A solid-state electrolyte prepared by a heterogeneous in-situ polymerization method and a solid-state lithium, sodium battery comprising the same

Abstract

The application belongs to the technical field of solid electrolyte, and more particularly relates to a solid electrolyte prepared by a heterogeneous in-situ polymerization method and a solid lithium or sodium battery containing the solid electrolyte. The solid electrolyte prepared by the heterogeneous in-situ polymerization method has a gradient structure, specifically, the electrolyte on the skeleton is completely solidified, and the electrolyte near the electrode is in a gel state. Meanwhile, the solid electrolyte can be used to prepare a solid-state battery. The solid electrolyte with gradient structure change is prepared by the heterogeneous in-situ polymerization method, the gradient change of the structure of the electrolyte is realized, the gradient structure from a solid state to a gel state is formed, the double advantages of the solid state and the gel state are combined, the interface combination is facilitated, the operation is simple, and the structure is easy to control.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of solid-state electrolyte, more particularly to a solid-state electrolyte prepared by a heterogeneous in-situ polymerization method and a solid-state lithium, sodium battery comprising the same. BACKGROUND

[0002] Solid-state electrolyte is the core of solid-state battery. At present, solid-state batteries are mainly classified according to the types of solid-state electrolytes, including two categories of ceramic (inorganic) solid-state electrolytes and polymer (organic) solid-state electrolytes, and the former can be further divided into oxides, sulfides, nitrides, and phosphides. At present, the two main types of oxides and sulfides have been studied in depth and have potential.

[0003] From the current research results, polymer solid-state electrolytes were the first to achieve application, but they have two fatal problems of high cost and low conductivity. The current mainstream polymer solid-state electrolytes are PEO, PVDF, PAN, etc. The polymer electrolyte has low conductivity at room temperature, and the upper limit of energy is not high. The ionic conductivity is greatly improved after heating, but it consumes energy and increases cost, which increases the difficulty of commercialization. Oxide solid-state electrolytes have good comprehensive performance, and the important factor restricting their development is the large interface impedance between the electrolyte and the electrode, and the interface reaction causes the capacity attenuation of the battery. Sulfide solid-state electrolytes have the highest conductivity, and the research difficulty is the highest. How to maintain high stability is a big problem. Sulfide electrolyte has high ionic conductivity and a wide electrochemical stability window (more than 5V), and is favored by many enterprises, but the interface stability with lithium electrode is poor. In comparison, organic / inorganic composite solid-state electrolyte has become the most promising technology to be commercialized first because it combines the characteristics of inorganic electrolyte and polymer electrolyte.

[0004] Inorganic / organic composite solid-state electrolyte is usually formed by adding inorganic nanoparticles to polymer electrolyte. The currently studied polymer electrolytes such as polyethylene oxide (PEO), polyacrylonitrile (PAN), polyvinylidene fluoride (PVDF), and polypropylene carbonate (PPC) have the problems of low room temperature ionic conductivity, narrow electrochemical window, and poor chemical / electrochemical stability. By adding inorganic nanoparticles, such as active fillers with ionic conductivity, Li7La3Zr2O 12 (LLZO), Li 0.33 La 0.56 TiO3(LLTO), Li 1.4 Al 0.4 Ti 1.6or non-ionic conductive inert fillers such as Al2O3, SiO2, TiO2, ZrO2, etc. The Lewis acidity of the inorganic fillers can improve the elution of lithium salts and reduce the crystallinity of the polymer, thereby improving the ionic conductivity of the composite electrolyte. The composite polymer electrolyte can effectively improve the mechanical strength, electrochemical stability and thermal stability of the polymer electrolyte. The use of composite polymer electrolyte and the control of ion transport path in the electrolyte by filler distribution mode is expected to provide a promising solution to promote the practical application of solid-state electrolyte.

[0005] Although great progress has been made in the research of solid-state batteries, in addition to solving the technical problems of electrolyte itself, the interface problems of solid-state electrolyte / electrode, including the interface contact impedance of positive electrode / electrolyte, the interface compatibility of negative lithium / electrolyte, etc. still need to be solved. The room temperature ionic conductivity of solid-state electrolyte, the ion transport of solid-solid interface of electrode / electrolyte and the cost and green process of battery assembly process still need to be greatly broken through.

