CN116995225A - Positive plate and lithium ion battery using same - Google Patents

Positive plate and lithium ion battery using same Download PDF

Info

Publication number
CN116995225A
CN116995225A CN202311167458.1A CN202311167458A CN116995225A CN 116995225 A CN116995225 A CN 116995225A CN 202311167458 A CN202311167458 A CN 202311167458A CN 116995225 A CN116995225 A CN 116995225A
Authority
CN
China
Prior art keywords
positive electrode
electrode active
layered
active material
lithium ion
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
CN202311167458.1A
Other languages
Chinese (zh)
Inventor
董志鑫
张潇阳
单旭意
王娟
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.)
China Innovation Aviation Technology Group Co ltd
Original Assignee
China Innovation Aviation Technology Group Co ltd
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 China Innovation Aviation Technology Group Co ltd filed Critical China Innovation Aviation Technology Group Co ltd
Priority to CN202311167458.1A priority Critical patent/CN116995225A/en
Publication of CN116995225A publication Critical patent/CN116995225A/en
Pending legal-status Critical Current

Links

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
    • H01M4/52—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
    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B1/00—Single-crystal growth directly from the solid state
    • C30B1/10—Single-crystal growth directly from the solid state by solid state reactions or multi-phase diffusion
    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
    • C30B29/10—Inorganic compounds or compositions
    • C30B29/16—Oxides
    • C30B29/22—Complex oxides
    • 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
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/131—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • 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
    • 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
    • H01M2004/021—Physical characteristics, e.g. porosity, surface area
    • 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
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/028—Positive electrodes

Abstract

The invention provides a positive plate and a lithium ion battery using the same. The positive plate comprises a positive electrode active coating, wherein the positive electrode active coating comprises a positive electrode active material, and the positive electrode active material comprises a layered cobalt-nickel compound; in the Raman spectrum of the positive electrode active material, the positive electrode active material is positioned at 607cm ‑1 ±15cm ‑1 The characteristic peak in the region is A peak with the peak intensity of I A Expressed in 494cm ‑1 ±15cm ‑1 The characteristic peak in the region is B peak with the peak intensity of I B Representation, I A /I B =1 to 5. The layered cobalt-nickel compound has a stable layered structure, so that the layered cobalt-nickel compound has good cycle characteristics, and in addition, the layered cobalt-nickel compound has a moderate interlayer spacing, can provide a path for efficient transmission of lithium ions, and for the reasons, the positive plate prepared by using the positive electrode active material has good cycle characteristics and rate capability.

