WO2023125545A1 - 一种电解质膜及其制备方法和电池 - Google Patents

一种电解质膜及其制备方法和电池 Download PDF

Info

Publication number
WO2023125545A1
WO2023125545A1 PCT/CN2022/142381 CN2022142381W WO2023125545A1 WO 2023125545 A1 WO2023125545 A1 WO 2023125545A1 CN 2022142381 W CN2022142381 W CN 2022142381W WO 2023125545 A1 WO2023125545 A1 WO 2023125545A1
Authority
WO
WIPO (PCT)
Prior art keywords
lithium
electrolyte membrane
block
imide
formula
Prior art date
Application number
PCT/CN2022/142381
Other languages
English (en)
French (fr)
Inventor
莫肇华
赵伟
唐伟超
张赵帅
李素丽
Original Assignee
珠海冠宇电池股份有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 珠海冠宇电池股份有限公司 filed Critical 珠海冠宇电池股份有限公司
Publication of WO2023125545A1 publication Critical patent/WO2023125545A1/zh

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0565—Polymeric materials, e.g. gel-type or solid-type
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • 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

  • the present disclosure relates to the technical field of batteries, in particular to an electrolyte membrane, a preparation method thereof, and a battery including the electrolyte membrane.
  • Lithium-ion batteries have been widely used due to their high energy density, long cycle life, and environmental friendliness.
  • researchers used gel electrolyte membranes instead of separators to improve the safety performance of batteries.
  • the commonly used gel electrolyte membrane is formed by adding a small amount of electrolyte swelling to polyether, polymethyl methacrylate, polyvinylidene fluoride and polyvinylidene fluoride-hexafluoropropylene copolymer.
  • the lithium ion conductivity of the above-mentioned gel electrolyte membrane mainly comes from the lithium salt in the electrolyte. Under the action of the potential, there is a concentration difference polarization between the lithium ion and the anion, which will reduce the potential of the battery and the migration rate of the lithium ion. thereby reducing the conductivity.
  • the migration number of lithium ions is low ( ⁇ 0.5), which will eventually seriously affect the energy density and cycle performance of the battery.
  • the present disclosure provides a single lithium ion polymer electrolyte membrane and a battery using the electrolyte membrane.
  • An electrolyte membrane includes a block copolymer, the block copolymer includes an A block and a B block, the A block has a structural unit shown in formula 2, and the B block has The structural unit shown in formula 3,
  • R 1 is H, C 1-4 alkyl, exemplarily H or methyl
  • R 2 is a lithium sulfonate group or a lithium sulfonylimide group
  • R is C 1-6 alkyl, exemplified by methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl and isomers thereof, n-Hexane and its isomers;
  • R 4 is H, C 1-4 alkyl, exemplarily H or methyl
  • R is selected from C 1-4 alkylene (such as methylene, ethylene, propylene or 2-methylpropylene), exemplified by absence, phenyl, amido or amido C 1-4 alkylene (for example, methylene, ethylene, propylene or 2-methylpropylene).
  • the A block and the B block can be connected in various ways.
  • the block copolymer is an AB block copolymer, wherein both the A block and the B block exist in the form of long chains.
  • the block copolymer is an ABA-type or BAB-type block copolymer, wherein both the A block and the B block exist in the form of long chains.
  • the block copolymer is an (AB) n -type block copolymer, wherein both the A block and the B block exist in the form of relatively short chains.
  • the A block may be referred to as a polymer lithium salt segment
  • the B block may be referred to as a polyester segment.
  • the total weight content of the A block (polymer lithium salt segment) (denoted as y) is 30-60wt% (exemplarily 30wt%, 40wt%) %, 50wt%, 60wt%)
  • the total weight content of the B block (polyester segment) (denoted as x) is 40 to 70wt% (exemplarily 40wt%, 50wt%, 60wt%, 70wt%) %).
  • y is 0.3 ⁇ 0.6, and is exemplarily 0.3, 0.4, 0.5, 0.6.
  • x is 0.7 ⁇ 0.4, and is exemplarily 0.7, 0.6, 0.5, 0.4.
  • the A block (polymer lithium salt segment) content When the A block (polymer lithium salt segment) content is too much, it may cause excessive swelling or even dissolution of the block copolymer in the electrolyte; and when the A block (polymer lithium salt segment) content is too small, it may As a result, the ion transport network membrane cannot be constructed so that the ion conductivity is low; and too much or too little A block (polymer lithium salt segment) cannot make the block copolymer form a microscopic phase separation structure of a bicontinuous phase, resulting in Decrease in Li-ion conductivity.
  • the molecular weight of the block polymer is 100,000-1,000,000.
  • the A block (polymer lithium salt segment) can be derived (for example, chain opening and polymerization) from a lithium salt monomer containing an olefinic double bond of the structure shown in formula II,
  • the B block (polyester segment) can be derived (for example, open chain and polymerized) from the acrylate monomer of the structure shown in formula III,
  • the R2 is selected from the following structures:
  • the block copolymer includes several structural units shown in formula 2 and formula 3, and in each structural unit, R 1 , R 2 , R 3 , R 4 , R 5 , R
  • the choices of 6 are all independent, and the choices among the structural units can be the same or different.
  • the lithium salt containing an olefinic double bond is one, two or more of the following lithium salts: lithium p-styrenesulfonate (LiPS), (p-styrenesulfonyl) (trifluoro Lithium methylsulfonyl)imide (LiPSTFSI), lithium (p-styrenesulfonyl)(fluorosulfonyl)imide (LiPSFSI), (p-styrenesulfonyl)[trifluoromethyl(S-trifluoromethyl Lithium sulfonylimide)sulfonyl]imide, lithium vinylsulfonate, lithium (vinylsulfonyl)(trifluoromethylsulfonyl)imide, (vinylsulfonyl)(fluorosulfonyl)imide Lithium, lithium propenesulfonate, lithium (propenylsulfonate,
  • the acrylate monomer is one, two or more of the following: methyl methacrylate (MMA), ethyl methacrylate (EMA), propyl methacrylate, Butyl methacrylate, pentyl methacrylate, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate (BA) and pentyl acrylate, etc.
  • the material of the electrolyte membrane is the block copolymer.
  • the electrolyte membrane may also contain other conventional materials used for electrolyte membranes in the art.
  • the weight percentage of the block copolymer in the electrolyte membrane is more than or equal to 60wt%.
  • weight percentages all refer to weight percentages based on dry weight.
  • the electrolyte membrane of the present disclosure may be produced and sold in a dry state.
  • the electrolyte membrane further contains a solvent for the electrolyte.
  • the solvent for the electrolyte includes but is not limited to propylene carbonate (PC), ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC) and methyl ethyl carbonate At least one of esters (EMC).
  • PC propylene carbonate
  • EC ethylene carbonate
  • DEC diethyl carbonate
  • DMC dimethyl carbonate
  • EMC methyl ethyl carbonate
  • a mixed solvent of EC, DEC, and DMC is preferred.
  • the volume ratio of EC, DEC, and DMC is (0.5-2):(0.5-2):(0.5-2), for example, 1:1:1.
  • the second aspect of the present disclosure also provides the preparation method of the electrolyte membrane described in the first aspect, the method comprising: using a lithium salt monomer containing an alkene double bond including a structure shown in formula II and a lithium salt monomer including a structure shown in formula III Acrylate monomers are used as raw materials, and polymerization reactions occur under the action of initiators;
  • the olefinic double bond-containing lithium salt monomer having the structure represented by formula II and the acrylate monomer having the structure represented by formula III have the same selection and mass ratio as described above.
  • the mass of the lithium salt monomer containing olefinic double bonds accounts for 30-60% of the total mass of the monomers (lithium salt monomers containing olefinic double bonds and acrylate monomers) , Exemplarily, it is 30%, 40%, 50%, 60%, or any value within the range formed by the aforementioned pairwise values.
  • the polymerization is carried out under an initiator.
  • the amount of the initiator is 0.1% to 3% of the mass of the lithium salt monomer containing olefinic double bonds, exemplarily 0.1%, 0.5%, 1%, 2%, 3% or It is any point value within the range composed of the aforementioned pairwise values.
  • the initiator is a free radical initiator, such as sodium persulfate, azobisisobutyronitrile (AIBN), cyclohexanone peroxide, dibenzoyl peroxide and tert-butyl hydroperoxide, etc. at least one of the
  • the polymerization is performed in a solvent system.
  • the solvent includes, but is not limited to, one, two or more of water, DMF, acetone, acetonitrile, NMP, DMAc and DMSO.
  • the polymerization is performed under an inert atmosphere.
  • the inert atmosphere may be in nitrogen and/or argon.
  • the polymerization temperature is 60-90°C, exemplarily 60°C, 70°C, 80°C, 85°C, 90°C.
  • the polymerization time is 4-12 hours, exemplarily 4 hours, 6 hours, 8 hours, 10 hours, 12 hours.
  • a mixed solution including the block copolymer described in the first aspect can be obtained.
  • the electrolyte membrane can be obtained.
  • the preparation method further includes: pouring the mixed solution onto a substrate for casting, and evaporating the solvent to obtain the block copolymer.
  • the method of evaporating the solvent to dryness is drying.
  • the drying temperature is 40-100° C.
  • the drying time is 8-24 hours.
  • the preparation method further includes: soaking the block copolymer in an electrolyte solution to swell to obtain the electrolyte membrane.
  • the swelling temperature is 40-60°C, exemplarily 40°C, 45°C, 50°C, 60°C; the swelling time is 6-24h, exemplarily 6-12h, exemplarily 6h , 8h, 12h, 24h.
  • the solvent in the electrolyte includes but is not limited to at least one of PC, EC, DEC, DMC and EMC.
  • a mixed solvent of EC, DEC, and DMC is preferred.
  • said block copolymers of type AB are obtained.
  • the preparation method of the block copolymer electrolyte membrane includes the following steps:
  • step (b) performing a second polymerization on the mixture of the material obtained in step (a) and the acrylate monomer represented by formula III.
  • the method further includes step (c), pouring the material in step (b) onto the substrate to cast and evaporating the solvent to obtain a block copolymer film.
  • the method further includes step (d), immersing the block copolymer film in an electrolyte solution to swell.
  • the preparation method of the block copolymer electrolyte membrane includes the following steps:
  • step (b) In the reaction mixture after the polymerization in step (a), add the acrylate monomer shown in formula III to continue polymerization for 4-12 hours;
  • step (c) pouring the material in step (b) onto the substrate for casting and evaporating the solvent in an oven to obtain a block copolymer film;
  • the present disclosure also provides an application of the above electrolyte membrane in a battery.
