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CN112599850A - Solid electrolyte composite layer and lithium ion battery - Google Patents

Solid electrolyte composite layer and lithium ion battery Download PDF

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Publication number
CN112599850A
CN112599850A CN202011449681.1A CN202011449681A CN112599850A CN 112599850 A CN112599850 A CN 112599850A CN 202011449681 A CN202011449681 A CN 202011449681A CN 112599850 A CN112599850 A CN 112599850A
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solid electrolyte
lithium
layer
composite layer
electrolyte layer
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张赵帅
赵伟
李素丽
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Zhuhai Cosmx Battery Co Ltd
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Zhuhai Cosmx Battery Co Ltd
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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
    • 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
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/4235—Safety or regulating additives or arrangements in electrodes, separators or electrolyte
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2300/00—Electrolytes
    • H01M2300/0085—Immobilising or gelification of electrolyte
    • 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

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Abstract

The invention provides a solid electrolyte composite layer and a lithium ion battery. The solid electrolyte composite layer comprises a near-anode side solid electrolyte layer, a middle solid electrolyte layer and a near-cathode side solid electrolyte layer which are sequentially stacked, wherein the middle solid electrolyte layer comprises inorganic ceramic electrolyte, the near-anode side solid electrolyte layer comprises a near-anode side polymer with strong oxidation resistance, the near-cathode side solid electrolyte layer comprises a near-cathode side compound stable with metal lithium, the solid electrolyte composite layer is high in mechanical strength, the situation that lithium dendrites pierce through electrolyte is avoided, the requirements of high-voltage resistance of the anode side and stability of the cathode side and the metal lithium are met, and meanwhile the interface wettability of the solid electrolyte composite layer is good. The lithium ion battery comprises the solid electrolyte composite layer, and the solid electrolyte composite layer has the advantages of high mechanical strength, excellent wettability and good stability with positive and negative electrode interfaces, so that the lithium ion battery has the advantages of small internal resistance, good cycle performance and high safety.

Description

Solid electrolyte composite layer and lithium ion battery
Technical Field
The invention belongs to the field of lithium ion batteries, and relates to a solid electrolyte composite layer and a lithium ion battery.
Background
In recent years, among various commercialized chargeable and dischargeable electrochemical energy storage devices, lithium ion batteries have the characteristics of high energy density, long service life and the like, and are widely applied to the fields of mobile phones, notebook computers, electric automobiles and the like. Most of the electrolyte used by the conventional lithium ion battery is liquid organic electrolyte, and the characteristics of volatility, flammability and explosiveness of the liquid organic electrolyte seriously affect the safety of the lithium ion battery in the use process.
The solid electrolyte has higher mechanical strength, excellent compactness and certain capability of resisting the growth of lithium dendrites, and has no characteristics of volatility, flammability and explosiveness of liquid organic electrolyte, so that the safety of the lithium ion battery in the using process can be greatly improved if the solid electrolyte replaces the liquid organic electrolyte to develop the all-solid lithium ion battery.
The solid electrolyte material mainly comprises three main categories of inorganic ceramic solid electrolyte, organic polymer solid electrolyte and inorganic ceramic/polymer composite solid electrolyte. The inorganic ceramic solid electrolyte has the advantages of good ionic conductivity, negligible electronic conductance, wider electrochemical window and the like, but has larger grain boundary resistance and poorer physical contact with the anode and the cathode; the organic polymer solid electrolyte has good flexibility and processability, but the room-temperature ionic conductivity is too low, and lithium dendrites easily pierce the electrolyte to cause short-circuiting of the battery; the inorganic ceramic/polymer composite solid electrolyte combines the advantages of the inorganic ceramic solid electrolyte and the polymer solid electrolyte, not only maintains stronger lithium ion transmission capability, but also avoids the short-circuit hidden trouble caused by the penetration of lithium dendrite into the electrolyte, but the current commonly used composite method is to uniformly mix inorganic ceramic powder and a polymer matrix, and the composite method is not easy to accurately adjust according to the requirements of high voltage resistance on the positive electrode side and stable compatibility with metallic lithium on the negative electrode side.
In view of the above, there is a need in the art to develop a high-performance solid electrolyte that can satisfy both high voltage resistance on the positive electrode side and stability of metallic lithium on the negative electrode side.
Disclosure of Invention
The invention provides a solid electrolyte composite layer, which comprises a near anode side solid electrolyte layer, a middle solid electrolyte layer and a near cathode side solid electrolyte layer which are sequentially stacked, by making the middle solid electrolyte layer comprise inorganic ceramic electrolyte, the near anode side solid electrolyte layer comprise near anode side polymer with strong oxidation resistance, the near cathode side solid electrolyte layer comprise near cathode side compound which is stable with metallic lithium, the solid electrolyte composite layer can have high mechanical strength, the short circuit of the battery caused by the penetration of lithium dendrite into the electrolyte can be avoided, and meets the requirements of high pressure resistance of the positive electrode side and stability of the negative electrode side and the metal lithium, has good stability with the positive and negative electrode interfaces, meanwhile, the solid electrolyte layer near the anode and the cathode has better flexibility and interface wettability, and the grain boundary resistance of the solid electrolyte composite layer can be reduced.
The invention also provides a lithium ion battery which comprises the solid electrolyte composite layer, and the solid electrolyte composite layer has the advantages of high mechanical strength, excellent wettability and good stability with positive and negative electrode interfaces, so that the lithium ion battery has the advantages of small internal resistance, good cycle performance and high safety performance.
In one aspect of the present invention, there is provided a solid electrolyte composite layer, fig. 1 is a schematic structural view of the solid electrolyte composite layer according to the present invention, and as shown in fig. 1, the solid electrolyte composite layer 1 includes: a near-positive electrode side solid electrolyte layer 1a, an intermediate solid electrolyte layer 1b, and a near-negative electrode side solid electrolyte layer 1c, which are stacked in this order;
the intermediate solid electrolyte layer 1b as described above includes an inorganic ceramic electrolyte;
the near-positive-electrode-side solid electrolyte layer 1a described above includes a near-positive-electrode-side polymer and a lithium salt;
the near-anode side solid electrolyte layer 1c as described above includes a near-anode side compound and a lithium salt;
the polymer near the positive electrode side is at least one selected from the group consisting of poly (ethylene carbonate), polycyanoacrylate, polycaprolactone, polymethyl methacrylate, polyvinyl acetate, polyvinyl butyral, polybutylene succinate, polyacrylonitrile, polymaleic anhydride, polyvinylidene fluoride-hexafluoropropylene and derivatives;
the near-negative electrode side compound is at least one selected from the group consisting of polyethylene oxide, polyphenylene ether, polyvinyl alcohol, polyacrylic acid, 2, 3-epoxybutane, 1, 3-dioxolane, 1, 4-dioxane and derivatives thereof.
