CN115579583A - Diaphragm slurry, battery diaphragm, preparation method of battery diaphragm and lithium battery - Google Patents
Diaphragm slurry, battery diaphragm, preparation method of battery diaphragm and lithium battery Download PDFInfo
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- 239000002002 slurry Substances 0.000 title claims abstract description 50
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 title claims abstract description 47
- 229910052744 lithium Inorganic materials 0.000 title claims abstract description 47
- 238000002360 preparation method Methods 0.000 title abstract description 20
- 239000002245 particle Substances 0.000 claims abstract description 84
- 125000003178 carboxy group Chemical group [H]OC(*)=O 0.000 claims abstract description 26
- 125000000524 functional group Chemical group 0.000 claims abstract description 20
- 239000011230 binding agent Substances 0.000 claims abstract description 18
- 150000004292 cyclic ethers Chemical class 0.000 claims abstract description 14
- 239000002904 solvent Substances 0.000 claims abstract description 14
- 125000002924 primary amino group Chemical group [H]N([H])* 0.000 claims abstract description 10
- LSNNMFCWUKXFEE-UHFFFAOYSA-M Bisulfite Chemical compound OS([O-])=O LSNNMFCWUKXFEE-UHFFFAOYSA-M 0.000 claims abstract description 4
- 239000000919 ceramic Substances 0.000 claims description 24
- 239000011248 coating agent Substances 0.000 claims description 16
- 238000000576 coating method Methods 0.000 claims description 16
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 15
- 239000007800 oxidant agent Substances 0.000 claims description 15
- 125000002887 hydroxy group Chemical group [H]O* 0.000 claims description 13
- 238000000034 method Methods 0.000 claims description 11
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 10
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 claims description 10
- 230000001590 oxidative effect Effects 0.000 claims description 10
- -1 polyethylene Polymers 0.000 claims description 10
- 125000000542 sulfonic acid group Chemical group 0.000 claims description 10
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 claims description 9
- QAOWNCQODCNURD-UHFFFAOYSA-N sulfuric acid Substances OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims description 9
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 claims description 8
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 8
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims description 7
- 238000002156 mixing Methods 0.000 claims description 7
- 229910017604 nitric acid Inorganic materials 0.000 claims description 7
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 claims description 6
- 239000004698 Polyethylene Substances 0.000 claims description 6
- 238000004519 manufacturing process Methods 0.000 claims description 6
- 239000003960 organic solvent Substances 0.000 claims description 6
- 229920000573 polyethylene Polymers 0.000 claims description 6
- 238000002791 soaking Methods 0.000 claims description 6
- 238000006243 chemical reaction Methods 0.000 claims description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 5
- NIXOWILDQLNWCW-UHFFFAOYSA-M Acrylate Chemical compound [O-]C(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-M 0.000 claims description 4
- 239000004743 Polypropylene Substances 0.000 claims description 4
- UHESRSKEBRADOO-UHFFFAOYSA-N ethyl carbamate;prop-2-enoic acid Chemical compound OC(=O)C=C.CCOC(N)=O UHESRSKEBRADOO-UHFFFAOYSA-N 0.000 claims description 4
- 239000004745 nonwoven fabric Substances 0.000 claims description 4
- 229920001155 polypropylene Polymers 0.000 claims description 4
- 239000004814 polyurethane Substances 0.000 claims description 4
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 claims description 3
- 239000004721 Polyphenylene oxide Substances 0.000 claims description 3
- 229920000058 polyacrylate Polymers 0.000 claims description 3
- 229920000570 polyether Polymers 0.000 claims description 3
- 229920002635 polyurethane Polymers 0.000 claims description 3
- 239000000377 silicon dioxide Substances 0.000 claims description 3
- 238000004528 spin coating Methods 0.000 claims description 3
- 238000005507 spraying Methods 0.000 claims description 3
- 239000004593 Epoxy Substances 0.000 claims description 2
- 239000002033 PVDF binder Substances 0.000 claims description 2
- 229920002981 polyvinylidene fluoride Polymers 0.000 claims description 2
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 abstract description 8
- 229910001416 lithium ion Inorganic materials 0.000 abstract description 8
- 238000001556 precipitation Methods 0.000 abstract description 8
- 229910052723 transition metal Inorganic materials 0.000 abstract description 7
- 150000003624 transition metals Chemical class 0.000 abstract description 7
