CN106887556B - Organic-inorganic composite modified diaphragm and preparation method and application thereof - Google Patents
Organic-inorganic composite modified diaphragm and preparation method and application thereof Download PDFInfo
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- CN106887556B CN106887556B CN201710142786.4A CN201710142786A CN106887556B CN 106887556 B CN106887556 B CN 106887556B CN 201710142786 A CN201710142786 A CN 201710142786A CN 106887556 B CN106887556 B CN 106887556B
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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
- H01M50/403—Manufacturing processes of separators, membranes or diaphragms
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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
- H01M50/446—Composite material consisting of a mixture of organic and inorganic materials
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Abstract
The invention relates to a ceramic diaphragm for in-situ generation of a composite binder, which comprises an organic diaphragm substrate, wherein the surface of the organic diaphragm substrate is coated with the composite binder on one side or two sides to form a ceramic protective layer; the composite binder is a composite monomer copolymer generated by adding a composite monomer into the ceramic slurry and carrying out in-situ polymerization; the composite monomer is a monomer A containing a polyphenol functional group and a monomer B containing an amino functional group. The invention also relates to a method for preparing the ceramic diaphragm of the in-situ generated composite binder and application of the ceramic diaphragm of the in-situ generated composite binder in a secondary battery, wherein the secondary battery comprises a lithium ion battery; the secondary battery comprises a positive electrode and a negative electrode, wherein a ceramic diaphragm for generating the composite binder in situ is arranged between the positive electrode and the negative electrode. The ceramic diaphragm prepared by the in-situ generated composite binder has excellent comprehensive performance, good innovativeness and practicability and good industrial application prospect.
Description
Technical Field
The invention belongs to the technical field of new energy, is applied to batteries, capacitors and the like, and particularly relates to an organic-inorganic composite modified diaphragm. More particularly, the present invention relates to an organic-inorganic composite modified separator comprising a composite monomer co-polymer having a ceramic coating layer and formed in situ on the surface and inside of a separator substrate and an inorganic ceramic layer. The invention also relates to the application of the organic-inorganic composite modified diaphragm in chemical power systems such as lithium ion batteries and the like, and a battery containing the organic-inorganic composite modified diaphragm.
Background
The lithium ion battery is a secondary battery, which consists of a positive electrode, a negative electrode, a diaphragm and electrolyte, wherein the positive electrode and the negative electrode are soaked in the electrolyte, and lithium ions move between the positive electrode and the negative electrode by taking the electrolyte as a medium, so that the charging and discharging of the battery are realized. During charging and discharging, Li+Intercalation and deintercalation to and from two electrodes: upon charging, Li+The lithium ion battery is extracted from the positive electrode and is inserted into the negative electrode through the electrolyte, and the negative electrode is in a lithium-rich state; the opposite is true during discharge. As a representative of modern high-performance batteries, lithium ion batteries have been widely used in portable devices due to their advantages such as high energy density and good cycle performance.
However, its application in larger-scale application fields, especially in the fields of grid energy storage and power batteries, places higher demands on the energy density and power density, as well as the safety performance of lithium ion batteries.
The safety of lithium ion batteries depends mainly on the nature of the electrolyte material and the electrode material used, while for current lithium ion batteries the separator in the battery plays to some extent the most critical role. The diaphragm is a microporous film arranged between the anode and the cathode of the battery, ions in the electrolyte can freely pass through the diaphragm, and electrons in the battery cannot freely pass through the diaphragm, so that the aim of isolating the direct contact of the anode and the cathode is fulfilled. In lithium ion batteries, the separator plays an important role in both the safety performance and the electrochemical performance of the battery.
At present, diaphragm materials used by various large battery manufacturers are mainly polyolefin porous polymer films, and large lithium ion batteries using the diaphragm materials are easy to induce high internal temperature of the batteries in an abusive state (internal local short circuit, external short circuit, overcharge and the like). Because the melting temperature of polyolefin is low (about 130 ℃ for polyethylene and 160 ℃ for polypropylene), thermal shrinkage is easy to occur at high temperature, large-area short circuit in the battery is further caused, heat accumulation is intensified, the internal air pressure of the battery is increased, and the battery is burnt or exploded. Therefore, in order to meet the development requirement of high-capacity lithium ion batteries, the development of high-safety separators is urgent. The ceramic coating modified diaphragm can fully pull open the temperature difference between the diaphragm closed pore temperature (Shutdown) and the melting temperature, and the excellent temperature resistance and high safety make the diaphragm become one of the main choices for replacing the traditional polyolefin diaphragm.
The ceramic-coated membrane (or ceramic membrane) is prepared by coating polyolefin membrane with oxide such as Al on one or both surfaces2O3、SiO2And the like are typical inorganic ceramic materials. The use of the ceramic coating diaphragm can effectively prevent the thermal shrinkage of the diaphragm and improve the safety performance of the lithium ion battery.
At present, the ceramic diaphragm is mainly prepared by ceramic powder (mainly nano or submicron oxide powder, such as Al)2O3、SiO2、TiO2Etc.), a binder, etc. are dispersed in a solvent to form a slurry, and then a ceramic coating is formed on the surface of the polyolefin membrane substrate by a casting method or a dipping method (see Journal of Power Sources 195(2010) 6192-6196, CN 200580036709.6)Cn200780035135.x, etc.). However, since the specific surface energy of the ceramic powder is large and easy to agglomerate, the surface of the ceramic powder is generally hydrophilic, and the polyolefin film is a hydrophobic material, most of research reports show that the uniformity of the ceramic powder coating is poor, and an obvious powder falling phenomenon exists, which can greatly affect the service performance of the ceramic diaphragm in the lithium ion battery. In addition, although the coating of the ceramic diaphragm can improve the affinity with the electrolyte, the existing ceramic diaphragm still has a certain risk of liquid leakage because the wetting capacity of the diaphragm base material and the electrolyte is poor.
Also, the improvement of the heat shrinkage performance of the separator by the ceramic coating is relatively limited due to the binder component in the inorganic ceramic layer and the relatively poor film forming property of the inorganic ceramic layer. For example, it has been shown from previous research results that the separator undergoes significant thermal shrinkage when the temperature is higher than 140 ℃ when polyethylene is used as a base film. And with the rise of temperature, after the polyolefin base film melts, the mechanical property of the diaphragm is greatly reduced, and the diaphragm is broken or even can not be supported to form a film. Obviously, this does not meet the requirements of applications requiring high security.
In order to meet the development requirement of high-capacity lithium ion batteries, the development of high-safety diaphragms is urgent.
In addition, the chinese patent application CN 103545474a discloses a polydopamine modified lithium ion battery separator and a preparation method thereof, wherein a film is formed on the surface and inside of a polymer matrix through self-polymerization of dopamine monomers, the modified separator obtained by the method has the advantages of stronger liquid absorption/retention capability, outstanding rate capability and the like, and a lithium ion battery using the modified separator as a separator has the advantages of high electrolyte ionic conductivity, excellent battery cycle performance and the like, and is particularly suitable for the field of power lithium ion batteries. Chinese patent application CN 105070868A discloses a dopamine modified ceramic composite diaphragm and application thereof, wherein the dopamine is adopted to carry out in-situ modification on the ceramic diaphragm, so that the powder falling phenomenon of ceramic powder can be improved, and excellent thermal stability is obtained.