The solid electrolyte composite layer 1 of the present invention is a layered solid structure having a "sandwich" structure, and includes a near-positive electrode side solid electrolyte layer 1a, an intermediate solid electrolyte layer 1b, and a near-negative electrode side solid electrolyte layer 1c, which are sequentially stacked.
The middle solid electrolyte layer 1b comprises inorganic ceramic electrolyte, and a solid electrolyte composite layer can have high mechanical strength, so that the phenomenon that lithium dendrite pierces the electrolyte to cause short circuit of the battery is avoided, and the safety performance of the battery is improved.
The near-positive electrode side solid electrolyte layer 1a comprises a near-positive electrode side polymer and a lithium salt, the near-positive electrode side polymer is a compound with strong oxidation resistance, and specifically, the near-positive electrode side polymer is selected from at least one of polyethylene carbonate, polycyanoacrylate, polycaprolactone, polymethyl methacrylate, polyvinyl acetate, polyvinyl butyral, polybutylene succinate, polyacrylonitrile, polymaleic anhydride, polyvinylidene fluoride-hexafluoropropylene and derivatives. Wherein, the derivative can be the derivative of any polymer of poly ethylene carbonate, polycyanoacrylate, polycaprolactone, polymethyl methacrylate, polyvinyl acetate, polyvinyl butyral, polybutylene succinate, polyacrylonitrile, polymaleic anhydride, polyvinylidene fluoride and polyvinylidene fluoride-hexafluoropropylene. In a specific application process, the solid electrolyte layer on the side close to the positive electrode is close to the positive plate, so that the polymer on the side close to the positive electrode can ensure that the lithium ion battery is not easy to decompose under high voltage, and the capacity of the lithium ion battery can be improved by improving the working voltage of the battery.
The near-negative electrode side solid electrolyte layer 1c includes a near-negative electrode side compound and a lithium salt, the near-negative electrode side compound is a compound stable to metallic lithium, and specifically, the near-negative electrode side compound of the present invention is at least one selected from the group consisting of polyethylene oxide, polyphenylene ether, polyvinyl alcohol, polyacrylic acid, 2, 3-butylene oxide, 1, 3-dioxolane, 1, 4-dioxane, and derivatives thereof. Wherein the derivative can be any one of polyoxyethylene, polyphenylether, polyvinyl alcohol, polyacrylic acid, 2, 3-epoxybutane, 1, 3-dioxolane and 1, 4-dioxane. In a specific application process, the solid electrolyte layer on the near-negative electrode side is close to the negative plate, so that the stability of the solid electrolyte composite layer and the negative electrode side can be ensured by the polymer on the near-negative electrode side, and lithium ions extracted from the positive electrode can be efficiently and uniformly inserted or deposited in the negative electrode through the solid electrolyte composite layer, so that the battery has higher coulombic efficiency and cycle performance.
In addition, the polymer close to the positive electrode side and the compound close to the negative electrode side have good flexibility and excellent wettability with positive and negative electrodes, so that the interface resistance of the composite layer of the positive and negative electrodes and the solid electrolyte is reduced, and the high-efficiency transmission of lithium ions is ensured.
In a specific embodiment, the near-positive electrode side solid electrolyte layer 1a accounts for 5 to 40% of the total mass of the solid electrolyte composite layer 1, the intermediate solid electrolyte layer 1b accounts for 20 to 90% of the total mass of the solid electrolyte composite layer 1, and the near-negative electrode side solid electrolyte layer 1c accounts for 5 to 40% of the total mass of the solid electrolyte composite layer 1.
The near-positive electrode side solid electrolyte layer 1a may include an additive in addition to the near-positive electrode side polymer and the lithium salt, and specifically, the near-positive electrode side solid electrolyte layer 1a includes, in terms of mass fraction: 50-80% of a polymer near the positive electrode side, 10-40% of lithium salt and 0-20% of additives.
Likewise, the near-anode side solid electrolyte layer 1c may include an additive in addition to the near-anode side compound and the lithium salt, and specifically, the near-anode side solid electrolyte layer 1c includes, in terms of mass fraction: 50-80% of a near-negative electrode side compound, 10-40% of lithium salt and 0-20% of an additive.
The inorganic ceramic electrolyte is at least one selected from perovskite type electrolyte, anti-perovskite type electrolyte, garnet type electrolyte, NASICON type electrolyte, LISICON electrolyte and sulfide electrolyte.
Wherein the perovskite electrolyte is selected from Li3xLa2/3-xTiO3(0.04＜x＜0.17)。
The anti-perovskite electrolyte is selected from Li3-n(OHn) Cl (n is more than or equal to 0.83 and less than or equal to 2) or Li3-n(OHn)Br(1≤n≤2)。
The garnet electrolyte is selected from lithium lanthanum zirconium oxygen electrolyte and Al, Ga, Fe, Ge, Ca, Ba, Sr, Y, Nb, Ta, W and Sb element doped derivatives thereof, and preferably Li7-nLa3Zr2-nTanO12(0≤n≤0.6)、Li7-nLa3Zr2-nNbnO12(0≤n≤0.6)、Li6.4-xLa3Zr2-xTaxAl0.2O12(x is more than or equal to 0.2 and less than or equal to 0.5).
NASICON-type electrolytes are selected from Li1+xTi2-xMx(PO4)3(M ═ Al, Cr, Ga, Fe, Sc, In, Lu, Y, La), and further preferably Li1+xAlxTi2-x(PO4)3(0.2≤x≤0.5)、Li1+xAlxGe2-x(PO4)3(x is more than or equal to 0.4 and less than or equal to 0.5).
The lisicoion electrolyte is selected from Li4-xGe1-xPxS4(x ═ 0.4 or x ═ 0.6).
The sulfide electrolyte is selected from Li2S-SiS2、Li2S-P2S5、Li2S-P2S5-GeS2、Li6PS5X (X ═ Cl, Br, I) is one of the compounds.
The lithium salt is selected from lithium perchlorate (LiClO)4) Lithium hexafluorophosphate (LiPF)6) Lithium hexafluoroarsenate (LiAsF)6) Lithium tetrafluoroborate (LiBF)4) Lithium bis (oxalato) borate (LiBOB), lithium bis (oxalato) difluoroborate (LiDFOB), lithium bis (difluorosulfonimide) (LiFSI), lithium bis (trifluoromethylsulfonimide) (LiTFSI), lithium (trifluoromethylsulfonate) (LiCF)3SO3) Lithium dimalonate borate (LiBMB), lithium malonate oxalate borate (LiMOB), lithium hexafluoroantimonate (LiSbF)6) Lithium difluorophosphate (LiPF)2O2) 4, 5-dicyano-2-trifluoromethylimidazole Lithium (LiDTI), LiN (SO)2C2F5)2、LiC(SO2CF3)3、LiN(SO2F)2At least one of (1). The addition of the lithium salt enables the near-positive electrode side solid electrolyte layer 1a or the near-negative electrode side solid electrolyte layer 1c to have good ion transport ability.