- 229910001428 transition metal ion Inorganic materials 0.000 abstract description 6
- 239000000203 mixture Substances 0.000 abstract description 5
- 229910052759 nickel Inorganic materials 0.000 abstract description 4
- 238000004090 dissolution Methods 0.000 abstract description 2
- 230000000052 comparative effect Effects 0.000 description 20
- 239000008139 complexing agent Substances 0.000 description 8
- OFOBLEOULBTSOW-UHFFFAOYSA-N Malonic acid Chemical compound OC(=O)CC(O)=O OFOBLEOULBTSOW-UHFFFAOYSA-N 0.000 description 6
- 125000003277 amino group Chemical group 0.000 description 5
- 230000005540 biological transmission Effects 0.000 description 5
- 239000003792 electrolyte Substances 0.000 description 4
- 230000014759 maintenance of location Effects 0.000 description 4
- 239000000243 solution Substances 0.000 description 4
- 238000001179 sorption measurement Methods 0.000 description 4
- 239000000853 adhesive Substances 0.000 description 3
- 230000001070 adhesive effect Effects 0.000 description 3
- 238000000151 deposition Methods 0.000 description 3
- 230000008021 deposition Effects 0.000 description 3
- 150000002500 ions Chemical class 0.000 description 3
- 229910021645 metal ion Inorganic materials 0.000 description 3
- 239000007774 positive electrode material Substances 0.000 description 3
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 229920000642 polymer Polymers 0.000 description 2
- 238000007761 roller coating Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- FFRBMBIXVSCUFS-UHFFFAOYSA-N 2,4-dinitro-1-naphthol Chemical compound C1=CC=C2C(O)=C([N+]([O-])=O)C=C([N+]([O-])=O)C2=C1 FFRBMBIXVSCUFS-UHFFFAOYSA-N 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 238000003556 assay Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 210000004027 cell Anatomy 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 230000001351 cycling effect Effects 0.000 description 1
- 239000008367 deionised water Substances 0.000 description 1
- 229910021641 deionized water Inorganic materials 0.000 description 1
- 210000001787 dendrite Anatomy 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 239000002270 dispersing agent Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000003822 epoxy resin Substances 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 238000009830 intercalation Methods 0.000 description 1
- 230000002687 intercalation Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 125000000962 organic group Chemical group 0.000 description 1
- 238000011056 performance test Methods 0.000 description 1
- 229920000647 polyepoxide Polymers 0.000 description 1
- 229920005749 polyurethane resin Polymers 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- CAXRKYFRLOPCAB-UHFFFAOYSA-N propane-1,1-disulfonic acid Chemical compound CCC(S(O)(=O)=O)S(O)(=O)=O CAXRKYFRLOPCAB-UHFFFAOYSA-N 0.000 description 1
- AOHJOMMDDJHIJH-UHFFFAOYSA-N propylenediamine Chemical compound CC(N)CN AOHJOMMDDJHIJH-UHFFFAOYSA-N 0.000 description 1
- 239000002562 thickening agent Substances 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
Images
Classifications
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
- H01M50/409—Separators, membranes or diaphragms characterised by the material
- H01M50/431—Inorganic material
- H01M50/434—Ceramics
-
- 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
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
- H01M50/403—Manufacturing processes of separators, membranes or diaphragms
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
- H01M50/409—Separators, membranes or diaphragms characterised by the material
- H01M50/449—Separators, membranes or diaphragms characterised by the material having a layered structure
-
- 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
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- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Ceramic Engineering (AREA)
- Inorganic Chemistry (AREA)
- Cell Separators (AREA)
Abstract
The embodiment of the application provides a diaphragm slurry, a battery diaphragm, a preparation method of the battery diaphragm and a lithium battery, and relates to the field of batteries. The diaphragm slurry comprises a solvent, a binder and modified oxide particles; the modified oxide particles are oxide particles with the surface modified by functional groups, and the functional groups comprise one or more of carboxyl, sulfonic acid, amino and cyclic ether. The diaphragm slurry has simple composition and easy preparation, can selectively adsorb transition metals such as Mn, co and Ni, can not adsorb lithium ions, and can well relieve the lithium precipitation of a negative electrode caused by the dissolution of transition metal ions of a positive electrode in a lithium battery when being used for preparing the battery diaphragm in the lithium battery.
