Clay / polyether artificial composite solid electrolyte, and preparation method and application thereof

Abstract

The application belongs to the field of battery materials, and particularly relates to a preparation method of a clay / polyether artificial composite solid electrolyte, which is obtained by polymerization of a precursor solution containing a polyether monomer, a crosslinking agent, an initiator, an electrolyte salt and modified clay; the modified clay is a clay grafted with a compound of formula 1 after being intercalated with metal M ions; the metal M comprises at least one of Li, Na and K; R1 is an alkyl group with 1-6 carbon atoms; R2 is a substituted alkyl group with a substituent group; the substituent group comprises at least one of an amino group, an epoxy group, a mercapto group, an acryloyloxy group, a vinyl group and an isocyanate group. The application also comprises the clay / polyether artificial composite solid electrolyte prepared by the preparation method and an application thereof. The application can improve ion conduction and solve the problem of clay segregation, so that the electrochemical performance of the composite solid electrolyte can be significantly improved.

Description

Technical Field

[0001] This invention belongs to the field of battery materials, specifically the field of solid electrolyte technology. Background Technology

[0002] With the innovation of electric vehicles and energy storage systems, the demand for battery energy density is constantly increasing, leading to the development of metal secondary batteries. Among them, lithium / sodium / potassium metal anodes have high theoretical specific capacity and low standard electrode potential (compared to the standard hydrogen potential), and their introduction into battery systems is expected to further improve battery energy density. However, during the entire lithium / sodium / potassium charge-discharge electrochemical process, uneven ion flow distribution at the interface causes significant concentration polarization at the anode interface, resulting in uncontrolled dendrite growth and SEI layer rupture, which limits the further application of lithium / sodium / potassium metal anodes.

[0003] A stable solid-state interface (SEI) is crucial for the development of next-generation high-energy-density metal batteries. Naturally formed SEI layers can optimize the interface between the metal anode and the electrolyte; however, they are inherently inhomogeneous and fragile, easily leading to performance degradation and battery failure. Inorganic SEIs offer advantages such as excellent interfacial energy and superior ionic conductivity, accelerating the lateral diffusion of ions along the SEI / Li interface, effectively forming a uniform ion flux, thereby suppressing dendrite formation and improving the stability of the metal anode. However, the inherent stiffness of inorganic SEIs results in low tolerance for volume expansion of the metal anode, leading to fracture and failure of the metal anode during long-term battery cycling. Organic SEIs possess higher volume change tolerance and superior SEI structural stability, which is beneficial for constructing high-quality composite SEI layers. However, the low ionic conductivity of organic SEIs limits their development. Therefore, constructing an organic-inorganic composite artificial solid-state interface to modulate the interface between the metal and electrolyte is of vital importance for the cycling performance of the metal anode and the practical implementation of high-energy-density batteries.

[0004] There are also some existing reports on clay-organic solid electrolytes. For example, Chinese patent document EP1171927A1 discloses microporous solid electrolytes and methods for their preparation, which describe the addition of a certain amount of clay to the solid electrolyte. Chinese patent document CN117594871A also discloses an all-solid polymer composite electrolyte and its preparation method, similarly describing a scheme involving the addition of clay to the electrolyte.

[0005] In summary, although there are some existing technologies that involve adding clay to solid electrolytes, these technologies still struggle to address issues such as clay segregation, poor compatibility leading to uneven dispersion, and slow ion transport resulting in excessive impedance. Summary of the Invention

[0006] To address the problems existing in current artificial composite solid electrolytes, this invention provides a method for preparing a clay / polyether artificial composite solid electrolyte, aiming to provide a composite electrolyte with low impedance and excellent ion conduction performance.

[0007] The second objective of this invention is to provide a clay / polyether artificial composite solid electrolyte prepared by the aforementioned method and its application in solid-state batteries.

[0008] A third objective of this invention is to provide a solid-state battery comprising the aforementioned clay / polyether artificial composite solid electrolyte and an electrode.

[0009] A method for preparing a clay / polyether artificial composite solid electrolyte involves polymerization of a precursor solution comprising polyether monomers, a crosslinking agent, an initiator, an electrolyte salt, and modified clay.

