Gel-state polymer material of lithium ion battery, preparation method of gel-state polymer material and gel-state lithium ion battery

Abstract

The invention provides a gel-state polymer material for a lithium ion battery, a preparation method of the gel-state polymer material and the gel-state lithium ion battery, and relates to the technical field of battery preparation. Wherein the polymer comprises one or more than two of polyacrylate polymers, polyacrylic acid polymers, polycarbonate polymers, polyoxyethylene, polyamide, polyvinyl alcohol, polyimide and polyacrylonitrile, or a copolymer of more than two of the polyacrylate polymers, the polyacrylic acid polymers, the polycarbonate polymers, the polyoxyethylene, the polyamide, the polyvinyl alcohol, the polyimide and the polyacrylonitrile. The implementation effect is remarkable, the electrolyte stably exists in a gel state, the adsorption capacity is high, and the ionic conductivity is improved; free electrolyte molecules are reduced, and the safety performance is improved; the liquid leakage risk is reduced and the reliability is enhanced; the cycle life is prolonged; the cost is reduced by matching with the existing process; the inorganic powder enhances the safety and high-temperature performance, and promotes the development of the lithium ion battery technology.

Description

Technical Field

[0001] The invention provides a lithium ion battery gel polymer material and a preparation method thereof and a gel lithium ion battery, and relates to the technical field of battery preparation. Background Art

[0002] Lithium-ion batteries, as a type of energy storage device that has developed rapidly in recent decades, have a wide range of applications, and have penetrated into multiple key fields such as power, energy storage, and 3C (computers, communications, and consumer electronics), showing strong market adaptability and technical potential. However, most of the lithium-ion batteries currently produced are based on liquid electrolyte systems. While this feature gives them high energy conversion efficiency, it also poses risks in terms of thermal stability and safety. In particular, with the rapid expansion of the application field of lithium-ion batteries towards large-scale power sources, the energy density and capacity requirements of batteries are increasing, and the current rate and power density are also increasing. This series of changes has undoubtedly exacerbated the challenges of lithium-ion battery safety, making safety issues a key factor restricting their further widespread application.

[0003] In this context, semi-solid-state battery technology, as an important bridge for the transition from liquid batteries to all-solid-state batteries, has attracted widespread attention and research investment from the industry in recent years. There are various strategies for the implementation of semi-solid-state batteries. One effective way is to scientifically and rationally mix solid electrolytes with liquid electrolytes. The solid electrolytes here cover a variety of types such as sulfides, oxides, polymers, etc., each of which has unique physical and chemical properties. Through the ingenious combination of solid electrolytes and liquid electrolytes, it not only effectively makes up for the performance deficiencies of a single component, but also significantly improves the overall safety performance of the battery. At the same time, it maintains the high conductivity and good interface bonding of the liquid electrolyte, providing new ideas for optimizing battery performance. Another design scheme for semi-solid-state batteries focuses on improving the stability of the battery interface. The specific approach is to carefully coat a layer of solid electrolyte coating on the surface of the battery's base membrane. This innovative design greatly enhances the stability of the battery interface and effectively improves the overall performance and service life of the battery. The uniqueness of this design idea is that it can maintain the relative stability of battery performance when the external ambient temperature changes, significantly reducing the decomposition and repair process of the solid electrolyte interface (SEI) film, thereby effectively extending the battery life and improving the reliability and durability of the battery. Of course, the industry has never stopped exploring all-solid-state batteries. The all-solid-state battery solution fundamentally eliminates the existence of liquid electrolytes, and in theory can completely solve the safety problems of liquid batteries. However, the realization of this ideal state is not easy. The production process of all-solid-state batteries is more complicated and cumbersome, the cost is relatively high, and at the current level of technology, its battery performance is still difficult to fully meet the expected standards. Therefore, although all-solid-state batteries represent an important development direction of lithium-ion battery technology in the future, many technical difficulties still need to be overcome in practical applications. Semi-solid-state battery technology, as a transitional solution, will continue to play an important role in the current and future period of time, providing strong support for the continuous advancement of lithium-ion battery technology and the continuous expansion of its application fields. Summary of the invention

[0004] To solve the above problems, the present invention is characterized in that it provides a gel polymer material including a polymer and an inorganic powder for absorbing and storing an electrolyte. The specific scheme is as follows:

[0005] A lithium ion battery gel polymer material comprises a polymer and an inorganic powder, wherein the polymer comprises one or more of polyacrylate polymers, polyacrylic acid polymers and polycarbonate polymers.