[0006] In-situ polymerization is an important method to solve the interface problem of solid-state battery. Researchers have reported a variety of polymers and in-situ polymerization techniques, but the current in-situ polymerization is usually homogeneous polymerization, that is, the electrolyte slurry mixed with initiator is directly poured into the battery, and the solidification is realized by thermal polymerization, photopolymerization or catalyst-induced polymerization. The result is that the internal space structure of the battery is single, either completely solidified with poor interface flexibility or gelled with incomplete solidification. It can be seen that complete solidification or complete gelation is not conducive to the stability of solid-state battery. The actual demand is that the electrolyte should be solidified to a certain strength to inhibit lithium dendrite growth and thermodynamic deformation, while the flexibility of the electrode / electrolyte interface should be maintained to prevent interface separation caused by volume change of the electrode during charging and discharging. SUMMARY

[0007] The purpose of the present application is to provide a solid-state electrolyte prepared by a heterogeneous in-situ polymerization method and a solid-state lithium, sodium battery containing the same. The gradient polymerization structure, i.e. heterogeneous in-situ polymerization, solves the practical demand problem of structural gradient change and operation simplification of the electrolyte, realizes structural regulation (from ordinary homogeneous structure to gradient structure), easily forms a gradient structure with both rigidity and flexibility from solid state to gel state, combines the dual advantages of solid state and gel state, and has good mechanical properties for inhibiting lithium dendrites. The gel state is beneficial to the interface combination and the stress concentration caused by the volume change of the electrode during charging and discharging, thereby solving the problems existing in the prior art.

[0008] To achieve the above purpose, the present application provides the following solutions:

[0009] One of the technical solutions of the present application: a solid-state electrolyte prepared by a heterogeneous in-situ polymerization method, comprising a porous framework and an electrolyte with a gradient structure loaded on the porous framework;

[0010] The electrolyte is completely solidified on the porous framework and is in a gel state near the electrode.

[0011] Further, the electrolyte comprises a metal salt and a monomer.

[0012] The second technical solution of the present application: a preparation method of the above-mentioned solid-state electrolyte, comprising the following steps:

[0013] The initiator, the binder and the filler are prepared into a slurry;

[0014] The slurry is coated on the porous framework, and after drying, an electrolyte solution is cast and subjected to gradient polymerization to obtain the solid-state electrolyte;

[0015] The electrolyte solution comprises a metal salt and a polymer monomer.

[0016] Further, the concentration of the initiator in the slurry is 1-5 wt.%.

[0017] Further, the concentration of the binder in the slurry is 1-5 wt.%.

[0018] Further, the concentration of the filler in the slurry is 10-50 wt.%.

[0019] Further, the initiator comprises at least one of aluminum triflate (Al(OTf)3), stannous octoate (Sn(Oct)2), lithium hexafluorophosphate (LiPF6) and azobisisobutyronitrile (AIBN).

[0020] Further, the binder comprises at least one of non-ionic block copolymer F127, water-based binder LA123, polyethylene oxide (PEO), polyvinylidene fluoride (PVDF), polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP) and polypropylene carbonate (PPC).

[0021] Further, the filler comprises at least one of YSZ, LLZO, LAGP, Li-β"-Al2O3, LLTO, NLZO and Na-β"-Al2O3.

[0022] The introduction of the filler improves the uniform distribution of the initiator and the compounding with the polymer, which can improve the ionic conductivity, thermal and mechanical properties of the polymer electrolyte.

[0023] Optionally, when preparing the slurry, the solvent is deionized water, DMF, NMP, ethanol or acetone.

[0024] Further, the porous framework is a framework with a porosity greater than 50%.

[0025] Optionally, the porous framework is a dry PE membrane, an electrospun PI fiber membrane, a PET fiber membrane, a PVDF fiber membrane, a glass fiber membrane, or a cellulose membrane.

[0026] Further, the metal salt includes at least one of LiTFSI, LiFSI, LiClO3, LiBOB, NaTFSI, NaPF6, NaClO3, NaFSI, and NaBOB.