[0010] The modified clay is a clay that has been first intercalated with metal M ions and then grafted with Formula 1.

[0011] The metal M includes at least one of Li, Na, and K;

[0012]

[0013] R1 is a C1 to C6 alkyl group; R2 is a substituted alkyl group with a substituent; the substituent includes at least one of amino, epoxy, mercapto, acryloyloxy, vinyl, and isocyanate groups.

[0014] This invention innovatively employs the modified clay in conjunction with polyether monomers to prepare clay / polyether artificial composite solid electrolytes. Research in this invention shows that, based on the aforementioned special intercalation-form 1 two-stage modification process, and further combined with the polyether, ion conduction can be improved, and clay segregation problems can be mitigated, thus significantly improving the electrochemical performance of the composite solid electrolyte.

[0015] In this invention, clay is placed in a modified aqueous solution containing metal M ions for intercalation treatment to obtain an intercalated modified material. The intercalated modified material is then placed in a solution of Formula 1 for graft modification to obtain the modified clay.

[0016] In this invention, the combination of metal M ion intercalation and coating with Formula 1 can be combined with the polyether to improve ion conduction rate and pathway, thereby improving its electrochemical performance.

[0017] In this invention, the clay includes at least one of kaolinite, hydrous kaolinite, illite, montmorillonite, hydromica, glauconite, chlorite, vermiculite, sepiolite, halloysite, bentonite, and palygorskite.

[0018] In this invention, the metal M ion is provided by at least one of the following raw materials: lithium chloride, lithium acetate, lithium hydroxide, lithium bromide, lithium iodide, sodium chloride, sodium acetate, sodium hydroxide, sodium bromide, sodium iodide, potassium chloride, potassium acetate, potassium hydroxide, potassium bromide, and potassium iodide.

[0019] Preferably, the metal M ions include two or more of Li, Na, and K. Studies have shown that by combining these ions, a liquid alloy can be formed during charge and discharge, which helps to further enhance ion conduction rates and pathways, and can further synergistically enhance the electrochemical performance of the material.

[0020] In a further preferred embodiment, in this invention, sodium ions are first used to intercalate clay in the first stage, followed by lithium ions to intercalate the product of the first stage, thereby obtaining the intercalated modified material. Research in this invention shows that the two-stage intercalation treatment using sodium followed by lithium can further optimize the physicochemical structure of the material, further improve its synergistic effect with Formula 1, and further enhance the material's properties.

[0021] Preferably, the concentration of metal M ions in the modified aqueous solution is 0.1–4 mol / L, more preferably 1–3 M; more preferably 2–2.5 M.

[0022] Preferably, the solid-liquid ratio during the intercalation modification stage is 0.1–2 g / mL, and more preferably 0.5–1 g / mL.

[0023] Preferably, the temperature of the intercalation modification stage is 15–180°C, and more preferably 70–90°C.

[0024] Preferably, the intercalation modification time is 1 to 72 hours, for example, 10 to 30 hours; further, it can be 20 to 25 hours.

[0025] In this invention, the compound of formula 1 includes compounds with the following structures;

[0026]

[0027]

[0028] R3 is a saturated carbon chain of C1 to C6; R4 is an alkyl group of C1 to C6.

[0029] Preferably, the compound of formula 1 is selected from formula 1b and / or formula 1d, and more preferably a complex of formula 1b and formula 1d. In this invention, the weight ratio of formula 1b to formula 1d in the complex can be 1:0.5 to 2. Research in this invention shows that using the combination of formula 1d and formula 1d, and further combining it with the intercalation modification process, can further enhance the low impedance and performance of the material.

[0030] Preferably, the weight ratio of Formula 1 and the clay is 0.1 to 1:1; more preferably, it can be 0.2 to 0.5:1.

[0031] Preferably, the weight ratio of modified clay to polyether monomer is 0.1% to 50%; more preferably, it can be 1% to 15%, and even more preferably, it can be 5% to 10%.

[0032] In this invention, the polyether monomer includes at least one of 1,3-dioxolane (DOL), 1,3,5-trioxane, 1,3,5-trioxane, 1,3-dioxane, 1,4-dioxane, 1,2-epoxycyclopentene, 3,4-epoxy-1-butene, propylene oxide, 2-trifluoromethyl ethylene oxide, glycidyl 2,2,3,3-tetrafluoropropyl ether, tetrahydrofuran, methyltetrahydrofuran, tetrahydropyran, fluoroethylene carbonate, and vinylene carbonate.

