WO2020151357A1 - 一种锂电池隔膜及其制备方法 - Google Patents

一种锂电池隔膜及其制备方法 Download PDF

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WO2020151357A1
WO2020151357A1 PCT/CN2019/120235 CN2019120235W WO2020151357A1 WO 2020151357 A1 WO2020151357 A1 WO 2020151357A1 CN 2019120235 W CN2019120235 W CN 2019120235W WO 2020151357 A1 WO2020151357 A1 WO 2020151357A1
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battery separator
lithium battery
solvent
natural organic
mass
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PCT/CN2019/120235
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English (en)
French (fr)
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何伟东
韩玉培
甄诚
丁显波
陈太宝
周梅
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深圳锂硫科技有限公司
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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
    • H01M50/443—Particulate material
    • 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

Definitions

  • lithium metal negative electrodes and high energy density positive electrodes such as lithium sulfur batteries and lithium tellurium batteries
  • the lithium metal negative electrode has a high theoretical lithium storage capacity (3860mAh g -1 ).
  • a high energy density positive electrode such as sulfur (1672mAh g -1 )
  • the new lithium-based battery prepared can provide far more than lithium-ion batteries. Actual capacity.
  • they are expected to provide modular batteries with an energy density far exceeding that of lithium-ion batteries in the future, thereby replacing existing lithium-ion batteries in a large area.
  • Lithium metal is an extremely important part of the research and application of a new generation of high-energy density secondary batteries.
  • lithium metal faces many problems during the cycle, one of which is the growth of lithium dendrites. Because the flow of lithium ions through the SEI film is unstable and the surface of the lithium metal is uneven, lithium ions are unevenly deposited on the surface of the lithium metal, forming lithium dendrites. During the battery cycle, there is a strong electric field at the tip of the dendrite, which allows more lithium ions to be deposited on it. Lithium dendrites accelerate accumulation under this self-reinforced positive feedback mechanism, and eventually pierce the diaphragm, causing the battery to short circuit, causing thermal runaway, burning, and even explosion. How to inhibit the growth of lithium dendrites and make lithium metal negative electrodes have high cycle performance and rate performance has become a research focus and difficulty.
  • the technical problem to be solved by the present invention is to provide a lithium battery diaphragm and a preparation method thereof, enhance the strength of the lithium battery diaphragm, inhibit the formation of lithium dendrites, and avoid thermal runaway, combustion, and even explosion caused by battery short circuit.
  • a lithium battery separator which contains the following components by mass percentage:
  • the film-forming polymer is polyvinylidene fluoride-hexafluoropropylene (PVdF-HFP) and/or polyvinylidene fluoride (PVdF),
  • the natural organic additive is dry natural organic powder
  • the polyvinylidene fluoride- Hexafluoropropylene and/or polyvinylidene fluoride has a cross-linked network structure in the lithium battery separator, and the molecular chains of the polyvinylidene fluoride-hexafluoropropylene and/or polyvinylidene fluoride are inserted into the pores of the natural organic powder ,
  • the natural organic powder forms a chain in the cross-linked network structure.
  • the polyvinylidene fluoride-hexafluoropropylene and/or polyvinylidene fluoride form a cross-linked network structure in the lithium battery separator; the dry natural organic powder particles contain a large number of voids, and the polyvinylidene fluoride-hexafluoropropylene and/or The molecular chain of polyvinylidene fluoride can enter the pores of the natural organic powder particles, so that the natural organic powder can form a chain in the lithium battery separator. This effectively enhances the strength of the lithium battery diaphragm and prevents lithium dendrites from easily piercing the lithium battery diaphragm.
  • the sulfide-containing compounds and thiol-containing compounds in the natural organic powder will chelate with the metal ions in the natural organic powder to form a charged chelate M + .
  • the charged chelate M + will exist in the electrolyte.
  • This positively charged shield repels incoming lithium ions, thereby slowing the growth of protrusions. Avoid short-circuiting the battery due to lithium dendrites piercing the diaphragm, causing thermal runaway, burning, and explosion.
  • the organic powder is one or a combination of at least two of garlic powder, onion powder, sesame powder, and soybean powder; the particle size of the organic powder ranges from 0.1 ⁇ m to 300 ⁇ m.
  • the organic powder is obtained by grinding after drying the organic matter.
  • the sulfide compound is one or a mixture of at least two of diallyl ethyl sulfide, diallyl disulfide, and diallyl trisulfide, and the thiol compound is: Allyl mercaptan.
  • the sulfonic acid compound is: allyl sulfinic acid and/or allyl sulfinic acid
  • the invention also provides a method for preparing a lithium battery diaphragm, which includes the following steps.
  • step S3 Stir the suspension in step S2 for 10s-10min in a certain temperature range to form a uniform gel-like solution; the temperature range is: 30°C-95°C.
  • the film-forming polymer is completely dissolved in the solvent to form a cross-linked network structure.
  • the viscosity of the colloidal solution ranges from 300 cps to 2000 cps.
  • step S4 adding natural organic additives to the colloidal solution in step S3, mixing uniformly to form a uniform battery separator slurry.
  • the natural organic additive is swelled by the solvent, and at the same time, the molecular chains of the film-forming polymer enter the voids of the natural organic additive, and the natural organic additive acts as a link in the cross-linked network structure.
  • the viscosity range of the battery separator slurry is: 300 cps to 2000 cps.
  • step S5 The battery separator slurry in step S4 is made into a lithium battery separator by coating, electrophoresis, or pulling. Natural organic additives act as links in the cross-linked network structure formed by the film-forming polymer, thereby effectively enhancing the strength of the lithium battery separator and preventing lithium dendrites from easily piercing the lithium battery separator.
  • the solvents are: acetone, N-methylpyrrolidone (NMP), dimethylacetamide (DMAc), dimethylformamide (DMF), dimethylsulfoxide (DMSO), diethylacetamide (DEAc ), one or a mixture of at least two of trimethyl phosphate (TMP), triethyl phosphate (TEP), hexamethylammonium phosphate (HMPA) and tetramethylurine (TMU); in step S3,
  • the temperature range is: 40°C-90°C.
  • step S4 heating, stirring and mixing or ball milling are used to increase the number of molecular chains of the film-forming polymer entering the pores of the natural organic additive, and enhance the connection between the natural organic additive and the molecular chain of the film-forming polymer.
  • step S4 the method further includes: sieving the battery separator slurry with 50 meshes.
  • the present invention also provides a method for preparing a lithium battery diaphragm, including the following steps:
  • SS1 Weigh the film-forming polymer and natural organic additives according to a certain mass percentage, and weigh a certain mass of solvent, the mass of the solvent accounts for 50%-95% of the total mass.