Description
Technical Field
The application relates to the field of batteries, in particular to a diaphragm slurry, a battery diaphragm, a preparation method of the battery diaphragm and a lithium battery.
Background
The diaphragm is one of the most important components in the lithium battery, and can play a role in conducting lithium ions while preventing the anode and the cathode of the battery from being in direct contact so as to ensure the normal operation of the battery. In the process of charging and discharging of the lithium battery, ions of transition metals in the positive electrode material are inevitably dissolved in the electrolyte and migrate to the negative electrode through the separator, so that the phenomenon of lithium precipitation at the negative electrode occurs, which reduces the cycle stability and safety performance of the battery.
In order to relieve the phenomenon of lithium precipitation of a negative electrode, patent application No. CN201911144312.9 entitled "diaphragm slurry for efficiently capturing metal ions, a diaphragm and application thereof" discloses diaphragm slurry for efficiently capturing metal ions, which is formed by mixing deionized water, a dispersing agent, a thickening agent, a binder, a complexing agent and functional components and coating the mixture on the diaphragm to realize the adsorption of metal ions (Mn, co and Ni). The main substance for ion adsorption is a complexing agent, which comprises one of a multidentate complexing agent, a macrocyclic complexing agent and a polymer complexing agent or a mixture of the multidentate complexing agent, the macrocyclic complexing agent and the polymer complexing agent in any proportion.
However, the composition of the diaphragm slurry is complex, and the preparation process is complicated.
Disclosure of Invention
The embodiment of the application provides a diaphragm slurry, a battery diaphragm, a preparation method of the battery diaphragm and a lithium battery.
In a first aspect, embodiments of the present application provide a separator slurry, which includes a solvent, a binder, and modified oxide particles; the modified oxide particles are oxide particles with a surface modified with functional groups including one or more of carboxyl, sulfonic acid, amino, and cyclic ether.
In the above-mentioned embodiments, the functional group such as a carboxyl group, a sulfonic acid group, an amino group, or a cyclic ether has a coordinating ability, and easily coordinates with a transition metal ion such as Mn, co, or Ni, and does not coordinate with a lithium ion. Therefore, the separator slurry according to the embodiment of the present application can selectively adsorb ions of the transition metal eluted from the positive electrode material in the battery electrolyte, and does not inhibit the transport of lithium ions. The binder in the diaphragm slurry has good adhesive capacity, so that the modified oxide particles can be bonded together, and the adhesive capacity of the diaphragm slurry can be increased. The solvent can function to dissolve the modified oxide particles and the binder.
In one possible implementation, the oxide particles include one or more of alumina, silica, and zirconia, and the modified oxide particles have a molar ratio of the functional group to the oxide particles of 1000:1 to 10000000:1; and/or the mean diameter of the oxide particles is between 10 and 500nm.
In one possible implementation mode, the binder is 1 to 20 parts by weight; the solvent is 100 parts; 80-99 parts of modified oxide particles.
