CN113013414B - Cobalt-free positive electrode slurry, preparation method thereof, positive plate and lithium ion battery - Google Patents

Cobalt-free positive electrode slurry, preparation method thereof, positive plate and lithium ion battery Download PDF

Info

Publication number
CN113013414B
CN113013414B CN202110221155.8A CN202110221155A CN113013414B CN 113013414 B CN113013414 B CN 113013414B CN 202110221155 A CN202110221155 A CN 202110221155A CN 113013414 B CN113013414 B CN 113013414B
Authority
CN
China
Prior art keywords
cobalt
free
ion battery
glue solution
solvent
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.)
Active
Application number
CN202110221155.8A
Other languages
Chinese (zh)
Other versions
CN113013414A (en
Inventor
常兴奇
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.)
Svolt Energy Technology Co Ltd
Original Assignee
Svolt Energy Technology 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 Svolt Energy Technology Co Ltd filed Critical Svolt Energy Technology Co Ltd
Priority to CN202110221155.8A priority Critical patent/CN113013414B/en
Publication of CN113013414A publication Critical patent/CN113013414A/en
Application granted granted Critical
Publication of CN113013414B publication Critical patent/CN113013414B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

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
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/624—Electric conductive fillers
    • 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
    • H01M4/04—Processes of manufacture in general
    • 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
    • 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
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/624—Electric conductive fillers
    • H01M4/625—Carbon or graphite
    • 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

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Battery Electrode And Active Subsutance (AREA)

Abstract

The invention provides a cobalt-free anode slurry and a preparation method thereof, an anode plate and a lithium ion battery. The cobalt-free cathode slurry comprises a cobalt-free cathode material, a conductive agent, a binder, a conductive polymer and a solvent. According to the cobalt-free anode slurry provided by the invention, the polymer material with conductivity is added, so that the conductivity of the cobalt-free anode plate is improved, and the internal resistance of a battery cell is reduced; the conductive polymer has higher ionic conductivity, forms a 3D fast ionic conductor network structure, improves the power performance of the battery, and further improves the surface density of the positive pole piece, thereby improving the energy density of the battery; in addition, the weak acid environment on the surface of the polymer neutralizes the alkalinity on the surface of the cobalt-free material, so that the residual metal dissolution phenomenon is reduced, the self-discharge phenomenon of the battery is reduced, and the safety factor of the battery is further improved.