  • SS2 Add the film-forming polymer to a part of the solvent and stir evenly to form a first suspension; add natural organic additives to the remaining solvent and stir evenly to form a second suspension. In this step, the natural organic additives are infiltrated and swelled by the solvent.
  • the mass of the solvent mixed with the film-forming polymer accounts for 85%-95% of the total solvent mass, and the mass of the solvent mixed with the natural organic additive accounts for 5%-15% of the total solvent mass.
  • step SS3 Stir the first suspension in step SS2 for 10s-10min in a certain temperature range to form a uniform colloidal solution; the temperature range is: 30°C-95°C.
  • the film-forming polymer is completely dissolved in the solvent to form a cross-linked network structure.
  • the viscosity of the colloidal solution ranges from 300 cps to 2500 cps.
  • step SS4 The second suspension in step SS2 is added to the colloidal solution in step SS3 and mixed uniformly to form a uniform battery separator slurry.
  • the molecular chains of the film-forming polymer enter the voids of the natural organic additive, and the natural organic additive acts as a link in the cross-linked network structure.
  • the viscosity range of the battery separator slurry is: 300 cps to 2000 cps.
  • step SS5 The battery separator slurry in step SS4 is made into a lithium battery separator by coating, electrophoresis, or pulling. Natural organic additives act as links in the cross-linked network structure formed by the film-forming polymer, thereby effectively enhancing the strength of the lithium battery separator and preventing lithium dendrites from easily piercing the lithium battery separator.
  • the solvents are: acetone, N-methylpyrrolidone (NMP), dimethylacetamide (DMAc), dimethylformamide (DMF), dimethylsulfoxide (DMSO), diethylacetamide (DEAc ), one or a mixture of at least two of trimethyl phosphate (TMP), triethyl phosphate (TEP), hexamethylammonium phosphate (HMPA) and tetramethylurine (TMU).
  • NMP N-methylpyrrolidone
  • DMAc dimethylacetamide
  • DMF dimethylformamide
  • DMSO dimethylsulfoxide
  • DEAc diethylacetamide
  • TMP trimethyl phosphate
  • TEP triethyl phosphate
  • HMPA hexamethylammonium phosphate
  • TU tetramethylurine
  • step SS2 it also includes ball milling the second suspension for a period of time; in step SS3, the temperature range is: 40°C-90°C.
  • step SS4 heating, stirring and mixing or ball milling are used; in step S4, it further includes: sieving the battery separator slurry with 50 meshes.
  • the present invention provides a lithium battery separator, in which natural organic additives containing thioether compounds and/or thiol compounds and/or sulfonic acid compounds are added to the film-forming polymer, and the film-forming polymer is In a cross-linked network structure, the molecular chains of the film-forming polymer are inserted into the pores of the natural organic powder, and the natural organic powder forms a chain in the cross-linked network structure. This effectively enhances the strength of the lithium battery diaphragm and prevents lithium dendrites from easily piercing the lithium battery diaphragm.
  • the metal ions in the natural organic powder can be chelated with sulfide-containing compounds and/or mercaptan compounds to form a charged chelate M + .
  • This positively charged shield repels incoming lithium ions, thereby slowing the growth of protrusions. Avoid short-circuiting the battery due to lithium dendrites piercing the diaphragm, causing thermal runaway, burning, and explosion.
  • the invention also provides a method for preparing the lithium battery diaphragm.
  • FIG. 1 is a flowchart of the method of Embodiment 1 of the present invention.
  • Figure 3 is a graph showing the liquid absorption rate of the garlic membrane, PVdF-HFP membrane and PP membrane prepared in Example 1;
  • Figure 4 shows the LSV test of garlic membrane, PVdF-HFP membrane and PP membrane prepared in Example 1;
  • Example 5 is a graph showing the relationship between voltage and cycle time of Li/diaphragm/Li symmetric battery assembled from garlic diaphragm, PVdF-HFP diaphragm and PP diaphragm prepared in Example 1;
  • Figure 6 is an impedance test diagram of a Li/diaphragm/Li symmetric battery assembled from the garlic membrane, PVdF-HFP membrane and PP membrane prepared in Example 1;
  • Figure 7 is a graph showing the coulombic efficiency of the Li/diaphragm/Cu battery assembled from the garlic membrane, PVdF-HFP membrane and PP membrane prepared in Example 1;
  • Figure 8 is a voltage-capacity curve diagram of a Li/diaphragm/Cu battery assembled from the garlic membrane, PVdF-HFP membrane and PP membrane prepared in Example 1 respectively;
  • Figure 9 is a graph of voltage hysteresis (overpotential) of Li/diaphragm/Cu batteries assembled from the garlic membrane, PVdF-HFP membrane and PP membrane prepared in Example 1;
  • Figure 10 is the Nyquist impedance diagram of the LFP/diaphragm/Li battery assembled from the garlic membrane, PVdF-HFP membrane and PP membrane prepared in Example 1 respectively;
  • FIG. 11 is a diagram showing the cycle performance of the LFP/diaphragm/Li battery assembled from the garlic membrane, PVdF-HFP membrane and PP membrane prepared in Example 1 at a 2C charge-discharge rate;
  • Figure 12 is a graph showing the cycle performance of the LFP/diaphragm/Li battery assembled from the garlic membrane, PVdF-HFP membrane and PP membrane prepared in Example 1 at a 4C charge-discharge rate;
  • Figure 13 is a graph showing the cycle performance of the LFP/diaphragm/Li battery assembled from the garlic membrane, PVdF-HFP membrane and PP membrane prepared in Example 1 at a charge-discharge rate of 10C;
  • Figure 14 is a graph of voltage hysteresis (overpotential) of LFP/diaphragm/Li battery assembled from garlic membrane, PVdF-HFP membrane and PP membrane prepared in Example 1 at a charge and discharge rate of 2C;
  • Figure 15 is a graph of the voltage hysteresis (overpotential) of the LFP/diaphragm/Li battery assembled from the garlic membrane, PVdF-HFP membrane and PP membrane prepared in Example 1 at a 4C charge-discharge rate;
  • 16 is a graph of voltage hysteresis (overpotential) of LFP/diaphragm/Li battery assembled from garlic membrane, PVdF-HFP membrane and PP membrane prepared in Example 1 at a charge and discharge rate of 10C.
  • the present invention provides a lithium battery diaphragm.
  • it contains the following components by mass percentage:
  • the polyvinylidene fluoride-hexafluoropropylene forms a cross-linked network structure in the lithium battery separator; the dried garlic powder contains a large number of voids, and the molecular chain of polyvinylidene fluoride-hexafluoropropylene can enter the pores of the garlic powder. This allows garlic powder to form chains in the lithium battery separator. This effectively enhances the strength of the lithium battery diaphragm and prevents lithium dendrites from easily piercing the lithium battery diaphragm.
