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

Abstract

The invention provides a molybdenum disulfide / polyether-based in-situ composite solid electrolyte, and a preparation method and application thereof, and belongs to the technical field of solid electrolyte preparation. The preparation method of the molybdenum disulfide / polyether-based in-situ composite solid electrolyte comprises the following steps: dissolving a water-soluble binder and a nonionic surfactant in water, adding molybdenum disulfide, and uniformly mixing to obtain a mixed solution; coating a battery diaphragm with the mixed solution, and completely volatilizing water in the mixed solution to obtain a molybdenum disulfide coated diaphragm; dissolving a lithium source, a sodium source or a potassium source in dioxolane to obtain an electrolyte; and dropwise adding the electrolyte onto the molybdenum disulfide coated diaphragm, and standing at normal temperature to enable molybdenum disulfide to initiate dioxolane to perform cationic ring opening polymerization, thereby obtaining the molybdenum disulfide / polyether-based in-situ composite solid electrolyte. The molybdenum disulfide / polyether-based in-situ composite solid electrolyte prepared by the invention is simple to assemble in subsequent use, and no extra plasticizer is needed.

Description

Technical Field

[0001] The present invention relates to the technical field of solid electrolyte preparation, and more specifically to molybdenum disulfide / polyether-based in-situ composite solid electrolyte and its preparation method and application. Background Art

[0002] Organic-inorganic composite polymer electrolytes are usually composed of a polymer matrix (such as polyethylene oxide, polyvinylidene fluoride, etc.) and inorganic fillers. Among them, the polymer matrix has a certain ionic conductivity. However, affected by factors such as its own crystallinity and poor lithium salt dissociation ability, the polymer matrix is usually difficult to be used alone. And the surface of inorganic fillers usually has a special charge distribution and chemical composition. By introducing inorganic fillers into the polymer matrix to achieve organic-inorganic composite, the ionic conductivity of the polymer matrix can be affected. Traditional organic-inorganic composite electrolytes usually dissolve polymer powders with larger molecular weights in specific solvents, then mix inorganic fillers into the polymer solution and conduct physical dispersion through the action of external shear force, and finally prepare solid electrolyte membranes through processes such as solution casting and solvent evaporation, and then carry out the battery assembly process with positive and negative electrode sheets.

[0003] At present, there are three main problems with this mainstream strategy: 1. The ionic conductivity of the high molecular weight polymer electrolyte matrix is relatively low, usually lower than 10-4 S / cm at room temperature, which cannot meet the actual requirements; 2. The preparation process of the organic-inorganic composite electrolyte is cumbersome and complex, and subsequent steps such as solvent evaporation require a large amount of external energy (heating) and the commonly used organic solvents usually have potential hazards to the environment and safety (toxic, flammable); 3. After the electrolyte membrane is prepared, it needs to be assembled with the positive and negative electrodes, and it is difficult to ensure good contact between the electrolyte and the electrode (solid-solid contact).

[0004] In response to the above problems, the current mainstream solution is to add small molecule plasticizers (such as liquid electrolytes, etc.) to the composite electrolyte to make polymer gel electrolytes, so as to improve the problems of high crystallinity and low ionic conductivity of the polymer. However, the addition of plasticizers simultaneously reduces the overall mechanical properties of the polymer, increasing the difficulty of subsequent film formation and battery assembly; at the same time, the plasticizers also have the risk of volatilization and are prone to leakage during the film formation process, with potential hazards. Summary of the Invention

[0005] In view of the above problems, the present invention provides a molybdenum disulfide / polyether-based in-situ composite solid electrolyte and its preparation method and application. The molybdenum disulfide / polyether-based in-situ composite solid electrolyte prepared by the present invention is simple to assemble during subsequent use and does not require additional addition of plasticizers.

[0006] A preparation method of a molybdenum disulfide / polyether-based in-situ composite solid electrolyte, characterized by comprising the following steps: Dissolve a water-soluble binder and a non-ionic surfactant in water, add molybdenum disulfide and mix evenly to obtain a mixed solution; coat the mixed solution on a battery separator, and after the water in the mixed solution has evaporated completely, obtain a molybdenum disulfide-coated separator.

[0007] Dissolve an ionic salt in dioxolane to obtain an electrolyte solution.

[0008] Drop the electrolyte solution onto the molybdenum disulfide-coated separator, and let it stand at room temperature to initiate the cationic ring-opening polymerization of dioxolane by molybdenum disulfide to obtain a molybdenum disulfide / polyether-based in-situ composite solid electrolyte.