[0006] Preferably, the polymer further comprises one or more of polyethylene oxide, polyamide, polyvinyl alcohol, polyimide, polyacrylonitrile, or a copolymer of two or more thereof.

[0007] Preferably, the monomer of the polyacrylate includes one or more of methyl acrylate, ethyl acrylate, butyl acrylate, isobutyl acrylate, n-pentyl acrylate, isopentyl acrylate, n-hexyl acrylate, isooctyl acrylate, hydroxypropyl acrylate, 2-hydroxyethyl acrylate, lauryl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, isobutyl methacrylate, n-pentyl methacrylate, n-hexyl methacrylate, isooctyl methacrylate, hydroxypropyl methacrylate or 2-hydroxyethyl methacrylate.

[0008] Preferably, the inorganic powder includes one or more of aluminum oxide, boehmite, and solid electrolyte powder.

[0009] Preferably, the solid electrolyte powder includes one or more of LATP, LLZO, LLTO, LAGP, and LLZTO.

[0010] The present invention also provides a method for preparing the above-mentioned lithium ion battery gel polymer material, comprising the following steps:

[0011] Take the polymerization monomer corresponding to the polymer, add the solvent, initiator, and inorganic powder, heat to carry out polymerization reaction, and obtain the lithium ion battery gel polymer material after the reaction is completed; or take the polymerization monomer corresponding to the polymer, add the solvent and initiator, heat to carry out polymerization reaction, add inorganic powder and mix after the reaction is completed to obtain the lithium ion battery gel polymer material.

[0012] Preferably, the polymer solvent includes one or more of water or anhydrous ethanol; the heating polymerization reaction is carried out at a temperature of 50-95° C. and a time of 2-30 hours.

[0013] Preferably, the initiator includes one or more of benzoyl peroxide, lauroyl peroxide, cumene hydroperoxide, tert-butyl hydroperoxide, di-tert-butyl peroxide, and dicumyl peroxide.

[0014] Preferably, the obtained material has a solid content of 10-60wt%, and a Tg of -30-60°C.

[0015] Preferably, the inorganic powder in the obtained material accounts for 1-50 wt% of the polymer mass.

[0016] Preferably, the preparation method further comprises adding a cross-linking agent, wherein the cross-linking agent comprises one or more of ethylene glycol dimethacrylate, diacetone acrylamide, and adipic acid dihydrazide.

[0017] In addition, the present invention also provides a gel-state lithium-ion battery comprising the above-mentioned lithium-ion battery gel-state polymer material.

[0018] Preferably, the gel-state lithium-ion battery includes the gel-state polymer material, or includes a material obtained after the gel-state polymer material is molded, or includes a separator coated with the gel-state polymer material.

[0019] Preferably, the amount of electrolyte adsorbed by the gel polymer material is 100-1000wt%.

[0020] Preferably, the diaphragm comprises one or more of a polypropylene diaphragm, a filter paper, a glass fiber diaphragm, a cellulose diaphragm, a nylon diaphragm, and a ceramic diaphragm. The battery diaphragm is soaked in the gel polymer material for 0.001-100 hours, the treatment temperature is 30-200°C, and the treatment time is 0.1-100 hours. The coating amount of the gel polymer material on the diaphragm is 0.01-10 g / m 2 , the coating thickness is 500nm-5μm.

[0021] Preferably, the positive electrode of the gel lithium-ion battery includes one or more of ternary, lithium iron phosphate, and lithium cobalt oxide; the negative electrode material includes one or more of artificial graphite, natural graphite, silicon oxygen negative electrode, silicon carbon negative electrode, and lithium metal negative electrode; the electrolyte components include PC, EC, DEC, DMC, EMC, MF, MA, EA, MA, LiPF 6 、LiClO 4 , LiBF 4 、LiAsF 6 One or two or more of the following.

[0022] Beneficial effects of the present invention:

[0023] The implementation of the present invention brings about many significant beneficial effects. First, through the scheme of the present invention, the electrolyte can be stably present in the form of a gel state, and this gel state has a strong adsorption capacity for the electrolyte, ensuring the effective fixation of the electrolyte molecules. At the same time, the ionic conductivity in the gel state is significantly improved, optimizing the ion transmission path inside the battery, thereby improving the overall performance of the battery. Secondly, the design of the gel electrolyte effectively reduces or even eliminates the free electrolyte organic small molecules, which not only reduces the risk of adverse chemical reactions inside the battery, but also further improves the safety performance of the battery. Furthermore, due to the gelation of the electrolyte, potential risks such as battery leakage are significantly reduced, further enhancing the reliability and safety of battery use. In addition, the gel polymer material of the present invention also significantly extends the cycle life of the battery, providing a strong guarantee for the long-term use of the battery. It is worth noting that the gel lithium ion battery of the present invention is highly matched with the existing liquid lithium ion battery in terms of production process and equipment, and there is no need to carry out large-scale transformation of the production line, which is conducive to reducing production costs and promotion difficulties. Finally, through the clever use of inorganic powders, the battery of the present invention has been further enhanced in terms of safety, high temperature performance, etc., meeting higher standards of battery performance requirements and opening up a new path for the further development of lithium-ion battery technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Coated membrane samples prepared for some embodiments of the present invention;