  • the present invention also provides a method for preparing a lithium battery separator:
  • the method includes the following steps:
  • step S3 The first suspension prepared in step S2 is heated and stirred at 40° C. for 10 minutes to form a stable and uniform colloidal solution for later use; the viscosity of the colloidal solution ranges from 300 cps to 2500 cps.
  • step S4 The second suspension prepared in step S2 is added to the colloidal solution prepared in step S3, mixed uniformly, and the obtained battery slurry is sieved with 50 meshes to form a uniform battery diaphragm slurry. Coating for use.
  • the mass of the solvent mixed with polyvinylidene fluoride-hexafluoropropylene accounts for 85% of the total solvent mass, and the mass of the solvent mixed with garlic powder accounts for 15% of the total solvent mass.
  • the viscosity range of the battery separator slurry is: 300 cps to 2000 cps.
  • Garlic powder can reduce the crystallinity of PVDF-hexafluoropropylene or PVDF and improve The proportion of the amorphous phase is conducive to the formation of pores in the lithium battery separator, and the natural organic powder particles themselves also have a large number of pores, which can absorb more electrolyte and improve the liquid absorption and conductivity of the lithium battery separator.
  • the LSV test of garlic diaphragm and PVDF-hexafluoropropylene diaphragm showed stability higher than 5V (relative to Li + /Li), which is higher than 4.7V of PP diaphragm.
  • the wide electrochemical stability of the garlic diaphragm comes from the polymer main material.
  • the high wettability and electrolyte absorption of garlic powder further expand the electrochemical window.
  • the extensive electrochemical stability shows that the garlic separator is suitable for higher voltage battery environments.
  • EIS test was carried out before and after Li/diaphragm/Li symmetrical battery cycle, the test frequency range is 100MHz-100kHz, and the voltage signal amplitude is 10mV.
  • the EIS test is usually used to study the interface resistance of the SEI layer and the charge transfer resistance on the lithium metal surface. It can be seen that the EIS of Li/PVdF-HFP diaphragm/Li symmetric battery and Li/PP diaphragm/Li symmetric battery respectively exhibit high impedances of ⁇ 130 ⁇ and ⁇ 140 ⁇ before cycling. After 15 charge/discharge cycles, the interface impedance dropped to ⁇ 80 ⁇ and ⁇ 100 ⁇ , respectively. However, the Li/garlic separator/Li symmetric battery showed an impedance of about 36 ⁇ before cycling and a low impedance of about 16 ⁇ after cycling, which was attributed to the low charge transfer resistance and lower ion diffusion resistance of SEI.
  • Li/garlic diaphragm/Cu battery exhibits higher coulombic efficiency and cycle stability .
  • Li/garlic diaphragm/Cu battery also showed the lowest voltage hysteresis (overpotential). The voltage starts at ⁇ 0.03V in the early cycles, then drops to ⁇ 0.02V and maintains the overpotential at ⁇ 0.2V throughout 350 cycles.
  • the overpotential of Li/PVdF-HFP diaphragm/Cu battery and Li/PP diaphragm/Cu battery increased significantly with the increase of the number of cycles.
  • LFP/garlic diaphragm/Li battery exhibits lower ion diffusion resistance ⁇ 25 ⁇ , while the impedance of LFP/PVdF-HFP diaphragm/Li battery and LFP/PP diaphragm/Li battery are ⁇ 72 ⁇ and ⁇ 84 ⁇ , respectively .
  • the present invention provides a lithium battery diaphragm.
  • it contains the following components by mass percentage:
  • step S3 The first suspension prepared in step S2 is heated and stirred at 90° C. for 10 seconds to form a stable and uniform colloidal solution for later use; the viscosity of the colloidal solution ranges from 300 cps to 2500 cps.
  • step S4 The second suspension prepared in step S2 is added to the colloidal solution prepared in step S3, mixed uniformly, and the obtained battery slurry is sieved with 50 meshes to form a uniform battery diaphragm slurry. Coating for use.
  • the mass of the solvent mixed with polyvinylidene fluoride-hexafluoropropylene accounts for 90% of the total solvent mass, and the mass of the solvent mixed with garlic powder accounts for 10% of the total solvent mass.
  • the viscosity range of the battery separator slurry is: 300 cps to 2000 cps.
  • the battery separator slurry prepared in step S4 is prepared into a film on a substrate using a film coater, and dried at room temperature for 30 minutes and then peeled from the substrate to prepare an onion separator with a thickness ranging from 10 ⁇ m to 100 ⁇ m.
  • the film base can be metal plate, metal foil or PET plastic.
  • step S3 Heat and stir the first suspension prepared in step S2 at 60° C. for 5 minutes to form a stable and uniform colloidal solution for later use; the viscosity of the colloidal solution ranges from 300 cps to 2500 cps.
  • step S4 The second suspension prepared in step S2 is added to the colloidal solution prepared in step S3, mixed uniformly, and the obtained battery slurry is sieved with 50 meshes to form a uniform battery diaphragm slurry. Coating for use.
  • the mass of the solvent mixed with polyvinylidene fluoride-hexafluoropropylene accounts for 95% of the total solvent mass, and the mass of the solvent mixed with garlic powder accounts for 5% of the total solvent mass.
  • the viscosity range of the battery separator slurry is: 300 cps to 2000 cps.
  • the battery separator slurry prepared in step S4 is prepared into a film on a substrate using a film coater, and dried at room temperature for 30 minutes and then peeled from the substrate to prepare an onion separator with a thickness ranging from 10 ⁇ m to 100 ⁇ m.
  • the film base can be metal plate, metal foil or PET plastic.
  • the present invention provides a lithium battery separator, in which natural organic additives containing thioether compounds and/or thiol compounds are added to a film-forming polymer.
  • the film-forming polymer has a cross-linked network structure.
  • the molecular chains of the film-forming polymer are inserted into the pores of the natural organic powder, and the natural organic powder forms a chain in the cross-linked network structure. This effectively enhances the strength of the lithium battery diaphragm and prevents lithium dendrites from easily piercing the lithium battery diaphragm.
  • the metal ions in the natural organic powder can be chelated with sulfide-containing compounds and/or mercaptan compounds to form a charged chelate M + .
  • the invention also provides a method for preparing the lithium battery diaphragm.
  • the lithium battery separator prepared with the components and proportions provided by the present invention has excellent ion conductivity, electrolyte absorption rate and high voltage stability. In the battery system, it can reduce the occurrence of side reactions and help form a stable
  • the SEI film reduces the interface impedance and charge transfer resistance, reduces the battery overpotential, protects the lithium metal negative electrode, and inhibits the growth of lithium dendrites.