Description

Cobalt-free positive electrode slurry, preparation method thereof, positive plate and lithium ion battery
Technical Field
The invention belongs to the technical field of batteries, and relates to a positive electrode slurry and a preparation method thereof, a positive plate and a lithium ion battery, in particular to a cobalt-free positive electrode slurry and a preparation method thereof, a positive plate and a lithium ion battery.
Background
The lithium ion battery has the advantages of high energy density, no memory effect, wide use temperature, high voltage window and the like, and is widely applied to high-energy-density battery products. With the increasing demand of people on the energy density of the battery, the brand-open corner of the lithium ion battery adopting the lamination process has higher energy density and better cycle performance; with the intelligent development of the electrical appliance industry and the popularization of electric automobiles, the demand of people on lithium ion batteries is increased explosively, the energy density of the batteries is higher and higher, but the safety problem of the batteries is more and more prominent, and the production cost of the batteries is also rapidly improved; with the coming of the subsiding of the electric vehicle, the power battery industry is about to develop a price war, and various large battery manufacturers seek to improve the energy density of the battery, and meanwhile, the problem that how to reduce the production cost of the battery and improve the safety of the battery is urgently solved by each battery industry is solved.
The existing high-energy battery anode material is mainly concentrated on a ternary anode material, the main energy density carrier is lithium nickelate serving as a main body, and an NCM and NCA system; due to the shortage of cobalt resources and the uneven distribution of the resources, the price of the cobalt resources is greatly fluctuated, the price of the ternary cathode material is greatly fluctuated, and the cobalt cost accounts for a large amount in the material. In addition, cobalt resources are scarce, and with the large-scale application of electric automobiles, the consumption of the cobalt resources is continuously increased, so that the problem of cobalt resource exhaustion is faced in the near future.
At present, the common thick electrode coating technology of the cobalt-free anode is mainly wet coating, the electrode coating is thick, a large gap exists between active mass layers, and the electrolyte is difficult to infiltrate into the inside of a pole piece due to the thick pole piece, so that the ionic conductivity of the pole piece is reduced, and the reduction of the battery cycle and the performance in the multiplying power aspect is caused.
Secondly, polyvinylidene fluoride (PVDF) used for coating the positive electrode is an insulator of lithium ions/electrons, so that the electronic conductivity of the positive electrode is reduced, and lithium ions are prevented from being inserted into an active material; the thick electrode tends to cause an increase in PVDF usage, further reducing the ionic/conductivity of the pole piece.
And thirdly, because the main elements of the NMx cobalt-free cathode material are Ni and Mn binary materials, the surface of the NMx cobalt-free cathode material has high metal residues, such as elements of nickel oxide/cobalt and the like, and the materials are easily dissolved into electrolyte in the battery circulation process and migrate to the surface of a cathode to cause metal foreign matters, increase the self-discharge phenomenon of the battery and even have the risk of short circuit.
The current cobalt-free battery thick electrode is mainly realized by increasing the density of a coating surface, and in order to ensure the thickness of a pole piece, a thick electrode pole piece is prepared by adopting a multi-rolling mode; however, the thick electrode plate prepared by the method has the defects of poor performance of an electrolyte wetting electrode plate and overlarge electrode rebound due to high compaction density. Secondly, the cobalt-free material is mainly Ni and Mn binary materials, so that the surface alkalinity is high, metal residues exist, and the metal residues have the risk of being dissolved into electrolyte, thereby bringing immeasurable risk factors to the safety of the battery.
CN112271285A discloses a preparation process of lithium ion battery anode slurry, which comprises the following steps: preparing anode powder; preparing polyvinylidene fluoride (PVDF) glue solution; uniformly adding a novel carbon black conductive agent ECP-600JD into a polyvinylidene fluoride glue solution, and fully stirring to obtain a carbon black conductive glue solution; uniformly adding the oil single-walled carbon nanotubes into the carbon black conductive glue solution, and stirring and dispersing to obtain composite conductive slurry; adding the anode powder into the composite conductive slurry for preliminary kneading; kneading and stirring for the second time; adding the rest PVDF glue solution and appropriate NMP, and crushing and dispersing at high speed.
CN112289995A discloses a composite positive electrode slurry, a positive electrode plate and a solid-state battery. The preparation method of the composite anode slurry comprises the following steps: mixing the positive electrode active material with lithium-carbon boron oxide and sintering at 660-700 ℃ to obtain a prefabricated sintered material; and dissolving the obtained pre-sintered material, solid electrolyte, conductive agent, adhesive and lithium salt in a solvent, and mixing to obtain the composite anode slurry.
CN112234207A discloses positive electrode slurry and a positive electrode sheet of a lithium iron phosphate battery and a preparation method of the positive electrode sheet, wherein the positive electrode slurry of the lithium iron phosphate battery comprises the following components in parts by weight: 90-95 parts of positive active material, 4-6 parts of conductive agent, 5-7 parts of binder, 3-5 parts of dispersant, 2-4.2 parts of flexibilizer and 80-90 parts of solvent; the positive electrode active material is lithium iron phosphate, the binder is polyacrylic acid, the toughening agent is polymethyl methacrylate, and the weight ratio of the polyacrylic acid to the polymethyl methacrylate is 1.