[0025] Figure 2 Battery samples prepared for some embodiments of the present invention. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0027] Unless otherwise defined, all professional and scientific terms used herein have the same meanings as those familiar to those skilled in the art. In addition, any methods and materials similar or equivalent to those described herein may be applied to the present invention. The preferred implementation methods and materials described herein are for demonstration purposes only and are not intended to limit the content of this application.

[0028] The experimental methods in the following examples are conventional methods unless otherwise specified, and the experimental materials used in the following examples are purchased from commercial channels unless otherwise specified.

[0029] Embodiment A lithium-ion battery gel polymer material comprises a polymer and an inorganic powder, wherein the polymer comprises one or more of a polyacrylate polymer, a polyacrylic acid polymer, and a polycarbonate polymer.

[0030] The polymer also includes one or more of polyethylene oxide, polyamide, polyvinyl alcohol, polyimide, and polyacrylonitrile, or a copolymer of two or more of them.

[0031] The monomers of the polyacrylate include one or more of methyl acrylate, ethyl acrylate, butyl acrylate, isobutyl acrylate, n-pentyl acrylate, isopentyl acrylate, n-hexyl acrylate, isooctyl acrylate, hydroxypropyl acrylate, 2-hydroxyethyl acrylate, lauryl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, isobutyl methacrylate, n-pentyl methacrylate, n-hexyl methacrylate, isooctyl methacrylate, hydroxypropyl methacrylate or 2-hydroxyethyl methacrylate.

[0032] The inorganic powder includes one or more of aluminum oxide, boehmite, and solid electrolyte powder.

[0033] The solid electrolyte powder includes one or more of LATP, LLZO, LLTO, LAGP, and LLZTO.

[0034] Preparation of gel polymer materials for lithium-ion batteries:

[0035] Take the polymerization monomer corresponding to the polymer, add the solvent, initiator, and inorganic powder, heat to carry out polymerization reaction, and obtain the lithium ion battery gel polymer material after the reaction is completed; or take the polymerization monomer corresponding to the polymer, add the solvent and initiator, heat to carry out polymerization reaction, add inorganic powder and mix after the reaction is completed to obtain the lithium ion battery gel polymer material.

[0036] The polymer solvent includes one or more of water and anhydrous ethanol; the heating polymerization reaction is carried out at a temperature of 50-95° C. and a time of 2-30 hours.

[0037] The initiator includes one or more of benzoyl peroxide, lauroyl peroxide, cumene hydroperoxide, tert-butyl hydroperoxide, di-tert-butyl peroxide, and dicumyl peroxide.

[0038] The obtained material has a solid content of 10-60wt% and a Tg of 30-60°C.

[0039] The inorganic powder in the obtained material accounts for 1-50wt% of the polymer mass.

[0040] The preparation method further comprises adding a cross-linking agent, wherein the cross-linking agent comprises one or more of ethylene glycol dimethacrylate, diacetone acrylamide, and adipic acid dihydrazide.

[0041] A gel-state lithium-ion battery comprising the above-mentioned lithium-ion battery gel-state polymer material is prepared.

[0042] The gel-state lithium-ion battery includes the gel-state polymer material, or includes a material obtained after the gel-state polymer material is molded, or includes a diaphragm coated with the gel-state polymer material.

[0043] The adsorption amount of the gel polymer material to the electrolyte is 100-1000wt%.

[0044] The diaphragm includes one or more of polypropylene diaphragm, filter paper, glass fiber diaphragm, cellulose diaphragm, nylon diaphragm and ceramic diaphragm. The battery diaphragm is soaked in the gel polymer material for 0.001-100 hours, the treatment temperature is 30-200°C, and the treatment time is 0.1-100 hours. The coating amount of the gel polymer material on the diaphragm is 0.01-10g / m 2 , the coating thickness is 500nm-5μm.

