Solid-state electrolyte precursor and applications thereof, sodium metal battery and preparation method thereof

Abstract

The application relates to the field of batteries, and discloses a solid-state electrolyte precursor and application thereof, a sodium metal battery and a preparation method thereof. The solid-state electrolyte precursor comprises an ester solvent, an acrylic ester monomer, a crosslinking agent, a silane initiator, a Lewis acid catalyst and a sodium salt; the mass ratio of the acrylic ester monomer to the silane initiator is 1:0.00001-0.05. The acrylic ester polymer obtained by using the silane initiator to initiate monomer polymerization has a narrower molecular weight distribution, and the silane initiator does not deteriorate the battery; and the sodium metal battery prepared by using the solid-state electrolyte precursor has high cycle life and safety.

Description

Technical Field

[0001] This invention relates to the field of batteries, specifically to a solid electrolyte precursor and its application, and a sodium metal battery and its preparation method. Background Technology

[0002] The low energy density and safety issues of liquid sodium-ion batteries have made them unsuitable for the growing demand for large-scale energy storage systems. As a low-cost alternative, solid-state sodium metal batteries (SSMBs) have shown significant competitive advantages and broad application prospects due to their high energy density and ideal safety. However, solid-state electrolytes (SSEs) typically have low ionic conductivity, and poor interfacial compatibility and stability between SSEs and electrodes lead to continuous deterioration in electrochemical performance.

[0003] Currently, the reported methods mainly use dimethyl azobisisobutyrate (AIBME) and azobisisobutyronitrile (AIBN) to initiate monomer polymerization. However, these methods have drawbacks, such as requiring high temperatures for initiation, the initiator easily causing battery cycle degradation, and insufficient uniformity of polymer molecular weight, which affects the performance of the electrolyte.

[0004] Therefore, there is an urgent need for a sodium metal battery with a multifunctional gel polymer electrolyte capable of in-situ self-polymerization, which is of great significance for promoting the innovation and large-scale application of energy storage technology. Summary of the Invention

[0005] The purpose of this invention is to overcome the problems of existing technologies, such as the need for high-temperature initiation of solid-state electrolytes, the tendency of initiators to cause battery cycle degradation, and the low uniformity of polymer molecular weight. This invention provides a solid-state electrolyte precursor and its application, as well as a sodium metal battery and its preparation method. The solid-state electrolyte precursor comprises an ester solvent, an acrylate monomer, a silane initiator, a Lewis acid catalyst, and a sodium salt. The acrylate polymer obtained by using the silane initiator to initiate monomer polymerization has a narrower molecular weight distribution, and the silane initiator does not degrade the battery. The sodium metal battery prepared from this solid-state electrolyte precursor exhibits high cycle life and safety.

[0006] To achieve the above objectives, the first aspect of the present invention provides a solid electrolyte precursor comprising an ester solvent, an acrylate monomer, a crosslinking agent, a silane initiator, a Lewis acid catalyst, and a sodium salt;

[0007] The mass ratio of the acrylate monomer to the silane initiator is 1:0.00001-0.05.

[0008] Preferably, the silane initiator is selected from at least one of triphenylsilane, triisobutylsilane, dimethylphenylsilane, dimethylethylsilane, and dimethylchlorosilane.

[0009] Preferably, the Lewis acid catalyst is tris(pentafluorophenyl)borane.

[0010] Preferably, the mass ratio of the acrylate monomer to the Lewis acid catalyst is 1:0.00001-0.05.

[0011] Preferably, the mass ratio of the polymer monomer to the crosslinking agent is 1:0.01-0.5.

[0012] A second aspect of the present invention provides an application of the solid electrolyte precursor described in the first aspect in a sodium metal battery.

[0013] A third aspect of the present invention provides a method for preparing a sodium metal battery, comprising the following steps: placing the solid electrolyte precursor described in the first aspect between the positive and negative electrodes of the sodium metal battery, and initiating polymerization of acrylate monomers in the solid electrolyte precursor to obtain a solid electrolyte formed between the positive and negative electrodes.

[0014] A fourth aspect of the present invention provides a sodium metal battery, comprising a positive electrode, a negative electrode, a separator, and a solid electrolyte; wherein the solid electrolyte is obtained by polymerization of the solid electrolyte precursor described in the first aspect, and the solid electrolyte precursor undergoes in-situ polymerization between the positive electrode and the negative electrode.