However, the above solutions all have a problem that the electrochemical performance needs to be further improved when the cobalt-free cathode material is used.
Disclosure of Invention
Aiming at the defects in the prior art, the invention aims to provide cobalt-free anode slurry, a preparation method thereof, an anode plate and a lithium ion battery. The positive plate prepared from the cobalt-free positive electrode slurry provided by the invention has the advantages of good conductivity, small electrode rebound, less surface metal residue and less side reaction of the positive electrode material in electrolyte.
In order to achieve the purpose, the invention adopts the following technical scheme:
in a first aspect, the present invention provides a cobalt-free cathode slurry comprising a cobalt-free cathode material, a conductive agent, a binder, a conductive polymer, and a solvent.
In the cobalt-free anode slurry provided by the invention, the conductivity and ionic conductivity of the electrode plate are improved through the macromolecular crosslinking effect of the conductive polymer (the ionic conductivity refers to a measurement of conduction of a substance, and in the invention, refers to the speed of lithium ions transmitted on the electrode plate). In addition, the characteristics of the conductive polymer are utilized to neutralize the metal residue on the surface of the material, so that a metal complex is formed on the surface of the material, and the metal dissolved electrolyte is effectively relieved; meanwhile, the polymers effectively reduce the contact between the electrolyte and the anode material and reduce the side reaction of the anode material.
The cobalt-free anode slurry provided by the invention is mainly used for improving the conductivity and ionic conductivity of a high-surface-density pole piece. Meanwhile, the alkaline environment on the surface of the cobalt-free anode material is neutralized under the action of the high molecular polymer, the metal residue on the surface of the anode material is reduced to be dissolved into the electrolyte, and the safety of the battery cell is improved.
The following is a preferred technical solution of the present invention, but not a limitation to the technical solution provided by the present invention, and the technical objects and advantageous effects of the present invention can be better achieved and achieved by the following preferred technical solution.
In a preferred embodiment of the present invention, the conductive polymer is a single-stranded polymer. In the invention, the single-chain polymer has the advantages that the polymer has good ionic conductivity and ionic conductivity, thereby forming a polymer layer with a net-shaped cross-linked structure and improving the conductivity and ionic conductivity of the pole piece; the polymer material which is conductive and ionic is used for manufacturing the cobalt-free anode material pole piece.
Preferably, the conductive polymer comprises any one of polyvinyl formal, polyaniline, polyacrylate, polyimide, polyacrylonitrile, polysiloxane, or polyethylene oxide resin, or a combination of at least two thereof, preferably polyvinyl formal (PVFM). The above-mentioned kinds of conductive polymers are all single-chain polymers.
The polyvinyl formal can be used as a binder and an ionic conductive agent, and although the conductivity of the polyvinyl formal is slightly lower than that of polyaniline, the polyvinyl formal is not easy to oxidize and decompose, and is more suitable for cobalt-free anode slurry.
Preferably, the solvent is an organic solvent.
Preferably, the organic solvent comprises any one of N-methyl pyrrolidone, dimethyl sulfoxide, acetone or ethylene glycol or a combination of at least two thereof.
Preferably, the binder comprises polyvinylidene fluoride and/or sodium hydroxymethyl cellulose.
Preferably, the cobalt-free cathode material is a cathode material without cobalt element, and comprises lithium Nickel Manganese (NM) x ) Lithium iron phosphate (LiFePO) 4 ) Lithium manganate (LiMn) x O 2 ) Or lithium nickelate (LiNi) x O 2 ) Any one or a combination of at least two of them.
As a preferred embodiment of the present invention, the conductive agent includes any one or a combination of at least two of carbon nanotubes, conductive carbon black, and graphene.
Preferably, the conductive agent is a combination of carbon nanotubes and conductive carbon black.
Preferably, in the combination of the conductive carbon black and the carbon nanotubes, the mass ratio of the conductive carbon black to the carbon nanotubes is 6.
As a preferred technical solution of the present invention, the mass ratio of the cobalt-free positive electrode material, the conductive agent, the conductive polymer and the binder is 90 (0.9-1.1): 6-8 (0.1-0.3), for example, 90.
In the invention, if the conductive polymer is too much, the polymer is agglomerated, the good dispersion effect cannot be achieved, and the conductivity of the pole piece is influenced; if the conductive polymer is too little, the conductive polymer is distributed less on the surface of the active material, and a stable mesh conductive structure cannot be formed well, so that the conductivity of the pole piece is reduced. .
Preferably, the cobalt-free cathode slurry has a solids content of 50-80%, such as 50%, 60%, 70%, or 80%, etc., preferably a solids content of 68-72%.
In a second aspect, the present invention provides a method for preparing a cobalt-free cathode slurry as described in the first aspect, the method comprising the steps of:
(1) Mixing a conductive polymer and a first solvent to obtain a first mixed glue solution, and mixing a binder and a second solvent to obtain a second mixed glue solution;
(2) And (2) mixing a cobalt-free anode material, a conductive agent, the first mixed glue solution and the second mixed glue solution in the step (1) to obtain the cobalt-free anode slurry.
The method provided by the invention is simple and feasible and has the advantage of low cost.
In the preparation method provided by the invention, the first mixed glue solution and the second mixed glue solution are prepared, but the conductive polymer, the binder and the solvent are not directly mixed together, and the purpose is that the conductive polymer is a chain polymer and is easy to cause agglomeration, and the conductive polymer is uniformly dispersed under the action of the solvent.