In one possible implementation, the binder includes one or more of aqueous polyacrylate, urethane acrylate, polyether acrylate, polyvinylidene fluoride, polyurethane, or epoxy; and/or the solvent is water or an organic solvent, and the organic solvent can be one or more of acetone, ethanol, toluene and N-methylpyrrolidone.
In a second aspect, embodiments of the present application provide a method for preparing a separator slurry of the first aspect, which includes the following steps: mixing modified oxide particles with a binder and a solvent, wherein the modified oxide particles are oxide particles with surfaces modified by one or more functional groups of carboxyl, sulfonic acid group, amino and cyclic ether.
In one possible implementation, the modified oxide particles are prepared as follows: mixing an oxidant with the oxide particles to form hydroxyl or carboxyl on the surfaces of the oxide particles, and introducing one or more functional groups of carboxyl, sulfonic acid group, amino and cyclic ether on the surfaces of the oxide particles through grafting reaction by using the hydroxyl or carboxyl to modify the oxide particles, wherein the oxidant comprises one or more of concentrated sulfuric acid, concentrated nitric acid and hydrogen peroxide.
In the technical scheme, strong oxidants such as concentrated sulfuric acid, concentrated nitric acid and hydrogen peroxide are used to enable hydroxyl or carboxyl to be formed on the surface of the oxide particles, and the hydroxyl or carboxyl is easy to react with functional groups such as carboxyl, sulfonic acid group, amino and cyclic ether, so that modifying groups are introduced on the surface of the oxide particles to form modified oxide particles. The method is simple and easy to operate, and only needs to use strong oxidants such as concentrated sulfuric acid, concentrated nitric acid and hydrogen peroxide to form hydroxyl or carboxyl on the surfaces of the oxide particles, then utilizes the characteristic of easy reaction of the hydroxyl or carboxyl, and introduces functional groups with coordination capacity on the surfaces of the oxide particles.
In one possible implementation, the step of mixing the oxidizing agent with the oxide particles is: soaking the oxide particles in oxidant for 5-60 min at 25-45 deg.c.
In the technical scheme, the oxide particles are soaked in the oxidant, so that the reaction rate can be increased, hydroxyl groups can be more easily formed on the surfaces of the oxide particles, and the preparation time can be shortened.
In a third aspect, embodiments of the present application provide a battery separator, which includes a base film and a ceramic layer attached to a surface of the base film, where the ceramic layer is formed by curing the above separator slurry.
In the above-described aspect, the ceramic layer formed by curing the separator slurry contains a group having a coordinating ability, such as a carboxyl group, a sulfonic acid group, an amino group, or a cyclic ether, and can be coordinated well with the transition metal ion eluted from the positive electrode material. Therefore, the ceramic layer in the battery diaphragm can well prevent the transition metal ions in the electrolyte from being transmitted to the negative electrode on the premise of not influencing the transmission of the lithium ions, and the phenomenon of lithium precipitation of the battery negative electrode is greatly relieved. The base film in the battery diaphragm can provide an attachment position for the diaphragm slurry and can play a supporting role.
In one possible implementation manner, the base film is made of one or more of polyethylene, polypropylene and non-woven fabric; and/or, the thickness of the ceramic layer is 0.2-5 μm; and/or the thickness of the base film is 3 to 30 μm.
In the technical scheme, the base film formed by polyethylene, polypropylene, non-woven fabric and the like has high mechanical strength and is not easy to damage; the thicknesses of the base film and the ceramic layer cannot be too thick, otherwise, the transmission distance of lithium ions can be increased, and the loss of the lithium ions in the transmission process is improved; meanwhile, the thickness of the base film cannot be too thin, otherwise, the base film cannot play a sufficient supporting role; the thickness of the ceramic layer should not be too thin or the adsorption capacity to the transition metal is reduced.
In a fourth aspect, embodiments of the present application provide a method for preparing a battery separator of the third aspect, which includes the following steps: the diaphragm slurry is coated on the surface of the base film, and then the diaphragm slurry is cured to form the ceramic layer.