[0027] Further, the polymer monomer includes at least one of 1,3-dioxolane (DOL), polyethylene glycol methyl ether acrylate (PEGMEA), methyl methacrylate (MMA), polyethylene glycol diglycidyl ether (PEGDE), succinonitrile (SN), and isocyanuric acid triglycidyl ester (TGIC).

[0028] The polymer obtained by self-polymerization or combined polymerization of the above-mentioned polymer monomers includes, but is not limited to, one of PDOL, PEGMEA-PMMA, PDOL-PMMA, PEGDE-PMMA, PEGMEA-PMMA-SN, and PDOL-TGIC.

[0029] Further, the gradient polymerization is achieved by self-catalysis or thermal initiation, and the time is 30 min to 24 h.

[0030] Optionally, the temperature of the self-catalysis is room temperature, and the temperature of the thermal initiation is 40 to 60 DEG C.

[0031] The present application controls the position where the initiator exists, and the polymerization is fast and the degree of polymerization is high in the place where the initiator is concentrated (on the framework), the degree of polymerization is small outside the framework, the farther away from the framework, the lower the degree of polymerization.

[0032] Technical solution three of the present application: provide a solid-state electrolyte prepared by the above-mentioned heterogeneous in-situ polymerization method in a solid-state battery.

[0033] Optionally, the solid-state battery is a solid-state lithium battery or a solid-state sodium battery.

[0034] Technical solution four of the present application: provide a solid-state battery, which comprises a solid-state electrolyte prepared by the above-mentioned heterogeneous in-situ polymerization method.

[0035] Further, the preparation steps of the solid-state battery include:

[0036] S1, preparing the initiator, the binder and the filler into a slurry;

[0037] The concentration of the initiator in the slurry is 1-5 wt.%; the concentration of the binder in the slurry is 1-5 wt.%; the concentration of the filler in the slurry is 10-50 wt.%; and the solvent of the slurry is deionized water, DMF, NMP, ethanol or acetone.

[0038] S2, the slurry is uniformly coated on the surface of the porous framework with a porosity greater than 50% by using a doctor blade method, the coating thickness is 5-200 um, and the slurry is allowed to stand for 10-20 min (for sufficient adsorption of the slurry by the porous framework), and a separator is obtained after drying;

[0039] The porous framework is a dry PE film, an electrospun PI fiber film, a PET fiber film, a PVDF fiber film, a glass fiber film or a cellulose film.

[0040] S3, the separator is placed in a battery to form an electric core with an electrode, an electrolyte solution is poured into the battery, the battery is filled and sealed, and the battery is cured at room temperature or at a temperature of 40-60°C for 30 min-24 h to obtain a solid-state battery.

[0041] The electrolyte solution contains a metal salt and a polymer monomer.

[0042] Optionally, the initiator includes at least one of aluminum triflate (Al(OTf)3), stannous octoate (Sn(Oct)2), lithium hexafluorophosphate (LiPF6) and azobisisobutyronitrile (AIBN).

[0043] Optionally, the binder includes at least one of a non-ionic block copolymer F127, an aqueous binder LA123, polyethylene oxide (PEO), polyvinylidene fluoride (PVDF), polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP) and polypropylene carbonate (PPC).

[0044] Optionally, the filler includes at least one of YSZ, LLZO, LAGP, Li-β"-Al2O3, LLTO, NLZO and Na-β"-Al2O3.

[0045] Optionally, the metal salt includes at least one of LiTFSI, LiFSI, LiClO3, LiBOB, NaTFSI, NaPF6, NaClO3, NaFSI and NaBOB.

[0046] Optionally, the polymer monomer includes at least one of 1,3-dioxolane (DOL), polyethylene glycol methyl ether acrylate (PEGMEA), methyl methacrylate (MMA), polyethylene glycol diglycidyl ether (PEGDE), succinonitrile (SN) and isocyanuric acid triglycidyl ester (TGIC).

[0047] The polymer obtained by self-polymerization or combined polymerization of the above polymer monomers includes but is not limited to one of PDOL, PEGMEA-PMMA, PDOL-PMMA, PEGDE-PMMA, PEGMEA-PMMA-SN and PDOL-TGIC.

