on the finished product, but the method is easy to generate inert compound on the surface of the material to reduce the doping efficiency. In addition, most cations have electrochemical inertia and higher valence states, and an uneven inert salt rock phase structure is easily generated on the surface of the material while the structural stability is improved, so that the transmission of ions and electrons is hindered, and a certain capacity loss is caused. However, in the current positive electrode material, doping modification to improve the cycle performance of the material only stays for LiNizCo(1-z)O2Wherein z is a doping modification of 0.8 or less. It is impossible to further reduce the cost and to make the cycle stability and reversible capacity at a high level.
Disclosure of Invention
The invention aims to solve the technical problem that a lithium nickel cobalt oxide positive electrode material with high cycling stability, high reversible capacity and higher nickel content cannot be obtained in the prior art, and provides the lithium nickel cobalt oxide positive electrode material, a preparation method thereof and a lithium ion battery. The lithium nickel cobalt oxide cathode material of the invention is added with higher content of nickel (LiNi)zCo(1-z)O2Z in the formula is more than 0.8), and the high valence state and the high bond energy of molybdenum are combined at the same time, so that the molybdenum element doped lithium nickel cobalt oxide positive electrode material can obviously inhibit H2-H3 phase change, the structure of the lithium nickel cobalt oxide positive electrode material is more stable, the cycling stability is high, the reversible capacity is high, the process is simple, the cost is low, and the method can be applied to large-scale industrial production.
At present, lithium nickel cobalt oxide (LiNi) is the state of the artzCo(1-z)O2) Field of cathode materials, LiNizCo(1-z)O2The value of z representing the nickel content in the formula is generally not more than 0.8. When the content of the lithium nickel cobalt oxide is more than 0.8, the lithium nickel cobalt oxide positive electrode material has poor cycle stability and low reversible capacity, and cannot meet the use requirement. The inventor of the invention screens a plurality of experimental conditions through creative labor to obtain the technical scheme of the invention. For example, the content of Ni in the formula is 0.8-0.95 (excluding 0.8), and doped elements and the like have significant influence on the performance of the cathode material of the present invention. The invention skillfully limits the characteristics to ensure that the lithium nickel cobalt oxide cathode material has a plurality of excellent properties.
The invention provides a lithium nickel cobalt oxide positive electrode material, which has a chemical formula as follows: LiNiz-xCo1-zMoxO2，0<x≤0.02，0.8<z-x≤0.95。
The LiNiz-xCo1-zMoxO2In the above description, x is preferably 0.005-0.02, such as 0.005, 0.01 or 0.02.
The LiNiz-xCo1-zMoxO2In the above description, z-x is preferably 0.85 to 0.95, such as 0.87, 0.88, 0.89, 0.895 or 0.91. More preferably 0.85 to 0.9, such as 0.87, 0.88, 0.89, 0.895; alternatively, it is more preferably 0.9-0.95, such as 0.9-0.93, and further such as 0.91.
In a preferred embodiment of the present invention, the lithium nickel cobalt oxide cathode material has a chemical formula of LiNi0.89Co0.1Mo0.01O2、LiNi0.895Co0.1Mo0.005O2、LiNi0.88Co0.1Mo0.02O2、LiNi0.87Co0.12Mo0.01O2Or LiNi0.91Co0.08Mo0.01O2。
The invention also provides a preparation method of the lithium nickel cobalt oxide positive electrode material, which comprises the following steps: and sintering the total mixture of nickel cobalt hydroxide, lithium salt and ammonium molybdate tetrahydrate.
In the invention, the nickel cobalt hydroxide is reasonably selected according to the required lithium nickel cobalt oxide cathode material. According to the lithium nickel cobalt oxide cathode material, the chemical formula of the nickel cobalt hydroxide can be NiyCo1-y(OH)2In the formula, 0.8<y≤0.95。
Wherein said NiyCo1-y(OH)2In the above formula, y is preferably 0.85 to 0.9, for example, 0.88; or, the NiyCo1-y(OH)2In this case, y is preferably 0.9 to 0.95, more preferably 0.9 to 0.93, for example, 0.92. According to the invention, on the premise of adding higher content of nickel, the cycle stability and reversible capacity of the obtained cathode material still keep higher level.
In the present invention, the preparation method of the nickel cobalt hydroxide can be conventional in the art, and a chemical coprecipitation method is generally adopted.
Wherein the chemical co-precipitation process may be conventional in the art, typically comprising the steps of: and enabling the mixed solution of the nickel salt and the cobalt salt and the alkali solution to flow into a reaction kettle in a parallel mode, and carrying out mixing reaction.