  • the present disclosure also provides a battery including the above electrolyte membrane.
  • the battery further includes a positive electrode sheet and a negative electrode sheet.
  • the positive electrode active material of the positive electrode sheet is selected from lithium cobalt oxide, lithium iron phosphate (LiFePO 4 ), lithium cobalt oxide (LiCoO 2 ), lithium nickel cobalt manganate, lithium manganate (LiMnO 2 ) , lithium nickel cobalt aluminate, lithium nickel cobalt manganese aluminate, nickel cobalt aluminum tungsten material, lithium-rich manganese-based solid solution positive electrode material, lithium nickel cobalt oxide, lithium nickel titanium magnesium oxide, lithium nickelate (Li 2 NiO 2 ), tip At least one of spar lithium manganese oxide (LiMn 2 O 4 ), spinel lithium nickel manganese oxide (LNMO), and nickel-cobalt-tungsten materials.
  • the negative electrode active material of the negative electrode sheet is selected from at least one of carbon-based, silicon-based, metallic lithium, and metallic lithium alloy materials.
  • the positive electrode sheet and the negative electrode sheet optionally contain a binder and/or a conductive agent.
  • the positive electrode binder is selected from at least one of polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene and its copolymer derivatives;
  • the negative electrode binder is selected from polyacrylic acid, poly At least one of acrylate, styrene-butadiene rubber (SBR), sodium carboxymethylcellulose (CMC) and its copolymer derivatives.
  • the conductive agent may be at least one of conductive carbon black (SP), Ketjen black, conductive fiber, conductive polymer, acetylene black, carbon nanotube (CNT), graphene and flake graphite.
  • SP conductive carbon black
  • Ketjen black conductive fiber
  • conductive polymer conductive polymer
  • acetylene black carbon nanotube
  • graphene flake graphite
  • the present disclosure provides an electrolyte membrane, which includes the block copolymer, and the membrane has the following advantages:
  • the anions of the present disclosure are fixed on the polymer chain, allowing only lithium ions to migrate, thereby reducing the degree of polarization of the electrolyte under voltage, and the lithium ion migration number is high (>0.8);
  • the present disclosure adopts soft-hard (such as polyester-polystyrene) two kinds of segment blocks to combine, and control the content of both to form the microscopic phase separation state of bicontinuous phase, thereby improving The ionic conductivity of the polymer electrolyte membrane.
  • soft-hard such as polyester-polystyrene
  • alkene lithium salts used in the following examples are based on existing literature (see Ma Qiang. Synthesis of new sulfonyl imide lithium salts, characterization and research on its application to metal lithium secondary batteries [D]. Huazhong University of Science and Technology ) prepared by the method in ), and other reagents, materials, etc., unless otherwise specified, can be obtained from commercial sources.
  • electrolyte membranes prepared in Examples and Comparative Examples were cut into 5cm ⁇ 5cm membranes, and then placed between two steel sheets, and the electrochemical workstation was used to test the resistance at different temperatures by AC impedance, and then by the formula (1 ) to calculate the proton conductivity of the membrane at different temperatures;
  • ⁇ is the proton conductivity (S/cm)
  • t is the thickness of the proton exchange membrane (cm)
  • R is the in-plane resistance perpendicular to the membrane surface ( ⁇ )
  • S is the effective membrane area (cm 2 ).
  • the electrolyte membrane is cut into the size of a button battery, and the two sides are clamped with lithium sheets to make a button battery, and then the EIS and DC are tested, and then calculated using the following formula.
  • ⁇ V is the polarization voltage
  • I o and I s are the cook current and steady current obtained from the DC polarization test, respectively
  • R f and R i are the bulk resistance of the polymer electrolyte before and after the DC polarization test, respectively
  • R o and R s are the interface resistance before and after the DC polarization test, respectively.
  • step (3) pour the solution in step (2) onto the substrate and cast on the substrate and evaporate the solvent in an oven to obtain a block copolymer film;
  • the preparation process is the same as in Example 1, except that the lithium styrene sulfonate has a mass of 8 g, and the methyl methacrylate has a mass of 12 g.
  • the preparation process is the same as in Example 1, except that the mass of lithium styrene sulfonate is 10 g, and the mass of methyl methacrylate is 10 g.
  • the preparation process is the same as in Example 1, except that the lithium styrene sulfonate has a mass of 12 g, and the methyl methacrylate has a mass of 8 g.
  • step (3) the polymer in step (1) and step (2) is extruded into film by screw extruder;
  • step (3) pour the solution in step (2) onto the substrate and cast on the substrate and evaporate the solvent in an oven to obtain a block copolymer film;
  • the process is the same as in Example 5, except that the addition amounts of the two monomers are 8 g for LiTFSI and 12 g for BA.
  • the process is the same as in Example 5, except that the addition amounts of the two monomers are 10 g for LiTFSI and 10 g for BA.
  • the process is the same as in Example 5, except that the addition amounts of the two monomers are 12 g for LiTFSI and 8 g for BA.
  • step (3) the polymer in step (1) and step (2) is extruded into film by screw extruder;
  • step (3) pour the solution in step (2) onto the substrate and cast on the substrate and evaporate the solvent in an oven to obtain a block copolymer film;
  • the process is the same as in Example 9, except that the addition amounts of the two monomers are 8 g for LiTFSI and 12 g for MMA.
  • the process is the same as in Example 5, except that the addition amounts of the two monomers are 10 g for LiTFSI and 10 g for MMA.
  • the process is the same as in Example 5, except that the addition amounts of the two monomers are 12 g for LiTFSI and 8 g for MMA.
  • step (3) extruding the polymer in step (1) and step (2) into a film through a screw extruder.
  • LiFSI lithium (p-styrenesulfonyl)(fluorosulfonyl)imide
  • step (3) pour the solution in step (2) onto the substrate and cast on the substrate and evaporate the solvent in an oven to obtain a block copolymer film;
  • the process is the same as in Example 13, except that the addition amount of the two monomers is 8 g for LiFSI and 12 g for EMA.
  • the process is the same as in Example 13, except that the addition amounts of the two monomers are 10 g for LiFSI and 10 g for EMA.
  • the process is the same as in Example 13, except that the addition amounts of the two monomers are 12 g for LiFSI and 8 g for MMA.
  • step (3) extruding the polymer in step (1) and step (2) into a film through a screw extruder.
  • PVDF-HFP poly(vinylidene fluoride-co-hexafluoropropylene)
  • nickel-cobalt-manganese ternary positive electrode material Niobium-cobalt-manganese oxide lithium, NCM811, specific capacity 191mAh/g
  • acetylene Black conductive agent 0.5 parts by mass of carbon nanotube conductive agent, 1.5 parts by mass of PVDF binder and 50 parts by mass of solvent NMP
  • a double planetary mixer under the conditions of revolution 30r/min and rotation 2000r/min under vacuum 4h, disperse into a uniform slurry, coat it on a 9 ⁇ m thick aluminum foil current collector, then dry it at 130°C, roll it under a pressure of 35 tons, and cut it to obtain the positive electrode sheet, the surface density of the positive electrode sheet It is 16mg/cm 2 , and the compacted density is 3.45g/cm 3 .
  • Examples 1-16 and Comparative Examples 1-5 of the present disclosure all used the above-mentioned positive electrode sheet. (But those skilled in the art can also adjust the formula of the positive electrode sheet according to specific conditions. Those skilled in the art can also change the type of positive electrode material, such as replacing the nickel-cobalt-manganese ternary positive electrode material with lithium iron phosphate, lithium manganate, cobalt Commonly used battery positive electrode materials such as lithium oxide, or a mixture of these positive electrode materials.)
  • Examples 1-16 and Comparative Examples 1-5 of the present disclosure all used the above-mentioned negative electrode sheet.
  • those skilled in the art can also adjust the formula of the above-mentioned negative electrode sheet according to specific conditions, and also can change the type of negative electrode material, such as using graphite negative electrode material, silicon oxide negative electrode material, other types of silicon-based negative electrode materials, hard carbon negative electrode materials materials, soft carbon negative electrode materials, tin-based negative electrode materials, etc., and their mixtures in any proportion to prepare negative electrode sheets.
  • the positive pole piece and the negative pole piece prepared by the above method were respectively combined with the electrolyte membrane prepared in Examples 1-16 and Comparative Examples 1-5 of the present disclosure, and the positive pole lug (the aluminum lug of Lianyungang Delixin Electronic Technology Co., Ltd.) , Negative electrode tabs (nickel tabs from Lianyungang Delixin Electronic Technology Co., Ltd.) are prepared into batteries through conventional battery preparation processes by winding or stacking.
  • Example 1 4.23 0.81 71.1%
  • Example 2 5.31 0.83 73.4%
  • Example 3 6.67 0.84 75.3%
  • Example 4 7.59 0.85 75.4% Comparative example 1 4.21 0.73 68.2%
  • Example 5 5.88 0.84 76.1%
  • Example 6 7.92 0.88 80.7%
  • Example 7 10.63 0.90 85.0%
  • Example 8 12.08 0.93 84.7% Comparative example 2 5.02 0.76 72.1%
  • Example 9 6.28 0.83 77.2%
  • Example 10 8.12 0.85 80.8%
  • Example 11 10.83 0.90 85.4%
  • Example 12 12.32 0.92 85.0% Comparative example 3 6.32 0.74 72.7%
  • Example 13 5.55 0.82 75.0%
  • Example 14 7.63 0.85 79.5%
  • Example 15 10.13 0.88 83.5%
  • Example 16 11.74 0.90 83.5% Comparative example 4 5.52 0.74 70.9% Comparative example 5 3.4 0.39 63.5%
  • the block polymer electrolyte membrane prepared by the present disclosure has more than 20% of the ion conductivity of the conventional PVDF-HFP polymer hybrid membrane (comparative example 5)
  • the lithium-containing polymer electrolyte membrane of the present disclosure has improved ion conductivity and nearly doubled the number of ion migration in the gel state.
  • the rate retention of the battery made by the block polymer film of the present disclosure is about 8% higher than that of the battery made by the blend film at 3C; and compared with the PVDF-HFP film, the block polymer film of the present disclosure The rate retention of the battery made of the electrolyte membrane at 3C is also significantly improved.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Electrochemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • Dispersion Chemistry (AREA)
  • General Physics & Mathematics (AREA)
  • Inorganic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Materials Engineering (AREA)
  • Conductive Materials (AREA)
  • Secondary Cells (AREA)