However, it should be appreciated that dopamine is expensive in the market and the cost of the separator is greatly increased, which is very disadvantageous for the industrial application of the separator.
Disclosure of Invention
In order to solve the technical problems, the invention provides an organic-inorganic composite modified diaphragm, which comprises an organic diaphragm substrate, an inorganic ceramic layer coated on one side or two sides, and a composite monomer copolymer generated in situ on the surfaces and the inside of the diaphragm substrate and the inorganic ceramic layer at the same time. According to the invention, the organic diaphragm substrate and the inorganic ceramic layer are connected into a whole through the high-temperature-resistant composite monomer copolymer, and a high-temperature-resistant framework is provided, so that the organic-inorganic composite modified diaphragm obtained by the invention has extremely excellent thermal stability and mechanical property, and simultaneously has good affinity to electrolyte.
The invention also aims to provide a preparation method of the organic-inorganic composite modified diaphragm.
It is another object of the present invention to provide a battery comprising such an organic-inorganic composite modified separator.
The invention also aims to provide application of the organic-inorganic composite modified diaphragm in a battery.
In order to achieve the purpose, the invention adopts the following specific scheme:
an organic-inorganic composite modified diaphragm comprises an organic diaphragm substrate, wherein an inorganic ceramic layer is coated on one side or two sides of the surface of the organic diaphragm substrate, and composite monomer copolymer polymers generated in situ are arranged on the surface and the inner part of the organic diaphragm substrate and the surface and the inner part of the inorganic ceramic layer, wherein the composite monomer copolymer polymers are formed by dissolving a monomer A containing a polyphenol functional group and a monomer B containing an amino functional group in a solvent.
Further, the inorganic ceramic layer is an inorganic ceramic layer containing a binder and inorganic powder, and the thickness of the inorganic ceramic layer is 0.1-50 μm;
optionally, the material of the organic diaphragm substrate is at least one of polyolefin porous polymer, polytetrafluoroethylene, polyvinylidene fluoride-hexafluoropropylene copolymer, polyvinyl chloride, polyethylene terephthalate, polybutylene terephthalate, polymethyl methacrylate, polyacrylonitrile, polyimide, polyvinylpyrrolidone, polyethylene oxide, polyvinyl alcohol, or a blending and copolymerization system derived from the above polymers.
Preferably, the binder is an aqueous binder or an organic binder;
the water-based binder is one of a sodium methyl cellulose, styrene butadiene rubber, gelatin, polyvinyl alcohol and polyacrylate terpolymer latex system;
the organic binder is one of polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene and polymethyl methacrylate.
Optionally, the inorganic powder is at least one of aluminum oxide, titanium dioxide, silicon dioxide, zirconium dioxide, tin dioxide, magnesium oxide, zinc oxide, barium sulfate, boron nitride, aluminum nitride and magnesium nitride, and the particle size of the inorganic powder is 5nm-50 μm.
Further, the monomer A containing the polyphenol functional group is at least one of catechol, pyrogallol, p-methyl catechol, catechol violet, 3-fluoro catechol, 3-methyl catechol, p-tert-butyl catechol, caffeic acid, bromocatechol red and tannic acid;
optionally, the monomer B containing amino functional groups is at least one of diethylenetriamine, triethylene tetramine, tetraethylenepentamine, pentaethylenehexamine, polyethyleneimine with the molecular weight of 300-100000, phenethylamine, tyramine, p-bromophenethylamine, p-methylphenethylamine and 3-methoxyphenethylamine;
optionally, the solvent is an aqueous solution of at least one organic solvent selected from methanol, ethanol, isopropanol, acetone, dimethylformamide, dimethyl sulfoxide, dimethylacetamide and N-methylpyrrolidone, and the volume fraction of the organic solvent is 20-80%.
The invention also provides a preparation method of the organic-inorganic composite modified diaphragm, which comprises the following steps:
a) coating an inorganic ceramic layer containing a binder and inorganic powder on one side or two sides of the surface of the organic diaphragm substrate to prepare a ceramic diaphragm;
b) dissolving a monomer A containing a polyphenol functional group and a monomer B containing an amino functional group in a solvent to prepare a mixed monomer polymerization precursor solution with the monomer content of 0.01-1000mmol/L and the pH value of 7-12, wherein the molar ratio of the monomer A to the monomer B is 1:0.001-1: 1000;
c) coating the ceramic diaphragm prepared in the step a) with the mixed monomer polymerization precursor solution prepared in the step b), and reacting for 1-48h at room temperature under the condition of introducing oxygen;
d) cleaning the diaphragm treated in the step c), and drying at 60-120 ℃ for 1-24h to obtain the organic-inorganic composite modified diaphragm.
Further, the step of coating the ceramic diaphragm prepared in the step a) with the mixed monomer polymerization precursor liquid prepared in the step b) is to immerse the ceramic diaphragm prepared in the step a) into the mixed monomer polymerization precursor liquid prepared in the step b);
optionally, the step of coating the ceramic diaphragm prepared in the step a) with the mixed monomer polymerization precursor liquid prepared in the step b) is to coat or spray the mixed monomer polymerization precursor liquid prepared in the step b) on the ceramic diaphragm prepared in the step a);
optionally, the material of the organic diaphragm substrate is at least one of polyolefin porous polymer, polytetrafluoroethylene, polyvinylidene fluoride-hexafluoropropylene copolymer, polyvinyl chloride, polyethylene terephthalate, polybutylene terephthalate, polymethyl methacrylate, polyacrylonitrile, polyimide, polyvinylpyrrolidone, polyethylene oxide, polyvinyl alcohol, or a blending and copolymerization system derived from the above polymers.
Further, the binder is an aqueous binder or an organic binder;
the water-based binder is one of a sodium methyl cellulose, styrene butadiene rubber, gelatin, polyvinyl alcohol and polyacrylate terpolymer latex system;
the organic binder is one of polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene and polymethyl methacrylate;
optionally, the inorganic powder is at least one of aluminum oxide, titanium dioxide, silicon dioxide, zirconium dioxide, tin dioxide, magnesium oxide, zinc oxide, barium sulfate, boron nitride, aluminum nitride and magnesium nitride, and the particle size of the inorganic powder is 5nm-50 μm.
Further, the monomer A containing the polyphenol functional group is at least one of catechol, pyrogallol, p-methyl catechol, catechol violet, 3-fluoro catechol, 3-methyl catechol, p-tert-butyl catechol, caffeic acid, bromocatechol red and tannic acid;
optionally, the monomer B containing amino functional groups is at least one of diethylenetriamine, triethylene tetramine, tetraethylenepentamine, pentaethylenehexamine, polyethyleneimine with the molecular weight of 300-100000, phenethylamine, tyramine, p-bromophenethylamine, p-methylphenethylamine and 3-methoxyphenethylamine;
optionally, the solvent is an aqueous solution of at least one organic solvent selected from methanol, ethanol, isopropanol, acetone, dimethylformamide, dimethyl sulfoxide, dimethylacetamide and N-methylpyrrolidone, and the volume fraction of the organic solvent is 20-80%.