[0045] The positive electrode of the gel lithium ion battery includes one or more of ternary, lithium iron phosphate, and lithium cobalt oxide; the negative electrode material includes one or more of artificial graphite, natural graphite, silicon oxygen negative electrode, silicon carbon negative electrode, and lithium metal negative electrode; the electrolyte components include PC, EC, DEC, DMC, EMC, MF, MA, EA, MA, LiPF 6 、LiClO 4 , LiBF 4 、LiAsF 6 One or two or more of the following.

[0046] Example 1 Preparation of Lithium Ion Battery Gel Polymer Material and Coated Diaphragm:

[0047] Add 250 parts of deionized water and 2 parts of sodium dodecylbenzene sulfonate into the reactor, introduce nitrogen for 30 minutes, set the reactor to 80°C, and after reaching the set temperature, add 2 parts of ammonium persulfate. After 10 minutes, add 30 parts of butyl methacrylate, 10 parts of vinyl acetate, 10 parts of styrene and 10 parts of ethylene glycol dimethacrylate dropwise. Add for 2 hours, continue the reaction for 5 hours, and obtain an emulsion after entering the pressure reducing device system.

[0048] 100 parts of the emulsion after polymerization and 50 parts of alumina powder were prepared into a 20% aqueous dispersion slurry, which was mechanically stirred for 30 minutes to obtain a uniformly dispersed slurry.

[0049] The prepared slurry was coated on a polypropylene diaphragm with a thickness of 5 μm to a thickness of 2 μm, and dried at 80° C. for 5 h to obtain a coated diaphragm.

[0050] Example 2 Preparation of Lithium Ion Battery Gel Polymer Material:

[0051] Polymerization monomers: methyl acrylate (50g), ethyl methacrylate (30g)

[0052] Solvent: water (80g), anhydrous ethanol (20g)

[0053] Initiator: di-tert-butyl peroxide (2 g)

[0054] Inorganic powder: Aluminum oxide (10g)

[0055] Crosslinking agent: Ethylene glycol dimethacrylate (1 g)

[0056] Preparation steps: same as Example 1.

[0057] Example 3 Preparation of Lithium Ion Battery Gel Polymer Material:

[0058] Polymerization monomer: polyacrylic acid (40g), butyl acrylate (20g), butyl methacrylate (20g) Solvent: anhydrous ethanol (100g)

[0059] Initiator: Benzoyl peroxide (1.5 g), lauroyl peroxide (0.5 g)

[0060] Inorganic powder: boehmite (15g)

[0061] Cross-linking agent: diacetone acrylamide (0.8 g)

[0062] Preparation steps: same as Example 1.

[0063] Example 4 Preparation of Lithium Ion Battery Gel Polymer Material:

[0064] Polymerization monomer: polycarbonate polymer (pre-synthesized, 60g), isooctyl acrylate (10g) Solvent: water (70g)

[0065] Initiator: tert-butyl hydroperoxide (2.5 g)

[0066] Inorganic powder: LATP (5g), LLZO (5g)

[0067] Cross-linking agent: adipic acid dihydrazide (1.2 g)

[0068] Preparation steps: same as Example 1.

[0069] Example 5 Preparation of Lithium Ion Battery Gel Polymer Material:

[0070] Polymerization monomers: polyacrylonitrile (25g), hydroxypropyl acrylate (25g), hydroxypropyl methacrylate (25g)

[0071] Solvent: water (50g), anhydrous ethanol (50g)

[0072] Initiator: dicumyl peroxide (3 g)

[0073] Inorganic powder: LATP (10g)

[0074] Crosslinking agent: ethylene glycol dimethacrylate (0.5 g), diacetone acrylamide (0.5 g)

[0075] Preparation steps: same as Example 1.

[0076] Example 6 Preparation of Lithium Ion Battery Gel Polymer Material:

[0077] Polymerization monomers: polyethylene oxide (pre-synthesized, 30 g), ethyl acrylate (15 g), ethyl methacrylate (15 g)

[0078] Solvent: anhydrous ethanol (80g)

[0079] Initiator: Cumene hydroperoxide (2 g)

[0080] Inorganic powder: LLZTO (20g)

[0081] Cross-linking agent: adipic acid dihydrazide (1 g)

[0082] Preparation steps: same as Example 1.

[0083] Examples 7-12 include a gel-state lithium-ion battery having a separator coated with a gel-state polymer material for a lithium-ion battery:

[0084] The lithium ion battery gel polymer material obtained in the above examples 1-6 is coated with a separator as a battery separator. The positive electrode of the battery includes lithium iron phosphate; the negative electrode material includes artificial graphite; the electrolyte component includes LiPF 6 .