[0048] Optionally, the electrode comprises a positive electrode and a negative electrode; wherein the positive electrode comprises lithium iron phosphate, sodium vanadium phosphate, a ternary lithium positive electrode or a ternary sodium; and the negative electrode comprises metallic lithium, metallic sodium, graphite or hard carbon.

[0049] The present application discloses the following technical effects:

[0050] The present application realizes the structural gradient change of the electrolyte, forms the gradient structure from solid state to gel state, and combines the dual advantages of solid state and gel state, which is beneficial to interface combination, simple operation and convenient structure control.

[0051] The initiator is coated on the skeleton in advance, and then the electrolyte components are poured, so that the initiator with high concentration on the skeleton can make the electrolyte rapidly polymerize into a solid, and there is no initiator outside the skeleton, so that the polymerization can be initiated only by the initiator dissolved on the skeleton, the polymerization degree is not as high as that on the skeleton due to the small amount of initiator, and the farther away from the skeleton, the lower the polymerization degree, so that the gradient structure from solid state to gel state, or even semi-solid state is realized.

[0052] The filler is added to realize better uniform distribution of the initiator on the skeleton, to improve the ionic conductivity of the electrolyte, and to improve the mechanical and thermal properties of the coating. BRIEF DESCRIPTION OF DRAWINGS

[0053] The accompanying drawings, which form a part of the present application, are included to provide a further understanding of the application, and are incorporated herein for explanation by reference. The present application will become more fully understood from the detailed description and accompanying drawings, and numerous embodiments of the application will be apparent to one skilled in the art. In the drawings:

[0054] Figure 1 The cycle performance of the solid-state battery in Example 1.

[0055] Figure 2 The rate performance of the solid-state battery in Example 1.

[0056] Figure 3 The potential window of the solid-state battery in Example 1.

[0057] Figure 4 The SEM image of the polyethylene skeleton coated with initiator and filler in Example 1.

[0058] Figure 5 SEM image of the cross-section of the solid-state electrolyte after polymerization in Example 1.

[0059] Figure 6 SEM image of the PI fiber skeleton coated with initiator and filler in Example 2.

[0060] Figure 7 SEM image of the cross-section of the solid-state electrolyte after polymerization in Example 2.

[0061] Figure 8 Schematic diagram of the preparation of a solid-state electrolyte by homogeneous in-situ polymerization.

[0062] Figure 9 Schematic diagram of the preparation of a solid-state electrolyte by heterogeneous in-situ polymerization. DETAILED DESCRIPTION

[0063] Various illustrative embodiments of the present application are described in detail below. This detailed description is not intended to restrict the application unless so indicated, but merely to explain certain aspects, features and embodiments of the application.

[0064] It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. In addition, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present application, the preferred methods and materials are described. All publications mentioned herein are incorporated by reference to disclose and describe the methods and / or materials in connection with which the publications are cited. In case of conflict, the content of the present specification will control.

[0065] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present application, the preferred methods and materials are described. All publications mentioned herein are incorporated by reference to disclose and describe the methods and / or materials in connection with which the publications are cited. In case of conflict, the content of the present specification will control.

[0066] Various modifications and changes can be made to the specific embodiments of the present application described herein without departing from the scope or spirit of the application. Other embodiments of the application will be apparent to those of ordinary skill in the art from the description and examples presented herein. The description and examples are illustrative of the application and are not intended to limit the scope of the application.

[0067] As used herein, the terms "comprise", "comprising", "include", "including", "have", "having" and the like are open-ended and do not exclude additional, unrecited elements or method steps.

[0068] The raw materials and reagents used in the specific embodiments of the present application are commercially available; if no special instructions are given, the room temperature and normal temperature refer to 20-30°C.