In the "mixed solution of nickel salt and cobalt salt", the total concentration of the "nickel salt and cobalt salt" can be conventional in the art, and is generally 1-3 mol/L, for example 2 mol/L. In the mixed solution of nickel salt and cobalt salt, the molar ratio of the nickel salt to the cobalt salt is reasonably selected according to the required lithium nickel cobalt oxide cathode material. The solvent in the "mixed solution of nickel salt and cobalt salt" may be conventional in the art, and is typically deionized water. The kind of the nickel salt may be a kind conventional in the art, for example, nickel nitrate and/or nickel sulfate. The cobalt salt may be of a type conventional in the art, for example, cobalt nitrate and/or cobalt sulfate.
The feeding rate of the "mixed solution of nickel salt and cobalt salt" may be conventional in the art, and is typically 2 to 6mL/min, for example 5 mL/min.
The molar concentration of the alkali solution may be conventional in the art, and is generally 1 to 5mol/L, such as 1.95mol/L or 4 mol/L. In the alkali solution, the kind of alkali may be conventional in the art, such as sodium hydroxide and/or aqueous ammonia. The ammonia water is usually 25-28% by mass. In a preferred embodiment of the present invention, the alkali solution is a sodium hydroxide solution and an ammonia solution; the concentration of the sodium hydroxide solution is 3-5 mol/L, such as 4 mol/L; the concentration of the ammonia water solution is 1-3 mol/L, such as 1.95 mol/L.
In a preferred embodiment of the present invention, when the alkali solution is a sodium hydroxide solution and an ammonia solution, the co-current flows into the reaction kettle simultaneously as the "mixed solution of nickel salt and cobalt salt", the sodium hydroxide solution and the ammonia solution.
The feeding rate of the alkali solution is usually enough to keep the pH value in the reaction kettle between 10 and 12, for example, 11. The feed rate of the alkali solution may be conventional in the art and is typically 2 to 6 mL/min. When the alkali solution is ammonia water, the feeding rate of the ammonia water can be 2-6 mL/min, for example 5 mL/min.
The mixing reaction time can be conventional in the art, and is generally 20-25 h, for example 20 h. The mixing reaction is calculated from the fact that the reaction kettle contains the nickel salt and cobalt salt mixed solution and the alkali solution at the same time.
It is known to those skilled in the art that the base solution is added to the reaction vessel before the "mixed solution of nickel salt and cobalt salt" and the alkali solution are added to the reaction vessel. The base solution may be conventional in the art and is typically referred to as a base and/or water, such as ammonia. The concentration of the base solution can be, for example, 0.4-0.8 mol/L, and further, for example, 0.6 mol/L. The volume of the base solution can be conventional in the art, and can be 1400-1600 mL, for example. The reaction temperature in the reaction kettle can be a temperature conventional in the art, and is generally 40-60 ℃, for example 50 ℃.
In the present invention, the kind of the lithium salt may be conventional in the art, and is typically lithium hydroxide. The lithium hydroxide is commonly referred to as LiOH H2O。
In the present invention, the molar ratio of the nickel cobalt hydroxide and the ammonium molybdate tetrahydrate may be a molar ratio conventional in the art, and is preferably (50-200): 1, e.g. 100: 1.
in the present invention, the molar ratio of the nickel cobalt hydroxide and the lithium salt may be a molar ratio conventional in the art, and is preferably 1 (1-1.06), such as 1:1.03 or 1: 1.056.
In the present invention, the total mixture is a solid obtained by mixing the nickel cobalt hydroxide, the lithium salt, and the ammonium molybdate tetrahydrate.
Wherein the total mixture is preferably prepared by the following steps: and carrying out first mixing on the solid mixture of the nickel cobalt hydroxide and the ammonium molybdate tetrahydrate and the lithium salt. The time for the first mixing may be conventional in the art, and is preferably 10 to 30min, such as 15min, 20min or 25 min. The first mixing operation may be conventional in the art, typically grinding.
The preparation of the solid mixture of nickel cobalt hydroxide and ammonium molybdate tetrahydrate preferably comprises the steps of: and carrying out second mixing on the nickel cobalt hydroxide and the ammonium molybdate tetrahydrate solution. The solvent in the ammonium molybdate tetrahydrate solution may be conventional in the art and is typically deionized water. The second mixing preferably adds the nickel cobalt hydroxide to the ammonium molybdate tetrahydrate solution.
The time for the second mixing may be a time conventional in the art, and is preferably 3 to 5 hours, for example 4 hours.
The second mixing operation may be a solid-liquid mixing operation, typically stirring, as is conventional in the art. The stirring speed can be conventional in the field, and the stirring speed is usually enough to stir the mixture, and is generally 10-1000 r/min.