As a preferable technical scheme of the invention, the first solvent in the step (1) comprises N-methyl pyrrolidone.
Preferably, in the first mixed glue solution in step (1), the mass ratio of the conductive polymer to the first solvent is 1.
Preferably, the second solvent in step (1) comprises any one of N-methyl pyrrolidone, dichloroethane or dimethyl sulfoxide or a combination of at least two of the same.
Preferably, in the second mixed glue solution in the step (1), the mass ratio of the binder to the second solvent is 3.
As a preferred technical solution of the present invention, in step (2), the mass ratio of the cobalt-free positive electrode material, the conductive agent, the conductive polymer in the first mixed colloidal solution and the binder in the second mixed colloidal solution is (0.9-1.1) to (6-8) to (0.1-0.3), for example, the ratio of 90.
Preferably, in step (2), the mixing comprises stirring.
Preferably, the agitating mixing comprises dry homogenization and/or wet homogenization.
As a further preferable technical scheme of the preparation method, the method comprises the following steps:
(1) Mixing a conductive polymer and a first solvent to obtain a first mixed glue solution, and mixing a binder and a second solvent to obtain a second mixed glue solution;
wherein the conductive polymer of step (1) comprises polyvinyl formal;
in the first mixed glue solution, the mass ratio of the conductive polymer to the first solvent is 1-100;
in the second mixed glue solution in the step (1), the mass ratio of the binder to the second solvent is (3);
(2) Mixing a cobalt-free anode material, a conductive agent, the first mixed glue solution and the second mixed glue solution in the step (1) to obtain cobalt-free anode slurry; the mass ratio of the cobalt-free positive electrode material to the conductive agent to the conductive polymer in the first mixed glue solution to the binder in the second mixed glue solution is 90 (0.9-1.1) to (6-8) to (0.1-0.3).
In a third aspect, the present invention provides a positive electrode sheet coated with the cobalt-free positive electrode slurry according to the first aspect.
In a fourth aspect, the present invention provides a lithium ion battery comprising the positive electrode sheet according to the third aspect.
Compared with the prior art, the invention has the following beneficial effects:
(1) According to the cobalt-free anode slurry provided by the invention, the polymer material with conductivity is added, so that the conductivity of the cobalt-free anode plate is improved, and the internal resistance of a battery cell is reduced; the conductive polymer has higher ionic conductivity, forms a 3D fast ionic conductor network structure, improves the power performance of the battery, and further improves the surface density of the positive pole piece, thereby improving the energy density of the battery; in addition, the weak acid environment on the surface of the polymer neutralizes the alkalinity on the surface of the cobalt-free material, so that the residual metal dissolution phenomenon is reduced, the self-discharge phenomenon of the battery is reduced, and the safety factor of the battery is further improved.
(2) The preparation method provided by the invention is simple and feasible, and has the advantage of low cost.
Detailed Description
In order to better illustrate the present invention and facilitate the understanding of the technical solutions of the present invention, the present invention is further described in detail below. The following examples are merely illustrative of the present invention and do not represent or limit the scope of the claims, which are defined by the claims.
The following are typical but non-limiting examples of the invention:
example 1
The present embodiment provides a cobalt-free cathode slurry, which is composed of a cobalt-free cathode material, a conductive agent, a binder, a conductive polymer, and a solvent.
The conductive polymer is polyvinyl formal, the cobalt-free positive electrode material is lithium nickelate (NMx), the binder is polyvinylidene fluoride, the conductive agent is carbon nano tubes and conductive carbon black (mass ratio is 3. The mass ratio of the cobalt-free cathode material to the conductive agent to the conductive polymer to the binder is 93.8
This example prepares a cobalt-free positive electrode slurry as follows:
(1) Mixing a conductive polymer with a first solvent (N-methyl pyrrolidone) to obtain a first mixed glue solution, and mixing a binder with a second solvent (N-methyl pyrrolidone) to obtain a second mixed glue solution;
in the first mixed glue solution, the mass ratio of the conductive polymer to the first solvent is 7;
in the second mixed glue solution obtained in the step (1), the mass ratio of the binder to the second solvent is 6;
(2) And (2) stirring, mixing and homogenizing the cobalt-free anode material, the conductive agent, the first mixed glue solution and the second mixed glue solution in the step (1) according to the formula ratio to obtain the cobalt-free anode slurry. The mass ratio of the cobalt-free positive electrode material, the conductive agent, the conductive polymer in the first mixed glue solution and the binder in the second mixed glue solution is 90.
Example 2
The embodiment provides a cobalt-free cathode slurry, which is composed of a cobalt-free cathode material, a conductive agent, a binder, a conductive polymer and a solvent.
The conductive polymer is polyvinyl formal, the cobalt-free positive electrode material is lithium nickelate (NMx), the binder is polyvinylidene fluoride, the conductive agent is carbon nano tubes and conductive carbon black (mass ratio is 4. The mass ratio of the cobalt-free cathode material to the conductive agent to the conductive polymer to the binder is 90.9.
This example prepares a cobalt-free positive electrode slurry as follows:
(1) Mixing a conductive polymer with a first solvent (N-methylpyrrolidone) to obtain a first mixed glue solution, and mixing a binder with a second solvent (N-methylpyrrolidone) to obtain a second mixed glue solution;