  • the LFP/diaphragm/Li battery prepared by using the diaphragm of the present invention has excellent cycle performance and rate performance, as well as a higher capacity. Experiments have shown that it is cycled at 2C, 4C and 10C respectively (DOD100%) 500 , 2000 and 3000 weeks, the capacity retention rate is above 95%.
  • the preparation method of the lithium battery diaphragm provided by the present invention is simple in process, easy to implement, and beneficial to improving production efficiency and saving production costs.
  • the overall performance of the lithium battery diaphragm is better than PP diaphragm, PE diaphragm, PP/PE diaphragm and polyvinylidene fluoride Base polymer diaphragm.

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Abstract

本发明公开一种锂电池隔膜，包含以下质量百分比的组分：成膜聚合物90％-99.9％，含硫醚类化合物和/或硫醇类化合物和/或磺酸类化合物的天然有机物添加剂0.1％-10％；所述成膜聚合物为聚偏氟乙烯-六氟丙烯和/或聚偏氟乙烯，所述天然有机物添加剂为干燥的天然有机物粉末；本发明还公开一种锂电池隔膜的制备方法。本发明通过将含硫醚类化合物和/或硫醇类化合物和/或磺酸类化合物的天然有机物添加剂加入至成膜聚合物中，成膜聚合物为交联网状结构，所述成膜聚合物的分子链插入所述天然有机物粉末的孔隙中，所述天然有机物粉末在交联网状结构中形成链结。从而有效增强锂电池隔膜的强度，避免锂枝晶轻易刺穿锂电池隔膜。

Description

一种锂电池隔膜及其制备方法 技术领域
本发明涉及锂电池隔膜技术领域，特别涉及一种锂电池隔膜及其制备方法。
背景技术
近年来，随着新能源电动汽车和智能电子设备的不断发展，市场对二次电池能量密度的需求在不断提升，目前锂离子电池是首选商业二次电池。然而锂离子电池正极材料的理论能量密度低，实际能提供的能量密度不到200mAh g -1(根据正极材料的质量计算)。而且商业正极材料能实现的容量已经接近其理论值，容量提升空间较小。面对新能源电动汽车和智能电子设备对二次电池能量密度需求的快速增长，寻找更高能量密度的电化学反应体系是制备高能量密度二次电池的关键。近年来，基于锂金属负极、高能量密度正极的二次电池，例如锂硫电池、锂碲电池等，成为研究热点。锂金属负极具有很高的理论储锂容量(3860mAh g -1)，配合高能量密度的正极，例如硫(1672mAh g -1)，制备出的新型锂基电池能提供远超于锂离子电池的实际容量。随着新型锂基电池技术的高速发展，它们有望在将来在模块化电池中提供远超锂离子电池的能量密度，进而大面积取代现有的锂离子电池。锂金属是新一代高能量密度二次电池的研究和应用极其重要的一部分，然而，锂金属在循环过程中面临着诸多问题，其中之一是锂枝晶生长。由于通过SEI膜的锂离子流量不稳定而且锂金属表面不平整，锂离子不均匀地沉积在锂金属表面，形成锂枝晶。在电池循环过程中，枝晶尖端有较强的电场，使更多的锂离子在上面沉积。锂枝晶在这种自增强的正反馈机制下加速积累，最终刺穿隔膜，导致电池短路，引起热失控、燃烧、甚至爆炸。如何抑制锂枝晶生长，并且使锂金属负极具备高循环性能和倍率性能，成为一个研究重点和难点。
因此，现有技术存在缺陷，需要改进。
发明内容
本发明要解决的技术问题是：提供一种锂电池隔膜及其制备方法，增强锂电池隔膜的强度，抑制锂枝晶的形成，避免电池短路引起的热失控、燃烧、甚至爆炸。
本发明的技术方案如下：提供一种锂电池隔膜，包含以下质量百分比的组分：
成膜聚合物  90％-99.9％，
含硫醚类化合物和/或硫醇类化合物和/或磺酸类化合物的天然有机物添加剂  0.1％-10％。
所述成膜聚合物为聚偏氟乙烯-六氟丙烯(PVdF-HFP)和/或聚偏氟乙烯(PVdF)，所述天然有机物添加剂为干燥的天然有机物粉末；所述聚偏氟乙烯-六氟丙烯和/或聚偏氟乙烯在锂电池隔膜中为交联网状结构，所述聚偏氟乙烯-六氟丙烯和/或聚偏氟乙烯的分子链插入所述天然有机物粉末的孔隙中，所述天然有机物粉末在交联网状结构中形成链结。所述聚偏氟乙烯-六氟丙烯和/或聚偏氟乙烯在锂电池隔膜中形成交联网状结构；干燥的天然有机物粉末颗粒含有大量的空隙，聚偏氟乙烯-六氟丙烯和/或聚偏氟乙烯的分子链可以进入到天然有机物粉末颗粒的孔隙中，使得天然有机物粉末能够在锂电池隔膜中形成链结。从而有效增强锂电池隔膜的强度，避免锂枝晶轻易刺穿锂电池隔膜。
天然有机物粉末颗粒可降低聚偏氟乙烯-六氟丙烯或聚偏氟乙烯的结晶度，提高无定形相的比例，有利于锂电池隔膜的孔洞形成，而且天然有机物粉末颗粒自身也存在大量的孔隙，从而可以吸收更多的电解液，提升了锂电池隔膜吸液率和电导率；而且天然无机物粉末颗粒的孔隙可作为离子传输的通道，允许离子以较低的迁移活化能通过，从而提高锂电池隔膜的离子的电导率，可降低电池内部的阻抗。