[0033] Preferably, the initiator includes at least one of lithium hexafluorophosphate, aluminum trifluoromethanesulfonate, stannous octoate, azobisisobutyronitrile, lithium difluorooxalate borate, lithium tetrafluoroborate, lithium hexafluoroarsenate, sodium difluorooxalate borate, sodium tetrafluoroborate, sodium hexafluorophosphate, sodium hexafluoroarsenate, potassium fluoroborate, potassium hexafluorophosphate, boron trifluoride, and phosphorus pentafluoride.

[0034] The concentration of the initiator in the polymer monomer is 0.1–1 M; preferably 0.4–0.8 M.

[0035] Preferably, the crosslinking agent comprises at least one of pentaerythritol glycidyl ether, trimethylolpropane triglycidyl ether, polyethylene glycol diglycidyl ether, glycerol diglycidyl ether, trimethylolpropane allyl ether, tert-butyl glycidyl ether, ethyl glycidyl ether, polypropylene glycol diglycidyl ether, isopropyl glycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, and ethylene glycol diglycidyl ether.

[0036] Preferably, the crosslinking agent is 0.2-15% of the weight of the polyether monomer, more preferably 0.5-1.5%.

[0037] Preferably, the electrolyte salt is at least one of conductive lithium salt, conductive sodium salt, and conductive potassium salt.

[0038] Preferably, the concentration of the electrolyte salt in the precursor solution is 0.1–4 M, more preferably 1–3 M.

[0039] The present invention also provides a clay / polyether artificial composite solid electrolyte prepared by the preparation method described above.

[0040] The preparation method described in this invention can endow the prepared material with special physicochemical properties, and the material prepared by the method can improve the transport pathway and rate of active ions, avoid material segregation, reduce the impedance of the material, and thus significantly improve the electrochemical performance of the prepared material.

[0041] The present invention also provides a positive electrode and / or a negative electrode composited with a solid electrolyte, wherein the solid electrolyte includes the clay / polyether artificial composite solid electrolyte prepared by the preparation method described above.

[0042] In this invention, the clay / polyether artificial composite solid electrolyte can be composited in conventional positive and / or negative electrodes.

[0043] The present invention also provides a solid-state battery, comprising a positive electrode, a solid electrolyte, and a negative electrode sequentially stacked, wherein the solid electrolyte is the clay / polyether artificial composite solid electrolyte.

[0044] In this invention, the solid-state battery, apart from containing the clay / polyether artificial composite solid electrolyte described in this invention, can have other conventional components and structural parts.

[0045] The present invention also provides a method for preparing a solid-state battery, which involves combining a positive electrode, a solid electrolyte, and a negative electrode to obtain the battery; wherein the solid electrolyte is the clay / polyether artificial composite solid electrolyte.

[0046] Preferably, at least one of the positive and / or negative electrodes is a positive and / or negative electrode incorporating the solid electrolyte;

[0047] Preferably, the in-situ preparation method of the solid-state battery of the present invention comprises the following steps: filling a battery cell with a positive electrode and a negative electrode into a battery case, followed by liquid injection and encapsulation and in-situ polymerization, wherein the solution injected in the liquid injection stage is the precursor solution described in the preparation method.

[0048] In this invention, the positive and / or negative electrodes are the positive and / or negative electrodes of the composite solid electrolyte as described in claim 8.

[0049] Beneficial effects

[0050] 1. This invention innovatively combines the intercalation-type two-stage grafting modification process with the polyether, which can improve ion conduction and address issues such as clay segregation and poor compatibility. The clay / polyether artificial composite solid electrolyte of this invention has high ion transport capacity, desolvated structure, and good mechanical properties, which can promote uniform ion deposition, inhibit dendrite growth, and greatly improve the air stability of the metal anode.