The temperature of the second mixing may be a mixing temperature conventional in the art, typically room temperature.
After the second mixing, a post-treatment operation is generally required. The work-up may be carried out as is conventional in the art, and is usually dry. The drying temperature can be a drying temperature conventional in the art, and is generally 70-90 ℃, for example 80 ℃.
In the present invention, the sintering temperature may be a conventional sintering temperature in the art, preferably 700 to 750 ℃, more preferably 710 to 735 ℃, for example 720 ℃. The rate of temperature increase to the sintering temperature during the sintering process may be a rate of temperature increase conventional in the art. The heating rate is usually 3-5 deg.C/min, preferably 5 deg.C/min.
In the present invention, the sintering time can be conventional in the art, and is generally 10 to 15 hours, preferably 15 hours. The sintering time is calculated from the time of raising the temperature to the sintering temperature.
In the present invention, the environment of the sintering is typically an oxygen-rich environment, as is known to those skilled in the art.
Wherein, the skilled person knows that the oxygen-enriched environment is generally an environment in which the oxygen content of oxygen is 30-50%.
In the present invention, the equipment for sintering may be a tube furnace, as known to those skilled in the art.
In the present invention, as known to those skilled in the art, the sintering is usually preceded by a pre-firing treatment.
The temperature of the pre-sintering treatment may be conventional in the art, preferably 500 to 550 ℃, more preferably 500 to 540 ℃, for example 500 ℃. In the pre-firing treatment, the temperature increase rate of the temperature increase to the temperature of the pre-firing treatment may be a rate of temperature increase conventional in the art. The heating rate is usually 3-5 deg.C/min, preferably 5 deg.C/min.
The pre-sintering treatment time can be conventional in the art, and is preferably 5 to 8 hours, and is preferably 5 to 6 hours. The time of the pre-firing treatment is calculated from the time when the temperature is raised to the sintering temperature.
The environment of the pre-firing treatment is typically an oxygen-rich environment, as is known to those skilled in the art.
As known to those skilled in the art, the oxygen-rich environment is generally an environment in which the oxygen content of oxygen is 30-50%.
Wherein, the equipment of the pre-burning treatment can be a tube furnace, which is known by the technical personnel in the field.
In a preferred embodiment of the present invention, the sintering process further comprises a pre-sintering process, wherein the temperature of the pre-sintering process is 500 to 540 ℃, and the time of the pre-sintering process is 5 to 8 hours; the sintering temperature is 710-735 ℃, and the sintering time is 10-15 h.
In a preferred embodiment of the present invention, the sintering process further comprises a pre-sintering process, wherein the temperature of the pre-sintering process is 500 ℃, the time of the pre-sintering process is 5 hours, and the temperature rising rate of the pre-sintering process is 5 ℃/min; the sintering temperature is 720 ℃, the sintering time is 15h, and the heating rate of heating to the sintering temperature in the sintering process is 5 ℃/min.
The invention also provides a lithium ion battery, and the anode material of the lithium ion battery is the lithium nickel cobalt oxide anode material.
On the basis of the common knowledge in the field, the above preferred conditions can be combined randomly to obtain the preferred embodiments of the invention.
The reagents and starting materials used in the present invention are commercially available.
The room temperature in the invention is generally 0-40 ℃, for example 20-35 ℃.
The positive progress effects of the invention are as follows: the chemical formula of the lithium nickel cobalt oxide cathode material of the invention is LiNiz- xCo1-zMoxO2And the value of z-x is more than 0.8, and the molybdenum element is doped in the process of embedding lithium in the nickel-cobalt hydroxide precursor by combining parameters such as the type, the dosage and the like of specific molybdenum salt, so that the lithium nickel-cobalt oxide cathode material is finally obtained.
The lithium nickel cobalt oxide cathode material realizes trace Mo6+The doping amount is controllable,meanwhile, the phase change of H2-H3 is relieved, the generation and the propagation of microcracks are inhibited, and the stability of a crystal structure is improved, so that the electrochemical performance of the lithium nickel cobalt oxide anode material is improved, and the obtained lithium nickel cobalt oxide anode material has good cycling stability and high reversible capacity. The original specific capacity can still be kept 95.9% after the circulation is performed for 100 circles under 2.7-4.3V and 1C. 139.0mAh g can be maintained even under the large current density of 5C-1The specific capacity of (A). Meanwhile, the dosage of cobalt is obviously reduced, the preparation of kilogram-grade anode materials can be realized, and the method is suitable for industrial production.