Abstract

本公开公开一种单锂离子聚合物电解质膜及包括该膜的电池，所述电解质膜包括嵌段共聚物，所述嵌段共聚物包括A嵌段和B嵌段，所述A嵌段具有式2所示的结构单元，所述B嵌段具有式3所示的结构单元。本公开的阴离子固定于聚合物链上，只允许锂离子进行迁移，因而减少了电解质在电压下的极化程度，且锂离子迁移数较高(>0.8)。同时本公开采用两种链段嵌段相结合，从而提高了聚合物电解质膜的离子电导率。式2；式3。

Description

一种电解质膜及其制备方法和电池 技术领域
本公开涉及电池技术领域，尤其涉及一种电解质膜及其制备方法和包括该电解质膜的电池。
背景技术
锂离子电池因具有能量密度高、循环寿命长以及环境友好等优点而得到了广泛的应用。为了进一步提高锂离子电池的能量密度和安全性能，研究人员使用凝胶电解质膜代替隔膜以提高电池的安全性能。
目前，常用的凝胶电解质膜是通过在聚醚、聚甲基丙烯酸甲酯、聚偏氟乙烯和聚偏氟乙烯-六氟丙烯共聚物中加入少量的电解液溶胀形成。上述凝胶电解质膜的锂离子导电性主要来源于电解液中的锂盐，在电势作用下锂离子与阴离子之间因存在浓差极化，从而会降低电池的电势及锂离子的迁移速率，进而降低电导率。此外，由于是阴离子与阳离子的同时进行迁移，使锂离子的迁移数较低(<0.5)，因此，最终会严重影响电池的能量密度和循环性能。
发明内容
为了改善上述技术问题，本公开提供一种单锂离子聚合物电解质膜以及使用该电解质膜的电池。
本公开通过如下技术方案实现的：
一种电解质膜，所述电解质膜包括嵌段共聚物，所述嵌段共聚物包括A嵌段和B嵌段，所述A嵌段具有式2所示的结构单元，所述B嵌段具有式3所示的结构单元，
Figure PCTCN2022142381-appb-000001
其中：
R 1为H、C 1-4烷基，示例性为H或甲基；
R 2为磺酸锂基团或磺酰亚胺锂基团；
R 3为C 1-6烷基，示例性为甲基、乙基、正丙基、异丙基、正丁基、异丁基、叔丁基、正戊基及其同分异构体、正己烷及其同分异构体；
R 4为H、C 1-4烷基，示例性为H或甲基；
R 5为不存在、芳基、酰胺基或-(C＝O)-NH-R 6-；
R 6选自C 1-4的亚烷基(例如为亚甲基、亚乙基、亚丙基或2-甲基亚丙基)，示例性为不存在、苯基、酰胺基或酰胺基C 1-4亚烷基(例如为亚甲基、亚乙基、亚丙基或2-甲基亚丙基)。
在所述嵌段共聚物中，A嵌段和B嵌段可以以各种方式进行连接。
在一实例中，所述嵌段共聚物为AB型嵌段共聚物，其中A嵌段和B嵌段均以长链的形式存在。
在一实例中，所述嵌段共聚物为ABA型或BAB型嵌段共聚物，其中A嵌段和B嵌段均以长链的形式存在。
在一实例中，所述嵌段共聚物为(AB) n型嵌段共聚物，其中A嵌段和B嵌段均以相对较短链的形式存在。
在本公开中，可以将A嵌段称为聚合物锂盐链段，将B嵌段称为聚酯链段。
以所述嵌段共聚物的总重量为基准，所述A嵌段(聚合物锂盐链段)的总重量含量(将其记为y)为30-60wt％(示例性为30wt％、40wt％、50wt％、60wt％)，所述B嵌段(聚酯链段)的总重量含量(将其记为x)为40～70wt％(示例性为40wt％、 50wt％、60wt％、70wt％)。
为了方便描述，在本公开中将所述嵌段共聚物的分子式表示为A yB x(式1)，x+y＝1；其中y表示A嵌段占嵌段共聚物的重量含量(用小数表示)，x表示B嵌段占嵌段共聚物的重量含量(用小数表示)。
在一实例中，y为0.3～0.6，示例性为0.3、0.4、0.5、0.6。
在一实例中，x为0.7～0.4，示例性为0.7、0.6、0.5、0.4。
当A嵌段(聚合物锂盐链段)含量过多时，可能会导致嵌段共聚物在电解液中过渡溶胀甚至溶解；而当A嵌段(聚合物锂盐链段)含量过少时，可能导致不能构建离子传输网络膜从而使离子导电率低；且A嵌段(聚合物锂盐链段)过多或过少均不能使嵌段共聚物形成双连续相的微观相分离结构，从而导致锂离子电导率的降低。
在一实例中，所述嵌段聚合物的分子量为100000～1000000。
所述A嵌段(聚合物锂盐链段)可以衍生(例如开链和聚合)自式II所示结构的含烯烃双键的锂盐单体，
Figure PCTCN2022142381-appb-000002
所述B嵌段(聚酯链段)可以衍生(例如开链和聚合)自式III所示结构的丙烯酸酯类单体，
Figure PCTCN2022142381-appb-000003
在一实施例中，所述R 2选自以下结构：
Figure PCTCN2022142381-appb-000004
在本公开中，所述嵌段共聚物中包括若干式2所示结构单元和式3所示结构单元，每个结构单元中对R 1、R 2、R 3、R 4、R 5、R 6的选择都是各自独立的，各结构单元之间的选择可以相同也可以不同。
示例性地，所述含烯烃双键的锂盐为下述锂盐中的一种、两种或更多种：对苯乙烯磺酸锂(LiPS)、(对苯乙烯磺酰)(三氟甲基磺酰)亚胺锂(LiPSTFSI)、(对苯乙烯磺酰)(氟磺酰)亚胺锂(LiPSFSI)、(对苯乙烯磺酰)[三氟甲基(S-三氟甲基磺酰亚胺基)磺酰]亚胺锂、乙烯基磺酸锂、(乙烯基磺酰)(三氟甲基磺酰)亚胺锂、(乙烯基磺酰)(氟磺酰)亚胺锂、丙烯磺酸锂、(丙烯基磺酰)(氟磺酰)亚胺锂、(丙烯基磺酰)(三氟甲基磺酰)亚胺锂、2-丙烯酰胺基-2甲基丙磺酸锂、(2-丙烯酰胺基-2甲基丙磺酰)(三氟甲基磺酰)亚胺锂、(2-丙烯酰胺基-2甲基丙磺酰)(氟磺酰)亚胺锂等。
示例性地，所述丙烯酸酯类单体为下述中的一种、两种或更多种：甲基丙烯酸甲酯(MMA)、甲基丙烯酸乙酯(EMA)、甲基丙烯酸丙酯、甲基丙烯酸丁酯、甲基丙烯酸戊酯、丙烯酸甲酯、丙烯酸乙酯、丙烯酸丙酯、丙烯酸丁酯(BA)和丙烯酸戊酯等。
在一实例中，所述电解质膜的材料即为所述嵌段共聚物。
在一实例中，所述电解质膜中还可以含有其它本领域中用于电解质膜的常规材料。所述嵌段共聚物占所述电解质膜的重量百分含量≥60wt％。
在本公开中，重量百分含量均指的是以干重计的重量百分含量。
本公开的所述电解质膜可以以干燥的状态进行生产和销售。
在使用状态下或某些实施方式中，所述电解质膜中还含有电解液用溶剂。
在一实施例中，所述电解液用溶剂包括但不限于为碳酸丙烯酯(PC)、碳酸乙烯酯(EC)、碳酸二乙酯(DEC)、碳酸二甲酯(DMC)和碳酸甲乙酯(EMC)中的至少一种。优选为EC、DEC、DMC三种的混合溶剂。
在一实施例中，所述混合溶剂中，EC、DEC、DMC的体积比为(0.5-2):(0.5-2):(0.5-2)，例如为1:1:1。