[0009] In a preferred embodiment of the present invention, the mass ratio of molybdenum disulfide to dioxolane is 1:55 to 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 is not limited to the listed values, and other unlisted values within the above numerical range are equally applicable.

[0010] In a preferred embodiment of the present invention, the standing time is 15 min to 30 min. For example, the standing time is 15 min, 20 min, 25 min, 30 min, etc., but is not limited to the listed values, and other unlisted values within the above numerical range are equally applicable.

[0011] In a preferred embodiment of the present invention, the mass ratio of the water-soluble binder to molybdenum disulfide is 1:1 to 2. For example, the mass ratio of the 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 is not limited to the listed values, and other unlisted values within the above numerical range are equally applicable.

[0012] In a preferred embodiment of the present invention, the mass ratio of the water-soluble binder to the non-ionic surfactant is 1:1.7 to 2.5. For example, the mass ratio of the water-soluble binder to the 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 is not limited to the listed values, and other unlisted values within the above numerical range are equally applicable.

[0013] In a preferred embodiment of the present invention, in the electrolyte solution, the concentration of the ionic salt is 193 mg / mL to 455 mg / mL. For example, the concentration of the 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 is not limited to the listed values, and other unlisted values within the above numerical range are equally applicable.

[0014] The ionic salt is an organic lithium salt, an organic sodium salt or an organic potassium salt.

[0015] Furthermore, the organic lithium salt is lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate or lithium bis(fluorosulfonyl)imide.

[0016] The organic sodium salt is sodium bis(trifluoromethanesulfonyl).

[0017] The organic potassium salt is potassium bis(trifluoromethanesulfonyl).

[0018] In a preferred embodiment of the present invention, the water-soluble binder is sodium polyacrylate, polyvinyl alcohol or sodium alginate.

[0019] In a preferred embodiment of the present invention, the non-ionic surfactant is sorbitan oleate or fatty alcohol polyoxyethylene ether.

[0020] The second object of the present invention is to provide a molybdenum disulfide / polyether-based in-situ composite solid electrolyte prepared by the above preparation method.

[0021] The third object of the present invention is to provide the application of the above molybdenum disulfide / polyether-based in-situ composite solid electrolyte in the preparation of batteries.

[0022] Compared with the prior art, the present invention has the following beneficial effects: (1) Based on room temperature conditions, molybdenum disulfide in the present invention can initiate the cationic ring-opening polymerization of 1,3-dioxolane (DOL). After molybdenum disulfide is coated on the battery separator, when DOL in the electrolyte contacts the molybdenum disulfide-coated separator, molybdenum disulfide will initiate a polymerization reaction after contacting DOL, and an organic-inorganic composite electrolyte is in-situ constructed inside the battery. Part of the unpolymerized DOL or other components of the electrolyte act as plasticizers to maintain high ionic conductivity, and at the same time, the in-situ polymerization method avoids the use or leakage risk of other plasticizers. In the subsequent preparation process, the battery can be assembled directly according to the assembly process of traditional liquid batteries, and the operation is simple.

[0023] (2) The synthesis conditions of the present invention are simple, mild and green. The molybdenum disulfide / polyether composite polymer electrolyte can be obtained only through steps such as mixing, stirring and dropping, without cumbersome polymerization reaction steps and post-treatment steps.

[0024] (3) The composite electrolyte has excellent ionic conductivity and a rich organic-inorganic interface. 1,3-dioxolane itself is also an excellent electrolyte component, ensuring rapid ion migration inside the polymer electrolyte.

[0025] (4) Due to the rich organic-inorganic interface of the molybdenum disulfide / polyether composite polymer electrolyte and its excellent lithium salt dissociation and ion conduction capabilities, it exhibits excellent performance in solid-state batteries. Description of the Drawings

[0026] Figure 1 It is the reaction mechanism of the ring-opening polymerization of dioxolane catalyzed by molybdenum disulfide.

[0027] Figure 2 It is a schematic diagram for the preparation of molybdenum disulfide / polyether-based composite electrolyte.

[0028] Figure 3 These are SEM pictures of the molybdenum disulfide / polyether-based composite solid electrolyte before and after preparation in Example 2 of the present invention. Among them, a is before preparation and b is after preparation.

[0029] Figure 4 These are the results of the temperature-dependent ionic conductivity of the molybdenum disulfide / polyether-based composite solid electrolyte in Example 3 of the present invention.