The invention also provides a lithium ion battery which comprises a positive electrode material, a negative electrode material and a non-aqueous electrolyte, wherein the organic-inorganic composite modified diaphragm is arranged between the positive electrode material and the negative electrode material.
The invention also provides an application of the organic-inorganic composite modified diaphragm in a secondary battery, wherein the secondary battery comprises a lithium ion battery.
The nonaqueous electrolyte secondary battery provided by the present invention is not particularly limited as long as it has the organic-inorganic composite modified separator, and various configurations used in conventionally known nonaqueous electrolyte secondary batteries can be employed.
The positive electrode in the battery of the invention can be prepared by the following method: for example, a positive electrode active material is appropriately added with a conductive auxiliary agent or a binder such as polyvinylidene fluoride, and then a positive electrode mixture-containing composition (paste, slurry, or the like) in which the conductive auxiliary agent or the binder is dissolved and dispersed in a solvent such as N-methylpyrrolidone (NMP) is applied to one surface or both surfaces of a current collector such as an aluminum foil, and the solvent is removed to form a strip-shaped molded body (positive electrode mixture layer). However, the method for manufacturing the positive electrode in the battery of the present invention is not limited to the above-described exemplary method.
The positive electrode active material in the battery of the present invention is a compound capable of absorbing and releasing lithium (Li), and includes a positive electrode material commonly used for lithium ion batteries, and specifically, lithium cobaltate (LiCoO) can be used2) A transition metal oxide LiMO having a layered structure as represented2(M ═ Co, Ni, Mn, etc.), and LiMO in the above-mentioned material2A lithium-containing metal composite oxide in which a part of Co, Mn, and Ni of (M ═ Co, Ni, Mn, and the like) is substituted with another element such as Al, Ti, Zr, Mg, and W.
Preferably, the transition metal oxide having a layered structure includes LiCoO2、LiNiO2、LixNi1/ 3Mn1/3Co1/30Z、LiNixMnyCoz02(in each of the above chemical formulae, O<x<1，O<y<1，O<z<1，0.95<x+y+z<1.1)。
Preferably, the lithium-containing metal composite oxide is lithium manganate (LiMn)2O4) A lithium metal composite oxide LiM having a spinel structure as a representative2O4(M ═ Mn, Co, V, Ni, etc.), and examples thereof include Li, which is commonly usedyMn204(0.98<y<1.1). Or a lithium-containing composite oxide in which a part of the Mn is substituted with at least one element selected from the group consisting of Ge, Zr, Mg, Ni, Al and Co, for example, LiCoMn04、LiNi0.5Mn1.504And the like. Or with lithium iron phosphate (LiFePO)4) A lithium metal composite oxide LiMPO having an olivine structure as a representative4(M ═ Fe, Mn, Co, Ni, etc.), and examples thereof include LiFePO4、LiMnPO4、LiFexMnyPO4(in each of the above chemical formulae, O<x<1，O<y<1，0.95<x+y<1.05). Or a lithium-containing composite oxide in which a part of the metal is substituted with at least one element selected from the group consisting of Ge, Zr, Mg, Ni, Al and Co, such as Li4/3Ti5/304Lithium titanium composite oxides, metal oxides such as manganese dioxide, vanadium pentoxide, and chromium oxide, and metal sulfides such as titanium disulfide and molybdenum disulfide.
In the positive electrode active material, one kind of the lithium metal composite oxide may be used alone, or two or more kinds may be used in combination. Here, as the composition in the positive electrode mixture layer of the positive electrode, specifically, the following may be preferable: the content of the positive electrode active material is 90-98 mass%, the content of the conductive auxiliary agent is 1-5 mass%, and the content of the binder is 1-5 mass%.
The organic solvent in the aqueous electrolyte in the nonaqueous electrolyte secondary battery of the present invention is preferably an organic solvent having a high dielectric constant, for example, ethers, esters, etc., and it is particularly preferable to use an ester containing a dielectric constant of not less than 30. Examples of such esters having a high dielectric constant include sulfuric acid ester solvents such as Ethylene Carbonate (EC), Propylene Carbonate (PC), butylene carbonate, γ -butyrolactone, and ethylene glycol sulfite. Among them, cyclic lactones are preferable, and cyclic carbonates such as ethylene carbonate are particularly preferable. In addition to the above solvents, chain carbonates such as dimethyl carbonate (DMC), diethyl carbonate (DEC) and Ethyl Methyl Carbonate (EMC), chain alkyl esters such as methyl propionate, chain phosphoric triesters such as trimethyl phosphate, and nitrile solvents such as 3-methoxypropionitrile can be used.
As the electrolyte salt used in the nonaqueous electrolytic solution of the present invention, a lithium perchlorate salt containing lithium, an organoboron lithium salt, a lithium salt of a fluorine-containing compound typified by a trifluoromethanesulfonic acid lithium salt, an imide lithium salt, and the like are preferably used. Specific examples of these electrolyte salts include LiCl04、LiPF6、LiBF4、LiAsF6、LiSbF6、LiCF3S03.LiC4F9S03、LiCF3C02、Li2C2F4(S03)2、LiN(CF3S02)2、LiC(CF3S02)3、LiCnF2n+IS03(n≥2)、LiN(Rf30S02)2(Rf represents a fluoroalkyl group), and the like. These electrolyte salts may be used alone, or two or more of them may be used in combination. Among them, LiPF is particularly preferable from the viewpoint of satisfactory charge/discharge characteristics of the battery6And LiBF4。
The concentration of the electrolyte salt in the nonaqueous electrolytic solution of the present invention is not particularly limited, and among them, a preferable concentration range is 0.5 to 1.7mol/L, and a particularly preferable concentration range is 0.8 to 1.2 mol/L.
The nonaqueous electrolytic solution in the battery of the present invention may contain materials such as additives for improving the battery performance, and is not particularly limited. For example, by adding at least one additive selected from the group consisting of sulfonic anhydride, sulfonic acid ester derivative, cyclic sulfate derivative and cyclic sulfonate derivative having a specific structure to the nonaqueous electrolytic solution, the reaction with the nonaqueous electrolytic solution solvent on the surface of the positive electrode can be suppressed, and elution of Mn from the positive electrode active material and deposition of the Mn on the surface of the negative electrode can be greatly suppressed. For example, Vinylene Carbonate (VC) and its derivatives can be added to the nonaqueous electrolyte solution to effectively suppress the reduction and decomposition of the nonaqueous electrolyte solution solvent at the negative electrode. Thus, a nonaqueous electrolyte secondary battery having excellent performance such as charge-discharge cycle characteristics can be obtained.
The negative electrode in the nonaqueous electrolyte secondary battery of the present invention is also not particularly limited, and a negative electrode used in a conventionally known nonaqueous electrolyte secondary battery can be used. For example, the obtained negative electrode can be prepared using the following method: if necessary, a conductive aid, a binder such as polyvinylidene fluoride or styrene butadiene rubber, or the like is added to the negative electrode active material, and then the mixture is dissolved and dispersed in a solvent such as water to form a negative electrode mixture-containing composition (paste, slurry, or the like), and the composition is applied to one or both surfaces of a current collector such as a copper foil, and the solvent is removed to form a tape-shaped molded body (negative electrode mixture layer). However, the method for producing the negative electrode of the present invention is not limited to the above-described exemplary method.
