Molybdenum disulfide / polyether-based in-situ composite solid electrolyte, preparation method and application thereof

Abstract

The application provides a molybdenum disulfide / polyether-based in-situ composite solid-state electrolyte, a preparation method and application, and belongs to the technical field of solid-state electrolyte preparation. The preparation method of the molybdenum disulfide / polyether-based in-situ composite solid-state electrolyte comprises the following steps: dissolving a water-soluble binder and a non-ionic surfactant in water, adding molybdenum disulfide and uniformly mixing to obtain a mixed solution; coating the mixed solution on a battery separator, and after volatilizing the water in the mixed solution, a molybdenum disulfide-coated separator is obtained; dissolving a lithium source, a sodium source or a potassium source in dioxolane to obtain an electrolyte; dropping the electrolyte onto the molybdenum disulfide-coated separator, and standing at room temperature so that the molybdenum disulfide can initiate the cation ring-opening polymerization of dioxolane to obtain the molybdenum disulfide / polyether-based in-situ composite solid-state electrolyte. The molybdenum disulfide / polyether-based in-situ composite solid-state electrolyte prepared by the application is simple to assemble in subsequent use, and does not need to add a plasticizer additionally.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of solid electrolyte preparation, more particularly to a molybdenum disulfide / polyether-based in-situ composite solid electrolyte, a preparation method and an application thereof. BACKGROUND

[0002] An organic-inorganic composite polymer electrolyte is generally composed of a polymer body (polyethylene oxide, polyvinylidene fluoride, etc.) and an inorganic filler. The polymer body has a certain ion conduction capacity, but due to its own crystallinity, poor lithium salt dissociation capacity and other factors, the polymer body is usually difficult to use alone. The surface of the inorganic filler usually has a special charge distribution and chemical composition. By introducing the inorganic filler into the polymer body, organic-inorganic composite is realized, and the ion conduction performance of the polymer body is affected. The traditional organic-inorganic composite electrolyte is usually prepared by dissolving a polymer powder with a large molecular weight in a specific solvent, mixing the inorganic filler into the polymer solution, and physically dispersing the inorganic filler in the polymer solution under the action of external shear force. Finally, a solid electrolyte film is prepared by solution casting, solvent evaporation and other processes, and then the film is assembled with positive and negative electrodes.

[0003] Currently, this mainstream strategy has three main problems: 1. The ion conductivity of the polymer electrolyte matrix with high molecular weight is low, usually less than 10-4 S / cm at room temperature, which cannot meet the actual demand; 2. The preparation process of the organic-inorganic composite electrolyte is complicated, and a large amount of external energy (heating) is consumed in the subsequent solvent evaporation step, and the organic solvents used usually have hidden dangers to the environment and safety (toxic, flammable); 3. After the electrolyte film is prepared, it needs to be assembled with positive and negative electrodes, and it is difficult to ensure good contact between the electrolyte and the electrode (solid-solid contact).

[0004] In view of the above problems, the current mainstream solution is to add a small molecule plasticizer (liquid electrolyte, etc.) to the composite electrolyte to prepare a polymer gel electrolyte, so as to improve the problem of high crystallinity and low ion conduction of the polymer. However, the addition of the plasticizer reduces the overall mechanical properties of the polymer, making it more difficult to form a film and assemble a battery. At the same time, the plasticizer also has the risk of volatilization and leakage during the film forming process, which has potential hidden dangers. SUMMARY

[0005] In view of the above problems, the present application provides a molybdenum disulfide / polyether-based in-situ composite solid electrolyte, a preparation method and an application thereof. The molybdenum disulfide / polyether-based in-situ composite solid electrolyte prepared by the present application is simple to assemble in subsequent use, and does not need to add a plasticizer.

[0006] A preparation method of a molybdenum disulfide / polyether-based in-situ composite solid electrolyte, characterized in that it comprises the following steps:

[0007] The water-soluble binder and the non-ionic surfactant are dissolved in water, and then the molybdenum disulfide is added and uniformly mixed to obtain a mixed solution; the mixed solution is coated on the battery separator, and after the water in the mixed solution is volatilized, a molybdenum disulfide coated separator is obtained.

[0008] The ionic salt is dissolved in dioxolane to obtain an electrolyte.

[0009] The electrolyte is added dropwise to the molybdenum disulfide coated separator, and the molybdenum disulfide initiates the cationic ring-opening polymerization of dioxolane at room temperature to obtain a molybdenum disulfide / polyether-based in-situ composite solid-state electrolyte.