The additive used in the near-positive electrode side solid electrolyte layer 1a and the near-negative electrode side solid electrolyte layer 1c is one selected from succinonitrile, an ionic liquid, and fluoroethylene carbonate. The addition of the additive can improve the interface stability of the near-positive electrode side solid electrolyte layer 1a and the near-negative electrode side solid electrolyte layer 1c, so that the electrochemical performance and the safety performance of the battery are further improved.
The solid electrolyte composite layer 1 in the present invention may be prepared by:
1) drying inorganic ceramic electrolyte powder, pressing into a sheet shape, sintering and cooling to obtain an intermediate solid electrolyte layer 1 b;
2) dissolving a near-anode side polymer, a lithium salt and an additive in a solvent, uniformly stirring to obtain a near-anode side slurry, coating the near-anode side slurry on the functional surface of the middle solid electrolyte layer 1b close to the anode plate, and drying to obtain a near-anode side solid electrolyte layer 1 a;
3) and dissolving a near-negative electrode side compound, a lithium salt and an additive in a solvent, uniformly stirring to obtain a near-negative electrode side slurry, coating the near-negative electrode side slurry on the functional surface of the middle solid electrolyte layer 1b close to the negative plate, and drying to obtain a near-negative electrode side solid electrolyte layer 1 b.
Further, controlling the sintering temperature in step 1) to 600-.
The solvent in the steps 2) and 3) is at least one selected from acetonitrile, N-methylpyrrolidone (NMP), Dimethylformamide (DMF), Dimethylacetamide (DMAC), dimethyl sulfoxide (DMSO), deionized water, acetone, dichloromethane, trichloromethane and Tetrahydrofuran (THF); the stirring speed was set at 100 and 1000 rpm.
The solid content of the near-anode side slurry and the near-cathode side slurry can be controlled to be 3-30% by controlling the compositions of the slurries in the near-anode side and the near-cathode side in the steps 2) and 3) and using the solvent amount.
According to the difference of the boiling points of the solvents used in the steps 2) and 3), the drying temperature can be controlled to be 25-120 ℃, the drying time is 1-24h, the complete volatilization of the solvent can be ensured, and the near-anode side solid electrolyte layer 1a and the near-cathode side solid electrolyte layer 1c in solid forms can be obtained.
The solid electrolyte composite layer 1 obtained by the preparation process has uniform and good macroscopic morphology and no pore cracks on the surface.
The invention also provides a lithium ion battery, which comprises any one of the solid electrolyte composite layers, fig. 2 is a structural schematic diagram of the lithium ion battery, and as shown in fig. 2, the lithium ion battery comprises a positive plate 2, a solid electrolyte composite layer 1 and a negative plate 3 which are sequentially stacked.
Wherein, the near-positive side solid electrolyte layer 1a of the solid electrolyte composite layer 1 is disposed on the functional surface of the intermediate solid electrolyte layer 1b near the positive electrode sheet 2, and the near-negative side solid electrolyte layer 1c of the solid electrolyte composite layer 1 is disposed on the functional surface of the intermediate solid electrolyte layer 1b near the negative electrode sheet 3.
In the present invention, the positive electrode sheet 2 includes a positive electrode current collector and a positive electrode active material layer. The positive electrode active material layer includes, in mass fraction: 70-97% of positive active material, 0.1-25% of near-positive side solid electrolyte, 0.1-10% of binder and 1.5-15% of conductive agent.
Wherein the positive electrode active material is selected from lithium iron phosphate (LiFePO)4) Lithium cobaltate (LiCoO)2) Lithium nickel cobalt manganese oxide(LizNixCoyMn1-x-yO2Wherein z is more than or equal to 0.95 and less than or equal to 1.05, x>0，y>0，x+y<1) Lithium manganate (LiMnO2), lithium nickel cobalt aluminate (Li)zNixCoyAl1-x-yO2Wherein z is more than or equal to 0.95 and less than or equal to 1.05, x>0，y>0，0.8≤x+y<1) Lithium nickel cobalt manganese aluminate (Li)zNixCoyMnwAl1-x-y-wO2Wherein z is more than or equal to 0.95 and less than or equal to 1.05, x>0，y>0，w>0，0.8≤x+y+w<1) Nickel cobalt aluminum tungsten material, lithium-rich manganese-based solid solution positive electrode material, lithium nickel cobalt oxide (LiNi)xCoyO2Wherein x is>0，y>0, x + y ═ 1), lithium nickel titanium magnesium oxide (LiNi)xTiyMgzO2Wherein x is>0，y>0，z>0, x + y + z ═ 1), lithium nickelate (Li)2NiO2) Spinel lithium manganate (LiMn)2O4) One or a combination of more of spinel Lithium Nickel Manganese Oxide (LNMO) and nickel cobalt tungsten materials.
Wherein the binder in the positive electrode active material layer is at least one selected from the group consisting of polytetrafluoroethylene, polyvinylidene fluoride-hexafluoropropylene, and copolymer derivatives thereof.
Wherein the conductive agent in the positive electrode active material layer is at least one selected from conductive carbon black (SP), Ketjen black, conductive fiber, conductive polymer, acetylene black, Carbon Nanotube (CNT), graphene, and flake graphite.
The lithium conducting channel can be formed by adding the solid electrolyte close to the positive electrode side into the positive electrode active layer, the lithium ion conducting capacity of the positive electrode plate is improved, and the electrical performance of the solid battery is further improved.
In the invention, the negative plate 3 is selected from one or a combination of several of carbon-based, silicon-based, metal lithium and metal lithium alloy materials.
The carbon-based and silicon-based negative plate comprises a negative current collector and a negative active material layer. The negative electrode active material layer includes, in mass fraction: 70-98.4% of negative active material, 0.1-10% of binder and 1-20% of conductive agent.
Wherein the binder in the negative electrode active material layer is selected from at least one of polyacrylic acid, polyacrylate, Styrene Butadiene Rubber (SBR), sodium carboxymethylcellulose (CMC) and copolymer derivatives thereof.