In the technical scheme, the diaphragm slurry can be directly attached to the surface of the base film by using a coating mode, the operation is simple, the method can be well adapted to the existing production process route of the battery diaphragm, and the commercialization is facilitated; and the diaphragm slurry is adhered to the surface of the base film in a coating mode, so that the thickness of the diaphragm slurry can be well controlled.
In one possible implementation, the coating is one of spray coating, spot coating, spin coating, and roll coating.
In a fifth aspect, embodiments of the present application provide a lithium battery, which includes the above battery separator.
In the technical scheme, the lithium battery containing the battery diaphragm can well relieve the phenomenon of lithium precipitation of the negative electrode caused by the dissolution of the transition metal ions of the positive electrode, and the cycle stability and the safety performance of the battery are improved.
Drawings
To more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required to be used in the embodiments of the present application will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and that those skilled in the art can also obtain other related drawings based on the drawings without inventive efforts.
Fig. 1 is a schematic structural diagram of a battery separator provided in an embodiment of the present application;
FIG. 2 is a photograph of a negative electrode of a lithium battery fabricated using the battery separator of example 1;
fig. 3 is a photograph of a negative electrode of a lithium battery when the battery separator of comparative example 1 is used to manufacture the lithium battery.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions of the embodiments of the present application will be clearly and completely described below. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.
The separator slurry, the battery separator and the corresponding preparation method of the embodiments of the present application are specifically described below.
The components of the diaphragm slurry in the embodiment of the application comprise modified oxide particles, a binder and a solvent, wherein the modified oxide particles are oxide particles with coordination capacity and surface modified functional groups, the average particle diameter of the oxide particles is generally between 10 and 500nm, and the species is generally one or more of alumina, silica and zirconia; the functional group having a coordinating ability includes one or more of a carboxyl group, a sulfonic group, an amino group, and a cyclic ether, and in the modified oxide particles, the molar ratio of the functional group to the oxide particles is 1000:1 to 10000000:1. since functional groups such as carboxyl, sulfonic acid, amino, and cyclic ether are easily coordinated to transition metals such as Mn, co, and Ni, and not to main group metals such as Li, the modified oxide particles in the separator slurry can selectively adsorb the transition metals without inhibiting the transport of lithium ions.
The binder has good adhesion performance, so that the modified oxides can be bonded together, and the ceramic layer can be well adhered to the base film (see the following description for details), and the type of the binder generally comprises one or more of polyacrylate, polyurethane acrylate, polyether acrylate, polyurethane or epoxy resin.
The solvent can play a role in dispersing the binder and the modified oxide particles, so that the components of the diaphragm slurry are relatively uniform; since the binder is generally an organic substance and organic groups are also attached to the surfaces of the modified oxide particles, the components of the separator slurry can be more easily kept uniform by using an organic solvent, and the type of the organic solvent is generally one or more of acetone, ethanol, toluene, and N-methylpyrrolidone.
The adhesive is 1 to 20 parts by weight; the solvent is 100 parts; 80-99 parts of modified oxide particles.
The above separator slurry is generally prepared in the following manner:
s100, preparing modified oxide particles.
In the step, hydroxyl or carboxyl is formed on the surface of oxide particles by using a strong oxidant, and then functional groups which are easy to coordinate, such as carboxyl, sulfonic acid group, amino, cyclic ether and the like, are introduced on the surface of the oxide particles by utilizing the activity of the hydroxyl or carboxyl which is easy to generate chemical reaction, so that modified oxide particles can be formed. Wherein the strong oxidant is one or more of concentrated sulfuric acid (sulfuric acid aqueous solution with mass fraction of more than or equal to 70%) and concentrated nitric acid (nitric acid solution with mass fraction of more than 8 mol/L).