[0030] Figure 5 These are the potentiostatic current-time curve graphs of the molybdenum disulfide / polyether-based composite solid electrolyte in Example 4 of the present invention. Among them, the inset is the impedance change graph of the molybdenum disulfide / polyether-based composite solid electrolyte in Example 4 at the initial and stable states.

[0031] Figure 6 These are the optical photos of molybdenum disulfide and carbon nanotubes after being soaked in the dioxolane electrolyte and left standing. Among them, a is molybdenum disulfide and b is carbon nanotubes.

[0032] Figure 7 These are the test results of the electrochemical window of the molybdenum disulfide / polyether-based composite solid electrolyte and the pure polymer electrolyte in Comparative Example 1.

[0033] Figure 8 These are the test cycle results of the constant current charge and discharge of the full battery in Application Example 1 of the present invention.

[0034] Figure 9 These are the test cycle results of the constant current charge and discharge of the sodium symmetric battery in Application Example 2 of the present invention.

[0035] Figure 10 These are the test cycle results of the constant current charge and discharge of the potassium symmetric battery in Application Example 3 of the present invention. Detailed implementation manners

[0036] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0037] The present invention provides a method for preparing a molybdenum disulfide / polyether-based in-situ composite solid electrolyte, and the preparation schematic diagram is as Figure 2 shown, which includes the following steps: Dissolve sodium polyacrylate and sorbitan oleate in water, add molybdenum disulfide and mix evenly to obtain a mixed solution; coat the mixed solution on the battery separator, and after the water in the mixed solution evaporates, a molybdenum disulfide-coated separator is obtained.

[0038] Dissolve a lithium source, a sodium source or a potassium source in dioxolane to obtain an electrolyte solution.

[0039] Drop the electrolyte solution onto the molybdenum disulfide-coated separator, and let it stand at room temperature so that molybdenum disulfide can initiate cationic ring-opening polymerization of dioxolane to obtain a molybdenum disulfide / polyether-based in-situ composite solid electrolyte.

[0040] The mechanism is as Figure 1 shown. After molybdenum disulfide adsorbs bis(trifluoromethanesulfonyl)imide anions, pendant bonds are formed with the oxygen atoms on the anions, thereby weakening the charge density of the sulfur atoms on the anions and enhancing the electrophilicity of the sulfur atoms. Thus, the sulfur atoms act as attack sites to attack the oxygen atoms on the dioxolane molecules, and a cationic ring-opening polymerization reaction occurs.

[0041] The molecular weight of the sodium polyacrylate used in the present invention can be 100,000 - 500,000. In the following examples, the molecular weight of the specifically used sodium polyacrylate is 400,000. The polyvinyl alcohol used in the present invention can be polyvinyl alcohol of type 1788 or type 2488. In the following examples, the specifically used polyvinyl alcohol is polyvinyl alcohol of type 1788. The fatty alcohol polyoxyethylene ether used in the present invention has a carbon chain length R = 5 - 10. In the following examples, the specifically used fatty alcohol polyoxyethylene ether is C10 decanol polyoxyethylene ether, which can be purchased through conventional commercial channels, such as Hubei Xinyuhong Biomedical Technology Co., Ltd.

[0042] Example 1 A method for preparing a molybdenum disulfide / polyether-based in-situ composite polymer electrolyte includes the following steps: Step 1. Preparation of a molybdenum disulfide-coated separator Step 1.1. Dissolve 162.3 mg of sodium polyacrylate and 276.5 mg of sorbitan oleate in 5 mL of deionized water.

[0043] Step 1.2. Add 162.3 mg of molybdenum disulfide powder to the above solution under vigorous stirring and stir until homogeneous.

[0044] Step 1.3. Pour the above solution onto a PE battery separator and scrape it with a thickness of 20 μm, and use a heating plate at 40 °C to evaporate the water to obtain a molybdenum disulfide-coated separator.

[0045] Step 2: Preparation of molybdenum disulfide / polyether-based in-situ composite polymer electrolyte Step 2.1: Dissolve 290 mg of lithium bis(trifluoromethanesulfonyl)imide in 1 mL of dioxolane to prepare an electrolyte solution and transfer it to a glove box filled with nitrogen.

[0046] Step 2.2: In the glove box, take a molybdenum disulfide-coated separator of appropriate size, and drop the electrolyte solution obtained in Step 2.1 onto its surface at a rate of 30 μL / cm 2 . After standing for 30 minutes, molybdenum disulfide / polyether-based in-situ composite polymer electrolyte can be obtained.