Description

Positive plate and lithium ion battery using same
Technical Field
The invention belongs to the technical field of batteries, and particularly relates to a positive plate and a lithium ion battery using the same.
Background
The lithium ion battery is widely applied to the market of consumer electronic products due to the advantages of high energy density, no memory effect, environmental friendliness and the like; when the lithium ion battery is used in new energy automobile industry, the requirements of the electric automobile field on comprehensive performances such as endurance, fast charge, storage, safety and the like are more stringent, and development of a high-performance lithium ion power battery with higher energy density, excellent high-rate performance, long service life and strong stability, particularly a positive electrode material, is needed. With alpha-NaFeO 2 The nickel-based positive electrode material with the layered structure is widely focused on due to higher specific capacity, good cycle performance, lower price and the like, and has been used as a research focus of the obstetric and research community and is listed as a key material for important layout of all large-power battery enterprises worldwide.
However, have alpha-NaFeO 2 The nickel-based positive electrode material with the layered structure still has the defect that the lithium and nickel mixed discharge problem is most remarkable, and the lithium atoms and the nickel atoms are relatively close in atomic radius, so that the lithium ions and the nickel ions are easily exchanged in positions in the preparation process and the circulation process of the material to cause the mixed discharge of lithium and nickel cations. Lithium nickel cations are mixed and discharged to cause that the nickel-based positive electrode material is easy to generate a lithium precipitation phenomenon in the air, and plays a certain role in preventing the transmission of lithium ions on the positive electrode plate. On the other hand, the rearrangement of lithium nickel cations can bring adverse effects to the structural stability of the nickel-based positive electrode active material, and as more lithium ions are extracted from the nickel-based positive electrode material, the layered structure of the nickel-based positive electrode material is unstable, and when a large amount of lithium ions are extracted, the layered structure of the nickel-based positive electrode active material is easily caused to collapse, so that the positive electrode material is cracked and pulverized to lose efficacy, and the cycle performance and the multiplying power performance of the lithium ion battery are deteriorated.
Disclosure of Invention
The invention aims to provide a positive plate and a lithium ion battery using the positive plate, so that the structural stability and the lithium ion transmission effect of the positive plate adopting a layered nickel-based positive electrode material are simultaneously optimized, and the lithium ion battery using the positive plate has good cycle characteristics and rate capability.
According to a first aspect of the present invention, there is provided a positive electrode sheet comprising a positive electrode active coating layer comprising a positive electrode active material comprising a layered cobalt nickel compound; in the Raman spectrum of the positive electrode active material, the positive electrode active material is positioned at 607cm -1 ±15cm -1 The characteristic peak in the region is A peak with the peak intensity of I A Expressed in 494cm -1 ±15cm -1 The characteristic peak in the region is B peak with the peak intensity of I B Representation, I A /I B =1~5。
In the layered cobalt-nickel compound, co-O bonds occur by stretching in the c-axis direction through Co-O stretching vibration, the O-Co-O bond vibrates in the a-B direction by O-Co-O bending vibration, in contrast, in the raman spectrum of the positive electrode active material containing the layered cobalt-nickel compound, the a peak corresponds to Co-O stretching vibration, and the B peak corresponds to O-Co-O bending vibration. The positive electrode activity adopted by the invention meets I A /I B The positive electrode active material layered cobalt-nickel compound has a stable layered structure, the lithium ion layers and the transition metal layers are stacked alternately in the layered structure, nickel ions can be stably distributed in the transition metal layers under the action of sufficient van der Waals force and cannot occupy the positions of the lithium ions, so that the occurrence of lithium-nickel cation mixed arrangement in the layered structure is effectively inhibited, the lithium ions can be normally deintercalated in the layered structure, and the layered cobalt-nickel compound is favorable for keeping the structure stable after long-term cyclic charge and discharge. In addition, the layered cobalt-nickel compound of the above positive electrode active material has a moderate interlayer spacing, and can provide a path for efficient transport of lithium ions. For the above reasons, the positive electrode sheet prepared by using the positive electrode active material containing the layered cobalt-nickel compound has good cycle characteristics and rate performance. Compared with the layered cobalt-nickel compound adopted in the invention, the compound does not satisfy I A /I B The positive electrode active material having characteristics of =1 to 5 has stable layered structurePoor in property, and the collapse of the layered structure occurs earlier in the cyclic charge and discharge. Wherein, at I A /I B In the positive electrode active material less than 1, the lithium ion layer-by-layer spacing of the layered cobalt-nickel compound is smaller, and the lithium ion transmission path is longer, so that the lithium ion transmission efficiency is lower, the layered structure is unstable, and the rate capability and the cycle performance of the positive electrode active material are poor. And at I A /I B In the positive electrode active color particles more than 5, the transition metal layer-by-layer spacing of the layered cobalt-nickel compound is larger, so that the Van der Waals force which can be provided by the transition metal layer for nickel ions is smaller, based on the fact, when lithium ions are separated from the layered structure, the nickel ions easily occupy the positions of the lithium ions, lithium-nickel cation mixed arrangement occurs, so that the lithium ions can not be normally separated and intercalated in the layered structure, in the long-term circulation process, the structural defects are accumulated, the layered structure of the layered cobalt-nickel compound is easily collapsed, and the circulation performance of the positive electrode plate is attenuated.
According to a second aspect of the present invention, there is provided a lithium ion battery comprising the positive electrode sheet as described above. The lithium ion battery with the positive plate provided by the invention has good cycle characteristics and rate capability.
Detailed Description
According to a first aspect of the present invention, there is provided a positive electrode sheet comprising a positive electrode active coating layer comprising a positive electrode active material comprising a layered cobalt nickel compound; in the Raman spectrum of the positive electrode active material, the positive electrode active material is positioned at 607cm -1 ±15cm -1 The characteristic peak in the region is A peak with the peak intensity of I A Expressed in 494cm -1 ±15cm -1 The characteristic peak in the region is B peak with the peak intensity of I B Representation, I A /I B =1~5。
In the layered cobalt-nickel compound, co-O bonds occur by stretching in the c-axis direction through Co-O stretching vibration, the O-Co-O bond vibrates in the a-B direction by O-Co-O bending vibration, in contrast, in the raman spectrum of the positive electrode active material containing the layered cobalt-nickel compound, the a peak corresponds to Co-O stretching vibration, and the B peak corresponds to O-Co-O bending vibration. The positive electrode adopted by the inventionThe active material meets I A /I B The layered cobalt-nickel compound in the positive electrode active material has a stable layered structure, the lithium ion layers and the transition metal layers are stacked alternately in the layered structure, nickel ions can be stably distributed in the transition metal layers under the action of sufficient van der Waals force and cannot occupy the positions of the lithium ions, so that the occurrence of lithium-nickel cation mixed arrangement in the layered structure is effectively inhibited, the lithium ions can be normally deintercalated in the layered structure, and the layered cobalt-nickel compound is favorable for keeping the structure stable after long-term cyclic charge and discharge. In addition, the layered cobalt-nickel compound of the above positive electrode active material has a moderate interlayer spacing, and can provide a path for efficient transport of lithium ions. For the above reasons, the positive electrode sheet prepared by using the positive electrode active material containing the layered cobalt-nickel compound has good cycle characteristics and rate performance. Compared with the positive electrode active material adopted in the invention, the positive electrode active material does not satisfy I A /I B The layered cobalt-nickel compound in the positive electrode active material having the characteristics of =1 to 5 has poor stability of the layered structure, and the layered structure collapses earlier in the cycle charge and discharge. Wherein, at I A /I B In the positive electrode active material less than 1, the lithium ion layer-by-layer spacing of the layered cobalt-nickel compound is smaller, and the lithium ion transmission path is longer, so that the lithium ion transmission efficiency is lower, the layered structure is unstable, and the rate capability and the cycle performance of the positive electrode active material are poor. And at I A /I B In the positive electrode active material more than 5, the transition metal layer of the layered cobalt-nickel compound has larger layer-by-layer spacing, so that the Van der Waals force which can be provided by the transition metal layer for nickel ions is smaller, based on the fact, when lithium ions are separated from the layered structure, the nickel ions easily occupy the positions of the lithium ions, lithium-nickel cation mixed arrangement occurs, so that the lithium ions can not be normally separated and intercalated in the layered structure, and in the long-term circulation process, the structural defects are accumulated, the layered structure of the layered cobalt-nickel compound is easily collapsed, and the circulation performance of the positive electrode plate is attenuated.
Preferably, the positive electrode active material satisfies I A /I B =1.1 to 3. When I A /I B Further falls within a range of 1.1 to 3In the periphery, the layered cobalt-nickel compound has better layered structure and lower lithium-nickel cation mixing degree, and the layered cobalt-nickel compound is more beneficial to the transmission of lithium ions, so that the positive plate containing the layered cobalt-nickel compound shows better electrochemical performance.