[0069] Example 1

[0070] Preparation of the solid-state battery:

[0071] S1, dissolve 0.15 g of Al(OTf)3 and 0.03 g of PVDF in 3 g of DMF, add 0.3 g of YSZ nanoparticles, and defoam with a defoaming machine for 3 min, and then magnetically stir for 4-5 h to obtain a slurry;

[0072] S2, evenly drop the slurry on a glass plate, and then evenly spread it on the glass plate with a doctor blade with a gap of 150 μm, then evenly spread the polyethylene skeleton (porosity greater than 50%) on the slurry, and then drop the slurry on the upper layer, and then evenly spread it with a doctor blade with a gap of 200 μm, and then place it in a flat place and dry at room temperature for 10-20 min, and then sequentially dry in a forced air drying oven (60°C) until the surface is free of liquid, 80°C, hang in a forced air drying oven for 8 h, and then vacuum dry for 12 h to obtain a separator, which is stored in an argon glove box for standby;

[0073] S3, mix 0.287 g of LiTFSI and 1 g of DOL, and stir for 10 min until fully dissolved to obtain a uniform electrolyte solution;

[0074] S4, use a 2032 button cell as the assembly shell, lithium iron phosphate as the positive electrode and a lithium metal sheet as the negative electrode, place the separator (polyethylene skeleton loaded with initiator) prepared above between the positive and negative electrodes, and drop 40 μL of electrolyte solution on each side, and then press the button after standing for 20 min, and the pressure is 50 MPa, and then solidify at room temperature for 12 h to obtain a solid-state battery.

[0075] The solid-state battery prepared in Example 1 was subjected to electrochemical performance test, and the results are shown in Figures 1-3 .

[0076] Figure 1 The cycle performance of the solid-state battery in Example 1 is shown in Figure 2 The rate performance of the solid-state battery in Example 1 is shown in Figure 3 The potential window of the solid-state battery in Example 1 is shown in Figures 1-3 It can be seen that the solid-state battery prepared in Example 1 has an ionic conductivity of 2×10 -4 S / cm, a potential window of up to 5.2 V, good rate performance, and a capacity of more than 120 mAh / g at 1C, stable cycle for 500 weeks at 0.5C, and a capacity retention of 85%.

[0077] Figure 4SEM image of the polyethylene skeleton (separator) coated with initiator and filler in Example 1.

[0078] Figure 5 SEM image of the cross section of the solid-state electrolyte after polymerization in Example 1.

[0079] Analysis Figures 4-5 It can be found that the electrolyte on the skeleton has been completely solidified into a solid state, while the surface (i.e. the interface in contact with the electrode) remains in a clear colloidal state, which solves the interface problem of the solid-state battery well.

[0080] Example 2

[0081] Preparation of solid-state battery:

[0082] S1, 0.5g LLZO filler, 0.1g AIBN initiator, 0.03g F127 binder were mixed and dissolved in 3g anhydrous ethanol, and then degassed for 3min with a degassing machine, and magnetically stirred for 4-5h to obtain a slurry;

[0083] S2, the slurry was uniformly coated on the PI fiber skeleton (porosity greater than 50%) by using the doctor blade method, with a thickness of 200μm, and was allowed to stand for 10min for the skeleton to fully absorb, and then was dried in an oven (80℃) for 12h to obtain a separator, which was stored in an argon glove box for standby;

[0084] S3, LiTFSI lithium salt and PEGMEA+MMA+SN (mass ratio 1:9:7) were mixed and stirred for 10min until fully dissolved to obtain a uniform electrolyte solution;

[0085] S4, using a 2032 button cell as the assembly shell, lithium iron phosphate as the positive electrode and a metal lithium sheet as the negative electrode, the above prepared separator (PI fiber skeleton loaded with initiator) was placed between the positive and negative electrodes, and 40μL of electrolyte solution was added on both sides respectively, and after standing for 20min, the button was pressed with a pressure of 50Mpa, and was cured at 60℃ for 30min to obtain a solid-state battery.

[0086] The solid-state battery obtained in Example 2 was subjected to electrochemical performance test, in which the ionic conductivity of the electrolyte was 3.7×10 -4 S / cm, the potential window reached 5.0V, the rate performance was good, and the capacity could reach more than 131mAh / g at 1C, and the capacity retention was 87% after stable cycling for 500 cycles at 0.5C.

[0087] Figure 6 SEM image of the PI fiber skeleton (separator) coated with initiator and filler in Example 2.

[0088] Figure 7SEM image of the cross section of the solid-state electrolyte after polymerization in Example 2.