[0047] It should be noted that in Step 1.3 of this example, the width of the initial separator coated by scraping is 20 cm and the length is 60 cm. The separator used in Step 2.2 is a circular piece with a diameter of 16 mm. The mass ratio of molybdenum disulfide to dioxolane is 1:230.

[0048] Example 2 A preparation method of molybdenum disulfide / polyether-based in-situ composite polymer electrolyte, comprising the following steps: Step 1: Preparation of molybdenum disulfide-coated separator Step 1.1: Dissolve 162.3 mg of sodium polyacrylate and 276.5 mg of sorbitan oleate in 5 mL of deionized water.

[0049] Step 1.2: Add 162.3 mg of molybdenum disulfide powder to the above solution under vigorous stirring and stir until uniform.

[0050] Step 1.3: Pour the above solution onto a PE battery separator and scrape it with a thickness of 20 μm. Use a heating plate at 40 °C to volatilize the water, and then molybdenum disulfide-coated separator can be obtained.

[0051] Step 2: Preparation of molybdenum disulfide / polyether-based in-situ composite polymer electrolyte Step 2.1: Dissolve 450 mg of lithium bis(trifluoromethanesulfonyl)imide in 1 mL of dioxolane to prepare an electrolyte solution and transfer it to a glove box filled with nitrogen.

[0052] Step 2.2: In the glove box, take a molybdenum disulfide-coated separator of appropriate size, and drop the electrolyte solution obtained in Step 2.1 onto its surface at a rate of 10 μL / cm 2 . After standing for 15 minutes, molybdenum disulfide / polyether-based in-situ composite polymer electrolyte can be obtained.

[0053] It should be noted that in Step 1.3 of this embodiment, the width of the initially coated separator is 20 cm and the length is 60 cm. In Step 2.2, a round separator with a diameter of 16 mm is used, and the mass ratio of molybdenum disulfide to dioxolane is 1:230.

[0054] SEM images before and after the preparation of the composite solid electrolyte are shown in Figure 3 . The molybdenum disulfide particles on the surface of the separator before the addition of the electrolyte are evenly distributed and the holes in the separator can be clearly seen; after the addition of the electrolyte, the surface of the separator is covered with a polymer, indicating the feasibility of the experimental scheme of the present invention.

[0055] Example 3 A preparation method of a molybdenum disulfide / polyether-based in-situ composite polymer electrolyte, comprising the following steps: Step 1: Preparation of a molybdenum disulfide-coated separator Step 1.1: Dissolve 162.3 mg of sodium polyacrylate and 276.5 mg of sorbitan oleate in 5 mL of deionized water.

[0056] Step 1.2: Add 162.3 mg of molybdenum disulfide powder to the above solution under vigorous stirring and stir until homogeneous.

[0057] Step 1.3: Pour the above solution onto a PE battery separator and scrape it with a thickness of 20 μm, and use a heating plate at 40 °C to volatilize the water, thus obtaining a molybdenum disulfide-coated separator.

[0058] Step 2: Preparation of a molybdenum disulfide / polyether-based in-situ composite polymer electrolyte Step 2.1: Dissolve 370 mg of lithium bis(trifluoromethanesulfonyl)imide in 1.25 mL of dioxolane, prepare an electrolyte solution and transfer it to a glove box filled with nitrogen.

[0059] Step 2.2: In the glove box, take a molybdenum disulfide-coated separator of appropriate size and drop the electrolyte solution obtained in Step 2.1 onto its surface at a rate of 20 μL / cm 2 . After standing for 20 minutes, a molybdenum disulfide / polyether-based in-situ composite polymer electrolyte can be obtained.

[0060] It should be noted that in Step 1.3 of this embodiment, the width of the initially coated separator is 20 cm and the length is 60 cm. In Step 2.2, a round separator with a diameter of 16 mm is used, and the mass ratio of molybdenum disulfide to dioxolane is 1:153.

[0061] Perform electrochemical-related tests on the solid electrolyte membrane obtained in this embodiment, and the test method is as follows: Test on the change of ionic conductivity with time. The molybdenum disulfide / polyether-based in-situ composite polymer electrolyte membrane was cut into circular pieces with a diameter of 19 mm, and then clamped by two stainless steel sheets. After heat preservation at different temperatures for 30 minutes, the impedance was measured, and the ionic conductivity at the corresponding temperature was calculated. The test results are as Figure 4 shown. Figure 4 The results show that the composite electrolyte has high ionic conductivity, which can ensure the normal use of the battery at room temperature.