Drawings
Fig. 1 is an X-ray diffraction (XRD) pattern of the products obtained in example 1 and comparative example 1.
Fig. 2 is a Scanning Electron Microscope (SEM) image of the lithium nickel cobalt oxide positive electrode material of comparative example 1.
Fig. 3 is a Scanning Electron Microscope (SEM) image of the lithium nickel cobalt oxide positive electrode material of example 1.
Fig. 4 is a plot of Cyclic Voltammetry (CV) for the first three cycles of a cell assembled with the lithium nickel cobalt oxide positive electrode material of comparative example 1.
Fig. 5 is a plot of Cyclic Voltammetry (CV) for the first three cycles of a battery assembled with the lithium nickel cobalt oxide positive electrode material of example 1.
FIG. 6 shows electrochemical performance tests of batteries assembled by the lithium nickel cobalt oxide positive electrode materials obtained in example 1 and comparative example 1 at 2.7-4.3V. Fig. 6a is a specific capacity test of the lithium nickel cobalt oxide positive electrode materials of example 1 and comparative example 1 at different current densities, and fig. 6b is a cycle stability test of the lithium nickel cobalt oxide positive electrode materials of example 1 and comparative example 1.
Fig. 7 is a dQ/dV graph of a battery assembled with the lithium nickel cobalt oxide positive electrode materials obtained in example 1 and comparative example 1. Fig. 7a is a dQ/dV graph for a battery assembled with the lithium nickel cobalt oxide cathode material of example 1; fig. 7b is a dQ/dV graph of a battery assembled with the lithium nickel cobalt oxide cathode material of comparative example 1.
Detailed Description
The invention is further illustrated by the following examples, which are not intended to limit the scope of the invention. The experimental methods without specifying specific conditions in the following examples were selected according to the conventional methods and conditions, or according to the commercial instructions.
Example 1
The preparation method of the cathode material of the embodiment is as follows:
Ni-Co hydroxide precursor Ni0.9Co0.1(OH)2The preparation of (1): according to the weight ratio of Ni: co 9: weighing NiSO at a molar ratio of 14·6H2O solid 116.64g, CoSO4·7H215.12g of O solid; adding the two sulfates into 468.24mL of deionized water to prepare a mixed sulfate solution A with the total concentration of 2 mol/L; weighing 96g of sodium hydroxide solid, and dissolving the solid in deionized water to form 4mol/L sodium hydroxide solution B; 87.77mL of 25-28% concentrated ammonia water in mass fraction is weighed and mixed with deionized water to form 1.95mol/L ammonia water solution C. 1600mL of 0.6mol/L ammonia water solution is added into the reaction kettle as a base solution, the reaction kettle is heated by a water bath to keep the constant temperature of 50 ℃, and the stirring speed is controlled at 600 r/min. Introducing argon before the reaction starts, ensuring that the reaction is carried out in an argon atmosphere, and simultaneously pumping sodium hydroxide solution to adjust the pH of the base solution to be 11 +/-0.02. Slowly pumping the solution A, B, C into a reaction kettle at the same time, controlling the feeding speed of the solution A to be 5mL/min and the feeding speed of the solution C to be 5mL/min, controlling the feeding speed of the solution B to ensure that the pH value of the coprecipitation reaction is 11 +/-0.02, filtering, cleaning and drying at 100 ℃ after 20 hours of reaction to obtain Ni0.9Co0.1(OH)2。
Dissolving 0.019g of ammonium molybdate tetrahydrate in deionized water to obtain an ammonium molybdate tetrahydrate solution, adding 1g of nickel cobalt hydroxide into the ammonium molybdate tetrahydrate solution, stirring at the rotating speed of 10-1000 r/min for 4 hours at room temperature, and drying at 80 ℃ to obtain a mixed material of the ammonium molybdate tetrahydrate and the nickel cobalt hydroxide; the mixture was mixed with 0.4752g of LiOH H2Mixing and grinding the O solid for 20 min; and sequentially pre-burning and sintering the ground mixture in an oxygen-rich environment of a tube furnace to obtain the lithium nickel cobalt oxide cathode material, which is recorded as NCMo 1.
The pre-sintering temperature is 500 ℃, the pre-sintering time is 5 hours, the sintering temperature is 720 ℃, the sintering time is 15 hours, and the heating rates of the temperature to be pre-sintered and the temperature to be calcined are both 5 ℃/min. The time for the pre-firing treatment was calculated from the time when the temperature was raised to 500 ℃ and the time for the sintering was calculated from the time when the temperature was raised to 720 ℃.
The chemical formula of the lithium nickel cobalt oxide cathode material obtained in this example is LiNi0.89Co0.1Mo0.01O2And is designated as NCMo 1.
Example 2