进一步地，天然有机物粉末中的含硫醚类化合物、硫醇类化合物会与天然有机物粉末中的金属离子螯合，形成带电螯合物M +。含有该电池隔膜的锂电池，带电螯合物M +便会存在于电解液中。锂金属 沉积的过程中，M +将吸附在金属表面而不被还原；如果发生不均匀的锂金属沉积，锂金属突起处会吸附更多的M +，形成静电屏蔽。这个带正电的屏蔽排斥了进入的锂离子，从而减缓了突起的生长。避免因出现锂枝晶刺穿隔膜，导致电池短路，引起热失控、燃烧、爆炸。
所述有机物粉末为大蒜粉末、洋葱粉末、芝麻粉末、大豆粉末中的一种或至少两种的组合；所述有机物粉末的粒径范围为：0.1μm-300μm。所述有机物粉末为有机物干燥后碾磨获得。
所述硫醚类化合物为：二烯丙基乙硫醚、二烯丙基二硫醚、二烯丙基三硫醚中的一种或至少两种的混合，所述硫醇类化合物为：烯丙基硫醇。所述磺酸类化合物为：烯丙基次磺酸和/或烯丙基亚磺酸
本发明还提供一种锂电池隔膜的制备方法，包括以下步骤。
S1：按一定质量百分比称取成膜聚合物、天然有机物添加剂，称取一定质量的溶剂，所述溶剂的质量占总质量的50％-95％。
S2：将成膜聚合物加入至溶剂中，搅拌均匀，形成悬浊液。
S3：将步骤S2中的悬浊液在一定的温度范围下搅拌10s-10min，形成均一的胶状溶液；所述温度范围为：30℃-95℃。该步骤中成膜聚合物完全溶解于溶剂中，形成一个交联网状结构。所述胶状溶液的粘度范围为：300cps～2000cps。
S4：将天然有机物添加剂加入至步骤S3中的胶状溶液中，混合均匀，形成均一的电池隔膜浆料。该步骤中，天然有机物添加剂被溶剂溶胀，同时，成膜聚合物的分子链进入到天然有机物添加剂的空隙中，天然有机物添加剂在交联网状结构中充当链结。所述电池隔膜浆料的粘度范围为：300cps～2000cps。
S5：将步骤S4中的电池隔膜浆料采用涂布或电泳或提拉的方法制成锂电池隔膜。天然有机添加剂在成膜聚合物形成的交联网状结构中充当链结，从而有效增强锂电池隔膜的强度，避免锂枝晶轻易刺穿锂电池隔膜。
所述溶剂为：丙酮、N-甲基吡咯烷酮(NMP)、二甲基乙酰胺(DMAc)、二甲基甲酰胺(DMF)、二甲基亚砜(DMSO)、二乙基乙酰胺(DEAc)、磷酸三甲酯(TMP)、磷酸三乙酯(TEP)、六甲基磷酸铵(HMPA) 和四甲基尿(TMU)中的一种或至少两种的混合；在步骤S3中，所述温度范围为：40℃-90℃。
在步骤S4中，采用加热搅拌混合或球磨混合，可增强进入到天然有机物添加剂孔隙中的成膜聚合物的分子链的数量，增强天然有机物添加剂与成膜聚合物分子链的连接。在步骤S4中，还包括：对所述电池隔膜浆料进行50目的过筛处理。
本发明还提供一种锂电池隔膜的制备方法，包括以下步骤：
SS1：按一定质量百分比称取成膜聚合物、天然有机物添加剂，称取一定质量的溶剂，所述溶剂的质量占总质量的50％-95％。
SS2：将成膜聚合物加入至部分溶剂中，搅拌均匀，形成第一悬浊液；将天然有机物添加剂加入至剩余的溶剂中，搅拌均匀，形成第二悬浊液。在该步骤中，天然有机物添加剂被溶剂浸润和溶胀。与成膜聚合物混合的溶剂的质量占总溶剂质量的85％～95％，与天然有机物添加剂混合的溶剂的质量占总溶剂质量的5％～15％。
SS3：将步骤SS2中的第一悬浊液在一定的温度范围下搅拌10s-10min，形成均一的胶状溶液；所述温度范围为：30℃-95℃。该步骤中成膜聚合物完全溶解于溶剂中，形成一个交联网状结构。所述胶状溶液的粘度范围为：300cps～2500cps。
SS4：将步骤SS2中的第二悬浊液加入至步骤SS3中的胶状溶液中，混合均匀，形成均一的电池隔膜浆料。在该步骤中，成膜聚合物的分子链进入到天然有机物添加剂的空隙中，天然有机物添加剂在交联网状结构中充当链结。所述电池隔膜浆料的粘度范围为：300cps～2000cps。
SS5：将步骤SS4中的电池隔膜浆料采用涂布或电泳或提拉的方法制成锂电池隔膜。天然有机添加剂在成膜聚合物形成的交联网状结构中充当链结，从而有效增强锂电池隔膜的强度，避免锂枝晶轻易刺穿锂电池隔膜。
所述溶剂为：丙酮、N-甲基吡咯烷酮(NMP)、二甲基乙酰胺(DMAc)、二甲基甲酰胺(DMF)、二甲基亚砜(DMSO)、二乙基乙酰胺(DEAc)、磷酸三甲酯(TMP)、磷酸三乙酯(TEP)、六甲基磷酸铵(HMPA) 和四甲基尿(TMU)中的一种或至少两种的混合。
在步骤SS2中，还包括将第二悬浊液进行球磨一段时间；在步骤SS3中，所述温度范围为：40℃-90℃。
在步骤SS4中，采用加热搅拌混合或球磨混合；在步骤S4中，还包括：对所述电池隔膜浆料进行50目的过筛处理。
采用上述方案，本发明提供一种锂电池隔膜，将含硫醚类化合物和/或硫醇类化合物和/或磺酸类化合物的天然有机物添加剂加入至成膜聚合物中，成膜聚合物为交联网状结构，所述成膜聚合物的分子链插入所述天然有机物粉末的孔隙中，所述天然有机物粉末在交联网状结构中形成链结。从而有效增强锂电池隔膜的强度，避免锂枝晶轻易刺穿锂电池隔膜。天然有机物粉末中的金属离子可与含硫醚类化合物和/或硫醇类化合物螯合，形成带电螯合物M +。锂金属沉积的过程中，M +将吸附在金属表面而不被还原；如果发生不均匀的锂金属沉积，锂金属突起处会吸附更多的M +，形成静电屏蔽。这个带正电的屏蔽排斥了进入的锂离子，从而减缓了突起的生长。避免因出现锂枝晶刺穿隔膜，导致电池短路，引起热失控、燃烧、爆炸。本发明还提供一种锂电池隔膜的制备方法。
附图说明
图1为本发明的实施例1的方法流程图；
图2为实施例1制备的大蒜隔膜、PVdF-HFP隔膜和PP隔膜的离子电导率图；