[0062] Example 4 A preparation method of molybdenum disulfide / polyether-based in-situ composite polymer electrolyte, comprising the following steps: Step 1, Preparation of molybdenum disulfide-coated separator Step 1.1, Dissolve 162.3 mg of sodium polyacrylate and 276.5 mg of sorbitan oleate in 5 mL of deionized water.

[0063] Step 1.2, Add 162.3 mg of molybdenum disulfide powder to the above solution under vigorous stirring, and stir until uniform.

[0064] Step 1.3, Pour the above solution onto the PE battery separator for doctor blade coating, the coating thickness is 20 μm, and use a heating plate at 40 °C to volatilize the moisture, thus obtaining the molybdenum disulfide-coated separator.

[0065] Step 2, Preparation of molybdenum disulfide / polyether-based in-situ composite polymer electrolyte Step 2.1, Dissolve 400 mg of lithium bis(trifluoromethanesulfonyl)imide in 1.3 mL of 1,4-dioxolane, prepare an electrolyte solution and transfer it to a glove box filled with nitrogen.

[0066] Step 2.2, In the glove box, take a molybdenum disulfide-coated separator with a suitable size, and drop the electrolyte solution obtained in Step 2.1 onto its surface according to the amount of 25 μL / cm 2 . After standing for 25 minutes, the molybdenum disulfide / polyether-based in-situ composite polymer electrolyte can be obtained.

[0067] It should be noted that in Step 1.3 of this example, the width of the initial separator for doctor blade coating is 20 cm and the length is 60 cm. In Step 2.2, the separator used in the cell is a circular piece with a diameter of 16 mm, and the mass ratio of molybdenum disulfide to 1,4-dioxolane is 1:192.

[0068] The solid electrolyte membrane obtained in this example was subjected to electrochemical-related tests, and the test methods are as follows: Measurement of lithium ion transference number. The molybdenum disulfide / polyether-based in-situ composite polymer electrolyte membrane was cut into circular pieces with a diameter of 19 mm. In a glove box filled with argon (moisture content < 0.1 ppm, oxygen content < 0.1 ppm), a battery was assembled in the order of negative electrode shell + lithium sheet + solid electrolyte membrane + lithium sheet + positive electrode shell. First, the initial impedance of the battery was measured in an electrochemical workstation, then the change of current with time in the battery was measured at a constant potential of 10 mV. The test was ended after the current stabilized, 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), meeting the requirements of practical applications.

[0069] Example 5 A preparation method of molybdenum disulfide / polyether-based in-situ composite polymer electrolyte, comprising the following steps: Step 1. Preparation of molybdenum disulfide-coated separator Step 1.1. Dissolve 162.3 mg of sodium polyacrylate and 276.5 mg of sorbitan oleate in 5 mL of deionized water.

[0070] Step 1.2. Add 162.3 mg of molybdenum disulfide powder to the above solution under vigorous stirring and stir until uniform.

[0071] Step 1.3. Pour the above solution onto a PE battery separator for blade coating, with a coating thickness of 20 μm, and use a heating plate at 40 °C to volatilize the moisture, thus obtaining the molybdenum disulfide-coated separator.

[0072] Step 2. Preparation of molybdenum disulfide / polyether-based in-situ composite polymer electrolyte Step 2.1. Dissolve 320 mg of lithium bis(trifluoromethanesulfonyl)imide in 1.25 mL of dioxolane to prepare an electrolyte solution and transfer it to a glove box filled with nitrogen.

[0073] Step 2.2. In the glove box, take a molybdenum disulfide-coated separator of appropriate size, and drop the electrolyte solution obtained in (1) onto its surface at a rate of 20 μL / cm 2 . After standing for 20 minutes, the molybdenum disulfide / polyether-based in-situ composite polymer electrolyte can be obtained.

[0074] It should be noted that in Step 1.3 of this example, the width of the initial separator for blade coating is 20 cm and the length is 60 cm. In Step 2.2, a circular piece of separator with a diameter of 16 mm is used, and the mass ratio of molybdenum disulfide to dioxolane is 1:192.