in the first mixed glue solution, the mass ratio of the conductive polymer to the first solvent is 1;
in the second mixed glue solution obtained in the step (1), the mass ratio of the binder to the second solvent is 3;
(2) And (2) stirring, mixing and homogenizing the cobalt-free anode material, the conductive agent, the first mixed glue solution and the second mixed glue solution in the step (1) according to the formula ratio to obtain the cobalt-free anode slurry. The mass ratio of the cobalt-free cathode material, the conductive agent, the conductive polymer in the first mixed glue solution and the binder in the second mixed glue solution is 91.9.
Example 3
The present embodiment provides a cobalt-free cathode slurry, which is composed of a cobalt-free cathode material, a conductive agent, a binder, a conductive polymer, and a solvent.
Wherein the conductive polymer is polyvinyl formal, and the cobalt-free anode material is lithium manganate (LiMnO) 2 ) The binder is polyvinylidene fluoride, the conductive agent is carbon nanotubes and conductive carbon black (mass ratio is 2. The mass ratio of the cobalt-free cathode material to the conductive agent to the conductive polymer to the binder is 90.
This example prepares a cobalt-free positive electrode slurry as follows:
(1) Mixing a conductive polymer with a first solvent (N-methylpyrrolidone) to obtain a first mixed glue solution, and mixing a binder with a second solvent (N-methylpyrrolidone) to obtain a second mixed glue solution;
in the first mixed glue solution, the mass ratio of the conductive polymer to the first solvent is 15;
in the second mixed glue solution in the step (1), the mass ratio of the binder to the second solvent is 9;
(2) And (2) stirring, mixing and homogenizing the cobalt-free anode material, the conductive agent, the first mixed glue solution and the second mixed glue solution in the step (1) according to the formula ratio to obtain the cobalt-free anode slurry. The mass ratio of the cobalt-free positive electrode material to the conductive agent to the conductive polymer in the first mixed glue solution to the binder in the second mixed glue solution is 92.6:1.1:6:0.3.
Example 4
This example is different from example 1 in that the conductive polymer in the cobalt-free cathode slurry is polyaniline.
Example 5
The present embodiment is different from embodiment 1 in that the mass ratio of the cobalt-free cathode material, the conductive agent, the conductive polymer and the binder is 90.
Example 6
The difference between the present embodiment and embodiment 1 is that the mass ratio of the cobalt-free cathode material, the conductive agent, the conductive polymer and the binder is 94.
Comparative example 1
This comparative example differs from example 1 in that the cobalt-free positive electrode slurry does not contain a conductive polymer.
The cobalt-free anode material, the conductive agent and the binder in the formula amount are mixed according to the mass ratio: 95.
The test method comprises the following steps:
the cobalt-free positive electrode slurry provided in each example and comparative example was prepared into a positive electrode sheet as follows: coating the slurry on an aluminum foil, baking at 60 ℃ in vacuum, rolling and cutting pole pieces with proper sizes for later useThe areal density is controlled to be 4mg/cm 2 。
Mixing the prepared positive plate, negative electrode (lithium plate), diaphragm (PP diaphragm) and electrolyte (1 mol/L LiPF) 6 /EC + DMC + EMC (v/v = 1. The first discharge capacity, the first coulombic efficiency, the capacity retention rate after 100 cycles, and the alternating current resistance (DCR) after 100 cycles of the battery were measured under the above-mentioned charge-discharge conditions at 0.2C, and table 1 is shown below.
The test results are shown in the following table:
TABLE 1
Figure BDA0002954973150000101
Figure BDA0002954973150000111
It can be known from the above examples and comparative examples that the cobalt-free positive electrode slurry provided in examples 1 to 4 improves the conductivity of the cobalt-free positive electrode sheet and reduces the internal resistance of the battery cell by adding the polymer material with conductivity; the conductive polymer has higher ionic conductivity, forms a 3D fast ionic conductor network structure, improves the power performance of the battery, and further improves the surface density of the positive pole piece, thereby improving the energy density of the battery; in addition, the weak acid environment on the surface of the polymer neutralizes the alkalinity on the surface of the cobalt-free material, so that the residual metal dissolution phenomenon is reduced, the self-discharge phenomenon of the battery is reduced, and the safety factor of the battery is further improved.
However, example 4 used polyaniline, which is more conductive than polyvinyl formal; however, polyaniline is not the most preferred material in this application due to the fact that the energy of polyaniline HUMO is better than that of polyvinyl formal, which means that polyaniline is more easily oxidized and decomposed.
The conductive polymer of example 5 was too much in the slurry, resulting in poor battery performance, probably because the conductive polymer was more and prone to agglomeration, resulting in non-uniform conductivity of the electrode sheet.
The conductive polymer of example 6 was too little in the slurry, resulting in a lower capacity retention of the pole piece, which may be caused by non-uniformity of the conductive network.
Comparative example 1 the capacity retention of the positive electrode material and the DCR values were inferior to those of the examples because no conductive polymer was used.
The applicant states that the present invention is illustrated by the above examples to show the detailed method of the present invention, but the present invention is not limited to the above detailed method, that is, it does not mean that the present invention must rely on the above detailed method to be carried out. It should be understood by those skilled in the art that any modification of the present invention, equivalent substitutions of the raw materials of the product of the present invention, addition of auxiliary components, selection of specific modes, etc., are within the scope and disclosure of the present invention.