[0085] Table 1 Battery performance test results

[0086]

[0087]

[0088] From the above results, it can be seen that the battery prepared by the solution provided by the present invention has the characteristics of high capacity, thermal stability and long life, and provides a new solution for lithium-ion battery technology.

[0089] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

[0090] The present invention and its implementation methods are described above, which is not restrictive and is only one of the implementation methods of the present invention. The actual application is not limited thereto. In short, if ordinary technicians in the field are inspired by it and design methods and embodiments similar to the technical solution without creativity without departing from the purpose of the invention, they should all fall within the protection scope of the present invention.

Claims

1. A lithium ion battery gel polymer material, characterized in that: It includes polymers and inorganic powders, wherein the polymer includes one or more of polyacrylate polymers, polyacrylic acid polymers, polycarbonate polymers, polyethylene oxide, polyamide, polyvinyl alcohol, polyimide, and polyacrylonitrile, or a copolymer of two or more of them.

2. The lithium ion battery gel polymer material according to claim 1, characterized in that: The monomer of the polyacrylate includes one or more of methyl acrylate, ethyl acrylate, butyl acrylate, isobutyl acrylate, n-pentyl acrylate, isopentyl acrylate, n-hexyl acrylate, isooctyl acrylate, hydroxypropyl acrylate, 2-hydroxyethyl acrylate, lauryl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, isobutyl methacrylate, n-pentyl methacrylate, n-hexyl methacrylate, isooctyl methacrylate, hydroxypropyl methacrylate or 2-hydroxyethyl methacrylate; the inorganic powder includes one or more of aluminum oxide, boehmite and solid electrolyte powder; the solid electrolyte powder includes one or more of LATP, LLZO, LLTO, LAGP and LLZTO.

3. A method for preparing a lithium ion battery gel polymer material according to any one of claims 1 to 2, characterized in that: The method comprises the following steps: taking a polymerization monomer corresponding to a polymer, adding a solvent, an initiator and an inorganic powder, heating to carry out a polymerization reaction, and obtaining a lithium ion battery gel polymer material after the reaction is completed; or taking a polymerization monomer corresponding to a polymer, adding a solvent and an initiator, heating to carry out a polymerization reaction, and adding an inorganic powder and mixing to obtain a lithium ion battery gel polymer material after the reaction is completed.

4. The method for preparing a lithium ion battery gel polymer material according to claim 3, characterized in that: The polymer solvent includes one or more of water and anhydrous ethanol; the heating polymerization reaction is carried out at a temperature of 50-95° C. and a time of 2-30 hours.

5. The method for preparing a lithium ion battery gel polymer material according to claim 3, characterized in that: The initiator includes one or more of benzoyl peroxide, lauroyl peroxide, cumene hydroperoxide, tert-butyl hydroperoxide, di-tert-butyl peroxide, and dicumyl peroxide.

6. The method for preparing a lithium ion battery gel polymer material according to claim 3, characterized in that: The obtained material has a solid content of 10-60wt%, a Tg of -30-60°C; and the inorganic powder in the obtained material accounts for 1-50wt% of the polymer mass.

7. The method for preparing a gel polymer material for a lithium ion battery according to claim 3, characterized in that: The preparation method further comprises adding a cross-linking agent, wherein the cross-linking agent comprises one or more of ethylene glycol dimethacrylate, diacetone acrylamide, and adipic acid dihydrazide.

8. A gel-state lithium-ion battery comprising the lithium-ion battery gel-state polymer material according to any one of claims 1 to 2.

9. The gel-state lithium-ion battery according to claim 8, characterized in that: The battery comprises the gel polymer material, or comprises a material obtained after the gel polymer material is molded, or comprises a separator coated with the gel polymer material.

10. The gel-state lithium-ion battery according to claim 8, characterized in that: The adsorption amount of the gel polymer material to the electrolyte is 100-1000wt%; the diaphragm includes one or more of a polypropylene diaphragm, a filter paper, a glass fiber diaphragm, a cellulose diaphragm, a nylon diaphragm, and a ceramic diaphragm; the positive electrode of the gel lithium ion battery includes one or more of a ternary, lithium iron phosphate, and lithium cobalt oxide; the negative electrode material includes one or more of an artificial graphite, a natural graphite, a silicon oxygen negative electrode, a silicon carbon negative electrode, and a lithium metal negative electrode; the electrolyte components include one or more of PC, EC, DEC, DMC, EMC, MF, MA, EA, MA, LiPF6, LiClO4, LiBF4, and LiAsF6.

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