本公开第二方面还提供了第一方面所述的电解质膜的制备方法，所述方法包括：以包括式II所示结构的含烯烃双键的锂盐单体和包括式III所示结构的丙烯酸酯类单体为原料，在引发剂作用下发生聚合反应；
Figure PCTCN2022142381-appb-000005
在一实施例中，所述式II所示结构的含烯烃双键的锂盐单体和式III所示结构的丙烯酸酯类单体具有与上文所述的选择和质量比值。在一实施例中，所述含烯烃双键的锂盐单体的质量占单体总质量(含烯烃双键的锂盐单体与丙烯酸酯类单体)的百分含量为30～60％，示例性为30％、40％、50％、60％或者是前述两两数值组成的范围内的任一点值。
示例性地，所述聚合在引发剂下进行。
在一实施例中，所述引发剂的用量为所述含烯烃双键的锂盐单体质量的0.1％～3％，示例性为0.1％、0.5％、1％、2％、3％或者是前述两两数值组成的范围内的任一点值。
示例性地，所述引发剂为自由基引发剂，例如为过硫酸钠、偶氮二异丁腈(AIBN)、过氧化环己酮、过氧化二苯甲酰和叔丁基过氧化氢等中的至少一种。
在一实施例中，所述聚合在溶剂体系中进行。例如，所述溶剂包括但不限 于为水、DMF、丙酮、乙腈、NMP、DMAc和DMSO中的一种、两种或更多种。
在一实施例中，所述聚合在惰性气氛下进行。例如，所述惰性气氛可以为在氮气中和/或氩气中。
在一实施例中，所述聚合的温度为60～90℃，示例性为60℃、70℃、80℃、85℃、90℃。进一步地，所述聚合的时间为4～12h，示例性为4h、6h、8h、10h、12h。
通过所述聚合反应，能够得到包括第一方面中所述的嵌段共聚物的混合液。将该混合物进行后处理(例如抽滤、洗涤、干燥)，可以得到所述电解质膜。
在一实施例中，所述制备方法还包括：将所述混合液倒入基板上流延，蒸干溶剂，得到所述嵌段共聚物。
在一实施例中，所述蒸干溶剂的方式为烘干。例如，所述烘干的温度为40～100℃，时间为8～24h。
在一实施例中，所述制备方法还包括：将所述嵌段共聚物浸渍于电解液中溶胀，得到所述电解质膜。优选地，所述溶胀的温度为40～60℃，示例性为40℃、45℃、50℃、60℃；所述溶胀的时间为6～24h，示例性为6～12h，示例性为6h、8h、12h、24h。
优选地，所述电解液中的溶剂包括但不限于为PC、EC、DEC、DMC和EMC中的至少一种。优选为EC、DEC、DMC三种的混合溶剂。
本领域技术人员通过对聚合反应的控制，可以根据需要得到前述AB型、ABA型、BAB型和(AB) n型的嵌段共聚物。
在一实例中，得到AB型的所述嵌段共聚物。
在一实施例中，所述嵌段共聚物电解质膜的制备方法，包括如下步骤：
(a)在惰性气体保护下，将式II所示的含烯烃双键的锂盐单体和引发剂在溶剂中进行第一聚合；
(b)将步骤(a)所得物料与式III所示的丙烯酸酯类单体的混合物进行第二聚合。
可选地，该方法还包括步骤(c)，将步骤(b)中的物料倒入基板上流延并蒸发溶剂得到嵌段共聚物膜。
可选地，该方法进一步包括步骤(d)，将所述嵌段共聚物膜浸渍于电解液中溶胀。
在一实施例中，所述嵌段共聚物电解质膜的制备方法包括如下步骤：
(a)将式II所示的含烯烃双键的锂盐单体溶解到溶剂中，加入引发剂，在惰性气体保护下于60～85℃进行聚合4～12h；
(b)在步骤(a)聚合后的反应混合液中，加入式III所示的丙烯酸酯类单体继续聚合4～12h；
(c)将步骤(b)中的物料倒入基板上流延并于烘箱中蒸发溶剂得到嵌段共聚物膜；
(d)将嵌段共聚物膜浸渍于电解液中溶胀，得到所述电解质膜。
本公开还提供上述电解质膜在电池中的应用。
本公开还提供一种电池，其含有上述电解质膜。
在一实施例中，所述电池还含有正极片和负极片。
在一实施例中，所述正极片的正极活性材料选自钴酸锂、磷酸铁锂(LiFe PO 4)、钴酸锂(LiCoO 2)、镍钴锰酸锂、锰酸锂(LiMnO 2)、镍钴铝酸锂、镍钴锰铝酸锂、镍钴铝钨材料、富锂锰基固溶体正极材料、镍钴酸锂、镍钛镁酸锂、镍酸锂(Li 2NiO 2)、尖晶石锰酸锂(LiMn 2O 4)、尖晶石镍锰酸锂(LNMO)、镍钴钨材料中的至少一种。
在一实施例中，所述负极片的负极活性材料选自碳基、硅基、金属锂、金属锂合金材料中的至少一种。
在一实施例中，所述正极片、负极片中还任选地含有粘结剂和/或导电剂。
优选地，所述正极粘结剂选自聚四氟乙烯、聚偏氟乙烯、聚偏氟乙烯-六氟丙烯及其共聚衍生物中的至少一种；负极粘结剂选自聚丙烯酸、聚丙烯酸酯、聚丁苯橡胶(SBR)、羧甲基纤维素钠(CMC)及其共聚衍生物中的至少一种。
优选地，所述导电剂可以为导电炭黑(SP)、科琴黑、导电纤维、导电聚合物、乙炔黑、碳纳米管(CNT)、石墨烯和鳞片石墨中的至少一种。
本公开的有益效果
本公开提供了一种电解质膜，其中包括所述的嵌段共聚物，所述膜具有如下优势：
(1)本公开的阴离子固定于聚合物链上，只允许锂离子进行迁移，因而减少了电解质在电压下的极化程度，且锂离子迁移数较高(>0.8)；
(2)本公开采用软-硬(例如为聚酯类-聚对苯乙烯类)两种链段嵌段相结合，并控制两者的含量以形成双连续相的微观相分离状态，从而提高了聚合物电解质膜的离子电导率。
具体实施方式
下文将结合具体实施例对本公开的技术方案做更进一步的详细说明。应当理解，下列实施例仅为示例性地说明和解释本公开，而不应被解释为对本公开保护范围的限制。凡基于本公开上述内容所实现的技术均涵盖在本公开旨在保护的范围内。
除非另有说明，以下实施例中使用的原料和试剂均为市售商品，或者可以通过已知方法制备。
下述实施例中所用的烯烃类锂盐为采用现有文献(参见马强.新型磺酰亚胺锂盐的合成,表征及其应用于金属锂二次电池的研究[D].华中科技大学)中的方法制备得到，其他试剂、材料等，如无特殊说明，均可从商业途径得到。
1.测定质子电导率
将实施例和对比例制备得到的电解质膜裁切成5cm×5cm的膜，然后将其置于两钢片之间，使用电化学工作站通过交流阻抗测试不同温度下的电阻，然后通过公式(1)计算出膜在不同温度下的质子电导率；
σ＝t/R×S    (1)
其中：σ为质子电导率(S/cm)，t为质子交换膜的厚度(cm)，R为垂直于膜表面的面内电阻(Ω)，S为有效膜面积(cm 2)。
2.离子迁移数
将电解质膜裁剪成扣式电池大小，两侧用锂片夹紧制作扣式电池，然后测试EIS和DC，然后采用如下公式计算得到。
Figure PCTCN2022142381-appb-000006
公式(2)中，ΔV为极化电压，I o和I s分别为DC极化测试得到的厨师电流和稳定电流，R f和R i分别为DC极化测试前后聚合物电解质的本体电阻，R o和R s分别为DC极化测试前后的界面电阻。
3.常温倍率性能