[0010] In a preferred embodiment of the present application, the mass ratio of molybdenum disulfide to dioxolane is 1:55-230, for example, the mass ratio of molybdenum disulfide to dioxolane is 1:55, 1:100, 1:140, 1:190, 1:210, 1:230, etc., but not limited to the listed values, other values not listed within the above value range are also applicable.

[0011] In a preferred embodiment of the present application, the standing time is 15-30 minutes, for example, the standing time is 15 minutes, 20 minutes, 25 minutes, 30 minutes, etc., but not limited to the listed values, other values not listed within the above value range are also applicable.

[0012] In a preferred embodiment of the present application, the mass ratio of water-soluble binder to molybdenum disulfide is 1:1-2, for example, the mass ratio of water-soluble binder to molybdenum disulfide is 1:1, 1:1.2, 1:1.4, 1:1.6, 1:1.8, 1:2, etc., but not limited to the listed values, other values not listed within the above value range are also applicable.

[0013] In a preferred embodiment of the present application, the mass ratio of water-soluble binder to non-ionic surfactant is 1:1.7-2.5, for example, the mass ratio of water-soluble binder to non-ionic surfactant is 1:1.7, 1:1.8, 1:1.9, 1:2.1, 1:2.2, 1:2.3, 1:2.4, 1:2.5, but not limited to the listed values, other values not listed within the above value range are also applicable.

[0014] In a preferred embodiment of the present application, the concentration of ionic salt in the electrolyte is 193-455 mg / mL, for example, the concentration of ionic salt is 193 mg / mL, 220 mg / mL, 280 mg / mL, 320 mg / mL, 370 mg / mL, 400 mg / mL, 455 mg / mL, etc., but not limited to the listed values, other values not listed within the above value range are also applicable.

[0015] The ionic salt is an organic lithium salt, an organic sodium salt or an organic potassium salt.

[0016] Further, the organic lithium salt is bis-trifluoromethanesulfonyl lithium, lithium triflate or lithium bisfluorosulfonylimide.

[0017] The organic sodium salt is bis-trifluoromethanesulfonyl sodium.

[0018] The organic potassium salt is bis-trifluoromethanesulfonyl potassium.

[0019] In a preferred embodiment of the present application, the water-soluble binder is sodium polyacrylate, polyvinyl alcohol or sodium alginate.

[0020] In a preferred embodiment of the present application, the non-ionic surfactant is sorbitan oleate or a fatty alcohol polyoxyethylene ether.

[0021] A second object of the present application is to provide a molybdenum disulfide / polyether-based in-situ composite solid-state electrolyte prepared by the above preparation method.

[0022] A third object of the present application is to provide the use of the above molybdenum disulfide / polyether-based in-situ composite solid-state electrolyte in the preparation of a battery.

[0023] Compared with the prior art, the present application has the following beneficial effects:

[0024] (1) The present application is based on room temperature conditions, and molybdenum disulfide can initiate cationic ring-opening polymerization of dioxolane (DOL). The molybdenum disulfide is coated on the battery separator, and the DOL in the electrolyte contacts the molybdenum disulfide coated separator. After the molybdenum disulfide contacts the DOL, it will initiate a polymerization reaction, and an organic-inorganic composite electrolyte is constructed in-situ inside the battery. Part of the un-polymerized DOL or other components of the electrolyte act as plasticizers to maintain high ionic conductivity, while the in-situ polymerization method avoids the use or leakage of other plasticizers. In the subsequent preparation process, the battery can be assembled directly according to the traditional assembly process of liquid-state batteries, which is simple to operate.

[0025] (2) The synthesis conditions of the present application are simple, mild and green. The molybdenum disulfide / polyether composite polymer electrolyte can be obtained by only mixing, stirring and dropping steps, without complicated polymerization reaction steps and post-treatment steps.

[0026] (3) The composite electrolyte has excellent ionic conductivity and abundant organic-inorganic interfaces. Dioxolane is also an excellent electrolyte component, which ensures fast ion migration inside the polymer electrolyte.

[0027] (4) Due to the abundant organic-inorganic interfaces of the molybdenum disulfide / polyether composite polymer electrolyte, it has excellent lithium salt dissociation and ion conduction ability, and therefore exhibits excellent performance in solid-state batteries. Attached Figure Description

[0028] Figure 1 This describes the reaction mechanism of molybdenum disulfide-catalyzed ring-opening polymerization of dioxapentane.

[0029] Figure 2 This is a schematic diagram illustrating the preparation of a molybdenum disulfide / polyether-based composite electrolyte.