Wherein the conductive agent in the negative electrode active material layer is at least one selected from conductive carbon black (SP), Ketjen black, conductive fiber, conductive polymer, acetylene black, Carbon Nanotube (CNT), graphene, and flake graphite.
Compared with the prior art, the invention at least has the following beneficial effects:
1. the solid electrolyte composite layer provided by the invention has good interface wettability and mechanical strength, can effectively reduce the grain boundary resistance of the solid electrolyte composite layer, can avoid the short circuit hidden trouble caused by the penetration of the growth of lithium dendrite into the electrolyte in the charging and discharging processes of the lithium ion battery, and obviously improves the safety performance of the lithium ion battery.
2. According to the solid electrolyte composite layer provided by the invention, the solid electrolyte layer on the side close to the positive electrode has stronger oxidation resistance when matched with a high-voltage positive electrode, so that the battery can keep higher charge and discharge capacity.
3. According to the solid electrolyte composite layer provided by the invention, the solid electrolyte layer on the side close to the negative electrode is stable with metal lithium, and lithium ions extracted from the positive electrode can be uniformly inserted or deposited in the negative electrode through the solid electrolyte composite layer, so that the battery has higher coulombic efficiency and cycle performance.
4. The lithium ion battery provided by the invention has the advantages of small internal resistance, good cycle performance and high safety performance because the solid electrolyte composite layer has good stability with the positive and negative electrode interfaces, high mechanical strength and excellent wettability.
Drawings
FIG. 1 is a schematic structural view of a solid electrolyte composite layer according to the present invention;
FIG. 2 is a schematic structural diagram of a lithium ion battery of the present invention;
FIG. 3 is a plot of the linear sweep voltammetry test for the solid electrolyte composite layer of example 2;
FIG. 4 is a lithium symmetrical cycle plot of the solid state electrolyte composite layer of example 3;
fig. 5 is a specific capacity-voltage curve of the lithium ion battery of example 4.
Description of reference numerals:
1: a solid electrolyte composite layer;
1 a: a near-positive-side solid electrolyte layer;
1 b: an intermediate solid electrolyte layer;
1 c: a near-negative electrode side solid electrolyte layer;
2: a positive plate;
3: and a negative plate.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example 1
Referring to fig. 1 and 2, the solid electrolyte composite layer and the lithium ion battery structure of the present embodiment are prepared as follows:
1. preparation of solid electrolyte composite layer 1
1) Preparing NASICON type electrolyte Li according to the traditional solid phase sintering method1.5Al0.5Ti1.5(PO4)3Drying, pressing into sheet, sintering at 900 deg.C for 6 hr, and cooling to obtain intermediate solid electrolyte layer 1 b.
2) Polyacrylonitrile (PAN) and LiClO4Dissolving the mixture in DMF according to the mass ratio of 2:1, uniformly stirring at the rotating speed of 600rpm to obtain near-positive-electrode-side slurry with the solid content of 11%, coating the near-positive-electrode-side slurry on the functional surface, close to the positive electrode sheet 2, of the intermediate solid electrolyte layer 1b, and sufficiently drying in vacuum at 80 ℃ for 10h to obtain the positive-electrode-side solid electrolyte 1a, wherein the mass ratio of the intermediate solid electrolyte layer 1b to the near-positive-electrode-side solid electrolyte layer 1a is 80: 11.
3) Dissolving polyethylene oxide (PEO), LiTFSI and fluoroethylene carbonate in acetonitrile according to a mass ratio of 7:3:1, uniformly stirring at a rotating speed of 600rpm to obtain near-negative electrode side slurry with a solid content of 5%, coating the near-negative electrode side slurry on the functional surface, close to the negative plate 3, of the middle solid electrolyte layer 1b, and sufficiently drying in vacuum at 60 ℃ for 4 hours to obtain a near-negative electrode side solid electrolyte layer 1c, wherein the mass ratio of the middle solid electrolyte layer 1b to the near-positive electrode side solid electrolyte layer 1c is 80:9, so as to prepare the solid electrolyte composite layer 1.
2. Preparation of lithium ion battery
1) Dissolving lithium cobaltate, polyvinylidene fluoride, conductive carbon black (SP) and the near-positive-electrode-side solid electrolyte in DMF according to the mass ratio of 75:6:11:8, uniformly stirring to obtain positive active slurry, coating the positive active slurry on an aluminum foil current collector, drying and rolling to obtain the positive plate 2.
2) Metallic lithium is used as the negative electrode sheet 3.
3) And assembling the positive plate 2, the negative plate 3 and the solid electrolyte composite layer 1 by adopting a lamination process to manufacture the soft-package solid lithium ion battery.
Example 2
Referring to fig. 1 and 2, the solid electrolyte composite layer and the lithium ion battery structure of the present embodiment are prepared as follows:
1. preparation of solid electrolyte composite layer 1
1) Commercially available perovskite type electrolyte Li3xLa2/3-xTiO3(x ═ 0.11) was dried, and then, the sheet was pressed into a sheet in a mold, and after firing at 950 ℃ for 4 hours, the sheet was cooled to obtain an intermediate solid electrolyte layer 1 b.
2) Dissolving Polycaprolactone (PCL), LiDTI and succinonitrile in THF according to a mass ratio of 7:3:1.1, uniformly stirring at 400rpm to obtain near-positive electrode side slurry with the solid content of 23%, coating the near-positive electrode side slurry on the functional surface, close to the positive plate piece 2, of the intermediate solid electrolyte layer 1b, and fully drying in vacuum at 50 ℃ for 3 hours to obtain a near-positive electrode side solid electrolyte 1a, wherein the mass ratio of the intermediate solid electrolyte layer 1b to the near-positive electrode side solid electrolyte layer 1a is 76: 15.
3) Dissolving polyvinyl alcohol (PVA), LiDFOB and fluoroethylene carbonate in DMSO according to a mass ratio of 6.5:3:0.7, stirring at 800rpm to obtain near-negative electrode side slurry with a solid content of 6%, coating the near-negative electrode side slurry on the functional surface, close to the negative plate 3, of the middle solid electrolyte layer 1b, fully drying in vacuum at 120 ℃ for 8 hours to obtain a near-negative electrode side solid electrolyte layer 1c, wherein the mass ratio of the middle solid electrolyte layer 1b to the near-positive electrode side solid electrolyte layer 1c is 76:9, and thus preparing the solid electrolyte composite layer 1.
2. Preparation of lithium ion battery
1) Reacting LiNi0.5Co0.3Mn0.2O2Dissolving polyvinylidene fluoride-hexafluoropropylene, a Carbon Nano Tube (CNT) and a near-positive-electrode-side solid electrolyte layer in NMP according to the mass ratio of 81:5:4:10, uniformly stirring to obtain positive active slurry, coating the positive active slurry on an aluminum foil current collector, drying and rolling to obtain a positive plate 2.