Preferably, the layered cobalt-nickel compound comprises at least one of a nickel-cobalt-manganese ternary positive electrode material, a nickel-cobalt-aluminum ternary positive electrode material and a nickel-cobalt-manganese-aluminum quaternary positive electrode material.
Preferably, the positive electrode active material further includes at least one of lithium cobaltate and lithium-rich manganese-based material.
Preferably, the average particle diameter D of the positive electrode active material 50 =1～10 μm。
Preferably, the average particle diameter D of the positive electrode active material 50 =1～5 μm。
Preferably, the positive electrode active material has a BET specific surface area of 0.2 to 3 m 2 /g。
Preferably, the positive electrode active material has a BET specific surface area of 0.4 to 1 m 2 /g。
The particle size and BET specific surface area of the positive electrode active material respectively have certain influence on the adsorption performance of the positive electrode current collector on the positive electrode active material and the particle uniformity of the positive electrode active coating; if the particle size of the positive electrode active material is large or the BET specific surface area of the positive electrode active material is small, the adsorption capacity of the positive electrode current collector to the positive electrode active material is reduced; if the particle size of the positive electrode active material is small or the BET specific surface area thereof is large, the positive electrode active material is more likely to agglomerate, and is more difficult to be uniformly distributed in an organic solvent at the time of pulping, so that the particle uniformity of the positive electrode active coating layer may be lowered. By controlling the particle diameter and BET specific surface area of the positive electrode active material within the above ranges: on the one hand, the adsorption capacity of the positive electrode current collector to the positive electrode active material can be improved, the positive electrode active material is prevented from being separated from the positive electrode current collector and being dissociated in electrolyte, the positive electrode active material is prevented from reaching the negative electrode plate through the electrolyte to be contacted with the negative electrode active material, the safety performance of the lithium ion battery is improved, meanwhile, the particle size of the positive electrode active material is kept in the range, the diffusion path of lithium ions in the positive electrode active coating can be planned more reasonably, and the lithium ion transmission dynamics performance of the lithium ion battery is optimized; on the other hand, the dispersing effect of the positive electrode active material can be optimized, so that the positive electrode active material formed by the dispersing effect has excellent uniformity, the electrochemical energy of the positive electrode plate is improved, and the polarization degree of the lithium ion battery subjected to cyclic charge and discharge is reduced.
Preferably, the layered cobalt nickel compound is a single crystal particle. The single-crystal layered cobalt-nickel compound has better structural stability, can be subjected to multiple charge-discharge cycles without cracking, and can be used as a positive electrode active material to further improve the cycle performance of a lithium ion battery.
Preferably, the layered cobalt-nickel compound accounts for 90% -99% of the positive electrode active coating according to the mass percentage.
Preferably, the layered cobalt-nickel compound accounts for 95% -98.5% of the positive electrode active coating according to the mass percentage.
According to a second aspect of the present invention, there is provided a lithium ion battery comprising the positive electrode sheet as described above. The lithium ion battery with the positive plate provided by the invention has good cycle characteristics and rate capability.
In order that those skilled in the art will better understand the present invention, a technical solution of the embodiments of the present invention will be clearly and completely described below, and it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments.
Example 1
1. Preparation of layered Nickel cobalt manganese ternary Material (NCM)
Step 1, according to nickel element: cobalt element: elemental manganese = 0.93:0.06: weighing nickel sulfate, cobalt sulfate and manganese sulfate according to a stoichiometric ratio of 0.01, and preparing a soluble salt solution with the total metal ion concentration of nickel, cobalt and manganese of 110 g/L by utilizing the materials;
Step 2, pumping 30L ammonia water solution with the concentration of 4 g/L into a high-temperature high-pressure reaction kettle as bottom solution of the reaction kettle, introducing oxygen with the purity of 99.5% into the reaction kettle, starting a stirring device of the reaction kettle, and controlling the temperature of the reaction kettle to be 50 ℃;
step 3, fully mixing the soluble salt solution prepared in the step 1 with LiOH, wherein the ratio of the soluble salt solution to the LiOH is determined according to the molar ratio Li:M (M represents all metal elements in the soluble salt solution) =0.4; simultaneously adding a NaOH solution with the concentration of 320 g/L and ammonia water with the concentration of 120 g/L into a reaction kettle, controlling the reaction temperature to be 150 ℃, and controlling the oxygen partial pressure to be 2.5 MPa, so that the reaction system carries out coprecipitation reaction under the reaction conditions, wherein the reaction time is 5 hours; washing and drying the obtained precipitate after the coprecipitation reaction is finished to obtain a pre-lithiated primary positive electrode material with relatively high dispersion degree;
step 4, the pre-lithiated primary positive electrode material prepared in the step 3 is combined with LiOH-LiNO 3 Fully mixing molten salt, wherein the mixture ratio of the molten salt and the molten salt is determined according to the molar ratio Li of M=0.64; placing the obtained mixture into a heating reaction chamber of a high-temperature furnace, introducing oxygen into the reaction chamber, heating to 850 ℃ in an oxygen atmosphere, preserving heat for 10 hours, continuously dissolving and recrystallizing the primary positive electrode material in the high-temperature environment, cooling the product along with the furnace to room temperature, discharging, and grinding, rolling, separating and sieving to obtain the corresponding lamellar NCM ternary positive electrode active material.
2. Preparation of lithium ion batteries
(1) Preparation of positive plate
The layered NCM ternary material prepared in the embodiment is used as an anode active material, and the preparation of the anode plate is completed according to the following method. Mixing an anode active material, a conductive agent acetylene black and a binder PVDF according to a mass ratio of 96:2:2, adding a solvent NMP, and stirring under the action of a vacuum stirrer until the system is uniform to obtain anode slurry; and uniformly coating the positive electrode slurry on two surfaces of a positive electrode current collector aluminum foil, airing at room temperature, transferring to an oven, continuously drying, and then carrying out cold pressing and cutting to obtain the positive electrode plate.
(2) Preparation of negative electrode plate
Graphite is used as a negative electrode active material, and the preparation of the negative electrode sheet is completed according to the following method. Mixing a negative electrode active material, a conductive agent acetylene black, a thickener CMC and a binder SBR according to a mass ratio of 96.4:1:1.2:1.4, adding solvent deionized water, and stirring under the action of a vacuum stirrer until the system is uniform to obtain a negative electrode slurry; and uniformly coating the negative electrode slurry on two surfaces of a negative electrode current collector copper foil, airing at room temperature, transferring to an oven for continuous drying, and then carrying out cold pressing and slitting to obtain a negative electrode plate.
(3) Preparation of electrolyte
Mixing Ethylene Carbonate (EC), ethylmethyl carbonate (EMC) and diethyl carbonate (DEC) according to a volume ratio of 1:1:1 to obtain an organic solvent, and then fully drying lithium salt LiPF 6 Dissolving in the organic solvent to obtain LiPF 6 An electrolyte content of 1 mol/L.
(4) Preparation of a separator film
Selected from polyethylene films as barrier films.
(5) Preparation of lithium ion batteries
Sequentially stacking the positive plate, the isolating film and the negative plate, enabling the isolating film to be positioned between the positive plate and the negative plate to play a role of isolation, and then winding to obtain a bare cell; and placing the bare cell in an outer packaging shell of the lithium battery, drying, injecting electrolyte, and performing procedures such as vacuum packaging, standing, formation, shaping and the like to obtain the lithium ion battery.
Example 2
1. Preparation of layered NCM ternary materials
This example refers to example 1 for preparing a layered NCM ternary material, the layered NCM ternary material being made up with the difference from example 1: in step 3 of preparing a layered NCM ternary material, the oxygen partial pressure of 2.5 MPa set in example 1 was adjusted to 1.5 MPa; in step 4 of preparing the layered NCM ternary material, the heating temperature of 850 ℃ set in example 1 was adjusted to 950 ℃, thereby increasing the sintering temperature to grow single crystals. Except for the above differences, the materials and process operations of this example for preparing the layered NCM ternary material were strictly consistent with those of example 1, thereby preparing the layered NCM ternary material of this example.
2. Preparation of lithium ion batteries
This example the lithium ion battery of this example was prepared with reference to the method for preparing a lithium ion battery of example 1. The difference from example 1 is that the layered NCM ternary material prepared in this example is used as the positive electrode active material to prepare the positive electrode sheet of the lithium ion battery. Except for the above differences, the other operations of this example for preparing a lithium ion battery were strictly consistent with those of example 1.
Example 3
1. Preparation of layered NCM ternary materials