The amount of ammonium molybdate tetrahydrate added in this example was 0.0095g, and the amounts of the other raw materials added, the concentrations, and the preparation method were the same as those in example 1. The chemical formula of the lithium nickel cobalt oxide cathode material obtained in this example is LiNi0.895Co0.1Mo0.005O2。
Example 3
The amount of ammonium molybdate tetrahydrate added in this example was 0.038g, and the amounts of the other raw materials added, concentrations, and preparation method were the same as those in example 1. The chemical formula of the lithium nickel cobalt oxide cathode material obtained in this example is LiNi0.88Co0.1Mo0.02O2。
Example 4
In this embodiment, the precursor of Ni-Co hydroxide is Ni0.88Co0.12(OH)2According to the formula of Ni: co 0.88: NiSO was weighed at a molar ratio of 0.124·6H2O and CoSO4·7H2O, the remaining raw material contents, concentrations and preparation process parameters were the same as in example 1. The chemical formula of the lithium nickel cobalt oxide cathode material obtained in this example is LiNi0.87Co0.12Mo0.01O2。
Example 5
In this example, the temperature of the pre-firing treatment was 500 ℃ and the temperature of the sintering was 750 ℃. The other preparation process parameters were the same as in example 1. The chemical formula of the lithium nickel cobalt oxide cathode material obtained in this example is LiNi0.89Co0.1Mo0.01O2。
Example 6
This exampleThe precursor of the medium nickel cobalt hydroxide is Ni0.92Co0.08(OH)2According to the formula of Ni: co 0.92: NiSO was weighed at a molar ratio of 0.084·6H2O and CoSO4·7H2O, the remaining raw material contents, concentrations and preparation process parameters were the same as in example 1. The chemical formula of the lithium nickel cobalt oxide cathode material obtained in this example is LiNi0.91Co0.08Mo0.01O2。
Example 7
Based on example 1, 1g of Ni prepared in example 1 was added0.9Co0.1(OH)2And 0.019g of ammonium molybdate tetrahydrate solid, 0.4752g of LiOH H2The O solid was mixed and ground for 20min, and the other preparation method parameters were the same as example 1. The chemical formula of the lithium nickel cobalt oxide cathode material obtained in this example is LiNi0.89Co0.1Mo0.01O2。
Comparative example 1
Ammonium molybdate tetrahydrate is not added, and the parameters of the rest of the preparation method are the same as those of example 1. The chemical formula of the obtained lithium nickel cobalt oxide cathode material is LiNi0.9Co0.1O2Is counted as NC.
Comparative example 2
The precursor of the nickel-cobalt hydroxide is Ni0.8Co0.2(OH)2According to the formula of Ni: co 8: 2 molar ratio of NiSO4·6H2O and CoSO4·7H2O, content of the remaining raw materials, concentration and other preparation method parameters were the same as in example 1. The chemical formula of the lithium nickel cobalt oxide positive electrode material is LiNi0.79Co0.02Mo0.01O2。
Effect example 1
(1) X-ray diffraction (XRD) test: polymorph/D8 advanced da vinci, produced by brueck AXS ltd, germany.
The X-ray diffraction (XRD) patterns of the lithium nickel cobalt oxide positive electrode materials obtained in example 1 and comparative example 1 are shown in fig. 1. NC in the figure represents the lithium nickel cobalt oxide positive electrode material of comparative example 1, and NCMo1 in the figure refers to the lithium nickel cobalt oxide positive electrode material of example 1. As can be seen from fig. 1, the crystal structure of the lithium nickel cobalt oxide positive electrode material doped with 1 mol% of Mo element was not changed, and the crystal structure was not destroyed.
(2) Composition determination of lithium nickel cobalt oxide cathode material
ICP testing was performed on the lithium nickel cobalt oxide positive electrode materials of examples 1 to 3 and comparative example 1, and the test results are shown in Table 1 below, from which it can be seen that LiNi, which is the lithium nickel cobalt oxide positive electrode material in examples 1 to 3 and comparative example 1 of the present invention0.89Co0.1Mo0.01O2The compositions are identical. The model of ICP is ICP-AES, Agilent 725.
TABLE 1
Chemical formula of theoretical design Test results of ICP
Example 1 LiNi0.89Co0.1Mo0.01O2 LiNi0.889Co0.101Mo0.01O2
Example 2 LiNi0.895Co0.1Mo0.005O2 LiNi0.893Co0.103Mo0.004O2
Example 3 LiNi0.88Co0.1Mo0.02O2 LiNi0.878Co0.103Mo0.019O2
Comparative example 1 LiNi0.9Co0.1O2 LiNi0.895Co0.105O2
Similarly, the lithium nickel cobalt oxide positive electrode materials of examples 4 to 7 and comparative example 2 were subjected to ICP test, and the compositions of the lithium nickel cobalt oxide positive electrode materials of the examples and comparative examples were consistent with the ICP test results.
(3) Morphology characterization of lithium nickel cobalt oxide positive electrode material
Testing with Scanning Electron Microscope (SEM): the instrument model is as follows: nova NanoSEM 450, usa. The shapes of the lithium nickel cobalt oxide cathode materials in examples 1 to 7 are characterized by SEM, and the average particle size of the lithium nickel cobalt oxide cathode materials in examples 1 to 7 is 10 μm.