2) And dissolving SiOx, Styrene Butadiene Rubber (SBR) and Carbon Nano Tubes (CNT) in deionized water according to a mass ratio of 90:5:5, uniformly stirring to obtain negative active slurry, coating the negative active slurry on a copper foil current collector, and drying and rolling to obtain a negative plate 3.
3) And assembling the positive plate 2, the negative plate 3 and the solid electrolyte composite layer 1 by adopting a winding process to manufacture the soft-package solid lithium ion battery.
Example 3
Referring to fig. 1 and 2, the solid electrolyte composite layer and the lithium ion battery structure of the present embodiment are prepared as follows:
1. preparation of solid electrolyte composite layer 1
1) Preparation of garnet-type electrolyte Li according to conventional solid-phase sintering method6.6La3Zr1.6Ta0.4O12Drying, pressing into sheet, sintering at 1200 deg.C for 3 hr, and cooling to obtain intermediate solid electrolyte layer 1 b.
2) Dissolving polyvinyl carbonate (PVCA) and LiFSI in chloroform according to the mass ratio of 5:3, uniformly stirring at 900rpm to obtain near-positive electrode side slurry with the solid content of 12%, coating the near-positive electrode side slurry on the functional surface, close to the positive plate 2, of the intermediate solid electrolyte layer 1b, and sufficiently drying in vacuum at 25 ℃ for 6 hours to obtain a near-positive electrode side solid electrolyte layer 1a, wherein the mass ratio of the intermediate solid electrolyte layer 1b to the near-positive electrode side solid electrolyte layer 1a is 65: 28.
3) Mixing polyacrylic acid (PAA) and LiPF6And dissolving the ionic liquid in deionized water according to the mass ratio of 8:4:1, stirring at 600rpm to obtain near-negative electrode side slurry with the solid content of 6%, coating the near-negative electrode side slurry on the functional surface, close to the negative plate 3, of the middle solid electrolyte layer 1b, fully drying in vacuum at 100 ℃ for 10 hours to obtain a near-negative electrode side solid electrolyte layer 1c, wherein the mass ratio of the middle solid electrolyte layer 1b to the near-positive electrode side solid electrolyte layer 1c is 65:7, and thus preparing the solid electrolyte composite layer 1.
2. Preparation of lithium ion battery
1) Dissolving lithium iron phosphate, polyvinylidene fluoride, acetylene black and a near-anode side solid electrolyte in acetone according to a mass ratio of 86:5:6:3, uniformly stirring to obtain anode active slurry, coating the anode active slurry on an aluminum foil current collector, drying and rolling to obtain an anode sheet 2.
2) Dissolving artificial graphite, Styrene Butadiene Rubber (SBR) and sodium carboxymethylcellulose (CMC) in deionized water according to a mass ratio of 92:3:5, uniformly stirring to obtain negative active slurry, coating the negative active slurry on a copper foil current collector, and drying and rolling to obtain a negative plate 3.
3) And assembling the positive plate 2, the negative plate 3 and the solid electrolyte composite layer 1 by adopting a lamination process to manufacture the soft-package solid lithium ion battery.
Example 4
Referring to fig. 1 and 2, the solid electrolyte composite layer and the lithium ion battery structure of the present embodiment are prepared as follows:
1. preparation of solid electrolyte composite layer 1
1) Mixing a commercially available garnet-type electrolyte Li6.4La3Zr1.4Nb0.6O12Drying, pressing into sheet, sintering at 1100 deg.C for 8 hr, and cooling to obtain intermediate solid electrolyte layer 1 b.
2) Dissolving polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP), LiTFSI and succinonitrile in a mass ratio of 4:3:1 in DMAC, uniformly stirring at 500rpm to obtain near-positive-electrode-side slurry with the solid content of 18%, coating the near-positive-electrode-side slurry on the functional surface, close to the positive plate 2, of the middle solid electrolyte layer 1b, and fully drying in vacuum at 70 ℃ for 15 hours to obtain a near-positive-electrode-side solid electrolyte layer 1a, wherein the mass ratio of the middle solid electrolyte layer 1b to the near-positive-electrode-side solid electrolyte layer 1a is 58: 25.
3) Mixing 1, 3-dioxolane and LiPF6And mixing fluoroethylene carbonate according to the mass ratio of 5:1:4, stirring at 350rpm to obtain near-negative electrode side slurry with the solid content of 10%, coating the near-negative electrode side slurry on the functional surface, close to the negative plate 3, of the intermediate solid electrolyte layer 1b, standing at room temperature for 1h to obtain a near-negative electrode side solid electrolyte layer 1c, wherein the mass ratio of the intermediate solid electrolyte layer 1b to the near-positive electrode side solid electrolyte layer 1c is 58:17, and thus preparing the solid electrolyte composite layer 1.
2. Preparation of lithium ion battery
1) Dissolving spinel nickel lithium manganate, polyvinylidene fluoride-hexafluoropropylene, conductive carbon black (SP) and a near-positive-electrode-side solid electrolyte layer in NMP according to the mass ratio of 72:7:9:12, uniformly stirring to obtain positive active slurry, coating the positive active slurry on an aluminum foil current collector, and drying and rolling to obtain a positive plate 2.
2) Metallic lithium is used as the negative electrode sheet 3.
3) And assembling the positive plate 2, the negative plate 3 and the solid electrolyte composite layer 1 to prepare the button type solid lithium ion battery.
Example 5
Referring to fig. 1 and 2, the solid electrolyte composite layer and the lithium ion battery structure of the present embodiment are prepared as follows:
1. preparation of solid electrolyte composite layer 1
1) Preparation of sulfide electrolyte Li according to traditional solid-phase sintering method6PS5ClLi6.6And drying, pressing into a sheet in a mold, sintering at 650 deg.C for 21h, and cooling to obtain intermediate solid electrolyte layer 1 b.
2) Dissolving polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP), LiFSI and succinonitrile in a mass ratio of 4:3:1 in DMAC, uniformly stirring at 500rpm to obtain near-positive-electrode-side slurry with the solid content of 18%, coating the near-positive-electrode-side slurry on the functional surface, close to the positive plate 2, of the middle solid electrolyte layer 1b, and fully drying in vacuum at 70 ℃ for 15 hours to obtain a near-positive-electrode-side solid electrolyte layer 1a, wherein the mass ratio of the middle solid electrolyte layer 1b to the near-positive-electrode-side solid electrolyte layer 1a is 58: 25.