用电池充放电测试仪，将电池在25℃下进行充放电测试，充放电制度：0.2C恒电流充电至4.3V，转为4.25V恒电压充电至电流减小到0.02C，静置5min后，0.2C恒电流放电至2.75V,记录放电容量Q 0.2C；静置5min后，0.2C恒电流充电至4.3V，转为4.25V恒电压充电至电流减小到0.02C，静置5min后，3C恒电流放电至2.75V，记录放电容量Q 3C，3C放电容量保持率η＝Q 3C/Q 0.2C×100％。
实施例1
LiPS 0.3-b-PMMA 0.7的制备：
(1)将6g对苯乙烯磺酸锂溶于190g水中，再加入0.1g过硫酸钠，并在氩气保护下，于85℃反应4h；
(2)向步骤(1)聚合4h后的反应液中加入14g甲基丙烯酸甲酯继续聚合8h；
(3)将步骤(2)中的溶液倒入基板上流延并于烘箱中蒸发溶剂得到嵌段共聚物膜；
(4)将步骤(3)中得到的膜浸渍于电解液溶剂(DMC:EC:DEC＝1:1:1)中于45℃下溶胀12h，得到单锂离子聚合物电解质膜，将膜裁成极片大小以备用。
实施例2
LiPS 0.4-b-PMMA 0.6的制备
制备过程与实施例1相同，不同之处在于苯乙烯磺酸锂质量为8g，甲基丙烯酸甲酯的质量为12g。
实施例3
LiPS 0.5-b-PMMA 0.5的制备
制备过程与实施例1相同，不同之处在于苯乙烯磺酸锂质量为10g，甲基丙烯酸甲酯的质量为10g。
实施例4
LiPS 0.6-b-PMMA 0.4的制备
制备过程与实施例1相同，不同之处在于苯乙烯磺酸锂质量为12g，甲基丙烯酸甲酯的质量为8g。
对比例1
LiPS 0.4/PMMA 0.6的制备：
(1)将8g对苯乙烯磺酸锂溶于190g水中，再加入0.1g过硫酸钠，并在氩气保护下，于85℃反应4h，反应结束后蒸发溶剂的到聚对苯乙烯磺酸锂；
(2)在溶解有3mmol MgCl 2和6mol NaOH的60mL水溶液中缓慢加入12g甲基丙烯酸甲酯(已经溶解0.15g BPO引发剂)，将温度升到78℃反应4h，反应结束后抽滤用水反复洗涤后晾干得到PMMA；
(3)将步骤(1)与步骤(2)中的聚合物通过螺杆挤出机挤出成薄膜；
(4)将步骤(3)中得到的膜浸渍于电解液溶剂(DMC:EC:DEC＝1:1:1)中于45℃下溶胀12h，得到LiPS 0.4/PMMA 0.6电解质膜，将膜裁成极片大小以备用。
实施例5
LiPTFSI 0.3-b-PBA 0.7的制备：
(1)将6g(对苯乙烯磺酰)(三氟甲基磺酰)亚胺锂(LiTFSI)溶于100g乙腈中，再加入0.2g AIBN，并在氩气保护下，于65℃反应6h；
(2)向步骤(1)聚合6h后的反应液中加入14g丙烯酸丁酯(BA)继续聚合8h；
(3)将步骤(2)中的溶液倒入基板上流延并于烘箱中蒸发溶剂得到嵌段共聚物膜；
(4)将步骤(3)中得到的膜浸渍于电解液溶剂(DMC:EC:DEC＝1:1:1)中于45℃下溶胀12h，得到单锂离子聚合物电解质膜，将膜裁成极片大小以备用。
实施例6
LiPTFSI 0.4-b-PBA 0.6的制备
过程与实施例5相同，不同之处在于两种单体的加入量，LiTFSI为8g，BA为12g。
实施例7
LiPTFSI 0.5-b-PBA 0.5的制备
过程与实施例5相同，不同之处在于两种单体的加入量，LiTFSI为10g，BA为10g。
实施例8
LiPTFSI 0.6-b-PBA 0.4的制备
过程与实施例5相同，不同之处在于两种单体的加入量，LiTFSI为12g，BA为8g。
对比例2
LiPTFSI 0.4/PBA 0.6混合膜的制备
(1)将8g(对苯乙烯磺酰)(三氟甲基磺酰)亚胺锂(LiTFSI)溶于100g乙腈中，再加入0.2g AIBN，并在氩气保护下，于65℃反应6h；反应结束后蒸发溶剂的到LiPTFSI；
(2)在溶解有3mmol MgCl 2和6mol NaOH的60mL水溶液中缓慢加入12g丙烯酸丁酯(已经溶解0.15g BPO引发剂)，将温度升到78℃反应4h，反应结束后抽滤用水反复洗涤后晾干得到PBA；
(3)将步骤(1)与步骤(2)中的聚合物通过螺杆挤出机挤出成薄膜；
(4)将步骤(3)中得到的膜浸渍于电解液溶剂(DMC:EC:DEC＝1:1:1)中于 45℃下溶胀12h，得到LiPTFSI 0.4/PBA 0.6电解质膜，将膜裁成极片大小以备用。
实施例9
LiPTFSI 0.3-b-PMMA 0.7的制备：
(1)将6g(对苯乙烯磺酰)(三氟甲基磺酰)亚胺锂(LiTFSI)溶于100g乙腈中，再加入0.2g AIBN，并在氩气保护下，于65℃反应6h；
(2)向步骤(1)聚合6h后的反应液中加入14g甲基丙烯酸甲酯(MMA)继续聚合8h；
(3)将步骤(2)中的溶液倒入基板上流延并于烘箱中蒸发溶剂得到嵌段共聚物膜；
(4)将步骤(3)中得到的膜浸渍于电解液溶剂(DMC:EC:DEC＝1:1:1)中于45℃下溶胀12h，得到单锂离子聚合物电解质膜，将膜裁成极片大小以备用。
实施例10
LiPTFSI 0.4-b-PMMA 0.6的制备
过程与实施例9相同，不同之处在于两种单体的加入量，LiTFSI为8g，MMA为12g。
实施例11
LiPTFSI 0.5-b-PMMA 0.5的制备
过程与实施例5相同，不同之处在于两种单体的加入量，LiTFSI为10g，MMA为10g。
实施例12
LiPTFSI 0.6-b-PMMA 0.4的制备
过程与实施例5相同，不同之处在于两种单体的加入量，LiTFSI为12g，MMA为8g。
对比例3
LiPTFSI 0.4/PMMA 0.6混合膜的制备
(1)将8g(对苯乙烯磺酰)(三氟甲基磺酰)亚胺锂(LiTFSI)溶于100g乙腈 中，再加入0.2g AIBN，并在氩气保护下，于65℃反应6h；反应结束后蒸发溶剂的到LiPTFSI；
(2)在溶解有3mmol MgCl 2和6mol NaOH的60mL水溶液中缓慢加入12g MMA(已经溶解0.15g BPO引发剂)，将温度升到78℃反应4h，反应结束后抽滤用水反复洗涤后晾干得到PMMA。
(3)将步骤(1)与步骤(2)中的聚合物通过螺杆挤出机挤出成薄膜。
(4)将步骤(3)中得到的膜浸渍于电解液溶剂(DMC:EC:DEC＝1:1:1)中于45℃下溶胀12h，得到LiPTFSI 0.4/PMMA 0.6电解质膜，将膜裁成极片大小以备用。
实施例13
LiPFSI 0.3-b-PEMA 0.7的制备：
(1)将6g(对苯乙烯磺酰)(氟磺酰)亚胺锂(LiFSI)溶于100g乙腈中，再加入0.2g AIBN，并在氩气保护下，于65℃反应6h；
(2)向步骤(1)聚合6h后的反应液中加入14g甲基丙烯酸乙酯(EMA)继续聚合8h；