Specifically, a Scanning Electron Microscope (SEM) image of the product obtained in comparative example 1 is shown in fig. 2, and a Scanning Electron Microscope (SEM) image of the product obtained in example 1 is shown in fig. 3. As can be seen from fig. 2 and 3, the morphology and sphericity of the lithium nickel cobalt oxide cathode material doped with Mo in example 1 are unchanged from the raw material, which indicates that the structure of the lithium nickel cobalt oxide cathode material is not damaged during the doping process, and it can be seen from the figure that the average particle size of the lithium nickel cobalt oxide cathode material in example 1 is 10 μm.
(4) Electrochemical performance test
Multi-rate CV test: the instrument model is as follows: autolab PGSTAT 302N.
Assembly and testing of CR2016 button cells: the positive electrode materials prepared in examples 1 to 6 and comparative examples 1 to 2, carbon black and PVDF (polyvinylidene fluoride) were prepared into slurry in a mass ratio of 8:1:1, coated on an aluminum foil, and cut into piecesCutting the dried aluminum foil loaded with slurry into small round pieces with the diameter of about 1.2cm by a machine to be used as a positive electrode, taking a metal lithium piece as a negative electrode, taking Celgard2400 as a diaphragm, and taking a 1M mixed organic solution as an electrolyte (wherein the solvent is a mixed solution of ethylene carbonate and ethylene dimethyl carbonate with the volume ratio of 3:7, and the solute is LiPF6) And assembling the cell into a CR2016 button cell in an argon glove box.
The Cyclic Voltammetry (CV) profile of the first three battery cycles assembled from the lithium nickel cobalt oxide cathode material of comparative example 1 is shown in fig. 4, where NC represents the lithium nickel cobalt oxide cathode material of comparative example 1. The Cyclic Voltammetry (CV) profile of the first three cycles of the battery assembled from the lithium nickel cobalt oxide positive electrode material of example 1 is shown in fig. 5, in which NCMo1 refers to the lithium nickel cobalt oxide positive electrode material of example 1, and the second cycle (2nd) and the third cycle (3rd) coincide with each other. As can be seen from fig. 4 and 5, compared to comparative example 1(0.28V), the overlap ratio of the first three circles of curves of the lithium nickel cobalt oxide positive electrode material (0.18V) doped with Mo in example 1 is better and the difference between the first circles of redox peaks is significantly reduced, which indicates that the polarization of the lithium nickel cobalt oxide positive electrode material in example 1 is significantly reduced, and thus indicates that the reversible capacity of the electrode material is high.
The electrochemical performance of the battery obtained by assembling the lithium nickel cobalt oxide cathode materials of examples 1 to 6 and comparative examples 1 to 2 under the conditions of 2.7 to 4.3V and the test temperature of 25 ℃ is shown in the following table 2.
TABLE 2 Performance parameters of the lithium nickel cobalt oxide cathode materials of examples 1 to 6 and comparative examples 1 to 2
Figure BDA0002377337430000121
Specifically, comparative analysis was performed on electrochemical properties of the lithium nickel cobalt oxide cathode materials of example 1 and comparative example, as shown in fig. 6, in which NC represents the lithium nickel cobalt oxide cathode material of comparative example 1, and NCMo1 represents the lithium nickel cobalt oxide cathode material of example 1. Fig. 6a is a graph showing the specific capacity test results of the lithium nickel cobalt oxide positive electrode materials of example 1 and comparative example 1 at different current densities, and fig. 6b is a graph showing the cycle stability test results of the lithium nickel cobalt oxide positive electrode materials of example 1 and comparative example 1. As can be seen from fig. 6, the lithium nickel cobalt oxide positive electrode material of example 1 has excellent rate capability and cycle performance, and the reversible capacity of the battery at 5C is up to 139 mAh/g; the reversible capacity retention rate is up to 95.9 percent and the reversible capacity is 171.3mAh/g after 100 cycles of circulation at 1C.
The dQ/dV curves of the batteries assembled by the lithium nickel cobalt oxide cathode materials obtained in example 1 and comparative example 1 are shown in FIG. 7. Wherein, fig. 7a is the dQ/dV graph of the battery assembled with the lithium nickel cobalt oxide cathode material of example 1; fig. 7b is a dQ/dV graph of a battery assembled with the lithium nickel cobalt oxide cathode material of comparative example 1. As can be seen from fig. 7, the curve coincidence degree of the lithium nickel cobalt oxide cathode material NCMo1 doped with Mo is higher, the reversibility of the phase transition of H2 to H3 is significantly improved, and the structure of the material is more stable.