This example refers to example 1 for preparing a layered NCM ternary material, the layered NCM ternary material being made up with the difference from example 1: in step 3 of preparing a layered NCM ternary material, the oxygen partial pressure of 2.5 MPa set in example 1 was adjusted to 1.5 MPa; in step 4 of preparing the layered NCM ternary material, the primary positive electrode material is pre-lithiated with LiOH-LiNO 3 And (3) carrying out heat treatment on the mixture obtained by mixing molten salt, wherein the process of heating to 850 ℃ in oxygen atmosphere and preserving heat for 10 hours is adopted in the embodiment 1, and the process is adjusted to the process of preserving heat for 10 hours in oxygen atmosphere at 950 ℃, continuously cooling to 895 ℃ and preserving heat for 8 hours, and then cooling to room temperature along with a furnace, so that in the step 4, the single crystal is fully developed and grown by adopting a double-platform sintering mode. Except for the above differences, the materials and process operations of this example for preparing the layered NCM ternary material were strictly consistent with those of example 1, thereby preparing the layered NCM ternary material of this example.
2. Preparation of lithium ion batteries
This example the lithium ion battery of this example was prepared with reference to the method for preparing a lithium ion battery of example 1. The difference from example 1 is that the layered NCM ternary material prepared in this example is used as the positive electrode active material to prepare the positive electrode sheet of the lithium ion battery. Except for the above differences, the other operations of this example for preparing a lithium ion battery were strictly consistent with those of example 1.
Example 4
1. Preparation of layered NCM ternary materials
This example refers to example 1 for preparing a layered NCM ternary material, the layered NCM ternary material being made up with the difference from example 1: in the step 1 of preparing the layered NCM ternary material, the following nickel elements are adopted: cobalt element: manganese element stoichiometric ratio=0.8: 0.1: weighing nickel sulfate, cobalt sulfate and manganese sulfate according to the stoichiometric ratio of 0.1; in the step 3 of preparing the layered NCM ternary material, the reaction condition of the related coprecipitation reaction is controlled to be 150 ℃ by the reaction temperature adopted in the embodiment 1, the oxygen partial pressure is controlled to be 2.5 MPa, the reaction system is subjected to the coprecipitation reaction under the reaction condition, the reaction time is controlled to be 150 ℃ by adjusting the reaction time to be 5 hours, and the reaction is carried out for 1 hour by adopting a microwave heating auxiliary coprecipitation method, wherein the specific setting of the microwave heating is that the microwave heating with the radiation power of 150W is provided in the whole process of the coprecipitation reaction, and the problem of uneven internal and external heating of the material by the conventional heating means is avoided by adopting a microwave heating mode, and meanwhile, the heating rate is improved, and the reaction time is reduced; in step 4 of preparing the layered NCM ternary material, the soak time set in example 1 was adjusted from 10 hours to 8 hours. Except for the above differences, the materials and process operations of this example for preparing the layered NCM ternary material were strictly consistent with those of example 1, thereby preparing the layered NCM ternary material of this example.
2. Preparation of lithium ion batteries
This example the lithium ion battery of this example was prepared with reference to the method for preparing a lithium ion battery of example 1. The difference from example 1 is that the layered NCM ternary material prepared in this example is used as the positive electrode active material to prepare the positive electrode sheet of the lithium ion battery. Except for the above differences, the other operations of this example for preparing a lithium ion battery were strictly consistent with those of example 1.
Example 5
1. Preparation of layered NCM ternary materials
This example refers to example 1 for preparing a layered NCM ternary material, the layered NCM ternary material being made up with the difference from example 1: in step 3 of preparing the layered NCM ternary material, after mixing the mixed metal soluble salt solution with LiOH, 0.001ppm of lithium perchlorate was added thereto, and the reaction conditions of the co-precipitation reaction involved were controlled to be the "reaction temperature" employed in example 1Controlling the oxygen partial pressure to be 2.5 MPa, enabling a reaction system to perform coprecipitation reaction under the reaction conditions, controlling the reaction time to be 5 hours, adjusting the temperature to be 150 ℃, and adopting a microwave heating auxiliary coprecipitation method to perform reaction for 1 hour, wherein the specific setting of microwave heating is that microwave heating with the radiation power of 300W is provided in the whole process of the coprecipitation reaction, and the problem of uneven internal and external heating of materials by a conventional heating means is avoided in a microwave heating mode, meanwhile, the heating rate is improved, and the reaction time is reduced; in step 4 of preparing the layered NCM ternary material, the primary positive electrode material is pre-lithiated with LiOH-LiNO 3 And (3) carrying out heat treatment on the mixture obtained by mixing molten salt, wherein the process of heating to 850 ℃ in oxygen atmosphere and preserving heat for 10 hours adopted in the embodiment 1 is adjusted to preserving heat for 8 hours at 850 ℃ in oxygen atmosphere, continuously cooling to 790 ℃ and preserving heat for 6 hours, and then cooling to room temperature along with a furnace, so that in the step 4, the single crystal is fully developed and grown by adopting a double-platform sintering mode. Except for the above differences, the materials and process operations of this example for preparing the layered NCM ternary material were strictly consistent with those of example 1, thereby preparing the layered NCM ternary material of this example.
2. Preparation of lithium ion batteries
This example the lithium ion battery of this example was prepared with reference to the method for preparing a lithium ion battery of example 1. The difference from example 1 is that the layered NCM ternary material prepared in this example is used as the positive electrode active material to prepare the positive electrode sheet of the lithium ion battery. Except for the above differences, the other operations of this example for preparing a lithium ion battery were strictly consistent with those of example 1.
Example 6
1. Preparation of layered NCM ternary materials
This example refers to example 1 for preparing a layered NCM ternary material, the layered NCM ternary material being made up with the difference from example 1: in the step 3 of preparing the layered NCM ternary material, the reaction conditions of the coprecipitation reaction involved were controlled to be 150℃from the "reaction temperature" employed in example 1, and the partial pressure of oxygen was controlled to be 2.5 MPa, so that the reaction system was subjected to the above-mentioned reaction The coprecipitation reaction is carried out under the condition that the reaction time is controlled to be 150 ℃ in 5 hours, the coprecipitation reaction is carried out for 1 hour by adopting a microwave heating auxiliary coprecipitation method, wherein the specific setting of microwave heating is that the radiation power of microwave heating is 50W in 0-20 minutes of the coprecipitation reaction, the radiation power of microwave heating is 100W in 20-40 minutes of the coprecipitation reaction, the radiation power of microwave heating is 150W' in 40-60 minutes of the coprecipitation reaction, and the problem of uneven internal and external heating of materials by a conventional heating means is avoided by adopting a microwave heating mode, meanwhile, the heating rate is improved, and the reaction time is reduced; in step 4 of preparing the layered NCM ternary material, the primary positive electrode material is pre-lithiated with LiOH-LiNO 3 And (3) carrying out heat treatment on the mixture obtained by mixing molten salt, wherein the process of heating to 850 ℃ in oxygen atmosphere and preserving heat for 10 hours is adopted in the embodiment 1, and the process is adjusted to the process of preserving heat for 8 hours at 850 ℃ in oxygen atmosphere, continuously cooling to 790 ℃ and preserving heat for 6 hours. Except for the above differences, the materials and process operations of this example for preparing the layered NCM ternary material were strictly consistent with those of example 1, thereby preparing the layered NCM ternary material of this example.
2. Preparation of lithium ion batteries
This example the lithium ion battery of this example was prepared with reference to the method for preparing a lithium ion battery of example 1. The difference from example 1 is that the layered NCM ternary material prepared in this example is used as the positive electrode active material to prepare the positive electrode sheet of the lithium ion battery. Except for the above differences, the other operations of this example for preparing a lithium ion battery were strictly consistent with those of example 1.
Example 7
1. Preparation of layered NCM ternary materials
This example refers to example 1 for preparing a layered NCM ternary material, the layered NCM ternary material being made up with the difference from example 1: in step 2 of preparing the layered NCM ternary material, the reaction temperature of the reaction kettle set in this step in example 1 was adjusted to 80 ℃ at 50 ℃. Except for the above differences, the materials and process operations of this example for preparing the layered NCM ternary material were strictly consistent with those of example 1, thereby preparing the layered NCM ternary material of this example.
2. Preparation of lithium ion batteries
This example the lithium ion battery of this example was prepared with reference to the method for preparing a lithium ion battery of example 1. The difference from example 1 is that the layered NCM ternary material prepared in this example is used as the positive electrode active material to prepare the positive electrode sheet of the lithium ion battery. Except for the above differences, the other operations of this example for preparing a lithium ion battery were strictly consistent with those of example 1.
Example 8
1. Preparation of layered NCM ternary materials
This example refers to example 1 for preparing a layered NCM ternary material, the layered NCM ternary material being made up with the difference from example 1: in the step 3 of preparing the layered NCM ternary material, the reaction condition of the related coprecipitation reaction is controlled to be 150 ℃ by the reaction temperature adopted in the embodiment 1, the oxygen partial pressure is controlled to be 2.5 MPa, the reaction system is subjected to the coprecipitation reaction under the reaction condition, the reaction time is controlled to be 5 hours, the temperature is controlled to be 150 ℃, and the coprecipitation reaction is carried out for 1 hour by adopting a microwave heating auxiliary coprecipitation method, wherein the specific setting of the microwave heating is that the radiation power of the microwave heating is 50W in 0-10 minutes of the coprecipitation reaction, the radiation power of the microwave heating is 100W in 10-20 minutes of the coprecipitation reaction, and the radiation power of the microwave heating is 150W in 20-30 minutes of the coprecipitation reaction. Except for the above differences, the materials and process operations of this example for preparing the layered NCM ternary material were strictly consistent with those of example 1, thereby preparing the layered NCM ternary material of this example.