[0030] Figure 3 The images shown are SEM images of the molybdenum disulfide / polyether-based composite solid electrolyte before and after preparation in Example 2 of this invention, where a is before preparation and b is after preparation.

[0031] Figure 4 The temperature-dependent ionic conductivity results are shown for the molybdenum disulfide / polyether-based composite solid electrolyte in Example 3 of this invention.

[0032] Figure 5 This is a constant potential current-time curve of the molybdenum disulfide / polyether-based composite solid electrolyte in Example 4 of the present invention, wherein the inset is a graph showing the impedance change of the molybdenum disulfide / polyether-based composite solid electrolyte in Example 4 after initial and stable conditions.

[0033] Figure 6 These are optical photographs of molybdenum disulfide and carbon nanotubes after they have been immersed in dioxane electrolyte and allowed to stand. In the photographs, a is molybdenum disulfide and b is carbon nanotubes.

[0034] Figure 7 The electrochemical window test results are for the molybdenum disulfide / polyether-based composite solid electrolyte and the pure polymer electrolyte in Comparative Example 1.

[0035] Figure 8 The results of the full-cell constant current charge-discharge test cycle in Application Example 1 of this invention are shown.

[0036] Figure 9 The results of the constant current charge-discharge test cycle of the sodium symmetric battery in Application Example 2 of this invention are shown.

[0037] Figure 10 The results of the constant current charge-discharge test cycle of the potassium symmetric battery in application example 3 of this invention are shown. Detailed Implementation

[0038] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] The application prepares a preparation method of a molybdenum disulfide / polyether-based in-situ composite solid-state electrolyte, and a preparation schematic diagram is shown in Figure 2 The preparation method comprises the following steps:

[0040] Sodium polyacrylate and sorbitan oleate are dissolved in water, and then molybdenum disulfide is added and uniformly mixed to obtain a mixed solution; the mixed solution is coated on a battery separator, and after the water in the mixed solution is volatilized, a molybdenum disulfide coated separator is obtained.

[0041] A lithium source, a sodium source or a potassium source is dissolved in dioxolane to obtain an electrolyte.

[0042] The electrolyte is added dropwise to the molybdenum disulfide coated separator, and the molybdenum disulfide can initiate the cationic ring-opening polymerization of dioxolane at room temperature, so as to obtain a molybdenum disulfide / polyether-based in-situ composite solid-state electrolyte.

[0043] The mechanism is shown in Figure 1 After the molybdenum disulfide adsorbs the bistrifluoromethanesulfonylimide anion, a hanging bond is formed between the molybdenum disulfide and the oxygen atom on the anion, thereby weakening the charge density of the sulfur atom on the anion and enhancing the electrophilicity of the sulfur atom. Thus, the sulfur atom acts as an attack site to attack the oxygen atom on the dioxolane molecule to perform a cationic ring-opening polymerization reaction.

[0044] The molecular weight of the sodium polyacrylate used in the application can be 100000-500000, and in the following examples, the molecular weight of the sodium polyacrylate used is 400000. The polyvinyl alcohol used in the application can be type 1788 polyvinyl alcohol or type 2488 polyvinyl alcohol, and in the following examples, the polyvinyl alcohol used is type 1788 polyvinyl alcohol. The fatty alcohol polyoxyethylene ether used in the application has a carbon chain length R=5-10, and in the following examples, the fatty alcohol polyoxyethylene ether used is C10 n-decanol polyoxyethylene ether, which can be purchased through a conventional commercial channel, such as Hubei Xinyu Hong Biological Medicine Technology Co., Ltd.

[0045] Example 1

[0046] A preparation method of a molybdenum disulfide / polyether-based in-situ composite polymer electrolyte, comprising the following steps:

[0047] Step 1, preparation of a molybdenum disulfide coated separator

[0048] Step 1.1, 162.3 mg of sodium polyacrylate and 276.5 mg of sorbitan oleate are dissolved in 5 mL of deionized water.

[0049] Step 1.2, 162.3 mg of molybdenum disulfide powder is added to the above solution under vigorous stirring, and stirring is performed until uniformity.

[0050] Step 1.3, pour the above solution on PE battery separator for blade coating, the blade coating thickness is 20 μm, use 40 ℃ hot plate for moisture evaporation, thus the molybdenum disulfide coated separator is obtained.

[0051] Step 2, preparation of molybdenum disulfide / polyether-based in-situ composite polymer electrolyte

[0052] Step 2.1, dissolve 290 mg of lithium bistrifluoromethanesulfonimide in 1 mL dioxolane to configure electrolyte and transfer to the glove box filled with nitrogen.

