A high-voltage all-ether gel electrolyte, a preparation method thereof and application thereof in quasi-solid sodium ion batteries

Abstract

The application discloses a high-pressure full-ether gel electrolyte, a preparation method thereof and application thereof in quasi-solid sodium ion batteries, and belongs to the technical field of new energy sources.The preparation method is as follows: firstly, dissolving a sodium salt in an ether organic solvent to obtain an electrolyte; secondly, adding a polymerization monomer to the electrolyte and fully stirring to obtain a precursor solution; and finally, adding an initiator to the precursor solution and fully stirring to initiate a self-polymerization reaction, so that the high-pressure full-ether gel electrolyte is obtained.The high-pressure full-ether gel electrolyte prepared by the application also has high ionic conductivity and high oxidation resistance, and can be used for preparing quasi-solid sodium ion batteries with high voltage and high rate.In addition, the method is low in cost, simple in process, convenient in operation and easy to realize commercial production.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of new energy, and particularly relates to a high-voltage full-ether gel electrolyte, a preparation method thereof and application thereof in quasi-solid sodium ion batteries. BACKGROUND

[0002] In recent years, with the development of the new energy industry and the high demand of the electric vehicle market, the low crust abundance and uneven regional distribution of lithium resources have led people to seek energy storage systems other than lithium ion batteries. Sodium ion batteries are considered to be a promising energy storage supplement system for lithium ion batteries because they have a similar "rocking chair" principle as lithium ion batteries, low cost, long service life and are suitable for large-scale energy storage. Electrolytes have the functions of isolating positive and negative materials and providing alkali metal ion transmission as a carrier, and play a key role in the electrochemical performance of sodium ion batteries. Ether-based electrolytes have the characteristics of low viscosity and high ionic conductivity, and can have good interface compatibility with sodium metal, carbon materials and other negative electrodes during the charging and discharging process compared to ester-based electrolytes, have lower interface resistance and thinner solid electrolyte interfaces, and can further improve the rate performance of sodium ion batteries. However, the high highest occupied molecular orbital energy level (HOMO) of ether-based electrolytes makes them inherently insufficient in oxidation resistance. When the battery voltage exceeds 4.0V (vs. Na + / Na), severe oxidative decomposition occurs, it is difficult to form a stable positive electrode / electrolyte interface (CEI), causing serious irreversible capacity loss and poor electrochemical stability, and therefore it is difficult to effectively apply to high-voltage positive electrode material systems. It is of great significance to improve the high-voltage stability of ether-based electrolytes.

[0003] Adding electrolyte additives or using solid-state electrolytes can improve the oxidation stability of the electrolyte. The former has some effect but is high in cost, and the latter has low ionic conductivity and poor interface contact with the electrolyte, which cannot meet the current demand for high-rate fast charging of sodium ion batteries.

[0004] Based on the above reasons, the present application is proposed. SUMMARY

[0005] Based on the above reasons, in view of the problems or defects of poor oxidation stability of ether-based electrolytes, high-voltage decomposition and the like in the prior art, the purpose of the present application is to provide a high-voltage full-ether gel electrolyte, a preparation method thereof and application thereof in quasi-solid sodium ion batteries, to solve or at least partially solve the above technical defects in the prior art. The full-ether gel electrolyte prepared by the present application not only has high-voltage resistance (>4.7V), but also has ionic conductivity comparable to that of liquid electrolytes, and has the mechanical strength of solid-state electrolytes. The full-ether gel electrolyte can further improve the safety performance and cycle performance of the battery while ensuring the electrochemical performance of the battery.

[0006] To achieve the above-mentioned one of the purposes of the present application, the technical solutions adopted by the present application are as follows:

[0007] A preparation method of a high-voltage all-ether gel electrolyte, the method specifically comprises the following steps:

[0008] (1) Dissolve sodium salt in an ether organic solvent according to a predetermined proportion, mix uniformly, and obtain an electrolyte;

[0009] (2) Add a polymer monomer to the electrolyte in step (1) according to a predetermined proportion, mix uniformly, and obtain a precursor solution;

[0010] (3) Add an initiator to the precursor solution in step (2) according to a predetermined proportion, mix uniformly, and then place the obtained mixed solution to obtain the high-voltage all-ether gel electrolyte.