3) Mixing 1, 3-dioxolane and LiPF6And mixing fluoroethylene carbonate according to the mass ratio of 5:1:4, stirring at 350rpm to obtain near-negative electrode side slurry with the solid content of 10%, coating the near-negative electrode side slurry on the functional surface, close to the negative plate 3, of the intermediate solid electrolyte layer 1b, standing at room temperature for 1h to obtain a near-negative electrode side solid electrolyte layer 1c, wherein the mass ratio of the intermediate solid electrolyte layer 1b to the near-positive electrode side solid electrolyte layer 1c is 58:17, and thus preparing the solid electrolyte composite layer 1.
2. Preparation of lithium ion battery
1) Dissolving nickel cobalt lithium aluminate, polytetrafluoroethylene, a Carbon Nano Tube (CNT) and a near-anode side solid electrolyte layer in DMAC according to the mass ratio of 88:2:6:4, uniformly stirring to obtain anode active slurry, coating the anode active slurry on an aluminum foil current collector, drying and rolling to obtain the anode plate 2.
2) The lithium indium alloy is used as the negative plate 3.
3) And assembling the positive plate 2, the negative plate 3 and the solid electrolyte composite layer 1 to prepare the grinding tool solid lithium ion battery.
Example 6
Referring to fig. 1 and 2, the solid electrolyte composite layer and the lithium ion battery structure of the present embodiment are prepared as follows:
1) NASICON type electrolyte Li prepared according to traditional sol-gel method1.5Al0.5Ge1.5(PO4)3Drying, pressing into sheet, sintering at 1050 deg.C for 8 hr, and cooling to obtain intermediate solid electrolyte layer 1 b.
2) Dissolving polymethyl methacrylate (PMMA), LiTFSI and succinonitrile in THF according to a mass ratio of 4:1.2:1, uniformly stirring at 700rpm to obtain near-positive electrode side slurry with solid content of 10%, coating the near-positive electrode side slurry on the functional surface, close to the positive plate sheet 2, of the intermediate solid electrolyte layer 1b, and fully drying in vacuum at 60 ℃ for 12 hours to obtain a near-positive electrode side solid electrolyte layer 1a, wherein the mass ratio of the intermediate solid electrolyte layer 1b to the near-positive electrode side solid electrolyte layer 1a is 50: 25.
3) Mixing polyphenylene oxide (PPO), LiMOB, LiPF6And dissolving 1, 4-dioxane in chloroform according to a mass ratio of 8:0.8:1.5:2.4, stirring at 500rpm to obtain near-negative electrode side slurry with a solid content of 7%, coating the near-negative electrode side slurry on the functional surface, close to the negative plate 3, of the intermediate solid electrolyte layer 1b, and fully drying at 30 ℃ for 2 hours to obtain a near-negative electrode side solid electrolyte layer 1c, wherein the mass ratio of the intermediate solid electrolyte layer 1b to the near-positive electrode side solid electrolyte layer 1c is 50:25, so as to prepare the solid electrolyte composite layer 1.
2. Preparation of lithium ion battery
1) Reacting LiNi0.8Co0.1Mn0.1O2Dissolving polyvinylidene fluoride-hexafluoropropylene, acetylene black and near-anode side electrolyte in DMAC according to the mass ratio of 81:3:8:8, uniformly stirring to obtain anode active slurry, coating the anode active slurry on an aluminum foil current collector, drying and rolling to obtain an anode sheet 2.
2) Dissolving the carbon-silicon composite material, the Styrene Butadiene Rubber (SBR), the polyacrylic acid and the acetylene black in deionized water according to the mass ratio of 94:2:1:3, uniformly stirring to obtain negative active slurry, coating the negative active slurry on a copper foil current collector, and drying and rolling to obtain a negative plate 3.
3) And assembling the positive plate 2, the negative plate 3 and the solid electrolyte composite layer 1 by adopting a lamination process to manufacture the soft-package solid lithium ion battery.
Comparative example 1
The solid electrolyte layer of this comparative example is not a composite layer and includes only a single inorganic ceramic solid electrolyte layer. The solid electrolyte layer and the lithium ion battery of the present comparative example were prepared as follows:
1. preparation of solid electrolyte layer
According toNASICON type electrolyte Li prepared by traditional solid phase sintering method1.5Al0.5Ti1.5(PO4)3Drying, pressing into sheet, sintering at 900 deg.C for 6 hr, and cooling to obtain solid electrolyte layer.
2. Preparation of lithium ion battery
Except that the solid electrolyte layer is different from the solid electrolyte composite layer of example 1, the preparation method of the lithium ion battery of the comparative example is the same as that of example 1, and the details are not repeated here.
Comparative example 2
The solid electrolyte composite layer and the lithium ion battery of the present comparative example were prepared as follows:
1. preparation of solid electrolyte composite layer
1) Commercially available perovskite type electrolyte Li3xLa2/3-xTiO3(x ═ 0.11) was dried, and then, the sheet was pressed into a mold, sintered at 950 ℃ for 4 hours, and cooled to obtain an intermediate solid electrolyte layer.
2) Dissolving polyvinyl alcohol (PVA), LiDFOB and fluoroethylene carbonate in DMSO according to a mass ratio of 6.5:3:0.7, stirring at 800rpm to obtain slurry with a solid content of 6%, respectively coating the slurry on the upper and lower functional surfaces of the intermediate solid electrolyte layer, and fully vacuum-drying at 120 ℃ for 8 hours to respectively obtain a near-positive-side solid electrolyte layer and a near-negative-side solid electrolyte layer, wherein the mass ratio of the intermediate solid electrolyte layer to the near-positive-side solid electrolyte layer and the near-negative-side solid electrolyte layer is 76:24, so as to prepare the solid electrolyte composite layer.
2. Preparation of lithium ion battery
Except that the solid electrolyte composite layer is different from that of example 2, the preparation method of the lithium ion battery of the present comparative example is the same as that of example 2, and is not repeated herein.
Comparative example 3
The solid electrolyte composite layer and the lithium ion battery of the present comparative example were prepared as follows:
1. preparation of solid electrolyte composite layer
1) According to the conventional solid phase sintering methodPreparation of garnet-type electrolyte Li6.6La3Zr1.6Ta0.4O12Drying, pressing into sheet, sintering at 1200 deg.C for 3 hr, and cooling to obtain intermediate solid electrolyte layer.
2) Dissolving polyvinyl carbonate (PVCA) and LiFSI in chloroform according to the mass ratio of 5:3, uniformly stirring at 900rpm to obtain slurry with the solid content of 12%, coating the slurry on the upper and lower functional surfaces of the middle solid electrolyte layer, and fully drying in vacuum at 25 ℃ for 6 hours to obtain a solid electrolyte layer on the near-positive side and a solid electrolyte layer on the near-negative side, wherein the mass ratio of the middle solid electrolyte layer to the solid electrolytes on the near-positive side and the near-negative side is 65:35, so as to prepare the solid electrolyte composite layer.