[0075] Example 6 A preparation method of molybdenum disulfide / polyether-based in-situ composite polymer electrolyte, comprising the following steps: Step 1: Preparation of molybdenum disulfide-coated separator Step 1.1: Dissolve 162.3 mg of sodium polyacrylate and 276.5 mg of sorbitan oleate in 5 mL of deionized water.

[0076] Step 1.2: Add 162.3 mg of molybdenum disulfide powder to the above solution under vigorous stirring and stir until homogeneous.

[0077] Step 1.3: Pour the above solution onto a PE battery separator for doctor blading. The doctor blading thickness is 20 μm, and a heating plate at 40 °C is used for water evaporation to obtain the molybdenum disulfide-coated separator.

[0078] Step 2: Preparation of molybdenum disulfide / polyether-based in-situ composite polymer electrolyte Step 2.1: Dissolve 440 mg of bis(trifluoromethanesulfonyl)imide sodium in 1.25 mL of dioxolane to prepare an electrolyte solution and transfer it to a glove box filled with nitrogen.

[0079] Step 2.2: In the glove box, take a molybdenum disulfide-coated separator of appropriate size, and drop the electrolyte solution obtained in Step 2.1 onto its surface at a rate of 22 μL / cm 2 . After standing for 20 minutes, the molybdenum disulfide / polyether-based in-situ composite polymer electrolyte can be obtained.

[0080] It should be noted that in Step 1.3 of this example, the width of the initial separator for doctor blading is 20 cm and the length is 60 cm. In Step 2.2, a circular separator with a diameter of 16 mm is used, and the mass ratio of molybdenum disulfide to dioxolane is 1:162.

[0081] Example 7 A method for preparing a molybdenum disulfide / polyether-based in-situ composite polymer electrolyte, comprising the following steps: Step 1: Preparation of molybdenum disulfide-coated separator 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 homogeneous.

[0083] Step 1.3: Pour the above solution onto a PE battery separator for doctor blading. The doctor blading thickness is 20 μm, and a heating plate at 40 °C is used for water evaporation to obtain the molybdenum disulfide-coated separator.

[0084] Step 2: Preparation of molybdenum disulfide / polyether-based in-situ composite polymer electrolyte Step 2.1: Dissolve 520 mg of potassium bis(trifluoromethanesulfonyl)imide in 1.25 mL of dioxolane to prepare an electrolyte solution, and transfer it to a glove box filled with nitrogen.

[0085] Step 2.2: In the glove box, take a molybdenum disulfide-coated separator of appropriate size, and drop the electrolyte solution obtained in Step 2.1 onto its surface at a rate of 20 μL / cm 2 . After standing for 20 minutes, a molybdenum disulfide / polyether-based in-situ composite polymer electrolyte can be obtained.

[0086] It should be noted that in this embodiment, the width of the initial separator coated in Step 1.3 is 20 cm, the length is 60 cm, the separator used in Step 2.2 is a circular disc with a diameter of 16 mm, and the mass ratio of molybdenum disulfide to dioxolane is 1:150.

[0087] Example 8 A method for preparing a molybdenum disulfide / polyether-based in-situ composite polymer electrolyte, comprising the following steps: Step 1: Preparation of a molybdenum disulfide-coated separator Step 1.1: Dissolve 173.2 mg of polyvinyl alcohol 1788 and 340.83 mg of sorbitan oleate in 5 mL of deionized water.

[0088] Step 1.2: Add 324.6 mg of molybdenum disulfide powder to the above solution under vigorous stirring, and stir until homogeneous.

[0089] Step 1.3: Pour the above solution onto a PE battery separator and scrape it with a thickness of 20 μm. Use a heating plate at 40 °C to volatilize the water, and a molybdenum disulfide-coated separator is obtained.

[0090] Step 2: Preparation of a molybdenum disulfide / polyether-based in-situ composite polymer electrolyte Step 2.1: Dissolve 193 mg of sodium bis(trifluoromethanesulfonyl)imide in 1 mL of dioxolane to prepare an electrolyte solution, and transfer it to a glove box filled with nitrogen.

[0091] Step 2.2: In the glove box, take a molybdenum disulfide-coated separator of appropriate size, and drop the electrolyte solution obtained in Step 2.1 onto its surface at a rate of 15 μL / cm 2 . After standing for 30 minutes, a molybdenum disulfide / polyether-based in-situ composite polymer electrolyte can be obtained.

[0092] It should be noted that in this embodiment, the width of the initial separator coated in Step 1.3 is 20 cm, the length is 60 cm, the separator used in Step 2.2 is a circular disc with a diameter of 16 mm, and the mass ratio of molybdenum disulfide to dioxolane is 1:55.