[0053] Step 2.2, in the glove box, take the molybdenum disulfide coated separator of appropriate size, drop the electrolyte obtained in step 2.1 on the surface of the separator according to the amount of 30 μL / cm 2 , and stand for 30 minutes to obtain the molybdenum disulfide / polyether-based in-situ composite polymer electrolyte.

[0054] It should be noted that the width of the initial separator for blade coating in step 1.3 in this embodiment is 20 cm, the length is 60 cm, the diameter of the separator used in step 2.2 is 16 mm, and the mass ratio of molybdenum disulfide to dioxolane is 1:230.

[0055] Example 2

[0056] A method for preparing a molybdenum disulfide / polyether-based in-situ composite polymer electrolyte, comprising the following steps:

[0057] Step 1, preparation of molybdenum disulfide coated separator

[0058] Step 1.1, dissolve 162.3 mg of sodium polyacrylate and 276.5 mg of sorbitan oleate in 5 mL of deionized water.

[0059] Step 1.2, add 162.3 mg of molybdenum disulfide powder to the above solution under vigorous stirring and stir until uniform.

[0060] Step 1.3, pour the above solution on PE battery separator for blade coating, the blade coating thickness is 20 μm, use 40 ℃ hot plate for moisture evaporation, thus the molybdenum disulfide coated separator is obtained.

[0061] Step 2, preparation of molybdenum disulfide / polyether-based in-situ composite polymer electrolyte

[0062] Step 2.1, dissolve 450 mg of lithium bistrifluoromethanesulfonimide in 1 mL dioxolane to configure electrolyte and transfer to the glove box filled with nitrogen.

[0063] Step 2.2, in the glove box, take the molybdenum disulfide coated separator of appropriate size, drop the electrolyte obtained in step 2.1 on the surface of the separator according to the amount of 30 μL / cm2 The electrolyte obtained in step 2.1 is added dropwise in an amount of 20 μL / cm2, and the molybdenum disulfide / polyether-based in-situ composite polymer electrolyte is obtained after standing for 15 minutes.

[0064] It should be noted that the width of the initial separator scraped in step 1.3 in the embodiment is 20 cm, the length is 60 cm, and the diameter of the separator disc used in step 2.2 is 16 mm. The mass ratio of molybdenum disulfide to dioxolane is 1:230.

[0065] The SEM pictures of the composite solid electrolyte before and after preparation are shown in Figure 3 The molybdenum disulfide particles on the surface of the separator before adding the electrolyte are uniformly distributed and the pores of the separator can be clearly seen; after adding the electrolyte, the surface of the separator is covered with polymer, indicating the feasibility of the experimental scheme of the application.

[0066] Example 3

[0067] A preparation method of a molybdenum disulfide / polyether-based in-situ composite polymer electrolyte, comprising the following steps:

[0068] Step 1, preparation of a molybdenum disulfide coated separator

[0069] Step 1.1, 162.3 mg of sodium polyacrylate and 276.5 mg of sorbitan oleate were dissolved in 5 mL of deionized water.

[0070] Step 1.2, 162.3 mg of molybdenum disulfide powder was added to the above solution under vigorous stirring and stirred until uniform.

[0071] Step 1.3, the above solution was poured onto a PE battery separator for scraping, with a scraping thickness of 20 μm, and a heating plate at 40 °C was used for water evaporation, thereby obtaining a molybdenum disulfide coated separator.

[0072] Step 2, preparation of a molybdenum disulfide / polyether-based in-situ composite polymer electrolyte

[0073] Step 2.1, 370 mg of bis-trifluoromethanesulfonate lithium was dissolved in 1.25 mL of dioxolane to prepare an electrolyte and transfer it to a nitrogen-filled glove box.

[0074] Step 2.2, in the glove box, a molybdenum disulfide coated separator of appropriate size was taken, and the electrolyte obtained in step 2.1 was added dropwise to the surface thereof in an amount of 20 μL / cm2. 2 The electrolyte obtained in step 2.1 is added dropwise in an amount of 20 μL / cm2, and the molybdenum disulfide / polyether-based in-situ composite polymer electrolyte is obtained after standing for 15 minutes.

[0075] It should be noted that the width of the initial separator scraped in step 1.3 in this embodiment is 20 cm, the length is 60 cm, and the diameter of the separator disc used in the step 2.2 pool is 16 mm, and the mass ratio of molybdenum disulfide to dioxolane is 1:153.