[0051] 2. The clay / polyether artificial composite solid electrolyte of the present invention can protect the negative electrode of a metal secondary battery, and the preparation method is simple to operate and mild under mild conditions. It can effectively improve the interfacial stability of the electrode / electrolyte while improving conductivity and mechanical strength. Attached Figure Description

[0052] Figure 1 This is a SEM image of the clay ore before modification in Example 1;

[0053] Figure 2 The image shows the SEM image of the modified clay ore in Comparative Example 1.

[0054] Figure 3 The image shows the EIS diagram of the solid electrolyte lithium metal symmetric battery in Example 1. Detailed Implementation

[0055] The following examples are intended to further illustrate the content of the present invention, rather than to limit the scope of protection of the claims of the present invention.

[0056] The optional clay modification method of this invention comprises the following steps:

[0057] (1) The clay is soaked in a solution of metal salt A and intercalated to obtain the first modified clay.

[0058] (2) The first modified clay is soaked in a solution containing Formula 1 and stirred evenly to obtain modified clay.

[0059] The solution of metal salt A is selected from one or more of lithium chloride, lithium acetate, lithium hydroxide, lithium bromide, lithium iodide, sodium chloride, sodium acetate, sodium hydroxide, sodium bromide, sodium iodide, potassium chloride, potassium acetate, potassium hydroxide, potassium bromide, and potassium iodide. The concentration of the selected metal salt is 0.1–4 mol / L.

[0060] The stirring time in step (1) is 1 to 72 hours, and the heating temperature is 15 to 180°C, preferably 35 to 100°C.

[0061] The optional method for preparing clay / polyether artificial composite solid electrolyte of the present invention includes the following steps:

[0062] Step 1: Mix the polyether monomer, crosslinking agent, initiator, electrolyte salt, and modified clay together to form a composite solid electrolyte precursor solution;

[0063] Step 2: The precursor liquid is used to form a liquid film on the electrode surface by means of hot shearing, casting, filtration, spin coating, spraying, etc., and then the artificial composite solid electrolyte interface protective layer with a thickness of 10nm-20μm is obtained by in-situ polymerization on the electrode surface.

[0064] The polyether monomer is selected from any one or more of the following: 1,3-dioxolane (DOL), 1,3,5-trioxane, 1,3,5-trioxane, 1,3-dioxane, 1,4-dioxane, 1,2-epoxycyclopentene, 3,4-epoxy-1-butene, propylene oxide, 2-trifluoromethyl ethylene oxide, glycidyl 2,2,3,3-tetrafluoropropyl ether, tetrahydrofuran, methyltetrahydrofuran, tetrahydropyran, fluoroethylene carbonate, vinylene carbonate and its derivatives.

[0065] The polymerization initiator is selected from at least one of lithium hexafluorophosphate, aluminum trifluoromethanesulfonate, stannous octoate, azobisisobutyronitrile, lithium difluorooxalate borate, lithium tetrafluoroborate, lithium hexafluoroarsenate, sodium difluorooxalate borate, sodium tetrafluoroborate, sodium hexafluorophosphate, sodium hexafluoroarsenate, potassium fluoroborate, potassium hexafluorophosphate, boron trifluoride, and phosphorus pentafluoride.

[0066] The polymerization initiator is selected from at least one of lithium hexafluorophosphate, aluminum trifluoromethanesulfonate, and lithium difluorooxalate borate. The initiator content is 0.1–15 wt%.

[0067] The electrolyte salt is selected from at least one of lithium bis(fluorosulfonyl)imide, lithium hexafluorophosphate, lithium perchlorate, lithium tetrafluoroborate, lithium bis(fluorosulfonyl)imide, lithium bis(oxalate)borate, lithium bis(fluorooxalate)borate, lithium difluorodioxalate phosphate, lithium difluorophosphate, lithium hexafluoroarsenate, sodium bis(fluorosulfonyl)imide, sodium hexafluorophosphate, sodium perchlorate, sodium tetrafluoroborate, sodium bis(fluorosulfonyl)imide, sodium bis(oxalate)borate, sodium difluorooxalateborate, sodium difluorodioxalate phosphate, sodium difluorophosphate, sodium hexafluoroarsenate, potassium bis(fluorosulfonyl)imide, potassium fluoroborate, potassium hexafluorophosphate, and potassium perchlorate. The concentration of the selected electrolyte salt is 0.1–4 M.