(3)将步骤(2)中的溶液倒入基板上流延并于烘箱中蒸发溶剂得到嵌段共聚物膜；
(4)将步骤(3)中得到的膜浸渍于电解液溶剂(DMC:EC:DEC＝1:1:1)中于45℃下溶胀12h，得到单锂离子聚合物电解质膜，将膜裁成极片大小以备用。
实施例14
LiPFSI 0.4-b-PEMA 0.6的制备
过程与实施例13相同，不同之处在于两种单体的加入量，LiFSI为8g，EMA为12g。
实施例15
LiPFSI 0.5-b-PEMA 0.5的制备
过程与实施例13相同，不同之处在于两种单体的加入量，LiFSI为10g，EMA为10g。
实施例16
LiPTFSI 0.6-b-PMMA 0.4的制备
过程与实施例13相同，不同之处在于两种单体的加入量，LiFSI为12g，MMA为8g。
对比例4
LiPFSI 0.4/PEMA 0.6混合膜的制备
(1)将8g LiTFSI溶于100g乙腈中，再加入0.2g AIBN，并在氩气保护下，于65℃反应6h；反应结束后蒸发溶剂的到LiPFSI；
(2)在溶解有3mmol MgCl 2和6mol NaOH的60mL水溶液中缓慢加入12g EMA(已经溶解0.15g BPO引发剂)，将温度升到78℃反应4h，反应结束后抽滤用水反复洗涤后晾干得到PEMA。
(3)将步骤(1)与步骤(2)中的聚合物通过螺杆挤出机挤出成薄膜。
(4)将步骤(3)中得到的膜浸渍于电解液溶剂(DMC:EC:DEC＝1:1:1)中于45℃下溶胀12h，得到LiPTFSI 0.4/PMMA 0.6电解质膜，将膜裁成极片大小以备用。
对比例5
使用聚(偏二氟乙烯-co-六氟丙烯)(PVDF-HFP，其中HFP占PVDF-HFP的20％)，溶解在DMAc里，然后再在玻璃板上流延制备成薄膜，再在电解液(新宙邦，NP018)中于25℃下浸渍溶胀12h得到电解质膜。
测试例
1.电池制备
(1)正极极片的制备
参照目前通用的电池生产方法，将97质量份的镍钴锰三元正极材料(宁波容百新能源科技股份有限公司镍钴锰酸锂，NCM811，比容量191mAh/g)、1质量份的乙炔黑导电剂、0.5质量份的碳纳米管导电剂、1.5质量份的PVDF粘结剂以及50质量份的溶剂NMP，通过双行星搅拌机在真空下以公转30r/min、自转2000r/min的条件搅拌4h，分散成均匀的浆料，将其涂布在9μm厚的铝箔集流体 上，然后在130℃下烘干、35吨压力下辊压，分切得到正极极片，正极极片的面密度为16mg/cm 2，压实密度为3.45g/cm 3。
为了方便对比电池性能，本公开实施例1-16及对比例1-5均使用了上述正极片。(但是本领域技术人员还可以根据具体情况调整正极极片的配方。本领域技术人员也可以改变正极材料的种类，例如将镍钴锰三元正极材料替换为磷酸铁锂、锰酸锂、钴酸锂等常用的电池正极材料，或者上述这些正极材料的混合。)
(2)负极极片的制备
参照目前通用的电池生产方法，将97份质量的石墨负极材料(贝特瑞新能源科技有限公司人造石墨，型号S360-L2-H，比容量357mAh/g)、1.5份质量的炭黑导电剂、1.0份质量的SBR粘结剂、0.5份质量的羧甲基纤维素以及100份质量的溶剂水，通过双行星搅拌机在真空下以公转30r/min、自转1500r/min的条件搅拌4h，分散成均匀的浆料，并涂布在6μm铜箔表面，然后在110℃下烘干、40吨压力下辊压，最后切成所需尺寸的负极极片，其中，负极极片的面密度为9.4mg/cm 2，极片压实密度为1.78g/cm 3。
为了方便对比电池性能，本公开实施例1-16及对比例1-5均使用了上述负极极片。(但是本领域技术人员还可以根据具体情况调整上述负极极片的配方，也可以改变负极材料的种类，例如使用石墨负极材料、氧化亚硅负极材料、其他种类的硅基负极材料、硬炭负极材料、软炭负极材料、锡基负极材料等以及他们的任意比例的混合物来制备负极极片。考虑到下一代电池技术中经常使用的金属锂负极对水分敏感，技术人员也可以直接采用纯金属锂箔、金属锂合金箔、纯金属锂箔+铜箔复合而成的复合箔材、金属锂合金箔+铜箔复合而成的复合箔材、纯金属锂箔+泡沫铜复合而成的复合箔材、金属锂合金箔+泡沫铜复合而成的复合箔材作为负极极片，而无需通过上述常规的制备负极浆料再涂布的方法制备负极极片。)
将上述方法制备的正极极片和负极极片、分别与本公开实施例1-16和对比例1-5所制备的电解质膜、正极极耳(连云港德立信电子科技有限公司的铝极耳)、 负极极耳(连云港德立信电子科技有限公司的镍极耳)通过电池常规制备工艺，通过卷绕或层叠方式制备成电池。
2.测试结果
实施例1-16和对比例1-5中电解质膜的电导率，离子迁移数，3C下容量保持率测试结果如表1所示。
表1
  电导率×10 -4mS/cm 2 离子迁移数 3C容量保持率η
实施例1 4.23 0.81 71.1％
实施例2 5.31 0.83 73.4％
实施例3 6.67 0.84 75.3％
实施例4 7.59 0.85 75.4％
对比例1 4.21 0.73 68.2％
实施例5 5.88 0.84 76.1％
实施例6 7.92 0.88 80.7％
实施例7 10.63 0.90 85.0％
实施例8 12.08 0.93 84.7％
对比例2 5.02 0.76 72.1％
实施例9 6.28 0.83 77.2％
实施例10 8.12 0.85 80.8％
实施例11 10.83 0.90 85.4％
实施例12 12.32 0.92 85.0％
对比例3 6.32 0.74 72.7％
实施例13 5.55 0.82 75.0％
实施例14 7.63 0.85 79.5％
实施例15 10.13 0.88 83.5％
实施例16 11.74 0.90 83.5％
对比例4 5.52 0.74 70.9％
对比例5 3.4 0.39 63.5％
从上表1中结果可以看出，在相同的条件下本公开制得的嵌段聚合物电解质膜在离子导电率方面较常规的PVDF-HFP聚合物混合膜(对比例5)有20％以上的提升，且在凝胶状态下本公开的含锂聚合物电解质膜，相比于常用的PVDF-HFP电解液电解质膜，在离子导电率提升，离子迁移数有接近2倍的提高。由本公开的嵌段聚合物膜制得的电池比由共混膜制得的电池在3C下的倍率保持率提高了8％左右；而与PVDF-HFP膜相比，由本公开的嵌段聚合物电解质膜制 得的电池在3C下的倍率保持率也显著提升。
以上，对本公开的实施方式进行了说明。但是，本公开不限定于上述实施方式。凡在本公开的精神和原则之内，所做的任何修改、等同替换、改进等，均应包含在本公开的保护范围之内。