Specifically, the method comprises the step of soaking oxide particles in an oxidant for 5-60 min at 25-45 ℃. Through the soaking mode, hydroxyl or carboxyl can be formed on the surface of the oxide particles more quickly, the preparation time is reduced, and the preparation efficiency is improved.
And S200, forming diaphragm slurry. Specifically, the present step is generally to wash the modified oxide particles with water to remove the surface oxidizing agent, and then mix the particles with a binder and a solvent to prepare a separator slurry.
As shown in fig. 1, the battery separator in the present embodiment includes a base film and a ceramic layer attached to a surface of the base film, and the ceramic layer is formed by curing the above-described separator slurry. The base film can be used for preparing a ceramic layer, and the ceramic layer can selectively adsorb transition metals such as Mn, co and Ni due to the fact that the ceramic layer contains groups with coordination capacity such as carboxyl, sulfonic acid groups, amino groups and cyclic ether. When the battery diaphragm in the embodiment of the application is used for a lithium battery, the transmission of transition metal ions in electrolyte to a negative electrode can be well prevented, and the phenomenon that lithium is separated from the negative electrode of the battery is greatly relieved.
In order to ensure that the battery diaphragm has good selective adsorption capacity and good mechanical strength without influencing the transmission efficiency of the lithium battery, the thickness of the base film is usually 3-30 μm, and the material is usually one or more of polyethylene, polypropylene and non-woven fabrics; the thickness of the ceramic layer is generally 0.2 to 5 μm.
The preparation method of the battery diaphragm comprises the following steps: the diaphragm slurry is attached to the surface of the base film in a coating mode, and then the diaphragm slurry is solidified to form the ceramic layer. The coating mode can be selected from one of spray coating, spot coating, spin coating and roll coating, and the diaphragm slurry can be coated on any one surface or two surfaces of the base film. The method is simple to operate, can be well adapted to the existing production process route of the battery diaphragm, and is beneficial to commercialization.
The features and properties of the present application are described in further detail below with reference to examples.
Example 1
The embodiment provides a battery separator, and the preparation method comprises the following steps:
soaking 80 parts by weight of alumina particles with the average particle size of 200nm in 98% concentrated sulfuric acid by mass percent for 10min at the soaking temperature of 25 ℃ to form hydroxyl groups on the surfaces of the alumina particles; and then, reacting malonic acid with hydroxyl to introduce carboxyl on the surface of the alumina particles to form modified alumina particles, wherein the molar ratio of the functional group to the alumina in the modified alumina particles is 10000:1; subsequently, 20 parts of urethane acrylate and 100 parts of ethanol were mixed with the modified alumina particles after water washing to form a separator slurry. And then coating diaphragm slurry on one surface of the base film made of polyethylene in a roller coating mode, and curing the diaphragm slurry to form the ceramic layer. Wherein the thickness of the base film is 15 μm and the thickness of the ceramic layer is 3 μm.
Example 2
The present embodiment provides a battery separator, and the preparation method thereof is mainly different from that of embodiment 1 in that:
85 parts of silica particles having an average particle diameter of 400nm were used in place of the alumina particles; the sulfonic acid group was introduced using propanedisulfonic acid instead of malonic acid.
Example 3
This example provides a battery separator, the preparation method of which compared to example 1 differs mainly as follows:
88 parts of zirconia particles having an average particle diameter of 500nm were used in place of the alumina particles; the amino group is introduced using propylenediamine instead of malonic acid.
Example 4
This example provides a battery separator whose preparation method has the following main differences compared to example 1:
9mol/L concentrated nitric acid is used instead of 98% concentrated sulfuric acid.
Comparative example 1
The comparative example provides a battery separator, the preparation method of which is as follows:
80 parts by weight of alumina particles with the average particle size of 200nm, 20 parts by weight of urethane acrylate and 100 parts by weight of ethanol are mixed to form the diaphragm slurry. And then coating diaphragm slurry on one surface of the base film made of polyethylene in a roller coating mode, and curing the diaphragm slurry to form the ceramic layer. Wherein the thickness of the base film is 15 μm and the thickness of the ceramic layer is 3 μm.