2. Preparation of lithium ion battery
Except that the solid electrolyte composite layer is different from that of example 3, the preparation method of the lithium ion battery of the present comparative example is the same as that of example 3, and is not repeated herein.
Comparative example 4
The solid electrolyte layer of this comparative example is not a composite layer and includes only a single inorganic ceramic solid electrolyte layer. The solid electrolyte layer and the lithium ion battery of the present comparative example were prepared as follows:
1. preparation of solid electrolyte layer
Mixing a commercially available garnet-type electrolyte Li6.4La3Zr1.4Nb0.6O12Drying, pressing into sheet in a mold, sintering at 1100 deg.C for 8 hr, and cooling to obtain solid electrolyte layer.
2. Preparation of lithium ion battery
Except that the solid electrolyte layer is different from the solid electrolyte composite layer of example 4, the preparation method of the lithium ion battery of the comparative example is the same as that of example 4, and the details are not repeated here.
Comparative example 5
The solid electrolyte layer of this comparative example is not a composite layer and includes only a single inorganic ceramic solid electrolyte layer. The solid electrolyte layer and the lithium ion battery of the present comparative example were prepared as follows:
1. preparation of solid electrolyte layer
Preparation of sulfide electrolyte Li according to traditional solid-phase sintering method6PS5ClLi6.6Drying, pressing into sheet, sintering at 650 deg.C for 21 hr, and cooling to obtain solid electrolyte layer.
2. Preparation of lithium ion battery
Except that the solid electrolyte layer is different from the solid electrolyte composite layer of example 5, the preparation method of the lithium ion battery of the comparative example is the same as that of example 5, and the details are not repeated here.
Comparative example 6
The preparation methods of the solid electrolyte composite layer and the lithium ion battery of the present comparative example were as follows:
1. preparation of solid electrolyte composite layer
1) Dissolving polymethyl methacrylate (PMMA), LiTFSI and succinonitrile in THF according to a mass ratio of 4:1.2:1, uniformly stirring at 700rpm to obtain a near-positive electrode side slurry with a solid content of 10%, coating the near-positive electrode side slurry on the functional surface, close to a positive electrode plate, of a commercially available PP (polypropylene) diaphragm, and fully drying in vacuum at 60 ℃ for 12 hours to obtain a near-positive electrode side solid electrolyte layer, wherein the mass ratio of the diaphragm to the near-positive electrode side solid electrolyte layer is 25: 40.
2) Mixing polyphenylene oxide (PPO), LiMOB, LiPF6And dissolving 1, 4-dioxane in chloroform according to a mass ratio of 8:0.8:1.5:2.4, stirring at 500rpm to obtain near-negative electrode side slurry with the solid content of 7%, coating the near-negative electrode side slurry on the functional surface of a commercially available PP diaphragm close to a negative plate, and fully drying at 30 ℃ for 2 hours to obtain a near-negative electrode side solid electrolyte layer, wherein the mass ratio of the diaphragm to the near-negative electrode side solid electrolyte layer is 25:35, and thus preparing the solid electrolyte composite layer.
2. Preparation of lithium ion battery
Except that the solid electrolyte composite layer is different from that of example 6, the preparation method of the lithium ion battery of the present comparative example is the same as that of example 6, and is not repeated herein.
Test example 1
The solid electrolyte composite layer of example 2 was subjected to a linear sweep voltammetry test (LSV) by the following method: adopting Shanghai Chenghua CHI600E electrochemical workstation, assembling a battery by Li foil/solid electrolyte composite layer/steel foil (SS) for LSV test, and setting parameters: the amplitude was 10mV, the sweep range was 2-6V, and the sweep rate was 0.02 mV/s.
Fig. 3 is a graph of a linear sweep voltammetry test of the solid electrolyte composite layer of example 2. As shown in fig. 3, the electrochemical window of the solid electrolyte composite layer is >5.1V, which indicates that the solid electrolyte composite layer has a strong high voltage resistance enough to match with most of the high voltage anode materials on the market.
Test example 2
The solid electrolyte composite layer of example 3 was subjected to a lithium symmetric battery cycling test, the test method being: the Wuhan blue battery test equipment is adopted, and the voltage is measured at 1mA/cm2The current density of the lithium/solid electrolyte composite layer/the Li symmetrical battery is tested for constant current charging and discharging.
Fig. 4 is a lithium symmetrical cycle graph of the solid electrolyte composite layer of example 3. As shown in FIG. 4, the lithium symmetry test of the solid electrolyte composite layer can be at 1mA/cm2The current density of the power supply is stable and circulates for 200 circles, the short circuit phenomenon does not occur, and the platform voltage is always<0.3V shows that the interface resistance of the solid electrolyte composite layer and the metal lithium is small, the interface performance is stable and excellent, and the battery safety performance is high.
Test example 3
The lithium ion battery of embodiment 4 of the present invention is subjected to a charge/discharge capacity test, and the test method is as follows: the lithium ion battery was subjected to a charge-discharge capacity test at room temperature at a current density of 0.1C.
Fig. 5 is a specific capacity-voltage curve of the lithium ion battery of example 4. As shown in FIG. 5, the lithium ion battery has a voltage test range of 3-4.95V, a good charge-discharge curve and a high gram capacity exertion.
Test example 4
The following parameter tests were performed on the lithium ion batteries of examples 1 to 6 of the present invention and comparative examples 1 to 6, and the test results are shown in table 1:
1. AC impedance
The test method comprises the following steps: adopting Shanghai Hua CHI600E electrochemical workstation to carry out alternating current impedance test on the lithium ion battery, and setting parameters: the amplitude is 10mV, and the frequency range is 0.1Hz-1 MHz.
2. Cycle life
The test method comprises the following steps: and (3) measuring the cycle times when the capacity of the lithium ion battery is attenuated to 80% of the initial value or the normal charge and discharge test cannot be carried out by adopting Wuhan blue battery testing equipment under the conditions of 25 ℃ and 0.2C/0.2C.
3. Coulombic efficiency
4. Short circuit rate
The determination method comprises the following steps: in the cycle life test process, the lithium ion battery fails or is short-circuited, and the lithium ion battery is marked as short-circuit, wherein the lithium ion battery cannot be normally charged and discharged. Battery short-circuit rate ═ number of short-circuited batteries/total number of batteries tested × 100%.