Claims (13)

  1. 一种电解质膜，其特征在于，所述电解质膜包括嵌段共聚物，所述嵌段共聚物包括A嵌段和B嵌段，所述A嵌段具有式2所示的结构单元，所述B嵌段具有式3所示的结构单元，
    Figure PCTCN2022142381-appb-100001
    其中：
    R 1为H、C 1-4烷基，优选为H或甲基；
    R 2为磺酸锂基团或磺酰亚胺锂基团；
    R 3为C 1-6烷基；
    R 4为H、C 1-4烷基；
    R 5为不存在、芳基、酰胺基或-(C＝O)-NH-R 6-；
    R 6选自C 1-4的亚烷基。
  2. 根据权利要求1所述的电解质膜，其特征在于，以所述嵌段共聚物的总重量为基准，所述A嵌段的重量含量为30-60wt％，所述B嵌段的重量含量为40～70wt％。
  3. 根据权利要求1或2所述的电解质膜，其特征在于，所述R 2选自下述结构：
    Figure PCTCN2022142381-appb-100002
  4. 根据权利要求1-3中任一项所述的电解质膜，其特征在于，所述A嵌段衍生自具有式II所示结构的含烯烃双键的锂盐单体，
    Figure PCTCN2022142381-appb-100003
  5. 根据权利要求4所述的电解质膜，其特征在于，所述含烯烃双键的锂盐单体为下述锂盐中的一种、两种或更多种：对苯乙烯磺酸锂、(对苯乙烯磺酰)(三氟甲基磺酰)亚胺锂、(对苯乙烯磺酰)(氟磺酰)亚胺锂、(对苯乙烯磺酰)[三氟甲基(S-三氟甲基磺酰亚胺基)磺酰]亚胺锂、乙烯基磺酸锂、(乙烯基磺酰)(三氟甲基磺酰)亚胺锂、(乙烯基磺酰)(氟磺酰)亚胺锂、丙烯磺酸锂、(丙烯基磺酰)(氟磺酰)亚胺锂、(丙烯基磺酰)(三氟甲基磺酰)亚胺锂、2-丙烯酰胺基-2甲基丙磺酸锂、(2-丙烯酰胺基-2甲基丙磺酰)(三氟甲基磺酰)亚胺锂、(2-丙烯酰胺基-2甲基丙磺酰)(氟磺酰)亚胺锂。
  6. 根据权利要求1-5中任一项所述的电解质膜，其特征在于，所述B嵌段衍生自具有式III所示结构的丙烯酸酯类单体，
    Figure PCTCN2022142381-appb-100004
  7. 根据权利要求6所述的电解质膜，其特征在于，所述丙烯酸酯类单体为下述中的一种、两种或更多种：甲基丙烯酸甲酯、甲基丙烯酸乙酯、甲基丙烯酸丙酯、甲基丙烯酸丁酯、甲基丙烯酸戊酯、丙烯酸甲酯、丙烯酸乙酯、丙烯酸丙酯、丙烯酸丁酯和丙烯酸戊酯。
  8. 根据权利要求1-7中任一项所述的电解质膜，其特征在于，所述电解质膜中还含有电解液用溶剂；
    优选地，所述电解液用溶剂为碳酸乙烯酯、碳酸二乙酯和碳酸二甲酯的混合溶剂。
  9. 一种制备权利要求1-8中任一项所述的电解质膜的方法，其特征在于，所述方法包括：以包括式II所示结构的含烯烃双键的锂盐单体和包括式III所示结构的丙烯酸酯类单体为原料，在引发剂作用下发生聚合反应；
    Figure PCTCN2022142381-appb-100005
  10. 根据权利要求9所述的方法，其特征在于，所述含烯烃双键的锂盐单体的质量占单体总质量的百分含量为30％～60％。
  11. 根据权利要求9或10所述的方法，其特征在于，所述引发剂的用量为所述含烯烃双键的锂盐单体质量的0.1％～3％；
    优选地，所述引发剂为自由基引发剂；
    优选地，所述引发剂选自过硫酸钠、偶氮二异丁腈、过氧化环己酮、过氧化二苯甲酰和叔丁基过氧化氢中的至少一种。
  12. 根据权利要求9-11中任一项所述的方法，其特征在于，所述方法包括：
    (a)在惰性气体保护下，将式II所示的含烯烃双键的锂盐单体和引发剂在溶剂中进行第一聚合；
    (b)将步骤(a)所得物料与式III所示的丙烯酸酯类单体的混合物进行第二聚合；
    优选地，该方法还包括步骤(c)，将步骤(b)中的物料倒入基板上流延并蒸发溶剂得到嵌段共聚物膜；
    优选地，该方法进一步包括步骤(d)，将所述嵌段共聚物膜浸渍于电解液中溶胀。
  13. 一种电池，其特征在于，其含有权利要求1-8任一项所述的电解质膜和/或权利要求9-12任一项所述的方法制备得到的电解质膜。
PCT/CN2022/142381 2021-12-31 2022-12-27 一种电解质膜及其制备方法和电池 WO2023125545A1 (zh)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN202111669960.3A CN114335715B (zh) 2021-12-31 2021-12-31 一种单锂离子聚合物电解质膜及包括该膜的电池
CN202111669960.3 2021-12-31