[0076] The solid electrolyte membrane obtained in this embodiment was subjected to electrochemical related tests, and the test method was as follows:

[0077] Test of ion conductivity change over time. The molybdenum disulfide / polyether-based in-situ composite polymer electrolyte membrane was cut into a disc with a diameter of 19 mm, then clamped with two stainless steel sheets, and after being kept at different temperatures for 30 minutes, the impedance was tested, and the ion conductivity at the corresponding temperature was calculated. The test results are shown in Figure 4 Figure 4 The results show that the composite electrolyte has high ion conductivity, which can ensure the normal use of the battery at room temperature.

[0078] Example 4

[0079] A method for preparing a molybdenum disulfide / polyether-based in-situ composite polymer electrolyte, comprising the following steps:

[0080] Step 1, preparation of molybdenum disulfide coated separator

[0081] Step 1.1, dissolve 162.3 mg of sodium polyacrylate and 276.5 mg of sorbitan oleate in 5 mL of deionized water.

[0082] Step 1.2, add 162.3 mg of molybdenum disulfide powder to the above solution under vigorous stirring, and stir until uniform.

[0083] Step 1.3, pour the above solution onto the PE battery separator for scraping, with a scraping thickness of 20 μm, and use a heating plate at 40 °C to volatilize the moisture, thereby obtaining a molybdenum disulfide coated separator.

[0084] Step 2, preparation of molybdenum disulfide / polyether-based in-situ composite polymer electrolyte

[0085] Step 2.1, dissolve 400 mg of bis(trifluoromethanesulfonyl) lithium in 1.3 mL of dioxolane to prepare an electrolyte and transfer it to a nitrogen-filled glove box.

[0086] Step 2.2, in the glove box, take a molybdenum disulfide coated separator with appropriate size, and drop the electrolyte obtained in step 2.1 onto the surface thereof at an amount of 25 μL / cm 2 , and after standing for 25 minutes, a molybdenum disulfide / polyether-based in-situ composite polymer electrolyte is obtained.

[0087] ​It should be noted that the width of the initial separator scraped in step 1.3 in the present embodiment is 20 cm, the length is 60 cm, and the diameter of the separator disc used in the step 2.2 pool is 16 mm, and the mass ratio of molybdenum disulfide to dioxolane is 1:192.

[0088] The solid electrolyte membrane obtained in the present embodiment was subjected to electrochemical related tests, and the test method was as follows:

[0089] Lithium ion transference number test. The molybdenum disulfide / polyether-based in-situ composite polymer electrolyte membrane was cut into a disc with a diameter of 19 mm, and in an argon-filled glove box (moisture content <0.1 ppm, oxygen content <0.1 ppm), a battery was assembled in the manner of negative electrode shell + lithium sheet + solid electrolyte membrane + lithium sheet + positive electrode shell, and in an electrochemical workstation, the initial impedance of the battery was first measured, then the current change with time in the battery was measured at a constant potential of 10 mV, and the test was ended after the current was stable, and finally the stable impedance of the battery was measured. The test results are shown in Figure 5 . The results show that the composite electrolyte has a high lithium ion transference number (>0.5), which meets the requirements of practical application.

[0090] Example 5

[0091] A preparation method of a molybdenum disulfide / polyether-based in-situ composite polymer electrolyte, comprising the following steps:

[0092] Step 1, preparation of molybdenum disulfide-coated separator

[0093] Step 1.1, 162.3 mg of sodium polyacrylate and 276.5 mg of sorbitan oleate were dissolved in 5 mL of deionized water.

[0094] Step 1.2, 162.3 mg of molybdenum disulfide powder was added to the above solution under vigorous stirring, and stirred until uniform.

[0095] Step 1.3, pour the above solution on the PE battery separator for scraping, the scraping thickness is 20 μm, and use a heating plate at 40 °C to volatilize the moisture, thereby obtaining a molybdenum disulfide-coated separator.

[0096] Step 2, preparation of molybdenum disulfide / polyether-based in-situ composite polymer electrolyte

[0097] Step 2.1, 320 mg of bis-trifluoromethanesulfonate lithium was dissolved in 1.25 mL of dioxolane to prepare an electrolyte and transfer it to a nitrogen-filled glove box.

[0098] Step 2.2, in the glove box, take a molybdenum disulfide-coated separator with a suitable size, and apply 20 μL / cm 2The electrolyte obtained in step 2.1 is added dropwise to the surface of the molybdenum disulfide coated separator in an amount of 22 μL / cm

[0099] It should be noted that the width of the initial separator scraped in step 1.3 in this embodiment is 20 cm, the length is 60 cm, and the diameter of the separator disc used in step 2.2 is 16 mm. The mass ratio of molybdenum disulfide to dioxolane is 1:192.