图3为实施例1制备的大蒜隔膜、PVdF-HFP隔膜和PP隔膜的吸液率图；
图4为实施例1制备的大蒜隔膜、PVdF-HFP隔膜和PP隔膜的LSV测试；
图5为分别由实施例1制备的大蒜隔膜、PVdF-HFP隔膜和PP隔膜组装的Li/隔膜/Li对称电池的电压与循环时间的关系图；
图6为分别由实施例1制备的大蒜隔膜、PVdF-HFP隔膜和PP隔膜组装的Li/隔膜/Li对称电池的阻抗测试图；
图7为分别由实施例1制备的大蒜隔膜、PVdF-HFP隔膜和PP隔膜组装的Li/隔膜/Cu电池的库伦效率图；
图8为分别由实施例1制备的大蒜隔膜、PVdF-HFP隔膜和PP隔膜组装的Li/隔膜/Cu电池的电压-容量曲线图；
图9为分别由实施例1制备的大蒜隔膜、PVdF-HFP隔膜和PP隔膜组装的Li/隔膜/Cu电池的电压滞后(过电位)图；
图10为分别由实施例1制备的大蒜隔膜、PVdF-HFP隔膜和PP隔膜组装的LFP/隔膜/Li电池的Nyquist阻抗图；
图11为分别由实施例1制备的大蒜隔膜、PVdF-HFP隔膜和PP隔膜组装的LFP/隔膜/Li电池在2C充放电倍率下的循环性能图；
图12为分别由实施例1制备的大蒜隔膜、PVdF-HFP隔膜和PP隔膜组装的LFP/隔膜/Li电池在4C充放电倍率下的循环性能图；
图13为分别由实施例1制备的大蒜隔膜、PVdF-HFP隔膜和PP隔膜组装的LFP/隔膜/Li电池在10C充放电倍率下的循环性能图；
图14为分别由实施例1制备的大蒜隔膜、PVdF-HFP隔膜和PP隔膜组装的LFP/隔膜/Li电池在2C充放电倍率下的电压滞后(过电位)图；
图15为分别由实施例1制备的大蒜隔膜、PVdF-HFP隔膜和PP隔膜组装的LFP/隔膜/Li电池在4C充放电倍率下的电压滞后(过电位)图；
图16为分别由实施例1制备的大蒜隔膜、PVdF-HFP隔膜和PP隔膜组装的LFP/隔膜/Li电池在10C充放电倍率下的电压滞后(过电位)图。
具体实施方式
以下结合附图和具体实施例，对本发明进行详细说明。
实施例1
本发明提供一种锂电池隔膜，在本实施例中，包含以下质量百分比的组分：
聚偏氟乙烯-六氟丙烯  95％，
大蒜粉末  5％。
所述聚偏氟乙烯-六氟丙烯在锂电池隔膜中形成交联网状结构；干燥的大蒜粉末含有大量的空隙，聚偏氟乙烯-六氟丙烯的分子链可以进入到大蒜粉末的孔隙中，使得大蒜粉末能够在锂电池隔膜中形成链结。从而有效增强锂电池隔膜的强度，避免锂枝晶轻易刺穿锂电池隔膜。
请参阅图1，本发明还提供一种锂电池隔膜的制备方法：在本实施例中，包括以下步骤：
S1：称取质量百分比为95％的聚偏氟乙烯-六氟丙烯、5％的大蒜粉末，并称取一定质量的溶剂，按质量比计算，溶剂控制在浆料总量的80％；
S2：将聚偏氟乙烯-六氟丙烯加入到部分溶剂中，搅拌形成第一悬浊液备用；将大蒜粉末分散到剩余溶剂中，使用球磨机球磨100分钟形成第二悬浊液；
S3：将步骤S2制备的第一悬浊液在40℃下加热搅拌10min，形成稳定均一的胶状溶液备用；所述胶状溶液的粘度范围为：300cps～2500cps。
S4：将步骤S2中制备的第二悬浊液加入到步骤S3制备的胶状溶液中，混合均匀，将得到的电池浆料进行50目的过筛处理，形成均一的电池隔膜浆料，以作涂布备用。与聚偏氟乙烯-六氟丙烯混合的溶剂的质量占总溶剂质量的85％，与大蒜粉末混合的溶剂的质量占总溶剂质量的15％。所述电池隔膜浆料的粘度范围为：300cps～2000cps。
S5：将步骤S4制备的电池隔膜浆料使用涂膜机在基底上制备成膜，室温下干燥30分钟后从基底剥离，制得大蒜隔膜，厚度范围为10μm～100μm。其中，制膜基底可以选择金属板、金属箔或PET塑料。
在同一条件下测试步骤S5中获得的大蒜隔膜、聚偏氟乙烯-六氟丙烯隔膜、PP隔膜的离子电导率、电解液吸收率和LSV测试；将步骤S5中获得的大蒜隔膜、聚偏氟乙烯-六氟丙烯隔膜、PP隔膜分别组装成电池，测试三种不同隔膜的组装的电池性能，包括：Li/隔膜/Li 对称电池的电压与循环时间的关系，其中每半周期持续30分钟；15次循环前后Li/隔膜/Li对称电池的阻抗测试；Li/隔膜/Cu电池的库伦效率、电压-容量曲线、电压滞后(过电位)；LFP/隔膜/Li电池的Nyquist阻抗；LFP/隔膜/Li电池的循环性能、电压滞后(过电位)。
请参阅图2，图2为大蒜隔膜、聚偏氟乙烯-六氟丙烯隔膜、PP隔膜的离子电导率图，从图中可以看出，大蒜隔膜具有比聚偏氟乙烯-六氟丙烯隔膜和PP隔膜更高的离子电导率。请参阅图3，大蒜隔膜具有比聚偏氟乙烯-六氟丙烯隔膜和PP隔膜更高的吸液量，大蒜粉末可降低聚偏氟乙烯-六氟丙烯或聚偏氟乙烯的结晶度，提高无定形相的比例，有利于锂电池隔膜的孔洞形成，而且天然有机物粉末颗粒自身也存在大量的孔隙，从而可以吸收更多的电解液，提升了锂电池隔膜吸液率和电导率。
请参阅图4，大蒜隔膜和聚偏氟乙烯-六氟丙烯隔膜的LSV测试显示出高于5V(相对于Li +/Li)的稳定性，均高于PP隔膜的4.7V。大蒜隔膜的较宽的电化学稳定性来自聚合物主体材料，同时，大蒜粉末的高润湿性和电解液吸收进一步扩大了电化学窗口。广泛的电化学稳定性表明，大蒜隔膜适用于更高电压的电池环境。
请参阅图5，Li/PVdF-HFP隔膜/Li对称电池和Li/PP隔膜/Li对称电池都在循环不到700小时时发生短路，这是电池内严重的副反应引起的电池故障。相反，含的Li/大蒜隔膜/Li对称电池在整个2000小时的测试期间内，表现出优异的循环稳定性。