[0093] Example 9 A preparation method of molybdenum disulfide / polyether-based in-situ composite polymer electrolyte, comprising the following steps: Step 1. Preparation of molybdenum disulfide-coated separator Step 1.1. Dissolve 162.3 mg of sodium alginate and 405.75 mg of fatty alcohol polyoxyethylene ether in 5 mL of deionized water.

[0094] Step 1.2. Add 243.45 mg of molybdenum disulfide powder to the above solution under vigorous stirring, and stir until uniform.

[0095] Step 1.3. Pour the above solution onto a PE battery separator for doctor blade coating, with a coating thickness of 20 μm, and use a heating plate at 40 °C to volatilize water, thus obtaining the molybdenum disulfide-coated separator.

[0096] Step 2. Preparation of molybdenum disulfide / polyether-based in-situ composite polymer electrolyte Step 2.1. Dissolve 455 mg of potassium bis(trifluoromethanesulfonyl)imide in 1 mL of dioxolane to prepare an electrolyte solution and transfer it to a glove box filled with nitrogen.

[0097] Step 2.2. In the glove box, take a molybdenum disulfide-coated separator with a suitable size cut, and drop the electrolyte solution obtained in Step 2.1 onto its surface at a rate of 20 μL / cm 2 . After standing for 15 minutes, the molybdenum disulfide / polyether-based in-situ composite polymer electrolyte can be obtained.

[0098] In order to further verify the excellent performance of the composite electrolyte prepared by the present invention, molybdenum disulfide is replaced by carbon nanotubes, and the specific operation steps are as follows: Step 1.1. Dissolve 800 mg of lithium bis(trifluoromethanesulfonyl)imide in 2 mL of dioxolane to prepare an electrolyte solution and transfer it to a glove box filled with nitrogen.

[0099] Step 1.2. In the glove box, add 1 mL of the above electrolyte solution to two glass bottles respectively, and then add 100 mg of molybdenum disulfide powder and carbon nanotube powder to each bottle. After standing for 1 h, observe, and the results are as Figure 6 shown. The results show that the ring-opening of dioxolane is selective and depends on the action of molybdenum disulfide. Other inorganic nanomaterials including carbon nanotubes cannot directly replace molybdenum disulfide for the preparation of composite electrolytes.

[0100] It should be noted that in Step 1.3 of this example, the width of the initial separator for doctor blade coating is 20 cm and the length is 60 cm. The separator used in Step 2.2 is a circular piece with a diameter of 16 mm, and the mass ratio of molybdenum disulfide to dioxolane is 1:100.

[0101] Comparative Example 1 A preparation method of a polyether-based polymer electrolyte comprises the following steps: Step 1.1: Dissolve 370 mg of lithium bis(trifluoromethanesulfonyl)imide in 1.25 mL of dioxolane, and then add 5 mg of aluminum trifluoromethanesulfonate to prepare an electrolyte solution, which is transferred into a glove box filled with nitrogen.

[0102] Step 1.2: In the glove box, take a pure PE separator with a suitable size cut, and drop the electrolyte solution obtained in (1) onto its surface at a rate of 20 μL / cm 2 . After standing for 60 minutes, the polymerization of dioxolane is completed to obtain a pure polymer electrolyte.

[0103] Perform electrochemical-related tests on the solid electrolyte membranes prepared in Example 5 and Comparative Example 1. The test method is as follows: Test of the electrochemical window. In a glove box filled with argon (moisture content < 0.1 ppm, oxygen content < 0.1 ppm), assemble a battery in the order of negative electrode shell + lithium sheet + solid electrolyte membrane + stainless steel sheet + positive electrode shell, and perform linear sweep voltammetry test in an electrochemical workstation. The test range is open circuit voltage ~ 6V. The test results are as Figure 7 shown. The results show that the molybdenum disulfide / polyether-based in-situ composite polymer electrolyte has an oxidation potential of 5.15V and can operate safely and stably in a lithium-ion battery, avoiding the oxidation and decomposition of the solid electrolyte by high-voltage cathode materials.

[0104] Application Example 1 In-situ prepare a composite electrolyte membrane inside the battery. Taking a button lithium battery as an example: In the glove box, place the components in the order of positive electrode plate (lithium iron phosphate), the molybdenum disulfide-coated separator prepared in Example 4, and negative electrode plate (lithium iron phosphate). Drop the electrolyte solution obtained in Step 2.1 of Example 4 into the separator at a rate of 20 μL / cm 2 . Assemble the battery, and after placing the assembled battery for 16 h, a molybdenum disulfide / polyether-based in-situ composite polymer electrolyte can be in-situ constructed inside the battery.