Comparative example 2
The comparative example provides a battery separator, and the preparation method thereof is mainly distinguished from comparative example 1 as follows:
500nm silica particles were used instead of 200nm alumina particles.
Comparative example 3
The comparative example provides a battery separator, and compared with comparative example 1, the preparation method thereof mainly differs in that:
300nm zirconia particles were used instead of 200nm alumina particles.
Comparative example 4
The comparative example provides a battery separator, and compared with comparative example 1, the preparation method thereof mainly differs in that:
a10 μm base film was used instead of the 15 μm base film.
Application example
The battery separators of examples 1 to 4 and comparative examples 1 to 4 were used to prepare lithium batteries, respectively, and all the lithium batteries were classified into parallel groups a and parallel groups B, ensuring that each group contained lithium batteries prepared using the battery separators of examples 1 to 4 and comparative examples 1 to 4, and then the performance of the lithium batteries in the parallel groups a and B were tested, respectively.
Cycle performance test
The cycle performance of the battery was determined by calculating the capacity retention rate using a constant current constant voltage charge-constant current discharge cycle of 500 times, and the test results are shown in the following table:
TABLE 1 lithium cell cycling performance
| Group of | Capacity retention of parallel group A | Capacity retention of parallel group B |
| Example 1 | 98％ | 97％ |
| Example 2 | 90％ | 90％ |
| Example 3 | 93％ | 93％ |
| Example 4 | 85％ | 85％ |
| Comparative example 1 | 80％ | 79％ |
| Comparative example 2 | 60％ | 61％ |
| Comparative example 3 | 76％ | 75％ |
| Comparative example 4 | 78％ | 79％ |
As can be seen from table 1, the lithium batteries using the battery separators provided in examples 1 to 4 have better cycle stability and higher capacity retention rate.
Negative electrode lithium extraction assay
The degree of lithium precipitation of the negative electrode of the battery after the battery is disassembled is observed, and the test results are shown in the following table:
TABLE 2 extent of lithium evolution from the negative electrode of lithium batteries
As is clear from table 2, the lithium batteries using the battery separators provided in examples 1 to 4 were less likely to cause a phenomenon of lithium deposition in the negative electrode.
A photograph of a negative electrode of a lithium battery when the battery separator of example 1 was used to fabricate a lithium battery is shown in fig. 2. The negative electrode in fig. 2 is golden yellow, which is a normal color after lithium intercalation in the negative electrode, and indicates that no lithium deposition occurs, which indicates that when a coordinating group such as a carboxyl group exists on the surface of the battery separator in example 1, the lithium deposition in the negative electrode of the lithium battery can be well alleviated.
A photograph of a negative electrode of a lithium battery when the battery separator of comparative example 1 was used to manufacture the lithium battery is shown in fig. 3. The negative electrode surface in fig. 3 is gray and is a typical feature of lithium dendrites, indicating that a severe lithium precipitation phenomenon occurs, which indicates that the lithium precipitation phenomenon of the negative electrode of the lithium battery cannot be alleviated when the surface of the battery separator in comparative example 1 has no coordinating group.
The above description is only an example of the present application and is not intended to limit the scope of the present application, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.
Claims (12)
1. The diaphragm slurry is characterized by comprising the components of a solvent, a binder and modified oxide particles;
the modified oxide particles are oxide particles with the surface modified by functional groups, and the functional groups comprise one or more of carboxyl, sulfonic acid groups, amino and cyclic ether.
2. The separator slurry according to claim 1, wherein the oxide particles comprise one or more of alumina, silica, and zirconia, and the modified oxide particles have a molar ratio of the functional group to the oxide particles of 1000:1 to 10000000:1;
and/or the oxide particles have an average diameter of 10 to 500nm.