[0100] Example 6

[0101] A method for preparing a molybdenum disulfide / polyether-based in-situ composite polymer electrolyte, comprising the following steps:

[0102] Step 1, preparation of a molybdenum disulfide coated separator

[0103] Step 1.1, 162.3 mg of sodium polyacrylate and 276.5 mg of sorbitan oleate were dissolved in 5 mL of deionized water.

[0104] Step 1.2, 162.3 mg of molybdenum disulfide powder was added to the above solution under vigorous stirring and stirred until uniform.

[0105] Step 1.3, the above solution was poured onto a PE battery separator for scraping, the scraping thickness was 20 μm, and a heating plate at 40 ℃ was used for water evaporation, thereby obtaining a molybdenum disulfide coated separator.

[0106] Step 2, preparation of a molybdenum disulfide / polyether-based in-situ composite polymer electrolyte

[0107] Step 2.1, 440 mg of bis-trifluoromethanesulfonate sodium was dissolved in 1.25 mL of dioxolane to prepare an electrolyte and transfer it to a nitrogen-filled glove box.

[0108] Step 2.2, in the glove box, a molybdenum disulfide coated separator of appropriate size was taken, and the electrolyte obtained in step 2.1 was added dropwise to the surface thereof in an amount of 22 μL / cm 2 After standing for 20 minutes, a molybdenum disulfide / polyether-based in-situ composite polymer electrolyte was obtained.

[0109] It should be noted that the width of the initial separator scraped in step 1.3 in this embodiment is 20 cm, the length is 60 cm, and the diameter of the separator disc used in step 2.2 is 16 mm. The mass ratio of molybdenum disulfide to dioxolane is 1:162.

[0110] Example 7

[0111] A method for preparing a molybdenum disulfide / polyether-based in-situ composite polymer electrolyte, comprising the following steps:

[0112] Step 1. Preparation of molybdenum disulfide coated separator

[0113] Step 1.1, 162.3 mg of sodium polyacrylate, 276.5 mg of sorbitan oleate were dissolved in 5 mL of deionized water.

[0114] Step 1.2, 162.3 mg of molybdenum disulfide powder was added to the above solution under vigorous stirring, and stirred until uniform.

[0115] Step 1.3, the above solution was poured on the PE battery separator for scraping, the scraping thickness was 20 μm, and the moisture was volatilized using a heating plate at 40 ℃, to obtain a molybdenum disulfide coated separator.

[0116] Step 2. Preparation of molybdenum disulfide / polyether-based in-situ composite polymer electrolyte

[0117] Step 2.1, 520 mg of bis-trifluoromethanesulfonate potassium was dissolved in 1.25 mL of dioxolane to prepare an electrolyte and transferred to a nitrogen-filled glove box.

[0118] Step 2.2, in the glove box, a molybdenum disulfide coated separator of appropriate size was taken, and an electrolyte obtained in step 2.1 was added to the surface thereof at an amount of 20 μL / cm 2 , and a molybdenum disulfide / polyether-based in-situ composite polymer electrolyte was obtained after standing for 20 minutes.

[0119] It should be noted that the initial separator scraped in step 1.3 in this embodiment has a width of 20 cm and a length of 60 cm, and the separator used in step 2.2 has a diameter of 16 mm, and the mass ratio of molybdenum disulfide to dioxolane is 1:150.

[0120] Example 8

[0121] A method for preparing a molybdenum disulfide / polyether-based in-situ composite polymer electrolyte, comprising the following steps:

[0122] Step 1. Preparation of molybdenum disulfide coated separator

[0123] Step 1.1, 173.2 mg of polyvinyl alcohol 1788, 340.83 mg of sorbitan oleate were dissolved in 5 mL of deionized water.

[0124] Step 1.2, 324.6 mg of molybdenum disulfide powder was added to the above solution under vigorous stirring, and stirred until uniform.

[0125] Step 1.3, the above solution was poured on the PE battery separator for scraping, the scraping thickness was 20 μm, and the moisture was volatilized using a heating plate at 40 ℃, to obtain a molybdenum disulfide coated separator.

[0126] Step 2, Preparation of molybdenum disulfide / polyether-based in-situ composite polymer electrolyte

[0127] Step 2.1, 193 mg of bis-trifluoromethanesulfonate sodium was dissolved in 1 mL of dioxolane to configure an electrolyte and transferred to a nitrogen-filled glove box.