Example 9
1. Preparation of layered NCM ternary materials
This example refers to example 1 for preparing a layered NCM ternary material, the layered NCM ternary material being made up with the difference from example 1: in step 3 of preparing the layered NCM ternary material, 0.001 ppm of lithium perchlorate is added thereto after mixing the mixed metal soluble salt solution with LiOH; in step 4 of preparing the layered NCM ternary material, the heating temperature 850 ℃ set in example 1 was adjusted to 700 ℃. Except for the above differences, the materials and process operations of this example for preparing the layered NCM ternary material were strictly consistent with those of example 1, thereby preparing the layered NCM ternary material of this example.
2. Preparation of lithium ion batteries
This example the lithium ion battery of this example was prepared with reference to the method for preparing a lithium ion battery of example 1. The difference from example 1 is that the layered NCM ternary material prepared in this example is used as the positive electrode active material to prepare the positive electrode sheet of the lithium ion battery. Except for the above differences, the other operations of this example for preparing a lithium ion battery were strictly consistent with those of example 1.
Example 10
1. Preparation of layered NCM ternary materials
This example refers to example 1 for preparing a layered NCM ternary material, the layered NCM ternary material being made up with the difference from example 1: in step 4 of preparing the layered NCM ternary material, the heating temperature of 850 ℃ set in example 1 was adjusted to 1300 ℃, thereby increasing the sintering temperature to grow single crystals. Except for the above differences, the materials and process operations of this example for preparing the layered NCM ternary material were strictly consistent with those of example 1, thereby preparing the layered NCM ternary material of this example.
2. Preparation of lithium ion batteries
This example the lithium ion battery of this example was prepared with reference to the method for preparing a lithium ion battery of example 1. The difference from example 1 is that the layered NCM ternary material prepared in this example is used as the positive electrode active material to prepare the positive electrode sheet of the lithium ion battery. Except for the above differences, the other operations of this example for preparing a lithium ion battery were strictly consistent with those of example 1.
Example 11
1. Preparation of layered NCM ternary materials
This example refers to example 1 for preparing a layered NCM ternary material, the layered NCM ternary material being made up with the difference from example 1: in step 4 of preparing the layered NCM ternary material, the heating temperature 850 ℃ set in example 1 was adjusted to 600 ℃. Except for the above differences, the materials and process operations of this example for preparing the layered NCM ternary material were strictly consistent with those of example 1, thereby preparing the layered NCM ternary material of this example.
2. Preparation of lithium ion batteries
This example the lithium ion battery of this example was prepared with reference to the method for preparing a lithium ion battery of example 1. The difference from example 1 is that the layered NCM ternary material prepared in this example is used as the positive electrode active material to prepare the positive electrode sheet of the lithium ion battery. Except for the above differences, the other operations of this example for preparing a lithium ion battery were strictly consistent with those of example 1.
Comparative example 1
1. Preparation of layered NCM ternary materials
This comparative example a layered NCM ternary material was prepared by the method for preparing a layered NCM ternary material according to example 1, and the specific procedure is as follows: step 1. The same as step 1 of example 1 for preparing the layered NCM ternary material is kept, and detailed description thereof is omitted;
Step 2. The same as step 2 for preparing the layered NCM ternary material in example 1 is maintained, and detailed description thereof is omitted;
step 3, pumping the soluble salt solution prepared in the step 1 into a reaction kettle at a pumping rate of 90 mL/min, and simultaneously adding a sodium hydroxide solution with a concentration of 320 g/L and ammonia water with a concentration of 120 g/L into the reaction kettle to control the pH value of the whole reaction system to reach 12.2, wherein materials in the reaction kettle undergo coprecipitation reaction under the reaction condition, and a precursor material is obtained after the coprecipitation reaction for 30 hours;
step 4, fully mixing the precursor material prepared in the step 3 with lithium salt, wherein the ratio of the precursor material to the lithium salt is determined according to the molar ratio Li:M (M represents all metal elements in the precursor material) =0.4; placing the obtained mixture into a heating reaction chamber of a high-temperature furnace, introducing oxygen into the reaction chamber, heating to 950 ℃ in an oxygen atmosphere, sintering at the temperature for 10 hours, cooling to 895 ℃, continuously preserving heat for 8 hours, cooling to room temperature along with the furnace, and grinding, rolling, separating and sieving to obtain the corresponding lamellar NCM ternary positive electrode active material.
2. Preparation of lithium ion batteries
Comparative example the lithium ion battery of the comparative example was prepared with reference to the method for preparing a lithium ion battery of example 1. The difference from example 1 is that the layered NCM ternary material prepared in this comparative example is used as a positive electrode active material to prepare a positive electrode sheet of a lithium ion battery. Except for the above differences, the other operations of this comparative example for preparing a lithium ion battery were strictly consistent with example 1.
Comparative example 2
1. Preparation of layered NCM ternary materials
This comparative example reference comparative example 1 the method for preparing a layered NCM ternary material prepared as follows:
step 1. The method is consistent with step 1 for preparing the layered NCM ternary material in comparative example 1, and is not described herein;
step 2. The method is consistent with step 2 for preparing the layered NCM ternary material in comparative example 1, and is not described herein; step 3, adding 0.001 ppm of lithium perchlorate into the soluble salt solution prepared in the step 1, pumping the obtained mixed solution into a reaction kettle at a pumping rate of 90mL/min, and simultaneously adding 320-g/L sodium hydroxide solution and 120-g/L ammonia water into the reaction kettle to control the pH value of the whole reaction system to be 12.2, wherein the materials in the reaction kettle undergo coprecipitation reaction under the reaction condition, and obtaining a precursor material after 30 hours of coprecipitation reaction;
step 3. Preparing a precursor material consistent with step 3 of comparative example 1 for preparing a layered NCM ternary material, and not described in detail herein; and 4, fully mixing the precursor material prepared in the step 3 with lithium salt, determining the mixture ratio of the precursor material and the lithium salt according to the molar ratio of Li to M (M represents all metal elements in the precursor material) =0.4, heating the mixture in an oxygen atmosphere, continuously preserving heat for 8 hours after reaching 800 ℃, cooling to room temperature along with a furnace, continuously growing and growing monocrystalline particles in a high-temperature environment, and grinding, rolling, separating and sieving to obtain the corresponding lamellar NCM ternary positive electrode active material.
2. Preparation of lithium ion batteries
Comparative example the lithium ion battery of the comparative example was prepared with reference to the method of comparative example 1 for preparing a lithium ion battery. The difference from comparative example 1 is that the layered NCM ternary material prepared in this comparative example is used as a positive electrode active material to participate in the preparation of a positive electrode sheet of a lithium ion battery. In addition to the above differences, the other operations of this comparative example for preparing a lithium ion battery were strictly consistent with comparative example 1.
Test case
1. Test object
The positive electrode sheets and the lithium ion batteries prepared in examples 1-11 and comparative examples 1-2 were used as test objects.
2. Test item
(1) Raman spectroscopy
CP-SEM test:
argon ions bombard the sample surface. The working voltage of the argon ion polishing instrument is set to be 5 kV, the current is about 100 mu A, and the polishing time is 10-12 hours. And fixing the sample polished by the argon ions on a sample table by using conductive adhesive, and spraying a very thin gold layer on the polished surface of the sample to increase the conductivity of the positive electrode active material. Firstly, the prepared sample is placed into a sample chamber of an FEI Helios 650 type focused ion beam scanning electron microscope (FIB-SEM), and vacuum pumping is carried out. And when the vacuum degree in the sample chamber meets the instrument requirement, opening an electron beam, adjusting the working distance of an electron microscope to 4 mm, observing the surface of the positive electrode active material by using a Back Scattering (BSE) mode, and selecting a test area. The size of the target area is generally selected to be about 10 μm by 10 μm for a combination of time and imaging effects. The sample stage is then rotated 52 ° to bring the ion beam perpendicular to the sample surface and platinum (Pt) is sprayed onto the surface of the test area to reduce damage to that area by the ion beam. Under the conditions of voltage of 30 kV and beam current of 10 nA, under the focused ion beam window, performing rough cutting on the periphery of a target area by utilizing the focused ion beam to obtain a rough cut sample; and under the conditions of voltage 30 kV and beam current of 1 nA, carrying out fine cutting on the periphery of the target area by utilizing the focused ion beam to obtain a target sample.
Raman test:
raman spectrum test is carried out on the positive electrode active materials prepared in each example and comparative example by using a spectrometer (Jobin Yvon LabRAM HR), wherein the light source is 532 nm, ar ion laser, the integration time is 10 seconds, the 50X long-focal-length objective lens is used, and the scanning range is 50-4000 cm -1 . In the Raman spectrum measured by the test object, at 607cm -1 ±15cm -1 Characteristic peaks in the region are A peaks, and the peak intensity of the A peaks is read to be I A Expressed in 494cm -1 ±15cm -1 Characteristic peaks in the region are B peaks, and the peak intensity of the B peaks is read to be I B Representation, based on measured I A 、I B Calculating I of test object A /I B Values.