Claims (16)

1. The lithium ion battery is characterized by comprising a positive plate, wherein electrolyte in the lithium ion battery is non-aqueous electrolyte, the surface of the positive plate is coated with cobalt-free positive electrode slurry, and the cobalt-free positive electrode slurry comprises a cobalt-free positive electrode material, a conductive agent, a binder, a conductive polymer and a solvent; the solvent is an organic solvent; the conductive polymer is a single-chain polymer; the conductive polymer comprises any one or the combination of at least two of polyvinyl formal, polyacrylate, polyimide, polyacrylonitrile, polysiloxane or polyethylene oxide resin; the cobalt-free positive electrode material is lithium nickel manganese oxide; the mass ratio of the cobalt-free positive electrode material to the conductive agent to the conductive polymer to the binder is 90 (0.9-1.1) to (6-8) to (0.1-0.3).
2. The lithium ion battery of claim 1, wherein the organic solvent comprises any one of N-methyl pyrrolidone, dimethyl sulfoxide, acetone, or ethylene glycol, or a combination of at least two thereof.
3. The lithium ion battery of claim 1, wherein the binder comprises polyvinylidene fluoride and/or sodium hydroxymethyl cellulose.
4. The lithium ion battery of claim 1, wherein the conductive agent comprises any one of carbon nanotubes, conductive carbon black, or graphene, or a combination of at least two thereof.
5. The lithium ion battery of claim 4, wherein the conductive agent is a combination of carbon nanotubes and conductive carbon black.
6. The lithium ion battery of claim 5, wherein in the combination of conductive carbon black and carbon nanotubes, the mass ratio of conductive carbon black to carbon nanotubes is 6.
7. The lithium ion battery of claim 1, wherein the cobalt-free cathode slurry has a solid content of 50-80%.
8. The lithium ion battery of claim 7, wherein the cobalt-free cathode slurry has a solids content of 68-72%.
9. The lithium ion battery of claim 1, wherein the cobalt-free positive electrode slurry is prepared by a method comprising the steps of:
(1) Mixing a conductive polymer and a first solvent to obtain a first mixed glue solution, and mixing a binder and a second solvent to obtain a second mixed glue solution;
(2) And (2) mixing a cobalt-free anode material, a conductive agent, the first mixed glue solution and the second mixed glue solution in the step (1) to obtain the cobalt-free anode slurry.
10. The lithium ion battery of claim 9, wherein the first solvent of step (1) comprises any one of N-methyl pyrrolidone, acetone, ethanol, dimethyl sulfoxide, or dichloroethane, or a combination of at least two thereof.
11. The lithium ion battery according to claim 9, wherein in the first mixed glue solution in the step (1), the mass ratio of the conductive polymer to the first solvent is 1.
12. The lithium ion battery of claim 9, wherein the second solvent of step (1) comprises any one of N-methylpyrrolidone, dichloroethane, or dimethylsulfoxide, or a combination of at least two thereof.
13. The lithium ion battery of claim 9, wherein in the second mixed glue solution in the step (1), the mass ratio of the binder to the second solvent is 3.
14. The li-ion battery of claim 9, wherein in step (2), the mixing comprises stirring.
15. The lithium-ion battery according to claim 14, wherein the agitation mixing comprises dry homogenization and/or wet homogenization.
16. The lithium ion battery of claim 9, wherein the method comprises the steps of:
(1) Mixing a conductive polymer and a first solvent to obtain a first mixed glue solution, and mixing a binder and a second solvent to obtain a second mixed glue solution;
wherein the conductive polymer of step (1) comprises polyvinyl formal;
in the first mixed glue solution, the mass ratio of the conductive polymer to the first solvent is 1-100;
in the second mixed glue solution in the step (1), the mass ratio of the binder to the second solvent is 3;
(2) Mixing a cobalt-free anode material, a conductive agent, the first mixed glue solution and the second mixed glue solution in the step (1) to obtain cobalt-free anode slurry; the mass ratio of the cobalt-free positive electrode material to the conductive agent to the conductive polymer in the first mixed glue solution to the binder in the second mixed glue solution is 90 (0.9-1.1) to (6-8) to (0.1-0.3).
CN202110221155.8A 2021-02-26 2021-02-26 Cobalt-free positive electrode slurry, preparation method thereof, positive plate and lithium ion battery Active CN113013414B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202110221155.8A CN113013414B (en) 2021-02-26 2021-02-26 Cobalt-free positive electrode slurry, preparation method thereof, positive plate and lithium ion battery