TABLE 1
Numbering AC impedance (omega) Cycle life/number Coulombic efficiency (%) Short circuit rate (%)
Example 1 141 544 93.3 0
Example 2 193 282 94.1 0
Example 3 202 326 92.5 0
Example 4 63 423 90.6 0
Example 5 104 519 89.7 0
Example 6 139 365 92.0 0
Comparative example 1 542 85 76.9 2.3
Comparative example 2 754 56 87.3 0.7
Comparative example 3 1108 43 84.2 0
Comparative example 4 321 67 82.1 1.3
Comparative example 5 667 142 78.3 0
Comparative example 6 935 93 84.6 4.1
As shown in table 1, the ac impedance of the lithium ion batteries of examples 1 to 6 is significantly lower than that of comparative examples 1 to 6, which indicates that the solid electrolyte composite layer of the present invention can effectively reduce the interfacial resistance between the electrolyte and the positive and negative electrode sheets; the cycle life and the coulombic efficiency of the lithium ion batteries of examples 1 to 6 are also obviously higher than those of comparative examples 1 to 6, which shows that the cycle performance and the discharge efficiency of the lithium ion batteries can be improved by the solid electrolyte composite layer of the invention; it can be seen from the data of the short circuit rate that the lithium ion batteries of examples 1 to 6 have no short circuit phenomenon, while the lithium ion batteries of comparative examples except comparative example 3 and comparative example 5 have short circuit phenomena of different degrees, which shows that the safety performance of the lithium ion battery can be obviously improved by the solid electrolyte composite layer of the present invention.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims (10)

1. A solid electrolyte composite layer, comprising: the near-anode side solid electrolyte layer, the middle solid electrolyte layer and the near-cathode side solid electrolyte layer are sequentially stacked;
the intermediate solid electrolyte layer comprises an inorganic ceramic electrolyte;
the near-positive electrode side solid electrolyte layer comprises a near-positive electrode side polymer and a lithium salt;
the near-anode side solid electrolyte layer includes a near-anode side compound and a lithium salt;
the polymer near the positive electrode side is selected from at least one of poly (ethylene carbonate), polycyanoacrylate, polycaprolactone, polymethyl methacrylate, polyvinyl acetate, polyvinyl butyral, polybutylene succinate, polyacrylonitrile, polymaleic anhydride, polyvinylidene fluoride-hexafluoropropylene and derivatives;
the near-negative electrode side compound is at least one selected from polyethylene oxide, polyphenyl ether, polyvinyl alcohol, polyacrylic acid, 2, 3-epoxybutane, 1, 3-dioxolane, 1, 4-dioxane and derivatives.
2. The solid electrolyte composite layer according to claim 1, wherein the near-positive electrode side solid electrolyte layer accounts for 5 to 40% of the total mass of the solid electrolyte composite layer, the intermediate solid electrolyte layer accounts for 20 to 90% of the total mass of the solid electrolyte composite layer, and the near-negative electrode side solid electrolyte layer accounts for 5 to 40% of the total mass of the solid electrolyte composite layer.
3. The solid electrolyte composite layer according to claim 1 or 2, wherein the near-positive electrode side solid electrolyte layer includes, in terms of mass fraction: 50-80% of a polymer near the positive electrode side, 10-40% of lithium salt and 0-20% of additives.
4. The solid electrolyte composite layer according to any one of claims 1 to 3, wherein the near-anode side solid electrolyte layer includes, in terms of mass fraction: 50-80% of a near-negative electrode side compound, 10-40% of lithium salt and 0-20% of an additive.
5. The solid electrolyte composite layer according to claim 1, wherein the inorganic ceramic electrolyte is selected from at least one of a perovskite-type electrolyte, an anti-perovskite-type electrolyte, a garnet-type electrolyte, a NASICON-type electrolyte, a LISICON electrolyte, and a sulfide electrolyte.
6. The solid electrolyte composite layer according to claim 1, wherein the lithium salt is selected from lithium perchlorate, lithium hexafluorophosphate, lithium hexafluoroarsenate, lithium tetrafluoroborate, lithium bisoxalato borate, lithium oxalato difluoroborate, lithium bisdifluorosulfonylimide, lithium bistrifluoromethylsulfonylimide, lithium trifluoromethanesulfonate, lithium malonato oxalato borate, lithium hexafluoroantimonate, lithium difluorophosphate, 4, 5-dicyano-2-trifluoromethylimidazolium, LiN (SO)2C2F5)2、LiC(SO2CF3)3、LiN(SO2F)2At least one of (1).
7. The solid electrolyte composite layer according to claim 3 or 4, wherein the additive is one selected from succinonitrile, an ionic liquid, fluoroethylene carbonate.
8. A lithium ion battery comprising the solid electrolyte composite layer according to any one of claims 1 to 7.
9. The lithium ion battery of claim 8, comprising: the positive plate, the solid electrolyte composite layer and the negative plate are sequentially stacked;
the solid electrolyte layer at the side close to the positive electrode of the solid electrolyte composite layer is arranged on the functional surface of the middle solid electrolyte layer close to the positive electrode plate;
the solid electrolyte layer at the side close to the negative electrode of the solid electrolyte composite layer is arranged on the functional surface of the middle solid electrolyte layer close to the negative plate.
10. The lithium ion battery according to claim 8 or 9, wherein the positive electrode active material layer of the positive electrode sheet comprises, in mass fraction: 70-97% of positive active material, 0.1-25% of near-positive side solid electrolyte, 0.1-10% of binder and 1.5-15% of conductive agent.
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CN114204142A (en) * 2021-12-02 2022-03-18 厦门大学 All-solid-state battery interface buffer layer, preparation method and battery thereof
CN114639869A (en) * 2022-03-25 2022-06-17 厦门海辰新能源科技有限公司 Solid electrolyte, preparation method and application thereof
CN115275362A (en) * 2022-07-29 2022-11-01 中国地质大学（武汉） Solid electrolyte containing heterogeneous ionic gel buffer layer and preparation and application thereof
CN115332725A (en) * 2022-08-22 2022-11-11 珠海冠宇动力电池有限公司 Diaphragm and battery
TWI850750B (en) * 2022-08-30 2024-08-01 鴻海精密工業股份有限公司 Solid electrolyte membrane and method for making the same
CN116598424A (en) * 2023-04-26 2023-08-15 中创新航科技集团股份有限公司 Solid lithium ion battery and preparation method thereof
CN116487724A (en) * 2023-06-26 2023-07-25 河北光兴半导体技术有限公司 Composite solid electrolyte sheet, preparation method and application thereof, and solid battery
CN116487724B (en) * 2023-06-26 2023-08-29 河北光兴半导体技术有限公司 Composite solid electrolyte sheet, preparation method and application thereof, and solid battery

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