(2) Capacity testing
The lithium ion battery was subjected to charge and discharge test (test temperature 25 ℃) on a blue tester: after the lithium ion battery is kept stand for 5 minutes, discharging to 2.75V at 0.33C, constant-current charging to 4.3V is carried out on the lithium ion battery at 0.33 multiplying power (C), and then constant-voltage charging is carried out to 0.05C, so that the capacity obtained by the step is the initial charging capacity of the lithium ion battery; then the lithium ion battery was charged to 4.3V at a constant current of 0.3 rate (C), charged to 0.05C at a constant voltage, and discharged to 2.75V at 1C after standing for 5 minutes. The capacity obtained in this step is the initial discharge capacity of the lithium ion battery.
(3) And (3) cyclic test:
the lithium ion battery was subjected to charge and discharge test (test temperature 60 ℃) on a blue electricity tester: the lithium ion battery was charged to 4.3V at a constant current at a rate of 0.33 (C), charged to 0.05C at a constant voltage, and discharged to 2.75V at a rate of 1C after standing for 5 minutes. Then, a cycle test of 0.33C charge/1C discharge was performed 200 times, and the discharge capacity at the 200 th cycle was recorded.
Cycle capacity retention= (discharge capacity of 200 th cycle/discharge capacity of first cycle) ×100%.
(4) Particle diameter D of positive electrode active material 50 BET specific surface area test
Removing the positive plate from the test object, placing the positive plate in a glove box, soaking the positive plate in DMC solvent for 12 hours, drying the positive plate, scraping the positive active coating on the surface of the positive current collector by a scraper, collecting scraped powder, placing the powder into a porcelain Zhou Zhongzhi to calcine in a tubular furnace, and collecting black powder substances for the particle size D of the positive active material after natural cooling 50 BET specific surface area test.
Particle diameter D of positive electrode active material 50 And (3) testing: adding 0.02 g of powder sample to be tested into a 50 mL clean beaker, then adding 20 mL of ethanol into the powder sample, then dripping 2 to 3 drops of 1% of surfactant into the powder sample to ensure that the powder sample is completely dispersed in water, and testing the particle size of the powder sample by using a laser particle size analyzer (MasterSizer 2000) after ultrasonic treatment in a 120W ultrasonic cleaner for 5 minutes.
BET specific surface area test of positive electrode active material: weighing the total weight of the empty small test tube and the plug, soaking the powder sample to be tested in absolute ethyl alcohol for 4 hours, taking out the powder sample, putting the powder sample into an oven with the temperature of 105 ℃ for baking for half an hour, putting the powder sample into a sample tube, weighing the total weight of the powder sample, the small test tube and the plug, calculating the mass of the sample, and calculating the mass of the sample; opening a degassing station, placing a small test tube filled with a powder sample into the degassing station at 105 ℃, purging with nitrogen (pure nitrogen) for 30 minutes, cooling for 15 minutes, and performing a test at 25 ℃ and 60% humidity on the machine; and (3) taking P/P0 with a point ranging from 0.05 to 0.25 as an x axis, P/V (P0-P) as a Y axis, and performing linear fitting by plotting a BET equation to obtain the slope and intercept of a straight line so as to calculate the BET specific surface area of the powder sample.
3. Test results
The test results of this test example are shown in Table 1. The positive electrode active coating layers of the positive electrode sheets used in comparative example 1 and comparative example 2 all exhibited a certain degree of breakage and pulverization after the completion of the test, compared to before the start of the test. The positive electrode sheets used in examples 1 to 9 were able to maintain the positive electrode active coating layer with an intact structure after the cyclic test, and the positive electrode active coating layer was free from significant deformation, crushing or pulverization, and the positive electrode sheets used in examples 1 to 9 had better structural stability than the positive electrode sheets used in comparative examples 1 and 2. As can be seen from the data shown in table 1, the lithium ion batteries provided in examples 1 to 9 have higher initial charge-discharge capacity of the battery and higher cycle retention rate than the lithium ion batteries provided in comparative examples 1 and 2.
In the Raman spectrum of cobalt-containing compounds, at 607cm -1 ±15cm -1 Within the region and 494cm -1 ±15cm -1 Characteristic peaks appear in the region to be located at 607cm -1 ±15cm -1 The characteristic peak in the region is A peak, and the stretching vibration of Co-O bond is 607cm -1 ±15cm -1 Characteristic peaks appear in the region, marked as A peak, and the bending vibration of the O-Co-O bond is 494cm -1 ±15cm -1 Characteristic peaks within the region are labeled B peaks. The positive electrode active materials used in examples 1 to 9 and comparative examples 1 to 2 were all layered cobalt-nickel compounds containing both Co element and Ni element, and the raman spectra of these positive electrode active materials were shown to have peaks in the a-peak characteristic peak region and the B-peak characteristic peak region.
Analysis of raman spectrum data of the positive electrode active materials in the test subjects, the positive electrode active materials employed in examples 1 to 9 all satisfy I A /I B The positive electrode active materials have stable layered structures and appropriate interlayer spacing =1 to 5. The positive electrode active materials have stable lamellar structures, and the positive electrode active materials still cannot obviously mix and discharge lithium and nickel cations after long-term cyclic charge and discharge, and the lithium ion battery using the positive electrode active materials has good cycle retention rate. Meanwhile, the stable layered structure is favorable for the lithium ions to be normally deintercalated in the layered structure of the positive electrode active materials, and the lithium ion transmission efficiency is improved. On the other hand, the positive electrode active material in a layered structure has a suitable interlayer spacing, so that the positive electrode active material can provide a path for efficient transmission of lithium ions, thereby improving the lithium ion transmission efficiency. To sum up the reasons, put into practice The positive electrode active materials of examples 1 to 9 all have higher lithium ion transmission efficiency, and therefore, the lithium ion batteries prepared by using the positive electrode active materials can achieve higher initial charge and discharge capacities, and exhibit good rate performance.
The positive electrode active material used in comparative example 1 was I A /I B <1, the layer-by-layer spacing of lithium ions of the type is smaller, the interlayer structure stability is poorer, the transmission path of the lithium ions in the material is longer, and the lithium ion transmission is limited. While the positive electrode active material used in comparative example 2 was I A /I B >5, in the layered structure of the type of the material, the transition metal layer is larger in layer-by-layer spacing, lithium-nickel cation mixed discharge is easy to occur, and as the cycle number increases, the lithium-nickel cation mixed discharge is aggravated, so that the layered structure defect of the positive electrode active material is accumulated or even collapsed, and lithium ions are difficult to normally deintercalate from the layered structure. For the above reasons, the lithium ion batteries produced in comparative examples 1 and 2 were low in both initial charge-discharge capacity and cycle retention rate as compared to the lithium ion batteries produced in examples 1 to 9.
I based further on the positive electrode active materials used in examples 1 to 9 A /I B The performance of the lithium ion battery was examined. The positive electrode active materials used in examples 1 to 6 each contained single crystal particles of layered NCM ternary material, wherein examples 2, 4, 5, and 6 were used as positive electrode active materials I A /I B The initial charge and discharge capacity of the lithium ion battery prepared by the embodiments is higher and the cycle retention rate is higher within the range of 1.1-3. The positive electrode active materials used in examples 7 to 9 each contained layered NCM ternary material polycrystalline particles, wherein examples 8 and 9 were used as positive electrode active materials I A /I B Falling within a range of 1.1 to 3, while the positive electrode active material used in example 7 has I A /I B Then less than 1.1, the lithium ion batteries of examples 8 and 9 respectively have higher initial charge and discharge capacities and higher cycle retention rates than the lithium battery of example 7. Thus, when the layered cobalt-nickel compound is further describedConform to I A /I B =1.1 to 3, can better inhibit lithium nickel cations from being mixed and discharged in the layered structure, and has better stability, thereby being beneficial to promoting the efficient transmission of lithium ions in the layered structure.
In the layered cobalt-nickel compound prepared by the scheme, when the particle diameter D of the layered cobalt-nickel compound 50 The lithium ion battery is prepared by using the lithium ion battery as the positive electrode active material within the range of 1-10 mu m, which is beneficial to further improving the initial charge-discharge capacity of the lithium ion battery and optimizing the cycle performance of the lithium ion battery. Specifically, in the test subjects of this test example, the positive electrode active materials obtained in examples 1, 10 and 11 were all I A /I B The layered cobalt-nickel compound of=1, however, the positive electrode active material prepared in example 10 had a larger particle diameter, and the positive electrode active material prepared in example 11 had a smaller particle diameter, and it can be seen from the test results that the battery initial charge-discharge capacity and the cycle retention rate of the lithium ion battery prepared in example 1 were higher than those of the lithium batteries of examples 10 and 11.
TABLE 1 statistics of test results for this test case
The above embodiments are only for illustrating the technical solution of the present invention and not for limiting the scope of the present invention, and although the present invention has been described in detail with reference to the above embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions can be made to the technical solution of the present invention, but these modifications or substitutions are all within the scope of the present invention.