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202110221155.8A CN113013414B (en) 2021-02-26 2021-02-26 Cobalt-free positive electrode slurry, preparation method thereof, positive plate and lithium ion battery

Publications (2)

Publication Number Publication Date
CN113013414A CN113013414A (en) 2021-06-22
CN113013414B true CN113013414B (en) 2023-02-24

Family

ID=76386682

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202110221155.8A Active CN113013414B (en) 2021-02-26 2021-02-26 Cobalt-free positive electrode slurry, preparation method thereof, positive plate and lithium ion battery

Country Status (1)

Country Link
CN (1) CN113013414B (en)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114050227A (en) * 2021-10-29 2022-02-15 北京理工大学 High-capacity lithium battery positive plate and lithium battery
CN114069024A (en) * 2021-11-15 2022-02-18 惠州亿纬锂能股份有限公司 3D printing solid-state battery and preparation method and application thereof
CN114420929B (en) * 2021-12-09 2023-11-03 万向一二三股份公司 Preparation method of solid battery containing conductive polymer binder
CN115312745A (en) * 2022-09-16 2022-11-08 深圳市研一新材料有限责任公司 Composite positive electrode active material and preparation method and application thereof
CN116525177B (en) * 2023-05-29 2024-03-19 盐城工学院 Graphene conductive agent for lithium ion battery and preparation method thereof