[0089] Example 3

[0090] Preparation of the solid-state battery:

[0091] S1, 0.5 g of Li-β"-Al2O3 filler, 0.1 g of Sn(Oct)2 initiator, and 0.03 g of PVDF binder were mixed and dissolved in 3 g of N,N-dimethylformamide, and then degassed for 3 min using a degassing machine and magnetically stirred for 4-5 h to obtain a slurry;

[0092] S2, the slurry was uniformly coated on a PET fiber skeleton (porosity greater than 50%) using a doctor blade method, with a thickness of 200 μm, and allowed to stand for 10 min for full absorption of the skeleton, and then dried in an oven (100°C) for 12 h to obtain a separator, which was stored in an argon glove box for standby;

[0093] S3, LiClO3 lithium salt and DOL+TGIC (mass ratio 10:1) were mixed and stirred for 10 min until fully dissolved to obtain a uniform electrolyte solution;

[0094] S4, a 2032 button cell was used as the assembly shell, NCM622 was used as the positive electrode and a lithium sheet was used as the negative electrode, the separator (PET fiber skeleton loaded with initiator) prepared above was placed between the positive and negative electrodes, and 40 μL of electrolyte solution was added to each side, and then pressed after standing for 20 min, with a pressure of 50 MPa, and then cured at 60°C for 60 min to obtain a solid-state battery.

[0095] The solid-state battery obtained in Example 3 was subjected to electrochemical performance testing, wherein the ionic conductivity of the electrolyte was 5.3 x 10 -4 S / cm, the potential window reached 5.2 V, the rate performance was good, and the capacity reached more than 161 mAh / g at 1C, and the capacity was maintained at 80% after stable cycling for 500 cycles at 0.5C.

[0096] Example 4

[0097] Preparation of the solid-state battery:

[0098] S1, 0.5 g of Li-β"-Al2O3 filler, 0.1 g of Sn(Oct)2 initiator, and 0.03 g of PVDF binder were mixed and dissolved in 3 g of N,N-dimethylformamide, and then degassed for 3 min using a degassing machine and magnetically stirred for 4-5 h to obtain a slurry;

[0099] S2, the slurry was uniformly coated on the PVDF fiber skeleton (porosity greater than 50%) by doctor blade method, the thickness was 200 μm, and it was left for 10 min for the skeleton to fully absorb, then it was dried in an oven (80℃) for 12 h to obtain a separator, which was stored in an argon glove box for standby;

[0100] S3, NaTFSI sodium salt and PEGMEA-MMA (mass ratio 2:9) were mixed and stirred for 10 min until fully dissolved to obtain a uniform electrolyte solution;

[0101] S4, a 2032 button cell was used as the assembly shell, sodium vanadium phosphate was used as the positive electrode and metal sodium was used as the negative electrode, the above prepared separator (PVDF fiber skeleton loaded with initiator) was placed between the positive and negative electrodes, and 40 μL of electrolyte solution was added on both sides respectively, and then it was pressed after standing for 20 min, the pressure was 50 Mpa, and it was cured at 60℃ for 30 min to obtain a solid-state battery.

[0102] The solid-state battery obtained in Example 4 was subjected to electrochemical performance test, wherein the ionic conductivity of the electrolyte was 3.1×10 -4 S / cm, the potential window reached 4.8V, the rate performance was good, and it could reach more than 101 mAh / g at 1C, and the capacity remained 80% after stable cycling for 500 cycles at 0.5C.

[0103] Comparative Example 1

[0104] Preparation of a homogeneous polymerization solid-state battery:

[0105] S1, 0.5 g of LLZO filler, 0.1 g of AIBN initiator, 0.5 g of LiTFSI lithium salt and 5 g of PEGMEA+MMA+SN (mass ratio 1:9:7) were mixed and stirred for 10 min until fully dissolved to obtain a uniform electrolyte solution;

[0106] S2, a 2032 button cell was used as the assembly shell, lithium iron phosphate was used as the positive electrode and metal lithium sheet was used as the negative electrode, the PI fiber skeleton was placed between the positive and negative electrodes, and 40 μL of electrolyte solution was added on both sides respectively, and then it was pressed after standing for 20 min, the pressure was 50 Mpa, and it was cured at 60℃ for 30 min to obtain a solid-state battery.