[0068] The modified clay content is 0.01–50 wt%.

[0069] The crosslinking agent comprises at least one selected from pentaerythritol glycidyl ether, trimethylolpropane triglycidyl ether, polyethylene glycol diglycidyl ether, glyceryl diglycidyl ether, trimethylolpropane allyl ether, tert-butyl glycidyl ether, ethyl glycidyl ether, polypropylene glycol diglycidyl ether, isopropyl glycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, and ethylene glycol diglycidyl ether. The crosslinking agent is 0.01–20 wt% of the weight of the ether monomer, preferably 0.5–5 wt%, and more preferably 0.5–1.5 wt%.

[0070] The precursor solution is polymerized in situ on the electrode surface at temperatures ranging from 25 to 80°C for 1 to 72 hours.

[0071] Furthermore, the solution described in this invention is applicable not only to lithium metal anodes, but also to any anode made of sodium or potassium metal.

[0072] Example 1

[0073] A clay / polyether artificial composite solid electrolyte, wherein the monomer for in-situ polymerization is 1,3-dioxolane (DOL) with a basic cyclic ether structure, the lithium salt is lithium bis(fluorosulfonyl)imide (LiTFSI), the in-situ polymerization initiator is lithium difluorooxalate borate (LiDFOB), and the nano-clay mineral is vermiculite.

[0074] Step (A): The method for preparing modified vermiculite nanoclay is as follows:

[0075] (A-1) Vermiculite was heated and stirred in a 2 mol / L intercalation modification solution (LiCl aqueous solution in this case) (solid-liquid ratio of 0.5-1 g / mL) for 24 h at a heating temperature of 80 °C to obtain the first modified material;

[0076] (A-2) Then the first modified material described above is added to 5 wt% of Formula 1 (Formula 1A in this case). Modified clay was obtained by stirring in an aqueous solution (0.4 times the weight of the clay) at 70°C for 1.0 h.

[0077] Step (B): Prepare the composite solid electrolyte in an argon glove box (oxygen content less than 0.05 ppm, moisture content less than 0.01 ppm). The preparation method is as follows:

[0078] 1) First, dissolve the main lithium salt lithium bisfluorosulfonylimide (LiTFSI) in the in-situ polymerization monomer DOL to form a basic electrolyte; the lithium salt concentration in the basic electrolyte is 1.5 mol / L;

[0079] 2) Based on the mass of the in-situ polymerized monomer, 5 wt% of the modified clay and 1 wt% of the crosslinking agent polyethylene glycol diglycidyl ether were dispersed in the base electrolyte to form a mixture.

[0080] 3) Based on the volume of the in-situ polymerization monomer, add 0.5 mol / L of the in-situ polymerization initiator lithium difluorooxalate borate (LiDFOB) and disperse it in the mixture to obtain the in-situ polymerization precursor solution.

[0081] 4) The precursor solution is sprayed onto the lithium metal surface to form a liquid film, and then polymerized at room temperature for 1 to 5 days, that is, in-situ polymerization on the lithium metal anode surface to obtain a composite artificial solid electrolyte interface protective layer (modified lithium metal anode).

[0082] 5) Impedance test:

[0083] Two modified lithium metal plates were composited as electrodes in a glove box, followed by the injection of an electrolyte precursor solution, encapsulation, and in-situ curing (3-4 days at room temperature) to form a CR2025 coin cell. The interfacial impedance of the cell was then measured at 25°C.

[0084] The electrolyte precursor solution is the in-situ polymerization precursor solution lacking modified clay in step B-3).

[0085] The interfacial impedance of the lithium metal symmetric battery is 55.3Ω.

[0086] Example 2

[0087] Compared with Example 1, the only difference is that clay minerals are replaced with montmorillonite, while all other operations and parameters are the same as in Example 1.

[0088] The assembled lithium metal symmetric battery has an interfacial impedance of 59.4Ω.

[0089] Example 3

[0090] Compared to Example 1, the only difference is the method of intercalation in step (A-1). The experimental groups are as follows:

[0091] Group A: Na-Li double intercalation scheme, the steps of which are as follows: vermiculite is first heated and stirred in 2 mol / L NaCl for 12 h at a heating temperature of 80 °C, and then heated and stirred in 2 mol / L LiCl for 12 h at a heating temperature of 80 °C to obtain the first modified material; other operations and parameters are the same as in Example 1.