[0011] In some embodiments, the sodium salt in step (1) is at least one of sodium hexafluorophosphate (NaPF6), sodium perchlorate (NaClO4), or sodium tetrafluoroborate (NaBF4).

[0012] In some embodiments, the ether organic solvent in step (1) is at least one of ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, or tetraethylene glycol dimethyl ether.

[0013] Specifically, in the above technical solution, the amount of the ether organic solvent in step (1) can not be specifically limited, as long as it can achieve complete and uniform dissolution of the sodium salt. For example, in some embodiments of the present application, the concentration of the sodium salt in the electrolyte is 0.1-1 mol / L. -1 .

[0014] In some embodiments, the mixing uniformity in step (1) is achieved by stirring, and the stirring time is 2-4 h, and the stirring speed is 500-1000 rpm.

[0015] In some embodiments, the polymer monomer in step (2) is at least one of trioxane, 1,3-dioxane, or 1,4-dioxane.

[0016] In some embodiments, the mass ratio of the polymer monomer to the electrolyte in step (2) is between 0.3:2 and 1:2. Preferably, the mass ratio is 0.5:2.

[0017] In some embodiments, the mixing uniformity in step (2) is also achieved by stirring, and the stirring time is 1.5-3.5 h, and the stirring speed is 500-1000 rpm.

[0018] In some embodiments, the initiator in step (3) is any one of boron trifluoride etherate, tin triflate, aluminum triflate, lithium tetrafluoroborate, or sodium hexafluorophosphate.

[0019] In some embodiments, the mass of the initiator in step (3) is between 0.5% and 2% of the mass of the precursor solution.

[0020] In some embodiments, the mixing in step (3) is also performed by stirring, which is performed for 10-30 min at a speed of 500-1000 rpm.

[0021] In some embodiments, the standing in step (3) is performed for 12-24 h. The purpose of the standing is to allow the polymerization monomers in the precursor solution to undergo self-polymerization to form a gel under the action of the initiator.

[0022] A second object of the present application is to provide a high-voltage all-ether gel electrolyte prepared by the above method.

[0023] A third object of the present application is to provide the use of the high-voltage all-ether gel electrolyte prepared by the above method in the field of sodium metal or sodium ion batteries, in particular, in quasi-solid sodium ion batteries.

[0024] In some embodiments, the quasi-solid sodium ion battery is at least one of an R2032 type button cell, a single-layer soft pack battery, or a multi-layer soft pack battery.

[0025] A fourth object of the present application is to provide a quasi-solid sodium ion battery, comprising: a gel electrolyte, a metal sodium sheet, a positive electrode sheet, a separator, and a battery shell, wherein the gel electrolyte is a high-voltage all-ether gel electrolyte prepared by the above method.

[0026] In some embodiments, the separator is a glass fiber separator.

[0027] In some embodiments, the positive electrode material used in the positive electrode sheet is composed of an active material, a conductive carbon material, a binder, and a dispersion solvent, wherein the mass ratio of the active material to the positive electrode material is 70-90%.

[0028] In some preferred embodiments, the active material is any one of sodium vanadium phosphate, sodium vanadium fluorophosphate, or sodium vanadium oxyfluorophosphate. The conductive carbon material includes at least one of Ketjen black, acetylene black, superconducting carbon black, carbon fiber, carbon nanotube, etc. The binder is at least one of polytetrafluoroethylene, polyvinylidene fluoride, sodium carboxymethyl cellulose, polyvinyl alcohol, or butylphenyl resin, etc. The dispersion solvent is at least one of N-methylpyrrolidone, N,N-dimethylformamide, ethanol, or methanol, etc.