请参阅图6，在Li/隔膜/Li对称电池循环前后进行了EIS测试，测试频率范围为100MHz-100kHz，电压信号幅值10mV。EIS测试通常用以研究SEI层的界面电阻和锂金属表面上的电荷转移电阻。可以看出，Li/PVdF-HFP隔膜/Li对称电池和Li/PP隔膜/Li对称电池的EIS在循环之前分别表现出～130Ω和～140Ω的高阻抗。在15次充电/放电循环后，界面阻抗分别降至～80Ω和～100Ω。然而，Li/大蒜隔膜/Li对称电池在循环前显示出约36Ω的阻抗，在循环后显示出约16Ω的低阻抗，这归因于SEI的低电荷转移电阻和更低的离子扩散电阻。
请参阅图7、图8和图9，与Li/PVdF-HFP隔膜/Cu电池、Li/PP 隔膜/Cu电池相比，Li/大蒜隔膜/Cu电池展示出更高的库仑效率和循环稳定性。而且Li/大蒜隔膜/Cu电池也表现出最低的电压滞后(过电位)。电压在早期循环中开始于～0.03V，然后降至～0.02V并在整个350个循环中将过电位维持在～0.2V。另一方面，Li/PVdF-HFP隔膜/Cu电池、Li/PP隔膜/Cu电池的过电位随着循环次数的增加而上升明显。这些结果明确地表明，大蒜隔膜为锂金属表面提供了充分保护作用。
请参阅图10，LFP/大蒜隔膜/Li电池表现出较低的离子扩散电阻～25Ω，而LFP/PVdF-HFP隔膜/Li电池和LFP/PP隔膜/Li电池的阻抗分别为～72Ω和～84Ω。
请参阅图11、图12和图13，在高电流密度下循环时，LFP/PVdF-HFP隔膜/Li电池和LFP/PP隔膜/Li电池都显示出了连续的容量衰减，证明PVdF-HFP隔膜和PP隔膜不足以维持电池长期的循环稳定性；相反，大蒜隔膜可以使电池长期稳定地循环充放电。LFP/大蒜隔膜/Li电池在2C、4C和10C充放电倍率下的平均放电容量为130mAh g -1、109mAh g -1和96mAh g -1，高于LFP/PVdF-HFP隔膜/Li电池的110mAh g -1、87mAh g -1和57mAh g -1，LFP/PP隔膜/Li电池的107mAh g -1、67mAh g -1和53mAh g -1。
请参阅图14、图15和图16，在2C、4C和10C充放电倍率下，含的LFP/大蒜隔膜/Li电池的电压滞后(过电位)数值最低、增速最慢。然而，LFP/PVdF-HFP隔膜/Li电池和LFP/PP隔膜/Li电池的过电位的增长较快，其中，LFP/PP隔膜/Li电池的过电位数值最高、增速最快。
实施例2
本发明提供一种锂电池隔膜，在本实施例中，包含以下质量百分比的组分：
聚偏氟乙烯-六氟丙烯  90％，
洋葱粉末  10％。
所述聚偏氟乙烯-六氟丙烯在锂电池隔膜中形成交联网状结构； 干燥的洋葱粉末含有大量的空隙，聚偏氟乙烯-六氟丙烯的分子链可以进入到洋葱粉末的孔隙中，使得洋葱粉末能够在锂电池隔膜中形成链结。从而有效增强锂电池隔膜的强度，避免锂枝晶轻易刺穿锂电池隔膜。
本发明还提供一种锂电池隔膜的制备方法：在本实施例中，包括以下步骤：
S1：称取质量百分比为90％的聚偏氟乙烯-六氟丙烯、10％的洋葱粉末，并称取一定质量的溶剂，按质量比计算，溶剂控制在浆料总量的95％；
S2：将聚偏氟乙烯-六氟丙烯加入到部分溶剂中，搅拌形成第一悬浊液备用；将洋葱粉末分散到剩余溶剂中，使用球磨机球磨100分钟形成第二悬浊液；
S3：将步骤S2制备的第一悬浊液在90℃下加热搅拌10s，形成稳定均一的胶状溶液备用；所述胶状溶液的粘度范围为：300cps～2500cps。
S4：将步骤S2中制备的第二悬浊液加入到步骤S3制备的胶状溶液中，混合均匀，将得到的电池浆料进行50目的过筛处理，形成均一的电池隔膜浆料，以作涂布备用。与聚偏氟乙烯-六氟丙烯混合的溶剂的质量占总溶剂质量的90％，与大蒜粉末混合的溶剂的质量占总溶剂质量的10％。所述电池隔膜浆料的粘度范围为：300cps～2000cps。
S5：将步骤S4制备的电池隔膜浆料使用涂膜机在基底上制备成膜，室温下干燥30分钟后从基底剥离，制得洋葱隔膜，厚度范围为10μm～100μm。其中，制膜基底可以选择金属板、金属箔或PET塑料。
实施例3
本发明提供一种锂电池隔膜，在本实施例中，包含以下质量百分比的组分：
聚偏氟乙烯-六氟丙烯  99.9％，
芝麻粉末  0.1％。
所述聚偏氟乙烯-六氟丙烯在锂电池隔膜中形成交联网状结构；干燥的芝麻粉末含有大量的空隙，聚偏氟乙烯-六氟丙烯的分子链可以进入到芝麻粉末的孔隙中，使得芝麻粉末能够在锂电池隔膜中形成链结。从而有效增强锂电池隔膜的强度，避免锂枝晶轻易刺穿锂电池隔膜。
本发明还提供一种锂电池隔膜的制备方法：在本实施例中，包括以下步骤：
S1：称取质量百分比为99.9％的聚偏氟乙烯-六氟丙烯、0.1％的芝麻粉末，并称取一定质量的溶剂，按质量比计算，溶剂控制在浆料总量的50％；
S2：将聚偏氟乙烯-六氟丙烯加入到部分溶剂中，搅拌形成第一悬浊液备用；将芝麻粉末分散到剩余溶剂中，使用球磨机球磨100分钟形成第二悬浊液；
S3：将步骤S2制备的第一悬浊液在60℃下加热搅拌5min，形成稳定均一的胶状溶液备用；所述胶状溶液的粘度范围为：300cps～2500cps。
S4：将步骤S2中制备的第二悬浊液加入到步骤S3制备的胶状溶液中，混合均匀，将得到的电池浆料进行50目的过筛处理，形成均一的电池隔膜浆料，以作涂布备用。与聚偏氟乙烯-六氟丙烯混合的溶剂的质量占总溶剂质量的95％，与大蒜粉末混合的溶剂的质量占总溶剂质量的5％。所述电池隔膜浆料的粘度范围为：300cps～2000cps。
S5：将步骤S4制备的电池隔膜浆料使用涂膜机在基底上制备成膜，室温下干燥30分钟后从基底剥离，制得洋葱隔膜，厚度范围为10μm～100μm。其中，制膜基底可以选择金属板、金属箔或PET塑料。