[0128] Step 2.2, In the glove box, cut the molybdenum disulfide-coated separator to an appropriate size, and drop the electrolyte obtained in step 2.1 onto its surface at an amount of 15 μL / cm 2 After standing for 30 minutes, a molybdenum disulfide / polyether-based in-situ composite polymer electrolyte was obtained.

[0129] It should be noted that the width of the initial separator scraped in step 1.3 in this embodiment is 20 cm, and the length is 60 cm. The separator used in step 2.2 is a round piece with a diameter of 16 mm, and the mass ratio of molybdenum disulfide to dioxolane is 1:55.

[0130] Example 9

[0131] A method for preparing a molybdenum disulfide / polyether-based in-situ composite polymer electrolyte, comprising the following steps:

[0132] Step 1, Preparation of molybdenum disulfide-coated separator

[0133] Step 1.1, 162.3 mg of sodium alginate and 405.75 mg of fatty alcohol polyoxyethylene ether were dissolved in 5 mL of deionized water.

[0134] Step 1.2, 243.45 mg of molybdenum disulfide powder was added to the above solution under vigorous stirring and stirred until uniform.

[0135] Step 1.3, Pour the above solution onto the PE battery separator for scraping, with a scraping thickness of 20 μm, and use a heating plate at 40 °C to volatilize the moisture, to obtain a molybdenum disulfide-coated separator.

[0136] Step 2, Preparation of molybdenum disulfide / polyether-based in-situ composite polymer electrolyte

[0137] Step 2.1, 455 mg of bis-trifluoromethanesulfonate potassium was dissolved in 1 mL of dioxolane to configure an electrolyte and transferred to a nitrogen-filled glove box.

[0138] Step 2.2, In the glove box, cut the molybdenum disulfide-coated separator to an appropriate size, and drop the electrolyte obtained in step 2.1 onto its surface at an amount of 20 μL / cm 2 After standing for 15 minutes, a molybdenum disulfide / polyether-based in-situ composite polymer electrolyte was obtained.

[0139] In order to further verify the excellent performance of the composite electrolyte prepared by the application, the molybdenum disulfide is replaced by carbon nanotubes, and the specific operation steps are as follows:

[0140] Step 1.1, 800 mg of bis-trifluoromethanesulfonate lithium is dissolved in 2 mL of dioxolane to prepare an electrolyte and transferred to a nitrogen-filled glove box.

[0141] Step 1.2, in the glove box, 1 mL of the above electrolyte is added to two glass bottles respectively, then 100 mg of molybdenum disulfide powder and carbon nanotube powder is added to each of the two bottles, and after standing for 1 h, the results are observed as shown in Figure 6 The results show that the ring opening of dioxolane is selective and depends on the action of molybdenum disulfide, and other inorganic nanomaterials inside the carbon nanotube cannot directly replace molybdenum disulfide for preparing a composite electrolyte.

[0142] It should be noted that the width of the initial separator scraped in step 1.3 in this embodiment is 20 cm, the length is 60 cm, and the diameter of the separator disc used in step 2.2 is 16 mm, and the mass ratio of molybdenum disulfide to dioxolane is 1:100.

[0143] Comparative Example 1

[0144] A preparation method of a polyether-based polymer electrolyte comprises the following steps:

[0145] Step 1.1, 370 mg of bis-trifluoromethanesulfonate lithium is dissolved in 1.25 mL of dioxolane, and 5 mg of aluminum triflate is added to prepare an electrolyte and transferred to a nitrogen-filled glove box.

[0146] Step 1.2, in the glove box, cut a pure PE separator to the appropriate size, and drop the electrolyte obtained in (1) onto its surface at an amount of 20 μL / cm 2 After standing for 60 minutes, the dioxolane is polymerized to obtain a pure polymer electrolyte.

[0147] The solid-state electrolyte membranes prepared in Example 5 and Comparative Example 1 are subjected to electrochemical tests, and the test method is as follows:

[0148] Test of electrochemical window. In an argon-filled glove box (moisture content <0.1 ppm, oxygen content <0.1 ppm), a battery is assembled in the form of negative electrode shell + lithium sheet + solid-state electrolyte membrane + stainless steel sheet + positive electrode shell, and linear sweep voltammetry test is carried out in an electrochemical workstation, the test range is open circuit voltage ~ 6V, and the test results are as shown in Figure 7As shown, the results show that the molybdenum disulfide / polyether-based in-situ composite polymer electrolyte has an oxidation potential of 5.15 V, and can be safely and stably operated in a lithium ion battery, avoiding the oxidation and decomposition of the solid-state electrolyte by the high-voltage positive electrode material.

[0149] Application Example 1

[0150] The composite electrolyte film is prepared in-situ inside the battery. Taking a button lithium battery as an example:

[0151] In a glove box, the positive electrode sheet (lithium iron phosphate), the molybdenum disulfide-coated separator prepared in Example 4, and the negative electrode sheet (lithium iron phosphate) are placed in order, 20 μL / cm 2 of the electrolyte obtained in step 2.1 of Example 4 is added to the inside of the separator, and the battery is assembled. After the assembled battery is placed for 16 h, the molybdenum disulfide / polyether-based in-situ composite polymer electrolyte is constructed in-situ inside the battery.

[0152] The cycle performance of the battery obtained in this application example is shown in Figure 8 . The results show that the in-situ composite electrolyte film can maintain good contact between the positive and negative electrodes and the electrolyte inside the battery, and keep the battery running normally.

[0153] Application Example 2

[0154] The composite electrolyte film is used non-in-situ. Taking a button sodium symmetric battery as an example:

[0155] In a glove box, the positive electrode sheet (sodium metal sheet), the molybdenum disulfide / polyether-based in-situ composite electrolyte film prepared in Example 6, and the negative electrode sheet (sodium metal sheet) are placed in order, and the battery is assembled for constant current charge and discharge test; the cycle performance of the battery obtained in this example is shown in Figure 9 . The normal charge and discharge cycle of the battery shows that the composite electrolyte has application potential in sodium batteries.

[0156] Application Example 3

[0157] The composite electrolyte film is used non-in-situ. Taking a button potassium symmetric battery as an example:

[0158] In a glove box, the positive electrode sheet (potassium metal sheet), the molybdenum disulfide / polyether-based in-situ composite electrolyte film prepared in Example 7, and the negative electrode sheet (potassium metal sheet) are placed in order, and the battery is assembled for constant current charge and discharge test; the cycle performance of the battery obtained in this example is shown in Figure 10 . The normal charge and discharge cycle of the battery shows that the composite electrolyte has application potential in sodium batteries.

[0159] While the preferred embodiments of the application have been described, additional variations and modifications can be made to these embodiments by those skilled in the art once they have the benefit of the present disclosure without departing from the spirit and scope of the application. Accordingly, it is intended that the appended claims include all such modifications and variations as fall within the scope of the present application.

[0160] It is apparent that those skilled in the art can make various changes and modifications to the application without departing from the spirit and scope of the application. It is therefore intended that the present application cover all such changes and modifications that are within its scope.

Claims

1. A method for preparing a molybdenum disulfide / polyether-based in-situ composite solid-state electrolyte, characterized by, The method comprises the following steps: dissolving the water-soluble binder and the non-ionic surfactant in water, adding and uniformly mixing the molybdenum disulfide to obtain a mixed solution; coating the mixed solution on a battery separator, and evaporating the water in the mixed solution to obtain a molybdenum disulfide coated separator; dissolving the ionic salt in dioxolane to obtain an electrolyte; dropping the electrolyte on the molybdenum disulfide coated separator, and standing at room temperature to initiate cationic ring-opening polymerization of dioxolane by the molybdenum disulfide to obtain a molybdenum disulfide / polyether based in-situ composite solid-state electrolyte; the mass ratio of the molybdenum disulfide to the dioxolane is 1:55-230, and the standing time is 15 min-30 min.

2. The method of claim 1, wherein the method is characterized by, The mass ratio of the water-soluble binder to the molybdenum disulfide is 1:1-2.

3. The method of claim 1, wherein the method is characterized by, The mass ratio of the water-soluble binder to the non-ionic surfactant is 1:1.7-2.

5.

4. The method of claim 1, wherein the method is characterized by, In the electrolyte, the concentration of the ionic salt is 193 mg / mL-455 mg / mL, and the ionic salt is an organic lithium salt, an organic sodium salt or an organic potassium salt.

5. The method of claim 1, wherein the method is characterized by: The water-soluble binder is sodium polyacrylate, polyvinyl alcohol or sodium alginate.

6. The method of claim 1, wherein the method is characterized by: The non-ionic surfactant is sorbitan oleate or a fatty alcohol polyoxyethylene ether.

7. A molybdenum disulfide / polyether based in-situ composite solid-state electrolyte prepared by the preparation method of any one of claims 1-6.

8. Use of the molybdenum disulfide / polyether based in-situ composite solid-state electrolyte of claim 7 in the preparation of a battery.

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