Claims (10)

1. The positive plate is characterized in that: the positive electrode comprises a positive electrode active coating, wherein the positive electrode active coating comprises a positive electrode active material, and the positive electrode active material comprises a layered cobalt-nickel compound;
in the Raman spectrum of the positive electrode active material, the positive electrode active material is positioned at 607cm -1 ±15cm -1 Within the region ofThe characteristic peak is A peak, the peak intensity of the A peak is I A Expressed in 494cm -1 ±15cm -1 The characteristic peak in the region is B peak with the peak intensity of I B Representation, I A /I B =1~5。
2. The positive electrode sheet according to claim 1, wherein: the positive electrode active material satisfies I A /I B =1.1~3。
3. The positive electrode sheet according to claim 1, wherein: the layered cobalt-nickel compound comprises at least one of a nickel-cobalt-manganese ternary positive electrode material, a nickel-cobalt-aluminum ternary positive electrode material and a nickel-cobalt-manganese-aluminum quaternary positive electrode material.
4. The positive electrode sheet according to claim 3, wherein: the positive electrode active material further comprises at least one of lithium cobaltate and a lithium-rich manganese-based material.
5. The positive electrode sheet according to claim 1, wherein: average particle diameter D of the positive electrode active material 50 =1～10 μm。
6. The positive electrode sheet according to claim 1, wherein: the BET specific surface area of the positive electrode active material is 0.2-3 m 2 /g。
7. The positive electrode sheet according to claim 6, wherein: the BET specific surface area of the positive electrode active material is 0.4-1 m 2 /g。
8. The positive electrode sheet according to claim 1, wherein: the layered cobalt-nickel compound is single crystal particles.
9. The positive electrode sheet according to any one of claims 1 to 8, wherein: the proportion of the layered cobalt-nickel compound in the positive electrode active coating is 90% -99% according to the mass percentage.
10. A lithium ion battery, characterized in that: comprising the positive electrode sheet according to any one of claims 1 to 9.
CN202311167458.1A 2023-09-12 2023-09-12 Positive plate and lithium ion battery using same Pending CN116995225A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202311167458.1A CN116995225A (en) 2023-09-12 2023-09-12 Positive plate and lithium ion battery using same