[0015] Through the above technical solution, the present invention has the following beneficial effects:

[0016] (1) The solid electrolyte precursor provided by the present invention uses a silane initiator and a Lewis acid as a catalyst. The silicon in the silane initiator forms silicon-rich inorganic species in the solid electrolyte interface, which combine with the inorganic substances in the Lewis acid to form a stable interface film. Through the synergistic effect of the silane initiator and the Lewis acid, the defect of traditional initiators that degrades the performance of solid batteries is avoided.

[0017] (2) The solid electrolyte precursor provided by the present invention has a narrower molecular weight distribution of acrylate polymers after monomer polymerization initiated by silane initiator, which is beneficial to improving the electronic conductivity of solid electrolyte. At the same time, silane initiator reduces the polymerization temperature of acrylate monomers and shortens the polymerization time. Sodium metal batteries prepared using the solid electrolyte precursor of the present invention have high cycle life and safety.

[0018] (3) In the preferred case, the solid electrolyte precursor provided by the present invention uses tris(pentafluorophenyl)borane as a Lewis acid catalyst. The fluorine and boron segments in tris(pentafluorophenyl)borane optimize the composition of the solid electrolyte interface. The silicon in the silane initiator combines with inorganic species such as boron and fluorine in the Lewis acid catalyst to form a more stable interface film. Furthermore, the solid electrolyte interface film contains abundant inorganic fluorides, borides and silicon-based inorganic species, which effectively improves the flux of anions and cations, inhibits the growth of sodium dendrites in sodium metal batteries, and further improves the interface stability and long cycle performance. Detailed Implementation

[0019] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0020] The first aspect of the present invention provides a solid electrolyte precursor comprising an ester solvent, an acrylate monomer, a crosslinking agent, a silane initiator, a Lewis acid catalyst, and a sodium salt;

[0021] The mass ratio of the acrylate monomer to the silane initiator is 1:0.00001-0.05.

[0022] In this invention, the solid electrolyte precursor uses a silane initiator and a Lewis acid as a catalyst. The silicon in the silane initiator forms silicon-rich inorganic species at the solid electrolyte interface, which combine with the inorganic substances in the Lewis acid to form a stable interfacial film. Through the synergistic effect of the silane initiator and the Lewis acid, the defect of traditional initiators that degrades the performance of solid-state batteries is avoided. Furthermore, the acrylate polymer obtained after monomer polymerization initiated by the silane initiator has a narrower molecular weight distribution. The sodium metal battery prepared using the solid electrolyte precursor of this invention is beneficial for improving the high conductivity and long cycle life of the solid electrolyte, and also has excellent safety performance.

[0023] In this invention, the molecular weight distribution index (Mw / Mn) of the polymerized acrylate polymer is determined by gel permeation chromatography. The specific test method is as follows: using an HLC-8320 gel permeation chromatograph from TOSOH Corporation of Japan, dimethylformamide (DMF) is used as the mobile phase, polystyrene is used for calibration, the polymer sample is prepared into a DMF solution with a concentration of 1 mg / mL, the flow rate is 1 mL / min, and the test temperature is 40.0℃.

[0024] In some embodiments of the present invention, preferably, the mass ratio of the acrylate monomer to the silane initiator is 1:0.00001-0.05, for example, it can be 1:0.00001, 1:0.001, 1:0.01, 1:0.015, 1:0.02, 1:0.025, 1:0.03, 1:0.035, 1:0.04, 1:0.045, 1:0.05, and any value within the range of any two of the above values, preferably 1:0.01-0.03.

[0025] In this invention, controlling the mass ratio of acrylate monomers to silane initiators within the aforementioned range is beneficial for effectively initiating the subsequent polymerization reaction of acrylate monomers, controlling the molecular weight distribution of the resulting acrylate polymers to make them more uniform, thereby improving the conductivity of the solid electrolyte and enhancing the lifespan and safety of sodium metal batteries. The preferred range has even better effects.

[0026] In this invention, the type of acrylate monomer is not particularly limited, and various acrylate monomers conventionally used in the art can be used in this invention. Preferably, the acrylate monomer is selected from at least one of methyl methacrylate, butyl acrylate, methyl acrylate, ethyl acrylate, and isooctyl acrylate, and more preferably from methyl methacrylate and / or methyl acrylate.

[0027] In this invention, the range of types of silane initiators is relatively wide, as long as they include alkyl groups and silicon and are capable of initiating the polymerization of acrylate monomers. Preferably, the silane initiator is selected from at least one of triphenylsilane, triisobutylsilane, dimethylphenylsilane, dimethylethylsilane, and dimethylchlorosilane, and more preferably from triphenylsilane and / or dimethylphenylsilane.

[0028] In this invention, the silane initiator is beneficial for significantly shortening the polymerization temperature and time of acrylate monomers, and works synergistically with Lewis acid catalysts to form a more stable interfacial film, inhibiting sodium dendrite growth and improving the conductivity, cycle life and safety of sodium metal batteries.

[0029] In some embodiments of the present invention, preferably, the mass ratio of the acrylate monomer to the Lewis acid catalyst is 1:0.00001-0.05, more preferably 1:0.01-0.03. For example, it can be 1:0.00001, 1:0.0001, 1:0.001, 1:0.01, 1:0.015, 1:0.02, 1:0.025, 1:0.03, 1:0.035, 1:0.04, 1:0.045, 1:0.05, or any value within the range of any two of the above values, preferably 1:0.01-0.03.

[0030] In this invention, controlling the mass ratio of acrylate monomers to Lewis acid catalysts within the aforementioned range is beneficial for effectively catalyzing the polymerization reaction of acrylate monomers, controlling the molecular weight distribution of the resulting acrylate polymers to make them more uniform and stable, thereby improving the conductivity of the solid electrolyte, and also facilitating the interaction with silicon in the silane initiator to enhance interfacial stability. The preferred range has even better effects.

[0031] In this invention, the selection range of the Lewis acid catalyst is relatively wide. Preferably, the Lewis acid catalyst is selected from Lewis acids with a boron atom at the center. More preferably, the Lewis acid catalyst is selected from at least one of tris(hexafluoroisopropyl) borate, triphenylboronic acid ester, and tris(pentafluorophenyl)borane. More preferably, the Lewis acid catalyst is tris(pentafluorophenyl)borane. In this invention, the fluorine and boron segments in the tris(pentafluorophenyl)borane synergistically interact with the silicon in the silane initiator to optimize the interfacial composition and form a more stable interfacial film, thereby improving the performance and safety of the battery and further promoting the in-situ polymerization of acrylate monomers at room temperature.

[0032] In this invention, the type of crosslinking agent has a wide range of selection, and can be various crosslinking agents containing acrylate groups conventionally used in the art. Preferably, the crosslinking agent includes at least one selected from polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, pentaerythritol tetraacrylate, pentaerythritol triacrylate, ethoxylated trimethylolpropane triacrylate, and polyether acrylate, and more preferably selected from at least one selected from polyethylene glycol diacrylate and polyethylene glycol dimethacrylate.

[0033] In this invention, the amount of crosslinking agent has a wide range of selection. Preferably, the mass ratio of the polymer monomer to the crosslinking agent is 1:0.01-0.5, for example, it can be 1:0.01, 1:0.03, 1:0.05, 1:0.1, 1:0.2, 1:0.3, 1:0.4, 1:0.5, and any value within the range of any two of the above values, preferably 1:0.03-0.1.

[0034] In this invention, the type of sodium salt is not particularly limited, and can be any sodium salt commonly used in the art that can provide sodium ions as an electrolyte. Preferably, the sodium salt is selected from at least one of sodium difluorooxalate phosphate, sodium difluorosulfonamide, sodium difluoromethanesulfonamide, sodium difluorophosphate, sodium hexafluorophosphate, sodium difluorooxalate borate, sodium difluorooxalate borate, sodium tetrafluoroborate, and sodium perchlorate, and more preferably from at least one of sodium hexafluorophosphate, sodium difluorosulfonamide, and sodium difluoromethanesulfonamide.

[0035] In this invention, the concentration of the sodium salt has a wide selection range. Preferably, the molar concentration of the sodium salt in the solid electrolyte precursor is 0.1-3 mol / L, and more preferably 0.5-1 mol / L. The concentration of sodium salt in the solid electrolyte precursor of this invention is beneficial for improving the ionic conductivity of the solid electrolyte, thereby enhancing the performance and lifespan of the sodium metal battery.

[0036] In this invention, the type of ester solvent is not particularly limited, as long as it can dissolve the acrylate monomer, crosslinking agent, silane initiator, Lewis acid catalyst, and sodium salt. Preferably, the ester solvent is selected from C2-C8 ester solvents, and more preferably at least one of ethylene carbonate, propylene carbonate, diethyl carbonate, dimethyl carbonate, and methyl ethyl carbonate.

[0037] In this invention, the amount of the ester solvent can be selected within a wide range. Preferably, the mass ratio of the acrylate monomer to the ester solvent is 1:2-20, more preferably 1:4-10. The amount of ester solvent used in this invention is beneficial for forming a uniform solid electrolyte precursor, ensuring the smooth progress of subsequent polymerization reactions, and improving the overall performance of the sodium metal battery.

[0038] In this invention, the preparation method of the solid electrolyte precursor is not particularly limited. For example, an ester solvent, an acrylate monomer, a crosslinking agent, a silane initiator, a Lewis acid catalyst, and a sodium salt can be mixed. Preferably, the acrylate monomer, Lewis acid catalyst, crosslinking agent, and silane initiator are mixed, and the resulting polymer precursor solution is mixed with a sodium salt solution to obtain the solid electrolyte precursor. In this invention, the mixing method is not particularly limited, but stirring is preferred. The mixing conditions are not particularly limited, as long as the ester solvent, acrylate monomer, crosslinking agent, silane initiator, Lewis acid catalyst, and sodium salt are mixed uniformly. Preferably, the mixing conditions each independently include: a temperature of 20-30°C and a time of 0.5-1 hour.

[0039] A second aspect of this invention provides the application of the solid electrolyte precursor described in the first aspect in a sodium metal battery. In this invention, the sodium metal battery prepared using the solid electrolyte precursor exhibits high cycle life and safety.

[0040] A third aspect of the present invention provides a method for preparing a sodium metal battery, comprising the following steps: placing the solid electrolyte precursor described in the first aspect between the positive and negative electrodes of the sodium metal battery, and initiating polymerization of acrylate monomers in the solid electrolyte precursor to obtain a solid electrolyte formed between the positive and negative electrodes.

[0041] In this invention, preferably, the method for preparing the sodium metal battery includes: assembling the positive electrode, separator, negative electrode of the sodium metal battery, and the solid electrolyte precursor described in the first aspect into a battery; allowing it to stand to initiate a polymerization reaction to obtain a solid electrolyte formed between the positive electrode and the negative electrode. In this invention, the stacking order of the positive electrode, separator, negative electrode of the sodium metal battery, and the solid electrolyte precursor described in the first aspect is not particularly limited. For example, the positive electrode, separator, solid electrolyte precursor, and negative electrode of the sodium metal battery can be placed sequentially; or the negative electrode, separator, solid electrolyte precursor, and positive electrode of the sodium metal battery can be placed sequentially; or the positive electrode, separator, and negative electrode of the sodium metal battery can be placed sequentially; or the negative electrode, separator, and positive electrode of the sodium metal battery can be placed sequentially, and the solid electrolyte precursor is added to the location of the separator.

[0042] In some embodiments of the present invention, preferably, the conditions for the in-situ polymerization include: a temperature of 10-40°C; and a time of 0.5-72 h, preferably 24-48 h. In the present invention, the solid electrolyte precursor enables the in-situ polymerization of acrylate monomers at room temperature, thereby improving the cycle life and safety of sodium metal batteries.

[0043] A fourth aspect of the present invention provides a sodium metal battery, comprising a positive electrode, a negative electrode, a separator, and a solid electrolyte; wherein the solid electrolyte is obtained by polymerization of the solid electrolyte precursor described in the first aspect, and the solid electrolyte precursor undergoes in-situ polymerization between the positive electrode and the negative electrode.

[0044] In this invention, the solid electrolyte precursor includes a silane initiator, a crosslinking agent, an acrylate monomer, and a Lewis acid catalyst. After the acrylate monomer undergoes a polymerization reaction, the solid electrolyte precursor forms a solid (gel state). This solid electrolyte precursor polymerizes inside the battery, and the resulting polymer network adsorbs the ester solvent and sodium salt, which remain in the acrylate polymer. This helps to solve potential risks such as electrolyte leakage and battery combustion, extends the cycle life of sodium metal batteries, and improves safety.

[0045] In this invention, the type of cathode material is not particularly limited, and various sodium metal battery cathode materials conventionally used in the art can be used in this invention. Preferably, the cathode is selected from layered transition metal oxides and / or polyanionic compounds, and more preferably layered oxygen P2 type cathode materials.

[0046] In this invention, the type of negative electrode material is not particularly limited, and various sodium metal battery negative electrode materials conventionally used in the art can be used in this invention. Preferably, the negative electrode is selected from at least one of sodium sheets, sodium foils, and sodium / fiber composite materials.

[0047] In this invention, the type of separator is not particularly limited, and various separators conventionally used in the art for sodium metal batteries can be used in this invention. Preferably, the separator is selected from at least one of PE separators, PP separators, and glass fibers.

[0048] In this invention, the type of sodium metal battery can be selected from a wide range. Preferably, the sodium metal battery is selected from at least one of pouch cells, button cells, and cylindrical cells, and more preferably, button cells.

[0049] The present invention will be described in detail below through embodiments. Unless otherwise specified, all raw materials used in the following embodiments are commercially available products.

[0050] In this invention, the molecular weight distribution index (Mw / Mn) of acrylate polymers is determined by gel permeation chromatography.

[0051] Example 1

[0052] (1) Preparation of positive electrode sheet: P2 type layered oxide sodium electrode positive electrode material (chemical formula Na) is prepared. 0.67 Mn 0.67 Ni 0.33O2), conductive carbon black, and polyvinylidene fluoride (weight-average molecular weight 1.1 million g / mol) binder are added to a mixing tank in a mass ratio of 90:5:5. Then, an appropriate amount of N-methylpyrrolidone is added and stirred to obtain a positive electrode slurry. 1 g of the positive electrode slurry is uniformly coated onto an aluminum foil with a width of 200 mm. After drying, rolling, and slitting, the positive electrode material is obtained. The loading of the positive electrode material is 20 mg / cm³. 2 ;

[0053] (2) Preparation of solid electrolyte precursor: In a glove box under argon atmosphere (H2O<0.5ppm, O2<0.5ppm), methyl methacrylate: polyethylene glycol dimethacrylate: tris(pentafluorophenyl)borane: triphenylsilane were mixed and stirred for 0.5h at a mass ratio of 1:0.05:0.02:0.02 to obtain a polymer precursor solution. Then, the polymer precursor solution was mixed with 1mol / L sodium hexafluorophosphate carbonate electrolyte (propylene carbonate: methyl ethyl carbonate mass ratio of 1:2), and the mass ratio of precursor solution to sodium hexafluorophosphate carbonate electrolyte was 1:6. The mixture was stirred for 1h to obtain a solid electrolyte precursor.

[0054] (3) Assemble a sodium metal battery: Using the positive electrode sheet described in step (1) as the positive electrode, a sodium sheet (14 mm in diameter) as the negative electrode, a PP separator (Celgard 2500) as the battery separator, and the solid electrolyte precursor obtained in step (2) as the solid electrolyte precursor, assemble a sodium positive electrode / sodium coin cell; after assembly, let the battery stand at room temperature for 48 h to allow the initiator to take effect and form a sodium metal battery with an in-situ polymerized solid electrolyte.

[0055] Example 2

[0056] The method described in Example 1 differs in that, in step (2), methyl methacrylate, polyethylene glycol dimethacrylate, tris(pentafluorophenyl)borane, and triphenylsilane are mixed in a mass ratio of 1:0.1:0.01:0.01 to form a sodium metal battery with an in-situ polymerized solid electrolyte.

[0057] Example 3

[0058] The method described in Example 1 differs in that, in step (2), methyl methacrylate, polyethylene glycol dimethacrylate, tris(pentafluorophenyl)borane, and triphenylsilane are mixed in a mass ratio of 1:0.1:0.03:0.03 to form a sodium metal battery with an in-situ polymerized solid electrolyte.