Publications (1)

Publication Number Publication Date
WO2023125545A1 true WO2023125545A1 (zh) 2023-07-06

Family

ID=81020079

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2022/142381 WO2023125545A1 (zh) 2021-12-31 2022-12-27 一种电解质膜及其制备方法和电池

Country Status (2)

Country Link
CN (1) CN114335715B (zh)
WO (1) WO2023125545A1 (zh)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114335715B (zh) * 2021-12-31 2024-07-16 珠海冠宇电池股份有限公司 一种单锂离子聚合物电解质膜及包括该膜的电池
CN118248936A (zh) * 2023-02-13 2024-06-25 深圳市固易能科技有限责任公司 包含离子型聚合物的凝胶电解质锂离子电池及制备方法
CN117497842B (zh) * 2023-12-27 2024-03-12 江苏蓝固新能源科技有限公司 一种聚合物电解质和制备方法及其在二次电池中的应用

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103509153A (zh) * 2012-06-15 2014-01-15 华中科技大学 一种聚合物单离子电解质及其制备方法
CN105693566A (zh) * 2014-12-10 2016-06-22 巴莱诺斯清洁能源控股公司 用于制备用于电化学器件的新型单离子导电聚合物家族的新型交联剂以及所述聚合物
CN106711503A (zh) * 2016-12-19 2017-05-24 西南石油大学 单离子凝胶聚合物电解质及其制备方法
CN114300684A (zh) * 2021-12-31 2022-04-08 珠海冠宇电池股份有限公司 一种单锂离子聚合物导锂粘结剂及含有该粘接剂的电池
CN114335715A (zh) * 2021-12-31 2022-04-12 珠海冠宇电池股份有限公司 一种单锂离子聚合物电解质膜及包括该膜的电池
CN114335714A (zh) * 2021-12-31 2022-04-12 珠海冠宇电池股份有限公司 一种单锂离子聚合物电解质膜及包括该膜的电池

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2016053065A1 (ko) * 2014-10-02 2016-04-07 주식회사 엘지화학 젤 폴리머 전해질 및 이를 포함하는 리튬 이차전지
CN110003399A (zh) * 2019-03-06 2019-07-12 南开大学 一种单离子导电聚合物电解质膜的制备及应用
CN112952191B (zh) * 2021-02-26 2024-09-10 南开大学 一种高性能的单离子聚合物固态电解质的制备及其应用
CN112993395A (zh) * 2021-04-13 2021-06-18 长春工业大学 一种锂单离子聚酰亚胺凝胶聚合物电解质及不同增塑剂和制备工艺

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103509153A (zh) * 2012-06-15 2014-01-15 华中科技大学 一种聚合物单离子电解质及其制备方法
CN105693566A (zh) * 2014-12-10 2016-06-22 巴莱诺斯清洁能源控股公司 用于制备用于电化学器件的新型单离子导电聚合物家族的新型交联剂以及所述聚合物
CN106711503A (zh) * 2016-12-19 2017-05-24 西南石油大学 单离子凝胶聚合物电解质及其制备方法
CN114300684A (zh) * 2021-12-31 2022-04-08 珠海冠宇电池股份有限公司 一种单锂离子聚合物导锂粘结剂及含有该粘接剂的电池
CN114335715A (zh) * 2021-12-31 2022-04-12 珠海冠宇电池股份有限公司 一种单锂离子聚合物电解质膜及包括该膜的电池
CN114335714A (zh) * 2021-12-31 2022-04-12 珠海冠宇电池股份有限公司 一种单锂离子聚合物电解质膜及包括该膜的电池

Also Published As

Publication number Publication date
CN114335715A (zh) 2022-04-12
CN114335715B (zh) 2024-07-16

Similar Documents

Publication Publication Date Title
TWI608023B (zh) Acrylonitrile Copolymer Adhesive and Its Application in Lithium Ion Battery
WO2019120140A1 (zh) 一种水性粘结剂及二次电池
WO2023125545A1 (zh) 一种电解质膜及其制备方法和电池
US20230127888A1 (en) Secondary battery with improved high-temperature and low-temperature properties
KR20200029961A (ko) 리튬 이차전지용 양극 활물질 및 이를 포함하는 리튬 이차전지
WO2022141508A1 (zh) 一种电化学装置和电子装置
CN107710470B (zh) 锂离子二次电池的负极用粘合剂、负极用浆料组合物及负极以及锂离子二次电池
EP3598544A1 (en) Conductive material dispersion liquid for electrochemical element electrodes, slurry composition for electrochemical element electrodes, method for producing same, electrode for electrochemical elements, and electrochemical element
KR101645773B1 (ko) 전극 활물질 슬러리 및 이를 포함하는 리튬 이차 전지
WO2020078359A1 (zh) 负极极片及电池
CN114335714B (zh) 一种单锂离子聚合物电解质膜及包括该膜的电池
WO2022120833A1 (zh) 一种电化学装置和电子装置
CN112279982B (zh) 一种硅基负极用粘结剂及含有该粘结剂的锂离子电池
JP2022536290A (ja) リチウムイオン電池用のその場重合されたポリマー電解質
CN114024099A (zh) 一种电池
CN114300684A (zh) 一种单锂离子聚合物导锂粘结剂及含有该粘接剂的电池
CN114024035A (zh) 一种电池
US20190273261A1 (en) Binder composition for non-aqueous secondary battery electrode, slurry composition for non-aqueous secondary battery electrode, electrode for non-aqueous secondary battery, and non-aqueous secondary battery
CN105814717A (zh) 电化学元件用电极及电化学元件
JP2022505211A (ja) 電極用水性バインダー組成物、及びその製造方法
CN105900272B (zh) 二次电池用粘合剂组合物
JP2023529531A (ja) 二次電池用バインダー組成物
JP7325886B2 (ja) 二次電池用バインダー組成物および電極合剤
CN114142176A (zh) 一种电池
JP2023064584A (ja) 電池用バインダー、電極形成用組成物、電池用電極、非水電解質二次電池及びこれらの製造方法

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 22914798

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE