WO2023108946A1 - 一种高分子薄膜修饰的正极极片及其制备方法 - Google Patents

一种高分子薄膜修饰的正极极片及其制备方法 Download PDF

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WO2023108946A1
WO2023108946A1 PCT/CN2022/082974 CN2022082974W WO2023108946A1 WO 2023108946 A1 WO2023108946 A1 WO 2023108946A1 CN 2022082974 W CN2022082974 W CN 2022082974W WO 2023108946 A1 WO2023108946 A1 WO 2023108946A1
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polymer film
electrode
pole piece
electrolyte
ion
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French (fr)
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吉长印
吕菲
徐宁
陈志宇
张玉伟
吴孟涛
陈要忠
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天津巴莫科技有限责任公司
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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
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/628—Inhibitors, e.g. gassing inhibitors, corrosion inhibitors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/04—Processes of manufacture in general
    • H01M4/0438—Processes of manufacture in general by electrochemical processing
    • H01M4/045—Electrochemical coating; Electrochemical impregnation
    • H01M4/0452—Electrochemical coating; Electrochemical impregnation from solutions
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/131—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/139—Processes of manufacture
    • H01M4/1391—Processes of manufacture of electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/624—Electric conductive fillers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/028—Positive electrodes

Definitions

  • the invention relates to the field of all-solid-state batteries, in particular to a polymer film-modified positive pole piece and a preparation method thereof.
  • All-solid-state batteries are considered to be the most promising next-generation battery technology due to their excellent safety, high energy density, and high power density.
  • the ionic conductivity of the electrolyte in solid-state batteries is low.
  • the interface binding force is poor, and there is great resistance between solid-phase interfaces, which greatly limit the application of solid-state batteries. How to solve these problems has become the focus of many research institutions.
  • the solid-state electrolytes of all-solid-state batteries are divided into inorganic oxide solid electrolytes, polymer-based solid electrolytes, and inorganic sulfide-based solid electrolytes.
  • the sulfide-based solid electrolyte Li 7 P 3 S 11
  • the sulfide-based solid electrolyte has the highest ionic conductivity, which can reach 10 -3 ⁇ 10 -2 S cm -1 , which is equal to that of the liquid electrolyte.
  • problems such as poor internal interface contact and interface side reactions are more serious.
  • Polymer electrolytes can be divided into polyethylene oxide (PEO), polyacrylonitrile (PAN), polyvinylidene fluoride (PVDF) and polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) according to the matrix, among which the most studied It is a PEO-based polymer electrolyte.
  • PEO polyethylene oxide
  • PAN polyacrylonitrile
  • PVDF polyvinylidene fluoride
  • PVDF-HFP polyvinylidene fluoride-hexafluoropropylene
  • Inorganic oxide solid electrolytes can be divided into crystalline solid electrolytes and glassy amorphous solid electrolytes according to their structures.
  • the crystalline solid electrolyte can be subdivided into perovskite type, sodium superionic conductor (NASICON) type, lithium zinc germanate (LISICON) type, lithium nitride (Li3N) type, garnet type and some other new types.
  • solid electrolyte solid electrolyte.
  • the intrinsic conductivity of LISICON solid electrolyte and garnet solid electrolyte is relatively high, which can reach 10 -3 ⁇ 10 -2 S cm -1 .
  • the lithium ion conductivity of inorganic oxide electrolytes varies greatly, and the difference in ion conductivity of some electrolytes can reach 5-6 orders of magnitude.
  • this type of solid electrolyte has poor mechanical properties, high grain boundary impedance of the material itself, poor interface contact with electrode materials, and high interface impedance, which greatly limits the application of this type of electrolyte.
  • the present invention provides a positive electrode sheet modified by electropolymerized polymer film and a preparation method thereof.
  • a positive pole piece modified by a polymer film A polymer film doped with an electrolyte is adsorbed on the surface of the positive pole piece, wherein the polymer film has a microporous structure and a thickness of 2 to 300 nm.
  • the deposition method is adsorbed on the surface of the positive pole piece; the electrolyte is adsorbed on the surface and micropores of the polymer film, and the electrolyte content is 10-1000ppm.
  • a method for preparing a positive electrode sheet modified by a polymer film comprising the steps of:
  • step 2) Put the working electrode, counter electrode and reference electrode obtained in step 1) into an electrolytic cell protected by an inert gas in step 2), place the electrolytic cell in an electrochemical shielding box, and shield the whole electrochemical Protect the inside of the box with inert gas, and then connect the electrolytic cell to the electrochemical workstation;
  • step 3) Set the scanning parameters of the electrochemical workstation in step 3): the scanning speed is 5 to 400 mV/s, the scanning voltage range is -1 to 1.4 V, and the electropolymerization modification reaction is completed after scanning for 5 to 50 weeks to obtain the high Positive electrode sheet modified by molecular film.
  • the polymer monomer in the step 2) is one or more of carbazole, pyrrole, thiophene and aniline, and the concentration is 0.1-20 mg/mL.
  • the electrolyte is a compound formed by combining the following anions and cations:
  • the anions are perchlorate ions, hexachloroplatinate ions, tetrafluoroborate ions, hexafluorophosphate ions , sulfate ion, hexafluoroarsenate ion, tetraphenylborate ion or one or more;
  • the cation is potassium ion, lithium ion, tetramethylammonium ion, tetraethylammonium ion, tetra-n-butyl One or more of ammonium ions.
  • the organic solvent is N,N-dimethylacetamide, N,N-dimethylformamide, acetonitrile, toluene, methylene chloride, chloroform, cyclohexane, pyridine , one or more of phenylacetonitrile.
  • the area of the working electrode is (0.5 ⁇ 0.5) ⁇ (2 ⁇ 2) cm 2
  • the area of the counter electrode is (0.5 ⁇ 0.5) ⁇ (2 ⁇ 2) cm 2
  • the area of the reference electrode is The concentration is 0.005 ⁇ 0.02mol/L.
  • the counter electrode in step 3) is one of gold, platinum, lead and titanium; the reference electrode is one of calomel electrode or Ag/Ag + electrode.
  • the scanning speed is 100mV/s
  • the voltage range is -0.8-0.89V
  • the scanning cycle is 15 cycles.
  • the present invention is a positive electrode sheet modified by electropolymerization polymer film to modify the surface of the positive electrode material.
  • the polymer film is filled with electrolyte, and a trace amount of electrolyte doping is used as an intermediate hub, which can improve the electrical conductivity of the material.
  • the effect of improving the spatial connectivity of the polymer film can effectively improve the contact effect between the positive electrode material and the solid electrolyte interface, inhibit the formation of the space charge layer, reduce the energy barrier between different interfaces, reduce the polarization effect, and improve the interface stability. , and can inhibit the occurrence of side reactions and improve safety performance.
  • the polymer film has a certain rigidity, which can play a role of structural support, protect the surface of the material, and prevent particles from falling off.
  • a certain amount of electrolyte material is doped in the pores of the film, which can well improve its ion conductivity.
  • Fig. 1 is the electropolymerization polymer film preparation device and schematic diagram of principle in the present invention
  • Fig. 2 is the reaction schematic diagram of electropolymerization reaction in embodiment 1 among the present invention.
  • Example 3 is an AFM image of the material prepared in Example 1.
  • test reagents used in the following examples are conventional biochemical reagents; the experimental methods, unless otherwise specified, are conventional methods.
  • a positive pole piece modified by a polymer film A polymer film doped with an electrolyte is adsorbed on the surface of the positive pole piece, wherein the polymer film has a microporous structure and a thickness of 2 to 300 nm.
  • the deposition method is adsorbed on the surface of the positive pole piece; the electrolyte is adsorbed on the surface and micropores of the polymer film, and the electrolyte content is 10-1000ppm.
  • the invention adopts the electropolymerization method to prepare the coating layer with the electrolyte deposited in the membrane.
  • the advantage of this method lies in the in-situ reaction, which improves the kinetic controllability in the reaction process and is easier to pass Adjust the type and ratio of reactants to design the experiment, and the reaction results are more controllable.
  • the electropolymerized polymer film prepared by the present invention has a thickness of 2 to 300nm, is a microporous structure, and is filled with a solid electrolyte.
  • the existence of the spatial structure greatly improves the problem of the contact interface of the solid-state battery. This structure can make the interface Obtain good electrical conductivity while ensuring the flatness of the polymer film, ensuring good interface contact, and ensuring that the material has excellent electrochemical performance in the battery.
  • a method for preparing a positive electrode sheet modified by a polymer film comprising the steps of:
  • step 1) Ultrasonic pre-cleaning is performed on the working electrode obtained in step 1), one of gold, platinum, lead and titanium is used as a counter electrode, and a calomel electrode or an Ag/Ag+ electrode is used as a reference electrode, and placed in step 2)
  • step 2) In the electrolytic cell protected by inert gas, place the electrolytic cell in the electrochemical shielding box, protect the inside of the overall electrochemical shielding box with inert gas, and then connect the electrolytic cell to the electrochemical workstation;
  • step 3) Set the scanning parameters of the electrochemical workstation in step 3): the scanning speed is 5 to 400 mV/s, the scanning voltage range is -1 to 1.4 V, and the electropolymerization modification reaction is completed after scanning for 5 to 50 weeks to obtain the high Positive electrode sheet modified by molecular film.
  • the present invention adopts the electrochemical deposition method to prepare the positive electrode sheet modified by electropolymerization film.
  • the electropolymerization method has the following advantages: the in-situ growth is on the surface of the positive electrode sheet, the contact between the two is good, and the The pole piece plays a protective role.
  • the polymer film has a certain degree of flexibility.
  • the solid-state battery is made, it can be pressed and in good contact with the solid-state electrolyte. It can be used as a transition layer to reduce the pressure between the positive pole piece and the solid-state electrolyte.
  • the interfacial impedance of direct contact thereby reducing interfacial polarization and improving cycle retention.
  • the positive electrode material in the step 1) is a lithium ion battery positive electrode material, such as lithium cobaltate, nickel-cobalt-manganese ternary material, nickel-cobalt-aluminum ternary material, high-nickel material, lithium nickelate, lithium manganate wait.
  • a lithium ion battery positive electrode material such as lithium cobaltate, nickel-cobalt-manganese ternary material, nickel-cobalt-aluminum ternary material, high-nickel material, lithium nickelate, lithium manganate wait.
  • the adhesive in the step 1) is one or more of polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyvinyl alcohol (PVA), and polyurethane.
  • PTFE polytetrafluoroethylene
  • PVDF polyvinylidene fluoride
  • PVA polyvinyl alcohol
  • polyurethane polyurethane
  • the conductive agent in step 1) is one or more of carbon black, conductive graphite, carbon nanotubes and carbon nanofibers.
  • the polymer monomer in the step 2) is one or more of carbazole, pyrrole, thiophene and aniline, and the concentration is 0.1-20 mg/mL.
  • the electrolyte is a compound formed by combining the following anions and cations:
  • the anions are perchlorate ions, hexachloroplatinate ions, tetrafluoroborate ions, hexafluorophosphate ions , sulfate ion, hexafluoroarsenate ion, tetraphenylborate ion or one or more;
  • the cation is potassium ion, lithium ion, tetramethylammonium ion, tetraethylammonium ion, tetra-n-butyl One or more of ammonium ions.
  • the organic solvent is N,N-dimethylacetamide, N,N-dimethylformamide, acetonitrile, toluene, methylene chloride, chloroform, cyclohexane, pyridine , one or more of phenylacetonitrile.
  • the area of the working electrode is (0.5 ⁇ 0.5) ⁇ (2 ⁇ 2) cm 2
  • the area of the counter electrode is (0.5 ⁇ 0.5) ⁇ (2 ⁇ 2) cm 2
  • the area of the reference electrode is The concentration is 0.005 ⁇ 0.02mol/L.
  • the counter electrode in step 3) is one of gold, platinum, lead and titanium; the reference electrode is one of calomel electrode or Ag/Ag + electrode.
  • the scanning speed is 100mV/s
  • the voltage range is -0.8-0.89V
  • the scanning cycle is 15 cycles.
  • a kind of preparation of the electropolymerization thin film modified positive pole piece comprises following preparation steps:
  • the scanning speed is 100mV/s
  • the voltage range is -0.8-0.89V
  • the scanning is performed for 10 cycles. After the electropolymerization modification reaction is completed, the positive electrode sheet modified by the polymer film is obtained.
  • step 2) becomes:
  • a kind of preparation of the electropolymerization thin film modified positive pole piece comprises following preparation steps:
  • the scanning speed is 100mV/s
  • the voltage range is -0.8-0.89V
  • the scanning is performed for 10 cycles. After the electropolymerization modification reaction is completed, the positive electrode sheet modified by the polymer film is obtained.
  • the small molecules of aniline are chemically deposited on the surface of the pole piece by evaporation, without electrolyte filling.
  • Fig. 1 is a schematic diagram of the preparation device and principle of the electropolymerization film in the present invention.
  • an all-solid-state battery system is used to test the electrochemical performance.
  • the test conditions are 2.8V-4.25V, 0.1C rate.
  • the electrode modified by the polymer film is punched, washed with an organic solvent, and dried in vacuum for about 12 hours. It is then used as the positive pole piece of the battery and applied to a solid-state lithium metal polymer battery.
  • a polyethylene oxide (PEO)-based polymer electrolyte membrane with a thickness of 25 ⁇ m was used as the solid polymer electrolyte (SPE) without using an additional separator.
  • a polymer electrolyte film was placed between the cathode electrode and Li metal foil (35 ⁇ m), and laminated at 80 °C to assemble a coin-type battery (CR2032).
  • the diameter of the cathode electrode was 16 mm. The process is carried out in a dry room with a dew point below -50°C or in a glove box filled with argon (H 2 O, O 2 ⁇ 5ppm).
  • High-temperature cycle performance test of lithium-ion battery In a constant temperature environment of 45°C, charge the lithium-ion battery with a constant current of 1/3C to 4.25V, then charge it with a constant voltage of 4.25V to a current ⁇ 0.05mA, let it stand for 5 minutes, and then charge it with 1/3C constant current discharge to 2.8V, this is a charge-discharge cycle process, the discharge capacity of this time is the discharge capacity of the first cycle. Lithium-ion battery is then carried out 50 cycle charge/discharge tests according to the above-mentioned method, detects the discharge capacity that obtains the 50th cycle.
  • Table 1 is a comparison of the electrochemical properties of the integrated electrodes prepared in Examples 1-2 and Comparative Examples 1-2 of the present invention.

Abstract

本发明提供了一种电聚合高分子薄膜修饰的正极极片及其全固态电池的制备方法。本发明首先采用电聚合方法在正极极片表面修饰一层电聚合高分子薄膜，该方法制备的电聚合薄膜内部有电解质掺杂，离子电导率高，聚合物薄膜有一定的呼吸作用，可以缓和正极材料和固态电解质接触时产生的应力，使得界面稳定，又能增加界面接触效果，降低界面阻抗，综合有机液态电解液和固态电解液的优点，采用本方法制备的固态电池循环性能优异。

Description

一种高分子薄膜修饰的正极极片及其制备方法
本申请要求于2021年12月14日提交中国专利局、申请号为202111513829.8、发明名称为“一种高分子薄膜修饰的正极极片及其制备方法”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本发明涉及全固态电池领域，具体涉及一种高分子薄膜修饰的正极极片及其制备方法。
背景技术
全固态电池以其具有优异的安全性和高能量密度及高功率密度的特点，被认为是最具应用前景的下一代电池技术，但是，固态电池中的电解质的离子电导率较低，电池内部界面结合力较差，固相界面之间存在极大的阻力，这些都极大的限制了固态电池的应用，如何解决这些问题也成为了众多研究机构角逐的焦点。
全固态电池的固态电解质分为无机氧化物固体电解质、聚合物基固体电解质和无机硫化物系固体电解质。其中，硫化物系固体电解质(Li 7P 3S 11)的离子电导率最高，可达10 -3～10 -2S cm -1，与液态电解液持平。但其电池内部界面接触较差和界面副反应等问题比较严重。聚合物电解质按照基体可分为聚氧化乙烯类(PEO)、聚丙烯腈(PAN)、聚偏氟乙烯(PVDF)和聚偏氟乙烯-六氟丙烯(PVDF-HFP)等，其中研究最多的是PEO基聚合物电解质。但是PEO本身结晶度较高，使得PEO基聚合物电解质室温电导率较低(约为10 -7S cm-1)，为此，人们探索了降低其结晶度等改进的方法。
无机氧化物固体电解质按结构可分为晶体型固体电解质和玻璃态非晶体固体电解质。具体地，晶体型固体电解质又可细分为钙钛矿型，钠超离子导体(NASICON)型、锗酸锌锂(LISICON)型、氮化锂(Li3N)型，石榴石型和其他一些新型固体电解质。其中，LISICON型固体电解 质和石榴石型固体电解质的本征电导率较高，可以达到10 -3～10 -2S cm -1。另外，由于晶型的不同，无机氧化物电解质之间的锂离子电导率差异较大，有些电解质的离子电导率差异可以达到5-6个数量级。但是这类固态电解质机械性能较差，材料本身晶界阻抗较高，与电极材料的界面接触效果较差，界面阻抗高，使得该类电解质的应用受到极大的限制。
这三类固体电解质在界面问题上的有共同的痛点，如何找到一种电导率高，界面稳定，又能增加界面接触效果，降低阻抗的方案，综合有机液态电解液和固态电解液的优点，才是这些问题的最优解。
发明内容
为了解决上述技术问题，本发明提供了一种电聚合高分子薄膜修饰的正极极片及其制备方法。
为了解决上述技术问题，本发明采用的技术方案是：
一种高分子薄膜修饰的正极极片，正极极片表面吸附了掺杂有电解质的高分子薄膜，其中所述高分子薄膜为微孔结构，厚度为2～300nm，所述高分子薄膜通过电沉积法吸附在正极极片表面；所述电解质吸附在高分子薄膜的表面和微孔中，电解质含量为10～1000ppm。
一种高分子薄膜修饰的正极极片的制备方法，包括如下步骤：
1)将15～18g正极材料、0.1～0.5g粘接剂、0.1～0.5g导电剂共同混合，进行高速搅拌匀浆，将分散均匀的浆料过滤后涂布到电极集流体上，再进行烘干、冷压得到初级极片，初级极片经过超声波清洗后即得工作电极；
2)将0.1～3g高分子聚合物单体、0.2～2.0mol/L的六氟磷酸四丁基铵(TBAPF 6)1～10mL、0.01～2g六氟磷酸锂、0.01～2g电解质加入到有机溶剂中，搅拌均匀后形成混合溶液后加入到电解槽中，电解槽中通入惰性气体保护；
3)将步骤1)中得到的工作电极、对电极，参比电极，放入步骤2)中由惰性气体保护的电解槽中，将电解槽放置于电化学屏蔽箱中，对整体电化学屏蔽箱内部进行惰性气体保护，后将电解槽与电化学工作站相连；
4)设置步骤3)中电化学工作站的扫描参数：扫描速度为5～400mV/s，扫描电压范围为-1～1.4V，扫描5～50周后完成电聚合修饰反应，即得所述高分子薄膜修饰的正极极片。
优选的，所述步骤2)中的高分子聚合物单体为咔唑、吡咯、噻吩、苯胺中的一种或多种，浓度为0.1～20mg/mL。
优选的，所述步骤2)中，所述电解质为下述阴离子与阳离子组合形成的化合物：所述阴离子为高氯酸根离子、六氯铂酸根离子、四氟硼酸根离子、六氟磷酸根离子、硫酸根离子、六氟砷酸根离子、四苯硼酸根离子中的一种或多种；所述阳离子为钾离子、锂离子、四甲基铵离子、四乙基铵离子、四正丁基铵离子中的一种或多种。
优选的，所述步骤2)中，有机溶剂为N,N-二甲基乙酰胺、N,N-二甲基甲酰胺、乙腈、甲苯、二氯甲烷、三氯甲烷、环己烷、吡啶、苯乙腈中的一种或者多种。
优选的，所述步骤3)中工作电极的面积为(0.5×0.5)～(2×2)cm 2，对电极的面积为(0.5×0.5)～(2×2)cm 2，参比电极的浓度为0.005～0.02mol/L。
优选的，所述步骤3)中对电极为金、铂、铅和钛中的一种；所述参比电极为甘汞电极或Ag/Ag +电极中的一种。
优选的，所述步骤4)中，扫描速度为100mV/s，电压范围为-0.8～0.89V，扫描周数为15周。
上述所述的高分子薄膜修饰的正极极片在全固态电池中的应用。
上述制备方法所制备的高分子薄膜修饰的正极极片在全固态电池中的应用。
本发明的有益效果为：
1)本发明为一种电聚合高分子薄膜修饰的正极极片对正极材料表面进行改性处理，高分子薄膜内填充有电解质，痕量的电解质掺杂作为中间枢纽，可以起到提高材料电导的作用，改善高分子薄膜的空间连接性，可有效改善正极材料与固态电解质界面的接触效果，抑制空间电荷层的形成，降低不同界面之间的能垒，降低极化作用，提高界面稳定性，并能抑制副反应的发生，提高安全性能。
2)该聚合物薄膜具有一定的刚性，可以起到结构支撑的作用，保护材料表面，防止颗粒脱落，薄膜孔隙中掺杂了一定量的电解质材料，可以很好的改善其离子电导性。
3)该聚合物薄膜原位生长在正极极片表面，两者接触较好，可以对极片起到保护作用，同时，该聚合物薄膜又富有一定的柔性，可以在固态电池制作时，经过压合，与固态电解质很好的接触，可以作为过渡层，降低正极极片与固态电解质直接接触的界面阻抗，从而降低界面极化，提高循环保持率。
附图说明
图1为本发明中电聚合高分子薄膜制备装置及原理示意图；
图2为本发明中实施例1中电聚合反应的反应原理图；
图3为实施例1制备的材料AFM图。
具体实施方式
除有定义外，以下实施例中所用的技术术语具有与本发明所属领域技术人员普遍理解的相同含义。以下实施例中所用的试验试剂，如无特殊说明，均为常规生化试剂；所述实验方法，如无特殊说明，均为常规方法。
一种高分子薄膜修饰的正极极片，正极极片表面吸附了掺杂有电解质的高分子薄膜，其中所述高分子薄膜为微孔结构，厚度为2～300nm，所述高分子薄膜通过电沉积法吸附在正极极片表面；所述电解质吸附在高分子薄膜的表面和微孔中，电解质含量为10～1000ppm。
本发明采用电聚合法制备了膜内沉积有电解质的包覆层，和传统的浸泡蒸发法相比，本方法的优点在于原位反应，提高了反应过程中的动力学可控性，更容易通过调整反应物的种类和比例，来对实验进行设计，反应结果更加可控。
本发明制备的电聚合高分子薄膜厚度为2～300nm，为微孔结构，中间填充有固态电解质，这种结构在实效固态电池中应用时，和传统正极材料相比，由于这种中间多孔的空间结构存在，极大的改善了固态电池的的接触界面问题，该结构通过适当的调节多孔高分子薄膜中的电解质掺杂 量，以及高分子薄膜的聚合度、孔隙率等参数，能够让界面获得良好的导电性同时保证高分子薄膜的平整性，保证界面接触良好，确保该材料在电池中具有优良的电化学性能。
一种高分子薄膜修饰的正极极片的制备方法，包括如下步骤：
1)将15～18g正极材料、0.1～0.5g粘接剂、0.1～0.5g导电剂共同混合，进行高速搅拌匀浆，将分散均匀的浆料过滤后涂布到电极集流体上，再进行烘干、冷压得到初级极片，初级极片经过超声波清洗后即得工作电极；
2)将0.1～3g高分子聚合物单体、0.2～2.0mol/L的六氟磷酸四丁基铵(TBAPF 6)1～10mL、0.01～2g六氟磷酸锂、0.01～2g电解质加入到有机溶剂中，搅拌均匀后形成混合溶液后加入到电解槽中，电解槽中通入惰性气体保护；
3)将步骤1)中得到的工作电极进行超声波预清洗，金、铂、铅和钛中的一种作为对电极，甘汞电极或Ag/Ag+电极作为参比电极，放入步骤2)中由惰性气体保护的电解槽中，将电解槽放置于电化学屏蔽箱中，对整体电化学屏蔽箱内部进行惰性气体保护，后将电解槽与电化学工作站相连；
4)设置步骤3)中电化学工作站的扫描参数：扫描速度为5～400mV/s，扫描电压范围为-1～1.4V，扫描5～50周后完成电聚合修饰反应，即得所述高分子薄膜修饰的正极极片。
本发明采用了电化学沉积法制备电聚合薄膜修饰的正极极片，和传统挥发成膜相比，电聚合法具有如下优点：原位生长在正极极片表面，两者接触较好，可以对极片起到保护作用，同时，该聚合物薄膜又富有一定的柔性，可以在固态电池制作时，经过压合，与固态电解质很好的接触，可以作为过渡层，降低正极极片与固态电解质直接接触的界面阻抗，从而降低界面极化，提高循环保持率。
优选的，所述步骤1)中的正极材料为锂离子电池用正极材料，如钴酸锂、镍钴锰三元材料，镍钴铝三元材料，高镍材料，镍酸锂，锰酸锂等。
优选的，所述步骤1)中的粘接剂为聚四氟乙烯(PTFE)，聚偏氟 乙烯(PVDF)，聚乙烯醇(PVA)，聚氨酯中的一种或多种。
优选的，所述步骤1)中的导电剂为炭黑、导电石墨、碳纳米管和纳米碳纤维中的一种或多种。
优选的，所述步骤2)中的高分子聚合物单体为咔唑、吡咯、噻吩、苯胺中的一种或多种，浓度为0.1～20mg/mL。
优选的，所述步骤2)中，所述电解质为下述阴离子与阳离子组合形成的化合物：所述阴离子为高氯酸根离子、六氯铂酸根离子、四氟硼酸根离子、六氟磷酸根离子、硫酸根离子、六氟砷酸根离子、四苯硼酸根离子中的一种或多种；所述阳离子为钾离子、锂离子、四甲基铵离子、四乙基铵离子、四正丁基铵离子中的一种或多种。
优选的，所述步骤2)中，有机溶剂为N,N-二甲基乙酰胺、N,N-二甲基甲酰胺、乙腈、甲苯、二氯甲烷、三氯甲烷、环己烷、吡啶、苯乙腈中的一种或者多种。
优选的，所述步骤3)中工作电极的面积为(0.5×0.5)～(2×2)cm 2，对电极的面积为(0.5×0.5)～(2×2)cm 2，参比电极的浓度为0.005～0.02mol/L。
优选的，所述步骤3)中对电极为金、铂、铅和钛中的一种；所述参比电极为甘汞电极或Ag/Ag +电极中的一种。
优选的，所述步骤4)中，扫描速度为100mV/s，电压范围为-0.8～0.89V，扫描周数为15周。
上述所述的高分子薄膜修饰的正极极片在全固态电池中的应用。
上述制备方法所制备的高分子薄膜修饰的正极极片在全固态电池中的应用。
下面结合具体实施例来详细说明本发明。
实施例1
一种电聚合薄膜修饰的正极极片的制备，包括如下制备步骤：
1)将高镍LiNi 0.9Co 0.06Mn 0.04正极材料16g、粘接剂PVDF：0.33g、导电剂Super P：0.25g，进行高速搅拌匀浆5min，将分散均匀的浆料过滤后涂布到集流体上，再进行烘干、冷压得到新鲜的正极极片，经过超声波清 洗1min后，作为工作电极；
2)将10ml 0.5mg/mL苯胺、5mL 1.0mol/L的六氟磷酸四丁基铵(TBAPF 6)，0.01g六氟磷酸锂,0.01g高氯酸铵加入到乙腈与二氯甲烷体积比为2:3中，搅拌均匀后将混合液加入电解槽中，电解槽中通入高纯N 2保护；
3)将表面经过超声波清洗的正极极片(2×2cm 2，工作电极)、钛板作为(2×2cm 2，对电极)，Ag +/Ag(0.01mol/L)电极(参比电极)放入电化学槽中，对整个电化学屏蔽箱进行N 2保护，再接通电化学工作站；
4)设置扫描参数：扫描速度为100mV/s，电压范围-0.8～0.89V，扫描10周，完成电聚合修饰反应后即得到聚合薄膜修饰的正极极片。
对比例1
和实施例1相比，步骤2)变成：
2)将聚苯胺溶解后，利用离子蒸镀的方法，蒸镀到极片上单独包覆高分子薄膜的正极极片，没有电解质的填充。
实施例2
一种电聚合薄膜修饰的正极极片的制备，包括如下制备步骤：
1)将高镍LiNi 0.9Co 0.06Mn 0.04正极材料16g、粘接剂PVDF：0.33g、导电剂Super P：0.25g，进行高速搅拌匀浆5min，将分散均匀的浆料过滤后涂布到集流体上，再进行烘干、冷压得到新鲜的正极极片，经过超声清洗1min后，作为工作电极；
2)将10ml 0.5mg/mL苯胺、5mL 1.0mol/L的六氟磷酸四丁基铵(TBAPF 6)0.01g六氟磷酸锂，0.01g加入到乙腈与二氯甲烷体积比为2:3中，搅拌均匀后将混合液加入电解槽中，电解槽中通入高纯N 2保护；
3)将表面经过超声波清洗的正极极片(2×2cm 2，工作电极)、钛板作为(2×2cm 2，对电极)，Ag +/Ag(0.01mol/L)电极(参比电极)放入电化学槽中，对整个电化学屏蔽箱进行N 2保护，再接通电化学工作站；
4)设置扫描参数：扫描速度为100mV/s，电压范围-0.8～0.89V，扫描10周，完成电聚合修饰反应后即得到聚合薄膜修饰的正极极片。
对比例2
将苯胺小分子通过蒸镀的方法，化学沉积到极片表面，没有电解质的填充。
实验情况
图1为本发明中电聚合薄膜制备装置及原理示意图。本发明中采用全固态电池体系测试电化学性能，测试条件为2.8V～4.25V,0.1C倍率，使用的设备为蓝电充放电仪，测试容量，45℃循环等电化学参数，将得到的高分子薄膜修饰电极进行冲片，有机溶剂清洗，真空干燥约12小时后，作为电池的正极极片，应用于固态锂金属聚合物电池。
使用厚度为25μm的基于聚氧化乙烯(PEO)的聚合物电解质膜作为固体聚合物电解质(SPE)，而无需使用额外的隔膜。聚合物电解质薄膜放置在阴极电极和锂金属箔(35μm)之间，并在80℃下层压以组装硬币型电池(CR2032)。阴极电极的直径为16mm。该过程在露点低于-50℃的干燥室内或充满氩气的手套箱内(H 2O，O 2<5ppm)进行。
容量测试：
在2.8V～4.25V电压下，将纽扣电池以0.1C恒流充电至4.25V，然后以4.25V恒压充电至电流≤0.05mA，静置2min，此时的充电容量记为C 0；然后以0.1C恒流放电至2.8V，此时的放电容量为记为D 0。放电容量D 0与正极活性材料质量的比值即为正极活性材料的克容量。正极活性材料的首次库伦效率(％)＝D 0/C 0×100％。
循环测试：
锂离子电池的高温循环性能测试在45℃的恒温环境下，将锂离子电池以1/3C恒流充电至4.25V，接着以4.25V恒压充电至电流≤0.05mA，静置5min，然后以1/3C恒流放电至2.8V，此为一个充放电循环过程，此次的放电容量为首次循环的放电容量。然后将锂离子电池按照上述方法 进行50次循环充电/放电测试，检测得到第50次循环的放电容量。
表1为本发明中实施例1～2，对比例1～2制备得到的一体化电极的电化学性能对比。
表1 本发明中制备的一体化电极的电化学性能对比
Figure PCTCN2022082974-appb-000001
可见，本发明中的实施例1、2都表现出较好的容量和循环保持率。对比例1、2由于没有适量的电解质掺杂，因此性能较差。
以上所述仅为本发明的较佳实施例而已，并不用以限制本发明，凡在本发明的精神和原则之内，所作的任何修改、等同替换、改进等，均应包含在本发明的保护范围之内。

Claims (10)

  1. 一种高分子薄膜修饰的正极极片，其特征在于：所述正极极片表面吸附了掺杂有电解质的高分子薄膜，所述高分子薄膜为微孔结构，高分子薄膜厚度为2～300nm，所述高分子薄膜通过电沉积法吸附在正极极片表面；所述电解质吸附在高分子薄膜的表面和微孔中，电解质含量为10～1000ppm。
  2. 制备如权利要求1所述高分子薄膜修饰的正极极片的方法，其特征在于，包括如下步骤：
    1)将15～18g正极材料、0.1～0.5g粘接剂、0.1～0.5g导电剂共同混合，进行高速搅拌匀浆，将分散均匀的浆料过滤后涂布到电极集流体上，再进行烘干、冷压得到初级极片，初级极片经过超声波清洗后即得工作电极；
    2)将0.1～3g高分子聚合物单体、0.2～2.0mol/L的六氟磷酸四丁基铵(TBAPF 6)1～10mL、0.01～2g六氟磷酸锂、0.01～2g电解质加入到有机溶剂中，搅拌均匀形成混合溶液后加入到电解槽中，电解槽中通入惰性气体保护；
    3)将步骤1)中得到的工作电极以及对电极、参比电极放入步骤2)中由惰性气体保护的电解槽中，将电解槽放置于电化学屏蔽箱中，对整体电化学屏蔽箱内部进行惰性气体保护，后将电解槽与电化学工作站相连；
    4)设置步骤3)中电化学工作站的扫描参数为：扫描速度为5～400mV/s，扫描电压范围为-1～1.4V，扫描5～50周后完成电聚合修饰反应，即得所述高分子薄膜修饰的正极极片。
  3. 根据权利要求2所述的制备方法，其特征在于：所述步骤2)中的高分子聚合物单体为咔唑、吡咯、噻吩、苯胺中的一种或多种，浓度为0.1～20mg/mL。
  4. 根据权利要求2所述的制备方法，其特征在于：所述步骤2)中，所述电解质为下述阴离子与阳离子组合形成的化合物：所述阴离子为高氯酸根离子、六氯铂酸根离子、四氟硼酸根离子、六氟磷酸根离子、硫酸根离子、六氟砷酸根离子、四苯硼酸根离子中的一种或多种；所述阳离子为 钾离子、锂离子、四甲基铵离子、四乙基铵离子、四正丁基铵离子中的一种或多种。
  5. 根据权利要求2所述的制备方法，其特征在于：所述步骤2)中，有机溶剂为N,N-二甲基乙酰胺、N,N-二甲基甲酰胺、乙腈、甲苯、二氯甲烷、三氯甲烷、环己烷、吡啶、苯乙腈中的一种或者多种。
  6. 根据权利要求2所述的制备方法，其特征在于：所述步骤3)中工作电极的面积为(0.5×0.5)～(2×2)cm 2，对电极的面积为(0.5×0.5)～(2×2)cm 2，参比电极的浓度为0.005～0.02mol/L。
  7. 根据权利要求2所述的制备方法，其特征在于：所述步骤3)中对电极为金、铂、铅和钛中的一种；所述参比电极为甘汞电极或Ag/Ag +电极中的一种。
  8. 根据权利要求2所述的制备方法，其特征在于：所述步骤4)中，扫描速度为100mV/s，电压范围为-0.8～0.89V，扫描周数为15周。
  9. 根据权利要求1所述的高分子薄膜修饰的正极极片在全固态电池中的应用。
  10. 根据权利要求2～6任意一项制备方法所制备的高分子薄膜修饰的正极极片在全固态电池中的应用。
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