[0092] Group B: Na-Li one-pot intercalation scheme, the steps of which are as follows: vermiculite is heated and stirred for 24 hours in a solution of NaCl and lithium chloride with a solute concentration of 2 mol / L (the molar ratio of sodium chloride and lithium chloride in the solute is the same) at a heating temperature of 80°C to obtain the first modified material; other operations and parameters are the same as in Example 1.

[0093] The test results are as follows:

[0094] Group A: The interface impedance of the assembled lithium metal symmetric battery is 52.6Ω.

[0095] Group B: The interface impedance of the assembled lithium metal symmetric battery is 56.8Ω.

[0096] Example 4

[0097] Compared with Example 1, the only difference is that Equation 1 in step A-2 is changed, and the experimental groups are as follows:

[0098] Group A: Equation 1 is Equation 1d, and its structure is as follows:

[0099] Group B: Equation 1 consists of Equations 1a and 1d with a weight ratio of 1:1;

[0100] The weight and other operations and parameters of Formula 1 are the same as those of Example 1.

[0101] The test results are as follows:

[0102] Group A: The interface impedance of the assembled lithium metal symmetric battery is 55.7Ω;

[0103] Group B: The interface impedance of the assembled lithium metal symmetric battery is 53.9Ω.

[0104] Example 5

[0105] A clay / polyether artificial composite solid electrolyte, wherein the monomer for in-situ polymerization is 1,3,5-trioxane (DOX) with a basic cyclic ether structure, the lithium salt is lithium bis(fluorosulfonyl)imide (LiTFSI), the in-situ polymerization initiator is lithium difluorooxalate borate (LiDFOB), and the nano-clay mineral is vermiculite.

[0106] Step (A): The method for preparing modified vermiculite nanoclay is as follows:

[0107] (A-1) Vermiculite was heated and stirred in 2.5 mol / L LiCl for 20 h at a heating temperature of 75 °C to obtain the first modified material;

[0108] (A-2) Then the above-mentioned first modified material is mixed with 10 wt% of Formula 1A ( Modified clay is obtained by stirring the solution (formula 1 is 0.3 times the weight of the clay) in a water bath at 70°C for 1.5 hours.

[0109] Step (B): Prepare the composite solid electrolyte in an argon glove box (oxygen content less than 0.05 ppm, moisture content less than 0.01 ppm). The preparation method is as follows:

[0110] 1) First, the main lithium salt lithium bisfluorosulfonylimide (LiTFSI) is dissolved in the in-situ polymerization monomer DOL to form the basic electrolyte; the lithium salt concentration in the basic electrolyte is 1.25 mol / L;

[0111] 2) Based on the volume and mass of the in-situ polymerized monomers, 10 wt.% of the monomer weight of modified clay and 1 wt% of the monomer weight of crosslinking agent polyethylene glycol diglycidyl ether were dispersed in the basic electrolyte to form a mixture.

[0112] 3) Based on the volume of the in-situ polymerization monomer, add 0.75 mol / L of the in-situ polymerization initiator lithium difluorooxalate borate (LiDFOB) and disperse it in the mixture to obtain the in-situ polymerization precursor solution.

[0113] 4) The precursor solution is sprayed onto the electrode surface to form a liquid film, and then polymerized at room temperature for 1 to 5 days, that is, the composite artificial solid electrolyte interface protective layer is obtained by in-situ polymerization on the electrode surface.

[0114] The assembled lithium metal symmetric battery has an interfacial impedance of 60.2Ω.

[0115] Example 6

[0116] Compared with Example 1, the only difference is that in step B-5), the injected electrolyte precursor solution is the in-situ polymerization precursor solution of step 3), and the other operations and parameters are the same as in Example 1.

[0117] The interfacial impedance of the lithium metal symmetric battery is 51.4Ω.

[0118] Comparative Example 1

[0119] Compared with Example 1, the only difference is that step A is missing, and in step B, the modified clay is replaced with vermiculite before modification. Other operations and parameters are the same as in Example 1.