Claims (10)

1. The lithium nickel cobalt oxide cathode material is characterized in that the chemical formula of the lithium nickel cobalt oxide cathode material is LiNiz-xCo1-zMoxO2，0<x≤0.02，0.8<z-x≤0.95。
2. The lithium nickel cobalt oxide positive electrode material of claim 1, wherein the LiNi isz-xCo1-zMoxO2Wherein x is 0.005-0.02, preferably 0.005, 0.01 or 0.02;
and/or, said LiNiz-xCo1-zMoxO2Wherein z-x is 0.85-0.95.
3. The lithium nickel cobalt oxide positive electrode material of claim 2, wherein the LiNi isz-xCo1-zMoxO2Wherein z-x is 0.85 to 0.9, preferably 0.87, 0.88, 0.89 or 0.895;
or, the LiNiz-xCo1-zMoxO2In the above formula, z-x is 0.9 to 0.95, preferably 0.9 to 0.93, and more preferably 0.91.
4. A method for preparing a lithium nickel cobalt oxide positive electrode material according to any one of claims 1 to 3, characterized in that it comprises the following steps: and sintering the total mixture of nickel cobalt hydroxide, lithium salt and ammonium molybdate tetrahydrate.
5. The method of claim 4, wherein the nickel cobalt hydroxide has the formula NiyCo1-y(OH)2In the formula, 0.8<y≤0.95；
And/or, the nickel cobalt hydroxide is prepared by a chemical coprecipitation method; preferably, the chemical coprecipitation method comprises the following steps: enabling the mixed solution of nickel salt and cobalt salt and alkali solution to flow into a reaction kettle in parallel, and carrying out mixing reaction;
and/or, the lithium salt is lithium hydroxide;
and/or the molar ratio of the nickel cobalt hydroxide to the ammonium molybdate tetrahydrate is (50-200): 1;
and/or the molar ratio of the nickel cobalt hydroxide to the lithium salt is 1 (1-1.06);
and/or, the total mixture is a solid obtained by mixing the nickel cobalt hydroxide, the lithium salt and the ammonium molybdate tetrahydrate; the total mixture is preferably prepared by the following steps: first mixing a solid mixture of the nickel cobalt hydroxide and the ammonium molybdate tetrahydrate with the lithium salt;
and/or the sintering temperature is 700-750 ℃; preferably, in the sintering process, the heating rate of heating to the sintering temperature is 3-5 ℃/min;
and/or the sintering time is 10-15 h;
and/or, the sintering process further comprises a pre-sintering treatment.
6. The method of claim 5, wherein the Ni isyCo1-y(OH)2Wherein y is 0.85 to 0.9 or 0.9-0.95; preferably, y is 0.88 or y is 0.9 to 0.93;
and/or in the mixed solution of nickel salt and cobalt salt, the total concentration of the nickel salt and cobalt salt is 1-3 mol/L;
and/or the feeding rate of the mixed solution of the nickel salt and the cobalt salt is 2-6 mL/min;
and/or the molar concentration of the alkali solution is 1-5 mol/L;
and/or, in the alkali solution, the alkali species comprises sodium hydroxide and/or ammonia water;
and/or the feeding rate of the alkali solution is 2-6 mL/min;
and/or the mixing reaction time is 20-25 h;
and/or adding a base solution into the reaction kettle before adding the mixed solution of the nickel salt and the cobalt salt and the alkali solution into the reaction kettle, wherein the base solution is alkali and/or water; preferably, the concentration of the base solution is 0.4-0.8 mol/L; preferably, the volume of the base solution is 1400-1600 mL.
7. The method of claim 5, wherein the molar ratio of nickel cobalt hydroxide to ammonium molybdate tetrahydrate is from 100: 1;
and/or, the molar ratio of the nickel cobalt hydroxide to the lithium salt is 1:1.03 or 1: 1.056;
and/or the first mixing time is 10-30 min, preferably 15min, 20min or 25 min;
and/or, the operation of the first mixing is milling;
and/or the preparation of the solid mixture of the nickel cobalt hydroxide and the ammonium molybdate tetrahydrate comprises the following steps: carrying out second mixing on the nickel cobalt hydroxide and the ammonium molybdate tetrahydrate solution;
and/or the sintering temperature is 710-735 ℃;
and/or the temperature of the pre-sintering treatment is 500-550 ℃, preferably 500-540 ℃; preferably, in the pre-sintering treatment, the temperature rise rate of the temperature rising to the temperature of the pre-sintering treatment is 3-5 ℃/min;
and/or the pre-sintering treatment time is 5-8 h, preferably 5-6 h.
8. The method of claim 7 wherein said second mixing is adding said nickel cobalt hydroxide to said ammonium molybdate tetrahydrate solution;
and/or the second mixing time is 3-5 h;
and/or, the operation of the second mixing is stirring;
and/or after the second mixing, the operation of post-treatment is also included.
9. The method of claim 8, wherein the second mixing is for a time of 4 hours;
and/or, the post-treatment operation is drying; preferably, the drying temperature is 70-90 ℃.
10. A lithium ion battery, characterized in that the positive electrode material is the lithium nickel cobalt oxide positive electrode material according to any one of claims 1 to 3.
CN202010071076.9A 2020-01-21 2020-01-21 Lithium nickel cobalt oxide positive electrode material, preparation method thereof and lithium ion battery Pending CN111211320A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202010071076.9A CN111211320A (en) 2020-01-21 2020-01-21 Lithium nickel cobalt oxide positive electrode material, preparation method thereof and lithium ion battery

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202010071076.9A CN111211320A (en) 2020-01-21 2020-01-21 Lithium nickel cobalt oxide positive electrode material, preparation method thereof and lithium ion battery

Publications (1)

Publication Number Publication Date
CN111211320A true CN111211320A (en) 2020-05-29

Family

ID=70789126

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202010071076.9A Pending CN111211320A (en) 2020-01-21 2020-01-21 Lithium nickel cobalt oxide positive electrode material, preparation method thereof and lithium ion battery

Country Status (1)

Country Link
CN (1) CN111211320A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112614989A (en) * 2020-12-17 2021-04-06 齐鲁工业大学 Molybdenum-doped nickel cobaltate porous yolk-shell structure material and preparation method and application thereof
CN114665088A (en) * 2022-03-08 2022-06-24 三峡大学 Preparation method of zinc-cobalt-nickel battery positive electrode composite material
WO2022138104A1 (en) * 2020-12-25 2022-06-30 パナソニックＩｐマネジメント株式会社 Nonaqueous electrolyte secondary battery

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2018110899A1 (en) * 2016-12-12 2018-06-21 주식회사 포스코 Positive electrode active material for lithium secondary battery, method for preparing same, and lithium secondary battery comprising same
CN108878868A (en) * 2018-07-19 2018-11-23 北京理工大学 A kind of surface layer and the NCM tertiary cathode material of bulk phase-doped Mo element and preparation method thereof
CN110137488A (en) * 2019-05-28 2019-08-16 郑州中科新兴产业技术研究院 A kind of nickelic positive electrode of secondary lithium batteries and preparation method thereof

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2018110899A1 (en) * 2016-12-12 2018-06-21 주식회사 포스코 Positive electrode active material for lithium secondary battery, method for preparing same, and lithium secondary battery comprising same
CN108878868A (en) * 2018-07-19 2018-11-23 北京理工大学 A kind of surface layer and the NCM tertiary cathode material of bulk phase-doped Mo element and preparation method thereof
CN110137488A (en) * 2019-05-28 2019-08-16 郑州中科新兴产业技术研究院 A kind of nickelic positive electrode of secondary lithium batteries and preparation method thereof

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
HOON-HEE RYU等: ""Li[Ni0.9Co0.09W0.01]O2: A New Type of Layered Oxide Cathode with High Cycling Stability"", 《ADV. ENERGY MATER.》 *
S. SIVAPRAKASH等: ""Crystal chemistry modification of lithium nickel cobalt oxide cathodes for lithium ion rechargeable batteries"", 《JOURNAL OF POWER SOURCES》 *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112614989A (en) * 2020-12-17 2021-04-06 齐鲁工业大学 Molybdenum-doped nickel cobaltate porous yolk-shell structure material and preparation method and application thereof
WO2022138104A1 (en) * 2020-12-25 2022-06-30 パナソニックＩｐマネジメント株式会社 Nonaqueous electrolyte secondary battery
CN114665088A (en) * 2022-03-08 2022-06-24 三峡大学 Preparation method of zinc-cobalt-nickel battery positive electrode composite material
CN114665088B (en) * 2022-03-08 2024-03-12 三峡大学 Preparation method of zinc cobalt nickel battery positive electrode composite material

Similar Documents

Publication Publication Date Title
CN109336193B (en) Multi-element in-situ co-doped ternary material precursor and preparation method and application thereof
CN113258060B (en) Sodium ion battery high-nickel layered oxide material and preparation method and application thereof
CN112151790B (en) High-nickel ternary cathode material precursor, crystal face controllable growth method thereof, ternary cathode material and lithium ion battery
CN109713297B (en) High-nickel anode material with directionally arranged primary particles and preparation method thereof
CN110797527A (en) Modified lithium-rich manganese-based oxide cathode material and preparation method thereof
CN108550791B (en) Spinel-coated layered cathode material and preparation method and application thereof
CN103715424A (en) Core-shell structured cathode material and preparation method thereof
CN110323432A (en) A kind of miscellaneous modification lithium-ion battery anode material of cation-anion co-doping and preparation method thereof
CN110233250A (en) A kind of preparation method of single crystal grain tertiary cathode material
CN113422033A (en) Yttrium ion doped yttrium oxide coated modified lithium-rich manganese-based positive electrode material, preparation method and application
CN108807918B (en) Surface-coated composite lithium-rich manganese-based cathode material and preparation method thereof
CN114005978B (en) Cobalt-free cathode material and preparation method and application thereof
CN111211320A (en) Lithium nickel cobalt oxide positive electrode material, preparation method thereof and lithium ion battery
CN114361440A (en) High-voltage ternary cathode material with core-shell structure and preparation method thereof
CN114920306A (en) Positive electrode material precursor, positive electrode material, preparation method of positive electrode material and sodium ion battery
CN113845152A (en) Lithium nickel manganese oxide positive electrode material, preparation method thereof and lithium ion battery
CN115241450A (en) Preparation and application of doped sodium ion nickel-iron-manganese-based single crystal battery positive electrode material
CN111200121A (en) High-performance composite binary anode material, preparation method thereof and lithium ion battery
CN115395007A (en) Layered-spinel composite phase monocrystal lithium-rich manganese-based positive electrode material and application thereof
CN111170369A (en) Lithium manganate or lithium nickel manganese material and preparation method and application thereof
CN113078316B (en) Lithium molybdate-coated lithium-rich manganese-based positive electrode material and preparation method and application thereof
CN104733706B (en) A kind of preparation method of high-tap density composite positive pole
CN116639740A (en) Cobalt-free lithium-rich manganese-based positive electrode material and preparation method thereof
CN114824267B (en) Layered lithium nickel manganese oxide positive electrode material and preparation method and application thereof
CN116470022A (en) Cerium modified layered positive electrode material of sodium ion battery and preparation method thereof

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
RJ01 Rejection of invention patent application after publication
RJ01 Rejection of invention patent application after publication

Application publication date: 20200529