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202311167458.1A CN116995225A (en) 2023-09-12 2023-09-12 Positive plate and lithium ion battery using same

Publications (1)

Publication Number Publication Date
CN116995225A true CN116995225A (en) 2023-11-03

Family

ID=88525026

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202311167458.1A Pending CN116995225A (en) 2023-09-12 2023-09-12 Positive plate and lithium ion battery using same

Country Status (1)

Country Link
CN (1) CN116995225A (en)

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004349132A (en) * 2003-05-22 2004-12-09 Mitsubishi Chemicals Corp Nonaqueous electrolyte, and nonaqueous electrolyte secondary battery using it
CN1577924A (en) * 2003-07-24 2005-02-09 三星Sdi株式会社 Cathode active material and lithium secondary battery using the same
CN101360685A (en) * 2006-01-20 2009-02-04 日矿金属株式会社 Lithium nickel manganese cobalt composite oxide and lithium rechargeable battery
JP2014197523A (en) * 2013-03-04 2014-10-16 株式会社豊田自動織機 Composite metal oxide, positive electrode for lithium ion secondary battery using the same, and lithium ion secondary battery
CN104241640A (en) * 2014-10-10 2014-12-24 国家电网公司 Lithium nickel-cobalt-aluminum positive electrode material, preparation method thereof and lithium ion battery
CN109811412A (en) * 2018-12-28 2019-05-28 广东邦普循环科技有限公司 A kind of stratiform nickel lithium manganate cathode material of monocrystalline pattern and preparation method thereof
CN112313821A (en) * 2018-06-21 2021-02-02 株式会社村田制作所 Positive electrode active material and battery
US20210257665A1 (en) * 2018-06-21 2021-08-19 Gs Yuasa International Ltd. Positive active material for nonaqueous electrolyte secondary battery, method for producing positive active material for nonaqueous electrolyte secondary battery, positive electrode for nonaqueous electrolyte secondary battery, nonaqueous electrolyte secondary battery, method for manufacturing nonaqueous electrolyte secondary battery, and method of using nonaqueous electrolyte secondary battery

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004349132A (en) * 2003-05-22 2004-12-09 Mitsubishi Chemicals Corp Nonaqueous electrolyte, and nonaqueous electrolyte secondary battery using it
CN1577924A (en) * 2003-07-24 2005-02-09 三星Sdi株式会社 Cathode active material and lithium secondary battery using the same
CN101360685A (en) * 2006-01-20 2009-02-04 日矿金属株式会社 Lithium nickel manganese cobalt composite oxide and lithium rechargeable battery
JP2014197523A (en) * 2013-03-04 2014-10-16 株式会社豊田自動織機 Composite metal oxide, positive electrode for lithium ion secondary battery using the same, and lithium ion secondary battery
CN104241640A (en) * 2014-10-10 2014-12-24 国家电网公司 Lithium nickel-cobalt-aluminum positive electrode material, preparation method thereof and lithium ion battery
CN112313821A (en) * 2018-06-21 2021-02-02 株式会社村田制作所 Positive electrode active material and battery
US20210257665A1 (en) * 2018-06-21 2021-08-19 Gs Yuasa International Ltd. Positive active material for nonaqueous electrolyte secondary battery, method for producing positive active material for nonaqueous electrolyte secondary battery, positive electrode for nonaqueous electrolyte secondary battery, nonaqueous electrolyte secondary battery, method for manufacturing nonaqueous electrolyte secondary battery, and method of using nonaqueous electrolyte secondary battery
CN109811412A (en) * 2018-12-28 2019-05-28 广东邦普循环科技有限公司 A kind of stratiform nickel lithium manganate cathode material of monocrystalline pattern and preparation method thereof

Similar Documents

Publication Publication Date Title
JP5076038B1 (en) High manganese polycrystalline cathode material, method for producing the same, and power lithium ion battery
CN110668509A (en) Selenium-coated high-nickel ternary layered positive electrode material and preparation method thereof
KR102398558B1 (en) Anode material and electrochemical and electronic devices comprising the anode material
CN110518209B (en) Preparation method of anode material and prepared anode material
CN113353985B (en) Lithium ion battery positive electrode material, preparation method thereof, positive electrode of lithium ion battery and lithium ion battery
CN116093308B (en) Positive electrode active material, positive electrode plate containing same and battery
CN114068919A (en) Lithium iron phosphate positive electrode active material, preparation method thereof, positive plate and battery
CN114709415A (en) Graphite material, secondary battery, and electronic device
CN111048775A (en) In-situ sodium doping modification method for improving lithium storage performance of ternary cathode material
US20220102700A1 (en) Secondary battery and battery module, battery pack and apparatus containing the same
CN116282226B (en) Micro-lithium-rich small single crystal cobalt-free lithium nickel oxide positive electrode material, and preparation method and application thereof
CN116314622B (en) Single crystal cobalt-free aluminum doped lithium nickelate positive electrode material with self-precipitation coating layer, and preparation method and application thereof
CN102544511A (en) Lithium ion battery positive electrode lithium ferrous phosphate material wrapped with strontium cerium doped cobaltate (SCC) and carbon, and preparation method for lithium ion battery positive electrode lithium ferrous phosphate material
WO2021146943A1 (en) Positive electrode material, electrochemical device comprising same, and electronic device
JP2023512011A (en) Negative electrode active material, manufacturing method thereof, secondary battery, battery module including secondary battery, battery pack, and device
WO2023078047A1 (en) Positive electrode active material and preparation method therefor, lithium-ion battery comprising same, battery module, battery pack, and electric apparatus
WO2019189801A1 (en) Positive electrode active material, positive electrode and secondary battery using such positive electrode active material, and positive electrode active material manufacturing method
CN116014103A (en) High-nickel ternary positive electrode material and preparation method and application thereof
CN107565128B (en) Li3Cr(MoO4)3Application in positive electrode of lithium ion battery
CN116995225A (en) Positive plate and lithium ion battery using same
CN115579506A (en) Lithium ion battery
CN114927674B (en) Lithium cobalt oxide positive electrode material, preparation method and application thereof
CN114944488B (en) Preparation method of coated positive electrode material, product and application thereof
WO2024020795A1 (en) Composite positive electrode material, preparation method therefor, secondary battery, battery module, battery pack and electrical apparatus
WO2023197240A1 (en) Positive electrode active material, secondary battery, battery module, battery pack, and electric device

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