[0105] The cycle performance of the battery obtained in this application example is as Figure 8 shown. The results show that the in-situ composite electrolyte membrane can maintain good contact between the positive and negative electrodes and the electrolyte inside the battery and keep the battery running normally.

[0106] Application Example 2 Use the composite electrolyte membrane ex-situ. Taking a button sodium symmetric battery as an example: Place them in the glove box in the order of the positive electrode plate (sodium metal sheet), the molybdenum disulfide / polyether-based in-situ composite electrolyte membrane prepared in Example 6, and the negative electrode plate (sodium metal sheet), and assemble the battery for constant current charge and discharge tests; the cycle performance of the battery obtained in this example is as Figure 9 shown. The normal charge and discharge cycle of this battery shows that the composite electrolyte has application potential in sodium batteries.

[0107] Application Example 3 Use the composite electrolyte membrane in-situ. Take the button-type potassium symmetric battery as an example: Place them in the glove box in the order of the positive electrode plate (potassium metal sheet), the molybdenum disulfide / polyether-based in-situ composite electrolyte membrane prepared in Example 7, and the negative electrode plate (potassium metal sheet), and assemble the battery for constant current charge and discharge tests; the cycle performance of the battery obtained in this example is as Figure 10 shown. The normal charge and discharge cycle of this battery shows that the composite electrolyte has application potential in sodium batteries.

[0108] Although the preferred embodiments of the present invention have been described, those skilled in the art can make additional changes and modifications once they know the basic creative concept. Therefore, the appended claims are intended to be construed to include the preferred embodiments as well as all changes and modifications falling within the scope of the present invention.

[0109] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these modifications and variations.

Claims

1. A method for preparing a molybdenum disulfide / polyether-based in-situ composite solid electrolyte, characterized in that: The following steps are involved: Dissolving a water-soluble binder and a nonionic surfactant in water, adding molybdenum disulfide and mixing evenly to obtain a mixed solution; coating the mixed solution on a battery separator, and volatilizing the water in the mixed solution to obtain a molybdenum disulfide coated separator; Dissolving an ionic salt in dioxolane to obtain an electrolyte; The electrolyte is added dropwise onto the molybdenum disulfide coated diaphragm and allowed to stand at room temperature to allow the molybdenum disulfide to initiate cationic ring-opening polymerization of dioxolane to obtain a molybdenum disulfide / polyether-based in-situ composite solid electrolyte.

2. The method for preparing a molybdenum disulfide / polyether-based in-situ composite solid electrolyte according to claim 1, characterized in that: The mass ratio of molybdenum disulfide to dioxolane is 1:55~230.

3. The method for preparing a molybdenum disulfide / polyether-based in-situ composite solid electrolyte according to claim 1, characterized in that: The standing time is 15min~30min.

4. The method for preparing a molybdenum disulfide / polyether-based in-situ composite solid electrolyte according to claim 1, characterized in that: The mass ratio of the water-soluble binder to molybdenum disulfide is 1:1~2.

5. The method for preparing a molybdenum disulfide / polyether-based in-situ composite solid electrolyte according to claim 1, characterized in that: The mass ratio of the water-soluble binder to the non-ionic surfactant is 1:1.7~2.

5.

6. The method for preparing a molybdenum disulfide / polyether-based in-situ composite solid electrolyte according to claim 1, characterized in that: In the electrolyte, the concentration of the ion salt is 193 mg / mL~455 mg / mL, and the ion salt is an organic lithium salt, an organic sodium salt or an organic potassium salt.

7. The method for preparing a molybdenum disulfide / polyether-based in-situ composite solid electrolyte according to claim 1, characterized in that: The water-soluble binder is sodium polyacrylate, polyvinyl alcohol or sodium alginate.

8. The method for preparing a molybdenum disulfide / polyether-based in-situ composite solid electrolyte according to claim 1, characterized in that: The nonionic surfactant is sorbitan oleate or fatty alcohol polyoxyethylene ether.

9. A molybdenum disulfide / polyether-based in-situ composite solid electrolyte prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the molybdenum disulfide / polyether-based in-situ composite solid electrolyte according to claim 9 in preparing a battery.

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