The negative electrode active material of the present invention is a material capable of absorbing and releasing lithium, and examples thereof include carbon materials such as graphite, pyrolytic carbon, coke, glassy carbon, a fired product of an organic polymer compound, mesocarbon microbeads, carbon fibers, and activated carbon, metals such as Si, Sn, and Ge, which are capable of forming an alloy with an element, and alloys containing the element.
In the negative electrode active material, the surface interval d of the (carbon 002) surface is preferable002Graphite of 0.340nm or less, a metal composed of an element capable of forming an alloy with lithium or an alloy containing the element, and d is particularly preferred002Graphite with the particle size less than or equal to 0.337 nm. This is because the use of such an active material enables further increase in the capacity of the battery. Invention d002The lower limit of (B) is not particularly limited, but is preferably 0.335 nm. For d002In the case of graphite having a crystal structure of 0.340nm or less, the crystallite size in the C-axis direction in the crystal structure is preferably at least 3nm in Lc, more preferably at least 8nm in Lc, and particularly preferably at least 25nm in Lc. This is because lithium can be absorbed and released more easily with such Lc. The upper limit of Lc in the present invention is not particularly limited, and preferably 200 nm. Further, the average particle diameter of the graphite is preferably in the range of 3 to 15 μm, more preferably 5 to 13 μm. Preferably, the purity of the graphite is not less than 99.9%. This is because graphite having such a particle diameter and purity does not hinder the characteristics of the battery, and is low in cost and easily available. Wherein d of the above-mentioned graphite of the present invention002And Lc is a value measured according to X-ray diffractometry.
The invention particularly uses d in the negative active materialOO2In the case of highly crystalline graphite such as graphite of 0.340nm or less, the nonaqueous electrolyte solvent is easily reduced and decomposed on the surface of the negative electrode as described above, but by adding vinylene carbonate or its derivative to the nonaqueous electrolyte solution in such a content as described above, the reduction and decomposition of the organic solvent concerned can be suppressed, and a nonaqueous electrolyte secondary battery excellent in overall battery characteristics can be produced.
As the composition in the negative electrode mixture layer of the negative electrode, specifically, the following may be preferable: for example, when a negative electrode active material requiring the use of a binder is used, the content of the negative electrode active material is 90 to 98 mass% and the content of the binder is 1 to 5 mass%. When the conductive aid is used, the content of the conductive aid in the negative electrode mixture layer is preferably 1 to 5% by mass.
The nonaqueous electrolyte secondary battery of the present invention is susceptible to the problem of gas generated during initial charge, and this problem can be solved by sealing the battery after the gas generated during initial charge is discharged to the outside of the battery system.
The charging may be performed in a state where the nonaqueous electrolytic solution is injected into the battery case from the injection port and the injection port is opened. Thereby, the generated gas can be discharged outside the battery case while charging. In this case, it is preferable to perform the charging in a dry chamber having a dew point of-30 ℃ or lower in order to prevent external moisture from entering the battery case through the liquid inlet during the charging. The above charging may be performed in a state where the nonaqueous electrolytic solution is poured into the battery case from the pouring port and the pouring port is temporarily sealed, and after the charging is completed, the pouring port is once opened to discharge the gas from the battery case, and the pouring port is completely sealed to seal the battery case. In this case, it is also preferred to carry out the reaction in a drying chamber having a dew point of-30 ℃.
In addition, the method of discharging gas from the battery case of the present invention is not particularly limited, and the gas may be naturally discharged according to the pressure difference between the inside and the outside of the battery case, or may be discharged in vacuum by changing the outside of the battery case to a low pressure lower than the atmospheric pressure. The nonaqueous electrolytic solution of the battery of the present invention is prepared by dissolving an electrolyte salt in an organic solvent as an electrolytic solution solvent.
The invention has the beneficial effects that:
1. the composite monomer copolymer is simultaneously generated in situ in the pores of the organic diaphragm substrate and the inorganic ceramic layer, so that the organic diaphragm substrate and the inorganic ceramic layer are connected into a whole by the composite monomer copolymer, and a high-temperature-resistant framework is provided. The invention combines the advantages of the heat-resistant composite monomer copolymer and the inorganic ceramic layer, the obtained organic-inorganic composite modified diaphragm has extremely excellent thermal stability and mechanical property, simultaneously has good affinity to electrolyte, can improve the powder falling phenomenon of the inorganic ceramic layer, and is very suitable for application scenes needing high safety characteristic.
2. The invention uses the cheap composite monomer to replace the expensive dopamine, has good economy and is very suitable for large-scale industrial production.
3. The substances used in the production process are all green and environment-friendly, and the preparation process has little environmental pollution and good industrial application prospect.
The organic-inorganic composite modified separator and the nonaqueous electrolyte secondary battery using the same according to the present invention have excellent physical and chemical properties. Therefore, the nonaqueous electrolyte secondary battery of the present invention can be widely applied not only to secondary batteries for driving power sources of mobile information devices such as mobile phones and notebook personal computers, but also to power sources of various devices such as electric vehicles, by utilizing such characteristics.
Drawings
FIG. 1a is a photograph of an unmodified alumina ceramic separator obtained in comparative example 1;
FIG. 1b is a photograph of the ceramic membrane of the in situ formed composite binder obtained in example 1;
fig. 2 is a graph comparing thermal shrinkage at 200 ℃ of the ceramic membrane of the in-situ generated composite binder obtained in example 1 and the unmodified alumina ceramic membrane obtained in comparative example 1. Wherein, the left side is the ceramic diaphragm of the in-situ generated composite binder obtained in the example 1, and the right side is the unmodified alumina ceramic diaphragm obtained in the comparative example 1;
fig. 3 is a graph showing cycle performance of batteries after the ceramic separator, the unmodified alumina ceramic separator and the ceramic separator, which are prepared by in-situ generation of the composite binder, are assembled into a battery using a PE-based film in example 1, comparative example 1 and comparative example 3.
Detailed Description
The technical solution of the present invention will be further illustrated and described below with reference to the accompanying drawings by means of specific embodiments. The embodiments described below by referring to the drawings are exemplary, and the examples of the embodiments are intended to explain the present invention and are not to be construed as limiting the present invention. The examples do not specify particular techniques or conditions, and are performed according to the techniques or conditions described in the literature in the art or according to the product specifications. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products commercially available.
Example 1: preparation of organic-inorganic composite modified diaphragm and application of diaphragm in lithium ion battery
Preparing an organic-inorganic composite modified diaphragm:
alumina powder with the particle size of 100-200nm and a binder (styrene butadiene rubber (SBR) and carboxymethyl cellulose (CMC)) are fully mixed to prepare ceramic slurry, wherein the mass ratio of the components is as follows: the alumina/SBR/CMC is 95/3/2, the solvent is a water/ethanol mixed solution with the volume ratio of 1:1, and the mass ratio of liquid to solid is 90% to 10%. And (3) uniformly coating the prepared ceramic slurry on a 16-micron Polyethylene (PE) diaphragm by using an automatic coating instrument on two sides, drying at room temperature, and then drying in vacuum at 50 ℃ for 10 hours to obtain the alumina ceramic coated diaphragm, wherein the thickness of the single side of the alumina ceramic layer is controlled to be about 3 microns.