[0059] Example 4

[0060] The method described in Example 1 is different except that in step (2), tri(pentafluorophenyl)borane is replaced by an equal amount of triphenylboronic acid ester to form a sodium metal battery with an in-situ polymerized solid electrolyte.

[0061] Example 5

[0062] The method described in Example 1 is different except that in step (2), methyl methacrylate is replaced with an equal amount of isooctyl acrylate to form a sodium metal battery with an in-situ polymerized solid electrolyte.

[0063] Example 6

[0064] The method described in Example 1 differs in that, in step (2), methyl methacrylate, polyethylene glycol dimethacrylate, tris(pentafluorophenyl)borane, and triphenylsilane are mixed in a mass ratio of 1:0.05:0.02:0.05 to form a sodium metal battery with an in-situ polymerized solid electrolyte.

[0065] Example 7

[0066] The method described in Example 1 is different except that in step (2), sodium hexafluorophosphate is replaced with sodium bis(trifluoromethanesulfonyl)imide in equal amounts to form a sodium metal battery with an in-situ polymerized solid electrolyte.

[0067] Example 8

[0068] The method described in Example 1 is different except that in step (2), triphenylsilane is replaced with an equal amount of dimethylethylsilane to form a sodium metal battery with an in-situ polymerized solid electrolyte.

[0069] Example 9

[0070] The method described in Example 1 differs in that, in step (3), after assembly, the battery is left to stand at room temperature for 24 hours to form a sodium metal battery with an in-situ polymerized solid electrolyte.

[0071] Comparative Example 1

[0072] The method described in Example 1 is different except that step (2) is omitted;

[0073] In step (3), a liquid electrolyte is used instead of a solid electrolyte. The liquid electrolyte is 1 mol / L NaPF6, and the solvent is EC:DMC = 1:2 (v:v); thus, a sodium metal battery is obtained.

[0074] Comparative Example 2

[0075] The method described in Example 1 is different except that triphenylsilane is not added in step (2); a sodium metal battery is obtained.

[0076] Comparative Example 3

[0077] The method described in Example 1 is different except that methyl methacrylate, polyethylene glycol dimethacrylate, tris(pentafluorophenyl)borane, and triphenylsilane are used in a mass ratio of 1:0.05:0.02:0.2 to obtain a sodium metal battery.

[0078] Test case

[0079] The sodium metal solid-state batteries prepared in the examples and comparative examples were subjected to cycle performance tests. The test method included: charging and discharging the batteries at a rate of 0.5C / 0.5C on a Land charge-discharge tester at room temperature (25±2℃), with a voltage range of 2.5-4V. After 100 cycles, the capacity retention rate was recorded. The test results are shown in Table 1.

[0080] The solid electrolyte precursor solutions prepared in the examples and comparative examples were assembled into stainless steel|solid electrolyte|stainless steel blocking batteries for ionic conductivity testing. The testing method included: injecting the solid electrolyte precursor solution between stainless steel components, followed by polymerization to obtain the battery; measuring the AC impedance at 25°C using an electrochemical workstation, and calculating the conductivity using the formula σ=d / (R·S). The results are shown in Table 1.

[0081] Table 1

[0082]

[0083] As can be seen from the results in Table 1, the acrylate polymers obtained by monomer polymerization initiated by the silane initiator provided by the present invention have a narrower molecular weight distribution and higher conductivity of the solid electrolyte. The sodium metal battery prepared using the solid electrolyte precursor described in the present invention has a high capacity retention rate after 100 cycles at 0.5C, and exhibits high cycle life and safety.

[0084] Based on Example 1, Comparative Examples 1-3 and Table 1, it can be seen that, compared with Example 1, Comparative Example 1 uses the solid electrolyte precursor provided by the present invention and uses a liquid electrolyte, which leads to a significant decrease in the service life of the sodium metal battery; Comparative Example 2 does not add an initiator; and the amount of silane initiator added in Comparative Example 3 is not within the range provided by the present invention, which leads to capacity decay of the battery.

[0085] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A solid electrolyte precursor, characterized in that, Including ester solvents, acrylate monomers, crosslinking agents, silane initiators, Lewis acid catalysts, and sodium salts; The mass ratio of the acrylate monomer to the silane initiator is 1:0.00001-0.