3. The separator slurry according to claim 1, wherein the binder is 1 to 20 parts by weight; the solvent is 100 parts; 80-99 parts of modified oxide particles.
4. The separator paste of claim 1, wherein the binder comprises one or more of aqueous polyacrylate, urethane acrylate, polyether acrylate, polyvinylidene fluoride, polyurethane, or epoxy;
and/or the solvent is water or an organic solvent, and the organic solvent can be one or more of acetone, ethanol, toluene and N-methylpyrrolidone.
5. A method of preparing the separator slurry of claim 1, comprising the steps of: mixing modified oxide particles with a binder and a solvent, wherein the modified oxide particles are oxide particles with surfaces modified by one or more functional groups of carboxyl, sulfonic acid groups, amino and cyclic ether.
6. The method for producing a separator slurry according to claim 5, wherein the modified oxide particles are produced by the steps of:
mixing an oxidant with the oxide particles to form hydroxyl or carboxyl on the surfaces of the oxide particles, and then further introducing one or more functional groups of carboxyl, sulfonic acid, amino and cyclic ether on the surfaces of the oxide particles through a grafting reaction to modify the oxide particles, wherein the oxidant comprises one or more of concentrated sulfuric acid, concentrated nitric acid and hydrogen peroxide.
7. The method for preparing a separator slurry according to claim 6, wherein the step of mixing an oxidizing agent with the oxide particles is: and soaking the oxide particles in the oxidant for 5-60 min at 25-45 ℃.
8. A battery separator comprising a base film and a ceramic layer attached to a surface of the base film, the ceramic layer being formed by curing the separator slurry according to any one of claims 1 to 4.
9. The battery separator according to claim 8, wherein the base film is made of one or more of polyethylene, polypropylene and non-woven fabric; and/or the thickness of the ceramic layer is 0.2-5 mu m; and/or the thickness of the base film is 3-30 μm.
10. A method of making a battery separator as in claim 8, comprising the steps of:
the method includes coating a separator slurry on a surface of a base film, and then curing the separator slurry to form a ceramic layer.
11. The method for preparing a battery separator according to claim 10, wherein the coating is performed by one of spray coating, spot coating, spin coating, and roll coating.
12. A lithium battery comprising a battery separator as claimed in any one of claims 8 to 9.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116315463A (en) * | 2023-05-11 | 2023-06-23 | 中创新航科技集团股份有限公司 | Lithium battery |
| CN116826308A (en) * | 2023-08-31 | 2023-09-29 | 天津市捷威动力工业有限公司 | Composite diaphragm, preparation method thereof and secondary battery |
| CN116845483A (en) * | 2023-08-31 | 2023-10-03 | 天津市捷威动力工业有限公司 | Composite diaphragm, preparation method thereof and secondary battery |
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2022
- 2022-09-09 CN CN202211103638.9A patent/CN115579583A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116315463A (en) * | 2023-05-11 | 2023-06-23 | 中创新航科技集团股份有限公司 | Lithium battery |
| CN116315463B (en) * | 2023-05-11 | 2023-08-18 | 中创新航科技集团股份有限公司 | Lithium battery |
| CN116826308A (en) * | 2023-08-31 | 2023-09-29 | 天津市捷威动力工业有限公司 | Composite diaphragm, preparation method thereof and secondary battery |
| CN116845483A (en) * | 2023-08-31 | 2023-10-03 | 天津市捷威动力工业有限公司 | Composite diaphragm, preparation method thereof and secondary battery |
| CN116826308B (en) * | 2023-08-31 | 2023-11-28 | 天津市捷威动力工业有限公司 | Composite diaphragm, preparation method thereof and secondary battery |
| CN116845483B (en) * | 2023-08-31 | 2023-11-28 | 天津市捷威动力工业有限公司 | Composite diaphragm, preparation method thereof and secondary battery |
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