A10 mmol/L tris (hydroxymethyl) aminomethane/hydrochloric acid pH buffer solution with a pH of 8.5 was prepared using water/ethanol as a solvent in a volume ratio of 1: 1. Dissolving catechol in a prepared pH buffer solution to prepare a solution with the concentration of 20mmol/L according to the mol ratio: catechol/tetraethylenepentamine ═ 4/1, and quantitative tetraethylenepentamine was added. Fully stirring, dissolving and mixing to obtain the mixed monomer polymerization precursor solution.
And immersing the prepared alumina ceramic coating membrane into the mixed monomer polymerization precursor solution, and soaking and reacting for 24 hours at room temperature under the condition of introducing oxygen. And then fishing out the diaphragm, repeatedly cleaning the diaphragm by using deionized water, and drying the diaphragm at 60 ℃ for 12 hours to obtain the organic-inorganic composite modified diaphragm of the embodiment 1.
Preparing a lithium ion battery:
manufacturing an electrode: first, a positive electrode is produced. 94 parts by mass of lithium manganate (LiMn) as a positive electrode active material2O4) In the method, 3 parts by mass of carbon black as a conductive aid is mixed, and the mixture is subjected toTo the mixture was added a solution obtained by dissolving 3 parts by mass of polyvinylidene fluoride in NMP, and the mixture was mixed to prepare a positive electrode mixture-containing slurry. The resultant was passed through a 70-mesh sieve to remove a large-particle fraction. The slurry containing the screened positive electrode mixture was uniformly applied to both surfaces of a positive electrode current collector formed of an aluminum case having a thickness of 15 μm. After drying, the sheet was compression-molded by a roll extruder, and the total thickness was pressed to 136 μm, and then cut off, and an aluminum tab was welded to produce a positive strip electrode. The negative electrode was made by pressing a metal lithium foil having a thickness of 50 μm on a 100 mesh nickel mesh. After cutting, a tab made of nickel was welded to produce a strip-shaped negative electrode.
Preparing a non-aqueous electrolyte: in a mixed solvent of EC, MEC, DEC and VC at a volume ratio of 10:10:30:1, LiPF is dissolved at a concentration of 1.0mo1/L6. The VC content of the nonaqueous electrolytic solution prepared in example 1 was about 2.1 mass%.
Manufacturing a battery: the above-prepared belt-shaped positive electrode (30 mm. times.60 mm) was laminated on the above-prepared belt-shaped negative electrode (33 mm. times.53 mm) via the above-prepared organic-inorganic composite modified separator (36 mm. times.56 mm) having a thickness of 16 μm, fixed, and then packaged with an aluminum plastic film (60 mm. times.100 mm) having a thickness of about 150 μm, and then heat-sealed on three sides (with both positive and negative electrode tabs left outside). The nonaqueous electrolytic solution prepared above was injected from the side which was not heat-sealed and still in an open state, and after standing for 1 hour, the side which was not heat-sealed and still in an open state of the aluminum plastic film was sealed by a method of heat-sealing under reduced pressure. The nonaqueous electrolyte secondary battery of example 1 had a design capacity of 45mAh when charged to 4.3V and a capacity of 107mAh/g as an active material. All the above procedures were carried out in an argon-filled glove box.
Charging: after the battery prepared above was stored at room temperature for 12 hours, the battery was charged according to the following conditions: after charging to 4.3V at a constant current of 0.2CmA, the cell was further charged at a constant voltage of 4.3V until the current value became 0.5mA, and then discharged to 3V at a constant current of 0.1CmA (4.5mA), thereby producing a cell for evaluation, i.e., a lithium ion cell of example 1.
Performance test conditions:
the lithium ion battery prepared in example 1 was charged at room temperature under the following conditions: after charging to 4.3V with a constant current of 1CmA, further charging to a current value of 0.5mA with a constant voltage of 4.3V or stopping after the total charging time reaches 2.5 hours, and then discharging to 3V with 1CmA, which is a cycle.
Example 2: preparation of organic-inorganic composite modified diaphragm and application of diaphragm in lithium ion battery
Preparing an organic-inorganic composite modified diaphragm:
fully mixing silica spheres with the particle size of 200nm and a binder (polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP)) to prepare ceramic slurry, wherein the mass ratio of each component is as follows: the silica spheres/PVDF-HFP (polyvinylidene fluoride-hexafluoropropylene) are 90/10, the solvent is an NMP/acetone mixed solution with the volume ratio of 1:1, and the mass ratio of liquid to solid is 90% to 10%. And uniformly coating the single surface of the prepared ceramic slurry on a 16-micron Polyethylene (PE) diaphragm by using an automatic coating instrument, drying at room temperature, and then drying in vacuum at 60 ℃ for 10 hours to obtain the silicon dioxide ceramic coated diaphragm, wherein the thickness of the single surface of the silicon dioxide ceramic layer is controlled to be about 4 microns.
A10 mmol/L tris (hydroxymethyl) aminomethane/hydrochloric acid pH buffer solution with pH of 10 was prepared using water/acetone as a solvent in a volume ratio of 1: 1. Dissolving caffeic acid in a prepared pH buffer solution to prepare a solution of 200mmol/L, wherein the mol ratio is as follows: caffeic acid/phenethylamine 1/4, a measured amount of phenethylamine was added. Fully stirring, dissolving and mixing to obtain the mixed monomer polymerization precursor solution.
Scraping 500mL of mixed monomer polymerization precursor liquid to 1m by using an automatic coater2The prepared silica ceramic was coated on a diaphragm and placed in an oxygen-containing vessel. The system is placed on a shaking table, oscillated at the frequency of 10r/min at normal temperature for 24 hours and then taken out, repeatedly washed by deionized water and dried at the temperature of 80 ℃ for 6 hours, and the organic-inorganic composite modified diaphragm of the embodiment 2 is obtained.
Preparing a lithium ion battery:
the lithium ion battery of this example 2 is prepared by using the organic-inorganic composite modified membrane prepared in this example 2, and the preparation method is the same as that of example 1.
Performance test conditions:
the lithium ion battery prepared in this example 2 was subjected to the performance test under the same test conditions as in example 1.
Example 3: preparation of organic-inorganic composite modified diaphragm and application of diaphragm in lithium ion battery
Preparing an organic-inorganic composite modified diaphragm:
fully mixing titanium dioxide powder with the particle size of 300nm with a binder (styrene butadiene rubber (SBR) and carboxymethyl cellulose (CMC)) to prepare ceramic slurry, wherein the mass ratio of the components is as follows: the titanium dioxide/SBR/CMC is 95/3/2, the solvent is a water/ethanol mixed solution with the volume ratio of 1:1, and the mass ratio of liquid to solid is 90% to 10%. And (3) uniformly coating the prepared ceramic slurry on a 16-micron Polyethylene (PE) diaphragm by using an automatic coating instrument on two sides, drying at room temperature, and then drying in vacuum at 50 ℃ for 10 hours to obtain the titanium dioxide ceramic coated diaphragm, wherein the thickness of the single side of the titanium dioxide ceramic layer is controlled to be about 3 microns.