[0029] The fifth object of the present application is to provide a preparation method of the above-mentioned quasi-solid sodium ion battery, and the steps are as follows:

[0030] The positive electrode sheet and the metal sodium sheet are respectively placed on both sides of the fiber diaphragm carrier, the mixed solution containing the sodium salt, the polymer monomer and the initiator is injected, and the quasi-solid sodium ion battery is prepared by packaging in a button cell and placing in a constant temperature and humidity box at 25 DEG C for 12-24 hours.

[0031] Compared with the prior art, the technical scheme realized by the design idea of the present application can achieve the following effects:

[0032] (1) The present application provides a larger HOMO-LOMO energy difference after ring opening of the monomer, thereby significantly enhancing the oxidation resistance.

[0033] (2) The raw materials of the present application are cheap and easy to obtain, and the preparation method of the gel electrolyte is simple.

[0034] (3) When using boron trifluoride ether as an initiator, a small amount of boron trifluoride can be decomposed to participate in the formation of an electrolyte interface, which is beneficial to the stability of the interface.

[0035] (4) The gel electrolyte prepared by using sodium hexafluorophosphate, diethylene glycol dimethyl ether, trioxane monomer and boron trifluoride ether initiator in the preferred scheme of the present application has an ionic conductivity of 1.99 mS cm -1 , and a voltage window of 5.0 V.

[0036] (5) The quasi-solid sodium ion battery prepared by using the gel electrolyte and sodium vanadium phosphate oxide as the positive electrode has a first charge specific capacity of 117 mAh g -1 , a discharge specific capacity of 107 mAh g -1 , a first cycle coulombic efficiency of 91.45%, a specific capacity of 100 mAh g -1 after 500 cycles, a capacity retention rate of 93.5%, and an average coulombic efficiency of 99.6%, which shows that the gel electrolyte has good high-voltage cycle performance. BRIEF DESCRIPTION OF DRAWINGS

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the accompanying drawings needed to be used in the embodiments or prior art description will be briefly introduced. Obviously, the accompanying drawings in the following description only constitute some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor.

[0038] Figure 1 is a scanning electron microscope image measured after the mixed solution prepared in step (3) of Example 3 is fully infiltrated into a glass fiber separator and left to stand for 12 hours;

[0039] Figure 2 is a comparison chart of ion conductivity of gel electrolyte-3, gel electrolyte-4, gel electrolyte-5, gel electrolyte-6, gel electrolyte-7 and gel electrolyte-9 prepared in Examples 1-6 of the present application, respectively;

[0040] Figure 3 is a comparison chart of voltage window of gel electrolyte-3, gel electrolyte-4, gel electrolyte-5 prepared in Examples 1-3 of the present application and sodium ion electrolyte prepared in Comparative Example 1;

[0041] Figure 4 is a comparison chart of electrochemical impedance spectroscopy results of the batteries assembled by dropping the mixed solutions prepared in steps (3) of Examples 7-10 on four identical glass fiber separators, respectively, and left to stand for 12 hours.

[0042] Figure 5 is a comparison chart of charging of the batteries prepared in Application Example 1 and Application Comparative Example 1.

[0043] Figure 6 is a first three circle charge-discharge curve chart of the battery prepared in Application Example 1.

[0044] Figure 7 is a cycle performance chart of the battery prepared in Application Example 1. DETAILED DESCRIPTION

[0045] The present application provides a high-pressure all-ether gel electrolyte, a preparation method thereof and an application thereof in quasi-solid sodium ion batteries. The preparation method comprises the following steps: firstly, dissolving a sodium salt in an ether organic solvent to obtain an electrolyte; secondly, adding a polymerization monomer to the electrolyte and fully stirring to obtain a precursor solution; and finally, adding an initiator to the precursor solution and fully stirring to initiate a self-polymerization reaction, thereby obtaining the high-pressure all-ether gel electrolyte.

[0046] The preparation of the high-voltage full ether gel electrolyte of the application adopts in-situ polymerization, can form a more compact electrode / electrolyte interface, and is beneficial to the interface transmission of ions. Moreover, the monomer used in the application is a cyclic ether, and the full ether type electrolyte can further highlight the advantages of ethers, and endow the battery with better electrochemical performance.

[0047] The high-voltage full ether gel electrolyte prepared by the application also has high ionic conductivity and high oxidation resistance, and can be used to prepare high-voltage and high-rate quasi-solid sodium ion batteries. In addition, the method has low cost, simple process and convenient operation, and is easy to realize commercial production.

[0048] The application will be further described in detail through the following implementation examples. The implementation examples are implemented on the premise of the application technology, and the detailed implementation mode and specific operation process are given to illustrate the creativity of the application, but the protection scope of the application is not limited to the following implementation examples.

[0049] According to the information contained in the present application, various changes to the precise description of the application can be easily made by those skilled in the art. It should be understood that the scope of the application is not limited to the defined processes, properties or components, as these embodiments and other descriptions are only illustrative of certain aspects of the application.

[0050] In order to better understand the application without limiting the scope of the application, all numbers, percentages and other numerical values used in this application to express amounts, percentages and other numerical values should be understood as being modified by the word ''about'' in all cases. Therefore, unless specifically stated otherwise, the numerical parameters set forth in the specification are approximations. They can vary depending on different desired properties sought to be obtained by varying the desired properties. Each numerical parameter should be considered as being at least as precise as the reporting of the effective digits and the rounding methods generally used.

[0051] The equipment and raw materials used in the application can be purchased from the market or are commonly used in the art. The methods in the following examples are conventional methods in the art, unless otherwise specified.

[0052] The test methods of ionic conductivity and electrochemical performance involved in the following examples or application examples of the application are as follows:

[0053] Ion conductivity test: stainless steel sheet as the counter electrode and working electrode, glass fiber as the separator, the obtained mixed solution after adding initiator and stirring was added dropwise on the glass fiber, the battery was assembled in the order of negative electrode shell, steel sheet, glass fiber, steel sheet, spring sheet, positive electrode shell, and was placed for 12 h for electrochemical impedance spectroscopy test, and the ion conductivity was calculated according to the formula L / AR, wherein L was the thickness of the prepared gel electrolyte, unit: cm; A was the area of the prepared gel electrolyte, unit: cm2; R was the impedance value obtained by test, unit: ohm.

[0054] Voltage window test: sodium metal as the counter electrode, stainless steel sheet as the working electrode, glass fiber as the separator, the obtained mixed solution after adding initiator and stirring was added dropwise on the glass fiber, the battery was assembled in the order of negative electrode shell, sodium sheet, glass fiber, steel sheet, spring sheet, positive electrode shell, and was placed for more than 12 h for linear sweep voltammetry test.

[0055] Electrochemical impedance spectroscopy test: sodium metal as the counter electrode and working electrode, glass fiber as the separator, the obtained mixed solution after adding initiator and stirring was added dropwise on the glass fiber, the battery was assembled in the order of negative electrode shell, sodium sheet, glass fiber, sodium sheet, steel sheet, spring sheet, positive electrode shell, and was placed for more than 12 h for electrochemical impedance spectroscopy test.

[0056] Charging comparison test: sodium metal as the negative electrode, positive electrode, glass fiber as the separator, the obtained mixed solution after adding initiator and stirring was added dropwise on the glass fiber, the battery was assembled in the order of negative electrode shell, negative electrode, glass fiber, positive electrode, steel sheet, spring sheet, positive electrode shell, and was placed for more than 12 h for constant rate charging test, the test rate was 1C, and the measurement range was 2.4-4.5V; wherein: the preparation method of the positive electrode was the same as that of the positive electrode in application example 1.

[0057] Charging and discharging test: sodium metal as the negative electrode, positive electrode, glass fiber as the separator, the obtained solution after adding initiator and stirring was added dropwise on the glass fiber, the battery was assembled in the order of negative electrode shell, negative electrode, glass fiber, positive electrode, steel sheet, spring sheet, positive electrode shell, and was placed for 12 h for constant rate charging and discharging test, the test rate was 5C, and the measurement range was 2.4-4.5V; wherein: the preparation method of the positive electrode was the same as that of the positive electrode in application example 1.

[0058] Example 1 (mass ratio of polymerized monomer to electrolyte is 0.3:2)

[0059] The preparation method of a high-pressure all-ether gel electrolyte (labeled as gel electrolyte-3) of the present example, the method specifically comprises the following steps:

[0060] (1) Dissolve sodium hexafluorophosphate in diethylene glycol dimethyl ether, stir at 1000 rpm for 2 h to prepare an electrolyte with a concentration of 1 mol / L;

[0061] (2) Add 0.3 g of polymeric monomer trioxane to 2 g of the electrolyte described in step (1) and stir at 1000 rpm for 2 h to obtain a precursor solution;

[0062] (3) Add initiator boron trifluoride ether to the precursor solution described in step (2) and continue to stir at 1000 rpm for 10 min. Let the obtained mixture stand for 12 h to obtain the high-pressure all-ether gel electrolyte; wherein the mass ratio of boron trifluoride ether to precursor solution is 0.5:100.

[0063] Example 2 (mass ratio of polymeric monomer to electrolyte is 0.4:2)

[0064] The preparation method of a high-pressure all-ether gel electrolyte (labeled as gel electrolyte-4) of this example is basically the same as that of example 1, except that the amount of polymeric monomer trioxane used in step (2) of this example is 0.4 g.

[0065] Example 3 (mass ratio of polymeric monomer to electrolyte is 0.5:2)

[0066] The preparation method of a high-pressure all-ether gel electrolyte (labeled as gel electrolyte-5) of this example is basically the same as that of example 1, except that the amount of polymeric monomer trioxane used in step (2) of this example is 0.5 g.

[0067] Example 4 (mass ratio of polymeric monomer to electrolyte is 0.6:2)

[0068] The preparation method of a high-pressure all-ether gel electrolyte (labeled as gel electrolyte-6) of this example is basically the same as that of example 1, except that the amount of polymeric monomer trioxane used in step (2) of this example is 0.6 g.

[0069] Example 5 (mass ratio of polymeric monomer to electrolyte is 0.7:2)

[0070] The preparation method of a high-pressure all-ether gel electrolyte (labeled as gel electrolyte-7) of this example is basically the same as that of example 1, except that the amount of polymeric monomer trioxane used in step (2) of this example is 0.7 g.

[0071] Example 6 (mass ratio of polymeric monomer to electrolyte is 0.9:2)

[0072] The preparation method of a high-voltage all-ether gel electrolyte (labeled as gel electrolyte-9) of the present example is basically the same as that of example 1, with the only difference being that the amount of the polymerization monomer trioxane used in step (2) of the present example is 0.9 g.

[0073] Comparative example 1

[0074] The preparation method of a sodium ion electrolyte of the present comparative example specifically comprises the following steps:

[0075] Sodium hexafluorophosphate was dissolved in diethylene glycol dimethyl ether, stirred at 1000 rpm for 2 h, and a sodium ion electrolyte with a concentration of 1 mol / L was prepared.

[0076] Test result analysis:

[0077] The mixed solution prepared in step (3) of example 3 was added dropwise to the glass fiber separator, fully soaked, and then left to stand for 12 h. Figure 1 The scanning electron microscope image of the glass fiber separator after standing for 12 h is shown in the figure. As shown in the figure, the gel electrolyte after curing is uniformly distributed on the glass fiber, and there is a lot of electrolyte inside.

[0078] Figure 2 is the ion conductivity comparison chart of gel electrolyte-3, gel electrolyte-4, gel electrolyte-5, gel electrolyte-6, gel electrolyte-7, and gel electrolyte-9 prepared in examples 1-7, respectively. As shown in the figure, with the increase of the monomer ratio, the ion conductivity of the gel electrolyte gradually decreases. The ion conductivities of gel electrolyte-3, gel electrolyte-4, gel electrolyte-5, gel electrolyte-6, gel electrolyte-7, and gel electrolyte-9 are 2.2 mS cm -1 , 2.19 mS cm -1 , 1.99 mS cm -1 , 1.31 mS cm -1 , 0.83 mS cm -1 , and 0.32 mS cm -1 , respectively.

[0079] Figure 3 is the voltage window comparison chart of gel electrolyte-3, gel electrolyte-4, and gel electrolyte-5 prepared in examples 1-3, respectively. As shown in the figure, with the increase of the monomer ratio, the current of the gel electrolyte significantly increases, and the corresponding potential also significantly increases, indicating that it has higher oxidation stability.

[0080] Example 7

[0081] The preparation method of a high-voltage all-ether gel electrolyte (labeled as initiator-0.5) of the present example specifically comprises the following steps:

[0082] (1) Dissolve sodium hexafluorophosphate in diethylene glycol dimethyl ether, stir at 1000 rpm for 2 h to prepare an electrolyte with a concentration of 1 mol / L;

[0083] (2) Add 0.5 g of polymeric monomer trioxane to 2 g of the electrolyte described in step (1) and stir at 1000 rpm for 2 h to obtain a precursor solution;

[0084] (3) Add initiator boron trifluoride etherate to the precursor solution described in step (2) and continue to stir at 1000 rpm for 10 min, and then let the obtained mixture stand for 12 h to obtain the high-pressure all-ether gel electrolyte; wherein the mass ratio of the boron trifluoride etherate to the precursor solution is 0.5:100.

[0085] Example 8

[0086] The preparation method of a high-pressure all-ether gel electrolyte (labeled as initiator-1) of the present example is basically the same as that of Example 7, except that the mass ratio of the boron trifluoride etherate to the precursor solution in step (3) of the present example is 1:100.

[0087] Example 9

[0088] The preparation method of a high-pressure all-ether gel electrolyte (labeled as initiator-1.5) of the present example is basically the same as that of Example 7, except that the mass ratio of the boron trifluoride etherate to the precursor solution in step (3) of the present example is 1.5:100.

[0089] Example 10

[0090] The preparation method of a high-pressure all-ether gel electrolyte (labeled as initiator-2) of the present example is basically the same as that of Example 7, except that the mass ratio of the boron trifluoride etherate to the precursor solution in step (3) of the present example is 2:100.

[0091] With sodium metal as both the counter electrode and the working electrode and glass fiber as the separator, the mixture prepared in step (3) of Examples 7-10, respectively, is added dropwise on four identical glass fiber separators, and the assembled battery is allowed to stand for 12 h before electrochemical impedance spectroscopy test. Figure 4 The impedance test result is shown in the figure. As shown in the figure, the interface impedance of the symmetrical battery increases with the increase of the initiator content, indicating that a high content of the initiator has serious side reactions at the interface, which is not conducive to ion transmission. In summary, the preferred initiator dosage is 0.5% of the mass of the precursor solution. Figure 4 It can be seen that the preferred initiator dosage is 0.5% of the mass of the precursor solution.

[0092] Application Example 1

[0093] The quasi-solid-state sodium-ion battery of the application embodiment comprises a gel electrolyte, a metal sodium sheet, a positive electrode sheet, a separator and a battery shell. The preparation method of the quasi-solid-state sodium-ion battery comprises the following steps:

[0094] A positive electrode sheet and a metal sodium sheet are respectively placed on both sides of a fiber separator carrier, a mixed solution prepared in step (3) of Example 7 is injected, and the quasi-solid-state sodium-ion battery is packaged in a button cell and placed in a 25℃ constant temperature and humidity box for 12 hours.

[0095] The positive electrode material used in the positive electrode sheet comprises an active substance sodium vanadium oxyfluorophosphate, a conductive carbon material, a binder and a dispersion solvent, wherein the mass ratio of the active substance to the positive electrode material is 70-90%. The specific preparation method of the positive electrode sheet is as follows: the active substance sodium vanadium oxyfluorophosphate, acetylene black and the binder (PVDF) are added to the solvent (1-methyl-2-pyrrolidone) according to a mass ratio of 7:2:1, zirconium balls are added, and then the balls are ball-milled on a ball mill for 3-5 times, each time for 3 minutes. The ball-mixed paste sample is uniformly coated on a clean aluminum foil by using a doctor blade coating method, the coating thickness can be controlled by adjusting the doctor blade according to requirements, and then the coated aluminum foil is placed in a 120℃ vacuum oven for drying for 12 hours, and then taken out and punched into a round sheet with a diameter of 12mm for testing. The coating load is controlled at 0.8-1.2mg / cm 2 .

[0096] Application Comparative Example 1

[0097] The quasi-solid-state sodium-ion battery of the application comparative example and the quasi-solid-state sodium-ion battery of the application embodiment 1 have basically the same structure and preparation method, and the only difference is that the electrolyte used in the application comparative example is the sodium-ion electrolyte prepared in Comparative Example 1.

[0098] Figure 5 The charging comparison diagram of the batteries prepared in the application embodiment 1 and the application comparative example 1. As shown in the figure, the battery electrolyte prepared in the application comparative example 1 decomposes at about 4.4V and cannot meet the high-voltage charging test of sodium vanadium oxyfluorophosphate. The battery prepared in the application embodiment 1 can withstand a high voltage of 4.5V without decomposition, which meets the high-voltage charging and discharging test of the ether-based gel electrolyte.

[0099] Figure 6 The first three circle charging and discharging curve diagram of the battery prepared in the application embodiment 1. As shown in the figure, the specific capacity of the first circle charging of the battery is 117mAh g -1 , the specific capacity of the first circle discharging is 107mAh g -1 , the first circle coulombic efficiency is 91.45%, and the coulombic efficiency of the second and third circles is 98.4% and 98.7%, respectively, which exhibits good coulombic efficiency.

[0100] Figure 7 A cycle performance graph of the battery prepared for Application Example 1. As shown in the graph, it still has a specific capacity of 100 mAh g -1 after 500 cycles of 5C high-rate cycling, the capacity retention rate is 93.5%, showing good high-voltage cycle performance of the gel electrolyte.

Claims

1. A quasi-solid sodium-ion battery, comprising: A gel electrolyte, a metal sodium sheet, a positive electrode sheet, a diaphragm and a battery shell, characterized in that: the gel electrolyte is a high-voltage all-ether gel electrolyte, and the preparation method of the high-voltage all-ether gel electrolyte is specifically as follows: (1) Dissolve sodium salt in an ether organic solvent according to a preset proportion, mix uniformly to obtain an electrolyte; the ether organic solvent is at least one of ethylene glycol dimethyl ether, diethylene glycol dimethyl ether or tetraethylene glycol dimethyl ether; the sodium salt is sodium hexafluorophosphate; (2) Add a polymer monomer to the electrolyte in step (1) according to a preset proportion, mix uniformly to obtain a precursor solution; the polymer monomer is trioxane; the mass ratio of the polymer monomer to the electrolyte is 0.3:2-0.9:2; (3) Add an initiator to the precursor solution in step (2) according to a preset proportion, mix uniformly, and then place the obtained mixed solution to obtain the high-voltage all-ether gel electrolyte; the initiator is boron trifluoride ether; the mass of the initiator is 0.5-2% of the mass of the precursor solution.

2. The quasi-solid sodium-ion battery according to claim 1, characterized in that: The standing time in step (3) is 12-24 h.

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