综上所述，本发明提供一种锂电池隔膜，将含硫醚类化合物和/或硫醇类化合物的天然有机物添加剂加入至成膜聚合物中，成膜聚合物为交联网状结构，所述成膜聚合物的分子链插入所述天然有机物粉末的孔隙中，所述天然有机物粉末在交联网状结构中形成链结。从而有效增强锂电池隔膜的强度，避免锂枝晶轻易刺穿锂电池隔膜。天然 有机物粉末中的金属离子可与含硫醚类化合物和/或硫醇类化合物螯合，形成带电螯合物M +。锂金属沉积的过程中，M+将吸附在金属表面而不被还原；如果发生不均匀的锂金属沉积，锂金属突起处会吸附更多的M +，形成静电屏蔽。这个带正电的屏蔽排斥了进入的锂离子，从而减缓了突起的生长。避免因出现锂枝晶刺穿隔膜，导致电池短路，引起热失控、燃烧、爆炸。本发明还提供一种锂电池隔膜的制备方法。
以本发明提供的各组分及配比制备出的锂电池隔膜，具有优异的离子电导率、电解液吸收率及高电压稳定性，在电池系统中，能减少副反应发生，帮助形成稳定的SEI膜，减少界面阻抗和电荷转移阻抗，降低电池过电位，保护锂金属负极，抑制锂枝晶成长。利用本发明中的隔膜制备出的LFP/隔膜/Li电池，具有优异的循环性能和倍率性能，以及较高的容量，实验证明：在2C、4C和10C的倍率下分别循环(DOD100％)500、2000和3000周，容量保持率均在95％以上。
本发明提供的锂电池隔膜的制备方法工艺简单，易于实施，有利于提高生产效率、节约生产成本，该锂电池隔膜的综合性能优于PP隔膜、PE隔膜、PP/PE隔膜和聚偏氟乙烯基聚合物隔膜。
以上仅为本发明的较佳实施例而已，并不用于限制本发明，凡在本发明的精神和原则之内所作的任何修改、等同替换和改进等，均应包含在本发明的保护范围之内。

Claims (9)

  1. 一种锂电池隔膜，包含以下质量百分比的组分：
    成膜聚合物 90％-99.9％，
    含硫醚类化合物和/或硫醇类化合物和/或磺酸类化合物的天然有机物添加剂 0.1％-10％；
    所述成膜聚合物为聚偏氟乙烯-六氟丙烯和/或聚偏氟乙烯，所述天然有机物添加剂为干燥的天然有机物粉末；所述聚偏氟乙烯-六氟丙烯和/或聚偏氟乙烯在锂电池隔膜中为交联网状结构，所述聚偏氟乙烯-六氟丙烯和/或聚偏氟乙烯的分子链插入所述天然有机物粉末的孔隙中，所述天然有机物粉末在交联网状结构中形成链结；
    所述有机物粉末为大蒜粉末、洋葱粉末、芝麻粉末、大豆粉末中的一种或至少两种的组合。
  2. 根据权利要求1所述的一种锂电池隔膜，其中，所述硫醚类化合物为：二烯丙基乙硫醚、二烯丙基二硫醚、二烯丙基三硫醚中的一种或至少两种的组合，所述硫醇类化合物为：烯丙基硫醇，所述磺酸类化合物为：烯丙基次磺酸和/或烯丙基亚磺酸。
  3. 一种权利要求1-2任一项所述的锂电池隔膜的制备方法，包括以下步骤：
    S1：按一定质量百分比称取成膜聚合物、天然有机物添加剂，称取一定质量的溶剂，所述溶剂的质量占总质量的50％-95％；
    S2：将成膜聚合物加入至溶剂中，搅拌均匀，形成悬浊液；
    S3：将步骤S2中的悬浊液在一定的温度范围下搅拌10s-10min，形成均一的胶状溶液；所述温度范围为：30℃-95℃。
    S4：将天然有机物添加剂加入至步骤S3中的胶状溶液中，混合均匀，形成均一的电池隔膜浆料；
    S5：将步骤S4中的电池隔膜浆料采用涂布或电泳或提拉的方法制成锂电池隔膜。
  4. 根据权利要求3所述的一种锂电池隔膜的制备方法，其中，所述溶剂为：丙酮、N-甲基吡咯烷酮(NMP)、二甲基乙酰胺(DMAc)、 二甲基甲酰胺(DMF)、二甲基亚砜(DMSO)、二乙基乙酰胺(DEAc)、磷酸三甲酯(TMP)、磷酸三乙酯(TEP)、六甲基磷酸铵(HMPA)和四甲基尿(TMU)中的一种或至少两种的混合；在步骤S3中，所述温度范围为：40℃-90℃。
  5. 根据权利要求3所述的一种锂电池隔膜的制备方法，其中，在步骤S4中，采用加热搅拌混合或球磨混合；在步骤S4中，还包括：对所述电池隔膜浆料进行50目的过筛处理。
  6. 一种权利要求1-2任一项所述的锂电池隔膜的制备方法，包括以下步骤：
    SS1：按一定质量百分比称取成膜聚合物、天然有机物添加剂，称取一定质量的溶剂，所述溶剂的质量占总质量的50％-95％；
    SS2：将成膜聚合物加入至部分溶剂中，搅拌均匀，形成第一悬浊液；将天然有机物添加剂加入至剩余的溶剂中，搅拌均匀，形成第二悬浊液；
    SS3：将步骤SS2中的第一悬浊液在一定的温度范围下搅拌10s-10min，形成均一的胶状溶液；所述温度范围为：30℃-95℃；
    SS4：将步骤SS2中的第二悬浊液加入至步骤SS3中的胶状溶液中，混合均匀，形成均一的电池隔膜浆料；
    SS5：将步骤SS4中的电池隔膜浆料采用涂布或电泳或提拉的方法制成锂电池隔膜。
  7. 根据权利要求6所述的一种锂电池隔膜的制备方法，其中，所述溶剂为：丙酮、N-甲基吡咯烷酮(NMP)、二甲基乙酰胺(DMAc)、二甲基甲酰胺(DMF)、二甲基亚砜(DMSO)、二乙基乙酰胺(DEAc)、磷酸三甲酯(TMP)、磷酸三乙酯(TEP)、六甲基磷酸铵(HMPA)和四甲基尿(TMU)中的一种或至少两种的混合。
  8. 根据权利要求6所述的一种锂电池隔膜的制备方法，其中，在步骤SS2中，还包括将第二悬浊液进行球磨一段时间；在步骤SS3中，所述温度范围为：40℃-90℃；与成膜聚合物混合的溶剂的质量占总溶剂质量的85％～95％，与天然有机物添加剂混合的溶剂的质量占总溶剂质量的5％～15％。
  9. 根据权利要求6所述的一种锂电池隔膜的制备方法，其中，在步骤SS4中，采用加热搅拌混合或球磨混合；在步骤SS4中，还包括：对所述电池隔膜浆料进行50目的过筛处理。
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