[0120] The assembled lithium metal symmetric battery has an interfacial impedance of 102.7Ω.

[0121] Comparative Example 2

[0122] Compared with Example 1, the only difference is that the clay is only grafted with Formula 1 and not intercalated. That is, in step A-1 of step A, the intercalation modification solution is changed to water and lithium chloride solute is missing. All other operations and parameters are the same as in Example 1.

[0123] The assembled lithium metal symmetric battery has an interfacial impedance of 93.9Ω.

[0124] Comparative Example 3

[0125] Compared with Example 1, the only difference is that only intercalation modification is performed on the clay, and the grafting modification of Formula 1 is missing. That is, in step A-2 of step A, Formula 1A is missing. All other operations and parameters are the same as in Example 1.

[0126] The assembled lithium metal symmetric battery has an interfacial impedance of 85.4Ω.

[0127] Comparative Example 4

[0128] Compared with Example 1, the only difference is that in step A, the processing order of step A is changed. For example, vermiculite is first processed in step A-2, and then the obtained product is used as raw material to process in step A-1, and the obtained modified material is used as modified clay to process in step B. All other operations and parameters are the same as in Example 1.

[0129] The assembled lithium metal symmetric battery has an interface impedance of 80.6Ω.

[0130] Comparative Example 5

[0131] Compared with Example 1, the only difference is that in step B-5, the original lithium sheet is used as the lithium metal negative electrode to assemble the battery and conduct tests. All other operations and parameters are the same as in Example 1.

[0132] The assembled lithium metal symmetric battery has an interfacial impedance of 150.2Ω.

Claims

1. A method for preparing a clay / polyether artificial composite solid electrolyte, characterized in that, It is obtained by polymerization of a precursor solution containing polyether monomers, crosslinking agents, initiators, electrolyte salts, and modified clay; Clay is placed in a modified aqueous solution containing metal M ions for intercalation treatment to obtain an intercalated modified material. The intercalated modified material is then placed in a solution of Formula 1 for graft modification to obtain the modified clay. The clay mentioned includes at least one of the following: kaolinite, hydrous kaolinite, illite, montmorillonite, hydromica, glauconite, chlorite, vermiculite, sepiolite, halloysite, bentonite, and palygorskite; The metal M includes at least one of Li, Na, and K; The compounds of Formula 1 include compounds with the following structures; Formula 1a Formula 1b Formula 1c Formula 1d R1 is a C1-C6 alkyl group; R3 is a C1-C6 saturated carbon chain; R4 is a C1-C6 alkyl group; The polyether monomers include at least one of the following: 1,3-dioxolane (DOL), 1,3,5-trioxane, 1,3,5-trioxane, 1,3-dioxane, 1,4-dioxane, 1,2-epoxycyclopentene, 3,4-epoxy-1-butene, propylene oxide, 2-trifluoromethyl ethylene oxide, glycidyl 2,2,3,3-tetrafluoropropyl ether, tetrahydrofuran, methyltetrahydrofuran, tetrahydropyran, fluoroethylene carbonate, and vinylene carbonate. The initiator includes at least one of lithium hexafluorophosphate, aluminum trifluoromethanesulfonate, stannous octoate, azobisisobutyronitrile, lithium difluorooxalate borate, lithium tetrafluoroborate, lithium hexafluoroarsenate, sodium difluorooxalate borate, sodium tetrafluoroborate, sodium hexafluorophosphate, sodium hexafluoroarsenate, potassium fluoroborate, potassium hexafluorophosphate, boron trifluoride, and phosphorus pentafluoride. The concentration of the initiator in the polymer monomer is 0.1~1 M.

2. The method for preparing the clay / polyether artificial composite solid electrolyte as described in claim 1, characterized in that, Metal M ions are provided from at least one of the following raw materials: lithium chloride, lithium acetate, lithium hydroxide, lithium bromide, lithium iodide, sodium chloride, sodium acetate, sodium hydroxide, sodium bromide, sodium iodide, potassium chloride, potassium acetate, potassium hydroxide, potassium bromide, and potassium iodide.