A10 mmol/L tris/L pH buffer solution of pH 12 was prepared using water/dimethylsulfoxide in a volume ratio of 1:1 as a solvent. Dissolving catechol in prepared pH buffer solution to prepare 800mmol/L solution, wherein the mol ratio is as follows: catechol/polyethyleneimine with a molecular weight of 600 ═ 10/1, quantitative polyethyleneimine was added. Fully stirring, dissolving and mixing to obtain the mixed monomer polymerization precursor solution.
Spraying 500mL of mixed monomer polymerization precursor liquid onto 1m by using an automatic spraying device2The prepared titanium dioxide ceramic is coated on a diaphragm and is placed in an oxygen-containing container. The system is placed on a shaking table, oscillated at the frequency of 10r/min at normal temperature for 24 hours and then taken out, repeatedly washed by deionized water and dried at the temperature of 120 ℃ for 4 hours, and the organic-inorganic composite modified diaphragm of the embodiment 3 is obtained.
Preparing a lithium ion battery:
the lithium ion battery of this example 3 is prepared by using the organic-inorganic composite modified membrane prepared in this example 3, and the preparation method is the same as that of example 1.
Performance test conditions:
the lithium ion battery prepared in this example 3 was subjected to the performance test under the same test conditions as in example 1.
Example 4: preparation of organic-inorganic composite modified diaphragm and application of diaphragm in lithium ion battery
Preparing an organic-inorganic composite modified diaphragm:
magnesium oxide powder with the particle size of 500nm is fully mixed with a binder (gelatin and polyvinyl alcohol) to prepare ceramic slurry, wherein the mass ratio of the components is as follows: the magnesium oxide/gelatin/polyvinyl alcohol (95/3/2) is a water/ethanol mixed solution with the volume ratio of 1:1, and the mass ratio of liquid to solid is 90% to 10%. And uniformly coating the single surface of the prepared ceramic slurry on a 16-micron Polyethylene (PE) diaphragm by using an automatic coating instrument, drying at room temperature, and then drying in vacuum at 50 ℃ for 10 hours to obtain the magnesia ceramic coated diaphragm, wherein the thickness of the single surface of the magnesia ceramic layer is controlled to be about 4 microns.
A10 mmol/L tris (hydroxymethyl) aminomethane/hydrochloric acid pH buffer solution with a pH of 12 was prepared using water/methanol as a solvent in a volume ratio of 1: 1. Dissolving tannic acid in a prepared pH buffer solution to prepare a solution with the concentration of 2 mmol/L according to the mol ratio: tannic acid/tetraethylenepentamine (1/5), a quantitative amount of tetraethylenepentamine was added. Fully stirring, dissolving and mixing to obtain the mixed monomer polymerization precursor solution.
And immersing the prepared magnesium oxide ceramic coating diaphragm into the mixed monomer polymerization precursor solution, and soaking and reacting for 48 hours at room temperature under the condition of introducing oxygen. And then fishing out the diaphragm, repeatedly cleaning the diaphragm by using deionized water, and drying the diaphragm at 60 ℃ for 12 hours to obtain the organic-inorganic composite modified diaphragm of the embodiment 4.
Preparing a lithium ion battery:
the lithium ion battery of this example 4 is prepared by using the organic-inorganic composite modified membrane prepared in this example 4, and the preparation method is the same as that of example 1.
Performance test conditions:
the lithium ion battery prepared in this example 4 was subjected to the performance test under the same test conditions as in example 1.
Example 5: preparation of organic-inorganic composite modified diaphragm and application of diaphragm in lithium ion battery
Preparing an organic-inorganic composite modified diaphragm:
fully mixing barium sulfate powder with the particle size of 200-300 nm and a binder (polymethyl methacrylate) to prepare ceramic slurry, wherein the mass ratio of each component is as follows: the barium sulfate/polymethyl methacrylate is 95/5, the solvent is a water/ethanol mixed solution with the volume ratio of 1:1, and the mass ratio of liquid to solid is 90% to 10%. And (3) uniformly coating the prepared ceramic slurry on a 16-micron Polyethylene (PE) diaphragm by using an automatic coating instrument on two sides, drying at room temperature, and then drying in vacuum at 50 ℃ for 10 hours to obtain the barium sulfate ceramic coated diaphragm, wherein the thickness of the single side of the barium sulfate ceramic layer is controlled to be about 3 microns.
A10 mmol/L tris/L pH buffer solution of pH 7.5 was prepared using water/isopropanol in a volume ratio of 1:1 as the solvent. Dissolving tannic acid in a prepared pH buffer solution to prepare a solution of 800mmol/L, wherein the molar ratio is as follows: tannic acid/diethylenetriamine ═ 1/5, a quantitative amount of diethylenetriamine was added. Fully stirring, dissolving and mixing to obtain the mixed monomer polymerization precursor solution.
And immersing the prepared barium sulfate ceramic coating membrane into the mixed monomer polymerization precursor solution, and soaking and reacting for 6 hours at room temperature under the condition of introducing oxygen. And then fishing out the diaphragm, repeatedly cleaning the diaphragm by using deionized water, and drying the diaphragm for 24 hours at the temperature of 60 ℃ to obtain the organic-inorganic composite modified diaphragm of the embodiment 5.
Preparing a lithium ion battery:
the lithium ion battery of this example 5 is prepared by using the organic-inorganic composite modified membrane prepared in this example 5, and the preparation method is the same as that of example 1.
Performance test conditions:
the lithium ion battery prepared in this example 5 was subjected to the performance test under the same test conditions as in example 1.
Comparative example 1: preparation of unmodified alumina ceramic diaphragm and application of unmodified alumina ceramic diaphragm in lithium ion battery
The unmodified alumina ceramic separator used in comparative example 1 was prepared in the same manner as in example 1 and evaluated. The lithium ion battery prepared in comparative example 1 was prepared in the same operation as in example l using the same positive electrode, negative electrode and nonaqueous electrolytic solution as in example 1, except that the unmodified alumina ceramic separator was used.
Comparative example 2: preparation of dopamine-modified alumina ceramic diaphragm and application of dopamine-modified alumina ceramic diaphragm in lithium ion battery
0.1g of dopamine hydrochloride (DA) is added into 5mL of a mixed solvent of water and ethanol (1:1, V: V), and the mixture is mechanically stirred for 1h to prepare a dopamine modified treatment solution.
The unmodified alumina ceramic diaphragm prepared in example 1 was immersed in the dopamine hydrochloride monomer solution obtained in the above step of comparative example 2, ammonia was added, the PH was adjusted to 8.5, and the alumina ceramic diaphragm was taken out after standing reaction at 20 ℃ for 5 hours.
And repeatedly cleaning the membrane with deionized water, and drying the membrane at 60 ℃ for 12h to obtain the dopamine modified alumina ceramic membrane of the comparative example 2.
The lithium ion battery of comparative example 2 was prepared using the dopamine-modified alumina ceramic separator of comparative example 2, and the preparation method was the same as in example 1.
Comparative example 3: preparation of lithium ion battery containing polyethylene base film
The lithium ion battery prepared in this comparative example 3 used the same positive electrode material and negative electrode material as in example 1, with an unmodified 16 μm Polyethylene (PE) -based film between the positive electrode material and the negative electrode material.