[0107] The solid-state battery obtained in Comparative Example 1 was subjected to electrochemical performance test, wherein the ionic conductivity of the electrolyte was 1.8×10 -4 S / cm, the potential window reached 4.4V, the rate performance was good, and it could reach more than 117 mAh / g at 1C, and the capacity remained 79% after stable cycling for 200 cycles at 0.5C.

[0108] Figure 8Schematic of preparation of solid state electrolyte for homogeneous in-situ polymerization.

[0109] Figure 9 Schematic of preparation of solid state electrolyte for heterogeneous in-situ polymerization.

[0110] The various embodiments described in this specification are presented by way of example, and are not intended to limit the scope of the application. Each embodiment described herein can be implemented in combination with one or more other embodiments described herein. The various embodiments described in this specification can be implemented in any combination.

[0111] The foregoing description of the disclosed embodiments enables a person skilled in the art to make or use the application. Modifications of these embodiments will occur to persons of skill in the art, and all such modifications that do not depart from the spirit of the application are intended to be within the scope of the application. The scope of the application is to be limited only by the claims appropriately amended when supported by pertinent evidence.

Claims

1. A solid-state electrolyte prepared by a heterogeneous in-situ polymerization process, characterized in that, The solid-state electrolyte comprises a porous framework and an electrolyte with a gradient structure loaded on the porous framework; The electrolyte is completely solidified on the porous framework and is in a gel state near the electrode; The steps of the heterogeneous in-situ polymerization method comprise: The initiator, the binder and the filler are prepared into a slurry; The slurry is coated on the porous framework, and after drying, an electrolyte solution is cast and subjected to gradient polymerization to obtain the solid-state electrolyte; The electrolyte solution comprises a metal salt and a polymer monomer; The metal salt comprises at least one of LiTFSI, LiFSI, LiClO3, LiBOB, NaTFSI, NaPF6, NaClO3, NaFSI and NaBOB; The polymer monomer comprises at least one of 1,3-dioxolane, polyethylene glycol methyl ether acrylate, methyl methacrylate, polyethylene glycol diglycidyl ether, butanedinitrile and isocyanuric acid triglycidyl ester.

2. A method of producing the solid-state electrolyte according to claim 1, characterized by the steps of The steps of the heterogeneous in-situ polymerization method comprise: The initiator, the binder and the filler are prepared into a slurry; The slurry is coated on the porous framework, and after drying, an electrolyte solution is cast and subjected to gradient polymerization to obtain the solid-state electrolyte; The electrolyte solution comprises a metal salt and a polymer monomer.

3. The production method according to claim 2, wherein The concentration of the initiator in the slurry is 1-5 wt.%; and / or, The concentration of the binder in the slurry is 1-5 wt.%; and / or, The concentration of the filler in the slurry is 10-50 wt.%.

4. The production method according to claim 2, wherein The initiator comprises at least one of aluminum triflate, stannous octoate, lithium hexafluorophosphate and azobisisobutyronitrile; and / or, The binder comprises at least one of non-ionic block copolymer F127, water-based binder LA123, polyethylene oxide, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer and polypropylene carbonate; and / or, The filler comprises at least one of YSZ, LLZO, LAGP, Li-β"-Al2O3, LLTO, NLZO and Na-β"-Al2O3; and / or, The porous framework has a porosity greater than 50%.

5. The production method according to claim 4, wherein The porous framework is a dry PE membrane, an electrospun PI fiber membrane, a PET fiber membrane, a PVDF fiber membrane, a glass fiber membrane or a cellulose membrane.

6. The production method according to claim 2, wherein The gradient polymerization is achieved by self-catalysis or thermal initiation, and the time is 30 min-24 h.

7. The production method according to claim 6, wherein The temperature of the self-catalysis is room temperature; and / or, The temperature of the thermal initiation is 40-60°C.

8. Use of the solid-state electrolyte prepared by the heterogeneous in-situ polymerization method of claim 1 in a solid-state battery.

9. A solid state battery, characterized by The solid-state battery comprises the solid-state electrolyte prepared by the heterogeneous in-situ polymerization method of claim 1.

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