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102280656A (en) * 2011-07-04 2011-12-14 南陵恒昌铜箔制造有限公司 Preparation method of lithium ion battery with positive electrode covered by conductive polymer
CN102487141A (en) * 2010-12-02 2012-06-06 比亚迪股份有限公司 Cathode material of lithium ion battery and battery
CN106328950A (en) * 2015-06-18 2017-01-11 苏州宝时得电动工具有限公司 Positive electrode material and battery
CN108232318A (en) * 2018-01-30 2018-06-29 陕西煤业化工技术研究院有限责任公司 A kind of production method of all solid state power lithium-ion battery
CN110858661A (en) * 2018-08-24 2020-03-03 比亚迪股份有限公司 Positive electrode assembly of lithium ion battery, preparation method of positive electrode assembly and all-solid-state lithium battery

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111029559A (en) * 2019-12-16 2020-04-17 银隆新能源股份有限公司 Lithium titanate battery and preparation method thereof
CN111584861B (en) * 2020-05-18 2022-02-22 蜂巢能源科技有限公司 Cobalt-free system, positive electrode slurry, homogenizing method and application thereof

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102487141A (en) * 2010-12-02 2012-06-06 比亚迪股份有限公司 Cathode material of lithium ion battery and battery
CN102280656A (en) * 2011-07-04 2011-12-14 南陵恒昌铜箔制造有限公司 Preparation method of lithium ion battery with positive electrode covered by conductive polymer
CN106328950A (en) * 2015-06-18 2017-01-11 苏州宝时得电动工具有限公司 Positive electrode material and battery
CN108232318A (en) * 2018-01-30 2018-06-29 陕西煤业化工技术研究院有限责任公司 A kind of production method of all solid state power lithium-ion battery
CN110858661A (en) * 2018-08-24 2020-03-03 比亚迪股份有限公司 Positive electrode assembly of lithium ion battery, preparation method of positive electrode assembly and all-solid-state lithium battery

Also Published As

Publication number Publication date
CN113013414A (en) 2021-06-22

Similar Documents

Publication Publication Date Title
CN113013414B (en) Cobalt-free positive electrode slurry, preparation method thereof, positive plate and lithium ion battery
US10326136B2 (en) Porous carbonized composite material for high-performing silicon anodes
KR101378235B1 (en) Lithium secondary battery
CN101116201B (en) Current collector for secondary battery, positive electrode for the secondary battery, negative electrode for the secondary battery, the secondary battery, and manufacturing method of them
CN109004229B (en) Lithium ion battery positive electrode material additive, positive electrode material thereof and lithium ion secondary battery
CN105470576A (en) High voltage lithium battery cell and preparation method therefor, and lithium ion battery
CN101228654A (en) Cathode active material and lithium secondary battery containing them
KR101697008B1 (en) Lithium secondary battery
CN1960040A (en) High-powered lithium ferric phosphate dynamic battery, and preparation technique
CN102427123A (en) Lithium ion secondary battery and anode sheet thereof
WO2016141861A1 (en) Battery, battery pack and uninterruptible power supply
JP2012022858A (en) Method for manufacturing electrode
JP6241911B2 (en) Active material particles, positive electrode for electricity storage device, electricity storage device, and method for producing active material particles
Oriňáková et al. Effect of PPy/PEG conducting polymer film on electrochemical performance of LiFePO 4 cathode material for Li-ion batteries
CN101640263A (en) Lithium ion battery composite cathode material and preparation method thereof
CN109167036B (en) TiN and conductive polymer composite modified lithium ion layered ternary positive electrode material and preparation method thereof
KR20160101870A (en) Manufacturing method of electrode
JP2015056311A (en) Method for manufacturing nonaqueous electrolyte secondary battery
CN113036125A (en) Positive electrode slurry, positive electrode plate, lithium ion cell, lithium ion battery pack and application
CN116364930A (en) Compound additive and electrochemical device using same
CN116093257A (en) Negative electrode for lithium ion secondary battery, method for preparing same, and lithium ion secondary battery comprising same
JP2000067918A (en) Lithium secondary battery
WO2019241509A1 (en) Fast charge feof cathode for lithium ion batteries
JP2017152122A (en) Negative electrode active material for lithium ion secondary batteries, negative electrode for lithium ion secondary battery and lithium ion secondary battery
Yoshida et al. High Rate Charge and Discharge Characteristics of Graphite/SiOx Composite Electrodes

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
GR01 Patent grant
GR01 Patent grant