And (3) performance testing:
the following tests and evaluations were performed on the organic-inorganic composite modified separators of examples 1 to 5 and lithium ion batteries prepared therefrom, the unmodified alumina ceramic separator of comparative example 1 and lithium ion batteries prepared therefrom, the modified alumina ceramic separator of comparative example 2 and lithium ion batteries prepared therefrom, and the lithium ion battery containing a polyethylene-based film of comparative example 3.
Testing the thermal shrinkage property of the separator:
the membrane was cut into 22mm × 22mm samples, placed in an air-blowing dry box (manufacturer: Shanghai sperm Macro laboratory instruments Co., Ltd.) preheated to 200 ℃ and left (heated) for 30 minutes and then taken out. After standing at room temperature for 1 hour, the film was measured for dimensional changes in the Machine Direction (MD) and Transverse Direction (TD). The number of samples tested was 5 each time, and the average was taken.
The heat shrinkage was calculated according to the following equation:
wherein S0Is the area of the separator before heat treatment, and S is the area after heat treatment. The smaller the thermal shrinkage value, the better the heat resistance of the separator.
Observation of the phenomenon of powder falling:
the glove with latex glove is pressed on the surface of the diaphragm to slide back and forth for 5 times, and whether the powder falls off or is adhered on the latex glove is observed visually.
And (3) testing charge-discharge cycle characteristics:
using the discharge capacity at the l-th cycle and the discharge capacity at the 100 th cycle, the capacity retention rate was calculated according to the following formula, and the charge-discharge cycle characteristics were evaluated:
capacity retention (%) -. 200 th cycle discharge capacity/1 st cycle discharge capacity). times.100%
And (3) analyzing a test result:
fig. 1 to 3 show the characteristics of the organic-inorganic composite modified separator of example 1 and the unmodified alumina ceramic separator of comparative example l, and the characteristics of a lithium ion battery using the separators, respectively.
Fig. 1a and 1b are photographs before and after the alumina ceramic coated separator of example 1 is compositely modified, fig. 1a is a photograph of example 1, and fig. 1b is a photograph of comparative example 1. It can be seen that the surface color of the alumina ceramic diaphragm is deepened after the organic and inorganic composite modification. This shows that the organic-inorganic composite modification treatment of example 1 effectively grows or adheres organic substances to the separator base material, and greatly changes the surface of the separator base material.
FIG. 2 is a graph showing the comparison of the thermal shrinkage at 200 ℃ of the organic-inorganic composite modified ceramic separator obtained in example 1 and the alumina ceramic coated separator in comparative example 1. It can be seen that the PE-based ceramic separator modified with the organic-inorganic composite exhibits very excellent high-temperature resistance, with almost no dimensional change even at a high temperature of 200 ℃. The untreated alumina ceramic coated separator was also improved compared to the PE-based membrane, but also changed in size significantly. Wherein, the pure PE basal membrane is completely melted at the high temperature of 200 ℃ and shrinks into a point).
Fig. 3 is a graph showing the cycle performance of the batteries assembled by the organic-inorganic composite modified alumina ceramic-coated separator, the unmodified alumina ceramic separator and the polyethylene-based film in example 1, comparative example 1 and comparative example 3. Wherein the abscissa represents the number of turns and the ordinate represents the volumetric value. It can be seen that the charge-discharge cycle characteristics of the three materials are the same, which shows that the composite modification has no influence on the electrochemical performance of the battery, and the modified material of the invention has no negative effect on the battery.
Table 1 shows the characteristics of the organic-inorganic composite modified separators of examples 1 to 5, the unmodified alumina ceramic separator of comparative example i, the dopamine modified alumina ceramic separator of comparative example 2, and the polyethylene-based membrane of comparative example 3, and the characteristics of the lithium ion battery prepared using the separators.
TABLE 1 comparison table of thermal shrinkage and charge-discharge cycle characteristics of separator
As can be seen from table 1, even at a high temperature of 200 ℃, the shrinkage rate of the organic-inorganic composite modified alumina ceramic separator of example 1 is only 1.0%, and compared with the shrinkage rates of 18.6% of the unmodified alumina ceramic separator of comparative example 1 and 94.2% of the PE-based membrane of comparative example 3, example 1 has a great improvement, shows excellent high-temperature dimensional stability, and greatly improves the high-temperature resistance of the separator, which is very important for ensuring the safety of the battery. Meanwhile, in terms of 100 charge-discharge cycle characteristics, the same as the unmodified alumina ceramic separator of comparative example 1 and the PE base film of comparative example 3, it is demonstrated that example 1 has a good capacity retention rate.
The organic-inorganic composite modified ceramic separators of examples 2 to 5 also had a small shrinkage ratio compared to the unmodified ceramic separator of comparative example i and the base film of comparative example 3, indicating that examples 2 to 5 were greatly improved in high temperature resistance and had the same results in terms of battery charge-discharge cycle characteristics.
Moreover, as shown in table 1, the organic-inorganic composite modified membranes of examples 1 to 5 had strong powder adhesion and no "dusting" phenomenon was observed, while the unmodified alumina ceramic membrane of comparative example 1 had slight "dusting" phenomenon.
In addition, compared with the dopamine modified diaphragm of the comparative example 2, the organic-inorganic composite modified ceramic diaphragms of the embodiments 1 to 5 have the same improvement effect, but can greatly reduce the cost, and have industrial application prospects.
While the invention has been particularly shown and described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.
Claims (10)
1. An organic-inorganic composite modified diaphragm is applied to a lithium ion battery and comprises an organic diaphragm substrate, and is characterized in that an inorganic ceramic layer is coated on one side or two sides of the surface of the organic diaphragm substrate, a composite monomer copolymer generated in situ is arranged on the surface and inside of the organic diaphragm substrate and on the surface and inside of the inorganic ceramic layer, and the composite monomer copolymer is formed by dissolving a monomer A containing a polyphenol functional group and a monomer B containing an amino functional group in a solvent and introducing oxygen.
2. The organic-inorganic composite modified membrane according to claim 1, wherein the inorganic ceramic layer is an inorganic ceramic layer containing a binder and inorganic powder, and the thickness of the inorganic ceramic layer is 0.1 μm to 50 μm;
the organic diaphragm base material is made of at least one of polyolefin porous polymer, polytetrafluoroethylene, polyvinylidene fluoride-hexafluoropropylene copolymer, polyvinyl chloride, polyethylene terephthalate, polybutylene terephthalate, polymethyl methacrylate, polyacrylonitrile, polyimide, polyvinylpyrrolidone, polyethylene oxide, polyvinyl alcohol or a blending and copolymerization system derived from the above polymers.
3. The organic-inorganic composite modified separator according to claim 2, wherein the binder is an aqueous binder or an organic binder;
the water-based binder is one of a sodium methyl cellulose, styrene butadiene rubber, gelatin, polyvinyl alcohol and polyacrylate terpolymer latex system;
the organic binder is one of polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene and polymethyl methacrylate;
the inorganic powder is at least one of aluminum oxide, titanium dioxide, silicon dioxide, zirconium dioxide, tin dioxide, magnesium oxide, zinc oxide, barium sulfate, boron nitride, aluminum nitride and magnesium nitride, and the particle size of the inorganic powder is 5nm-50 μm.