3. The method for preparing the clay / polyether artificial composite solid electrolyte as described in claim 2, characterized in that, In the modified aqueous solution, the concentration of metal M ions is 0.1~4 mol / L; The solid-liquid ratio during the intercalation modification stage is 0.1~2 g / ml; The temperature for the intercalation modification stage is 15~180 ℃; The intercalation modification time is 1~72 h.

4. The method for preparing the clay / polyether artificial composite solid electrolyte as described in claim 1, characterized in that, The clay was first intercalated with sodium ions, and then the product of the first intercalation was intercalated with lithium ions to obtain the intercalated modified material.

5. The method for preparing the clay / polyether artificial composite solid electrolyte as described in claim 1, characterized in that, The compound of formula 1 is of formula 1b and / or formula 1d.

6. The method for preparing the clay / polyether artificial composite solid electrolyte as described in claim 5, characterized in that, The compound of Formula 1 is a complex of Formula 1b and Formula 1d.

7. The method for preparing the clay / polyether artificial composite solid electrolyte as described in claim 1, characterized in that, The weight ratio of Formula 1 and the clay is 0.1 to 1:

1.

8. The method for preparing the clay / polyether artificial composite solid electrolyte as described in claim 1, characterized in that, The weight ratio of modified clay to polyether monomer is 0.1% to 50%.

9. The method for preparing the clay / polyether artificial composite solid electrolyte as described in claim 1, characterized in that, The crosslinking agent includes at least one of pentaerythritol glycidyl ether, trimethylolpropane triglycidyl ether, polyethylene glycol diglycidyl ether, glycerol diglycidyl ether, trimethylolpropane allyl ether, tert-butyl glycidyl ether, ethyl glycidyl ether, polypropylene glycol diglycidyl ether, isopropyl glycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, and ethylene glycol diglycidyl ether.

10. The method for preparing the clay / polyether artificial composite solid electrolyte as described in claim 1, characterized in that, The crosslinking agent is 0.2-15% of the weight of the polyether monomer.

11. The method for preparing the clay / polyether artificial composite solid electrolyte as described in claim 10, characterized in that, The crosslinking agent is 0.5 to 1.5% of the weight of the polyether monomer.

12. The method for preparing the clay / polyether artificial composite solid electrolyte as described in claim 1, characterized in that, The electrolyte salt is at least one of conductive lithium salt, conductive sodium salt, and conductive potassium salt.

13. The method for preparing the clay / polyether artificial composite solid electrolyte as described in claim 1, characterized in that, The concentration of the electrolyte salt in the precursor solution is 0.1~4 M.

14. A clay / polyether artificial composite solid electrolyte prepared by the preparation method according to any one of claims 1 to 13.

15. A positive electrode and / or negative electrode composited with a solid electrolyte, characterized in that, The solid electrolyte includes the clay / polyether artificial composite solid electrolyte prepared by the preparation method according to any one of claims 1 to 13.

16. A solid-state battery, comprising a positive electrode, a solid electrolyte, and a negative electrode sequentially combined, characterized in that, The solid electrolyte is the clay / polyether artificial composite solid electrolyte as described in claim 14.

17. The solid-state battery as claimed in claim 16, characterized in that, The solid-state battery includes the positive electrode and / or negative electrode with a solid electrolyte as described in claim 15.

18. A method for preparing a solid-state battery, characterized in that, The positive electrode, solid electrolyte, and negative electrode are combined to obtain the solid electrolyte, which is the clay / polyether artificial composite solid electrolyte as described in claim 14.

19. The method for preparing a solid-state battery as described in claim 18, characterized in that, At least one of the positive and / or negative electrodes is the positive and / or negative electrode with a solid electrolyte as described in claim 15.

20. The method for preparing a solid-state battery as described in claim 19, characterized in that, The solid-state battery preparation method is an in-situ preparation method, the steps of which are: filling a battery cell with a positive electrode and a negative electrode into a battery case, followed by liquid injection and encapsulation and in-situ polymerization, characterized in that the solution injected in the liquid injection stage is the precursor solution described in any one of claims 1 to 13.

21. The method for preparing a solid-state battery as described in claim 20, characterized in that, The positive and / or negative electrodes are the positive and / or negative electrodes with a solid electrolyte as described in claim 15.

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