05.

2. The solid electrolyte precursor according to claim 1, wherein, The mass ratio of the acrylate monomer to the silane initiator is 1:0.01-0.03; Preferably, the acrylate monomer is selected from at least one of methyl methacrylate, butyl acrylate, methyl acrylate, ethyl acrylate and isooctyl acrylate, and more preferably from methyl methacrylate and / or methyl acrylate.

3. The solid electrolyte precursor according to claim 1 or 2, wherein, The silane initiator is selected from at least one of triphenylsilane, triisobutylsilane, dimethylphenylsilane, dimethylethylsilane, and dimethylchlorosilane, preferably selected from triphenylsilane and / or dimethylphenylsilane.

4. The solid electrolyte precursor according to any one of claims 1-3, wherein, The Lewis acid catalyst is selected from Lewis acids with a boron atom at the center, preferably from at least one of tris(hexafluoroisopropyl) borate, triphenylboronic acid ester and tris(pentafluorophenyl)borane, more preferably tris(pentafluorophenyl)borane; Preferably, the mass ratio of the acrylate monomer to the Lewis acid catalyst is 1:0.00001-0.05, and more preferably 1:0.01-0.

03.

5. The solid electrolyte precursor according to any one of claims 1-4, wherein, The crosslinking agent includes at least one of polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, pentaerythritol tetraacrylate, pentaerythritol triacrylate, ethoxylated trimethylolpropane triacrylate, and polyether acrylate, preferably selected from polyethylene glycol diacrylate and / or polyethylene glycol dimethacrylate. Preferably, the mass ratio of the polymer monomer to the crosslinking agent is 1:0.01-0.5, and more preferably 1:0.03-0.

1.

6. The solid electrolyte precursor according to any one of claims 1-5, wherein, The sodium salt is selected from at least one of sodium difluorooxalate phosphate, sodium difluorosulfonamide, sodium difluoromethanesulfonamide, sodium difluorophosphate, sodium hexafluorophosphate, sodium difluorooxalate borate, sodium difluorooxalate borate, sodium tetrafluoroborate, and sodium perchlorate, preferably selected from at least one of sodium hexafluorophosphate, sodium difluorosulfonamide, and sodium difluoromethanesulfonamide. Preferably, the molar concentration of sodium salt in the solid electrolyte precursor is 0.1-3 mol / L, and more preferably 0.5-1 mol / L.

7. The solid electrolyte precursor according to any one of claims 1-6, wherein, The ester solvent is selected from C2-C8 ester solvents, preferably at least one of ethylene carbonate, propylene carbonate, diethyl carbonate, dimethyl carbonate and ethyl methyl carbonate; Preferably, the mass ratio of the acrylate monomer to the ester solvent is 1:2-20, and more preferably 1:4-10.

8. The application of the solid electrolyte precursor according to any one of claims 1-7 in sodium metal batteries.

9. A method for preparing a sodium metal battery, characterized in that, The process includes the following steps: placing the solid electrolyte precursor according to any one of claims 1-7 between the positive and negative electrodes of the sodium metal battery, and initiating polymerization of the acrylate monomers in the solid electrolyte precursor to obtain a solid electrolyte formed between the positive and negative electrodes; Preferably, the polymerization conditions include: a temperature of 10-40°C and a time of 0.5-72 h, preferably 24-48 h.

10. A sodium metal battery, characterized in that, It includes a positive electrode, a negative electrode, a membrane, and a solid electrolyte; the solid electrolyte is a solid electrolyte obtained by polymerization of the solid electrolyte precursor according to any one of claims 1-7, wherein the solid electrolyte precursor undergoes in-situ polymerization between the positive electrode and the negative electrode; Preferably, the positive electrode is selected from layered transition metal oxides and / or polyanionic compounds, and more preferably layered oxygen P2 type positive electrode materials; Preferably, the negative electrode is selected from at least one of sodium sheet, sodium foil, and sodium / fiber composite material; Preferably, the diaphragm is selected from at least one of PE diaphragm, PP diaphragm, and glass fiber; Preferably, the sodium metal battery is selected from at least one of pouch cells, button cells, and cylindrical cells.

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