4. The organic-inorganic composite modified membrane according to claim 1, wherein the polyphenol functional group-containing monomer A is at least one of catechol, pyrogallol, p-methylcatechol, catechol violet, 3-fluorocatechol, 3-methylcatechol, p-tert-butylcatechol, caffeic acid, bromocatechol red, and tannic acid;
the monomer B containing the amino functional group is at least one of diethylenetriamine, triethylene tetramine, tetraethylenepentamine, pentaethylenehexamine, polyethyleneimine with the molecular weight of 300-100000, phenethylamine, tyramine, p-bromophenylethylamine, p-methylphenylethylamine and 3-methoxyphenethylamine;
the solvent is an aqueous solution of at least one organic solvent selected from methanol, ethanol, isopropanol, acetone, dimethylformamide, dimethyl sulfoxide, dimethylacetamide and N-methylpyrrolidone, and the volume fraction of the organic solvent is 20-80%.
5. A method for preparing the organic-inorganic composite modified membrane according to any one of claims 1 to 4, characterized by comprising the following steps:
a) coating an inorganic ceramic layer containing a binder and inorganic powder on one side or two sides of the surface of the organic diaphragm substrate to prepare a ceramic diaphragm;
b) dissolving a monomer A containing a polyphenol functional group and a monomer B containing an amino functional group in a solvent to prepare a mixed monomer polymerization precursor solution with the monomer content of 0.01-1000mmol/L and the pH value of 7-12, wherein the molar ratio of the monomer A to the monomer B is 1:0.001-1: 1000;
c) coating the ceramic diaphragm prepared in the step a) with the mixed monomer polymerization precursor solution prepared in the step b), and reacting for 1-48h at room temperature under the condition of introducing oxygen;
d) cleaning the diaphragm treated in the step c), and drying at 60-120 ℃ for 1-24h to obtain the organic-inorganic composite modified diaphragm.
6. The method for preparing the organic-inorganic composite modified membrane according to claim 5, wherein the step of coating the ceramic membrane prepared in the step a) with the mixed monomer polymerization precursor solution prepared in the step b) is to immerse the ceramic membrane prepared in the step a) into the mixed monomer polymerization precursor solution prepared in the step b);
the mixed monomer polymerization precursor liquid prepared in the step b) is coated on the ceramic diaphragm prepared in the step a) in a blade coating or spraying manner;
the organic diaphragm base material is made of at least one of polyolefin porous polymer, polytetrafluoroethylene, polyvinylidene fluoride-hexafluoropropylene copolymer, polyvinyl chloride, polyethylene terephthalate, polybutylene terephthalate, polymethyl methacrylate, polyacrylonitrile, polyimide, polyvinylpyrrolidone, polyethylene oxide, polyvinyl alcohol or a blending and copolymerization system derived from the above polymers.
7. The method for preparing the organic-inorganic composite modified membrane according to claim 5, wherein the binder is an aqueous binder or an organic binder;
the water-based binder is one of a sodium methyl cellulose, styrene butadiene rubber, gelatin, polyvinyl alcohol and polyacrylate terpolymer latex system;
the organic binder is one of polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene and polymethyl methacrylate;
the inorganic powder is at least one of aluminum oxide, titanium dioxide, silicon dioxide, zirconium dioxide, tin dioxide, magnesium oxide, zinc oxide, barium sulfate, boron nitride, aluminum nitride and magnesium nitride, and the particle size of the inorganic powder is 5nm-50 μm.
8. The method for preparing an organic-inorganic composite modified membrane according to claim 5, wherein the polyphenol functional group-containing monomer A is at least one of catechol, pyrogallol, p-methylcatechol, catechol violet, 3-fluorocatechol, 3-methylcatechol, p-tert-butylcatechol, caffeic acid, bromocatechol red, and tannic acid;
the monomer B containing the amino functional group is at least one of diethylenetriamine, triethylene tetramine, tetraethylenepentamine, pentaethylenehexamine, polyethyleneimine with the molecular weight of 300-100000, phenethylamine, tyramine, p-bromophenylethylamine, p-methylphenylethylamine and 3-methoxyphenethylamine;
the solvent is an aqueous solution of at least one organic solvent selected from methanol, ethanol, isopropanol, acetone, dimethylformamide, dimethyl sulfoxide, dimethylacetamide and N-methylpyrrolidone, and the volume fraction of the organic solvent is 20-80%.
9. A lithium ion battery comprises a positive electrode material, a negative electrode material and a non-aqueous electrolyte, and is characterized in that: the organic-inorganic composite modified separator according to any one of claims 1 to 4, which is provided between a positive electrode material and a negative electrode material.
10. Use of an organic-inorganic composite modified separator as defined in any one of claims 1 to 4 in a secondary battery, including a lithium ion battery.
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| CN107230767B (en) * | 2017-07-14 | 2021-05-14 | 厦门益舟新能源科技有限公司 | Diaphragm with three-dimensional composite structure and preparation method and application thereof |
| CN109836622B (en) * | 2017-11-28 | 2020-08-21 | 中国科学院化学研究所 | Organic-inorganic hybrid nano antibacterial material and preparation method and application thereof |
| KR102132756B1 (en) * | 2017-12-06 | 2020-07-13 | 주식회사 엘지화학 | Separator coating slurry composition for secondary battery and seperator for secondary battery comprising the same |
| KR102207526B1 (en) * | 2018-02-19 | 2021-01-25 | 주식회사 엘지화학 | Separator for lithium sulfurbattery, manufacturing method thereof, and lithium sulfurbattery comprising the same |
| CN110854339B (en) * | 2018-08-20 | 2022-07-12 | 安徽美芯新材料有限公司 | In-situ composite ceramic diaphragm with core-shell structure and preparation method and application thereof |
| JP2021534558A (en) | 2018-08-21 | 2021-12-09 | アプライド マテリアルズ インコーポレイテッドApplied Materials, Incorporated | Ultra-thin ceramic coating on battery separator |
| CN109244320A (en) * | 2018-09-17 | 2019-01-18 | 湖北江升新材料有限公司 | A kind of secure high performance lithium ion battery separator and preparation method thereof |
| KR20200135178A (en) * | 2019-05-23 | 2020-12-02 | 주식회사 엘지화학 | Separator for lithium metal battery, manufacturing method of the same, lithium metal battery including the same |
| CN110416476B (en) * | 2019-07-15 | 2022-03-08 | 河北金力新能源科技股份有限公司 | High-conductivity slurry, preparation method and application thereof, lithium battery diaphragm and lithium battery |
| CN113078413B (en) * | 2019-12-17 | 2022-08-19 | 山东海科创新研究院有限公司 | Molybdenum disulfide composite diaphragm for lithium-sulfur battery, preparation method of molybdenum disulfide composite diaphragm and lithium-sulfur battery |
| CN111293256B (en) * | 2020-02-17 | 2023-05-23 | 珠海冠宇电池股份有限公司 | Ceramic particle, diaphragm comprising ceramic particle and battery |
| CN111584801A (en) * | 2020-04-29 | 2020-08-25 | 西安理工大学 | Lithium ion battery composite diaphragm and preparation method thereof |
| 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 |
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