A two-dimensional MoO 3-X Method for preparing a filler polymer electrolyte

Abstract

The application belongs to the technical field of solid-state batteries, and particularly relates to a two-dimensional MoO 3‑X Preparation method and application of filler polymer electrolyte. In view of the problems of low room temperature ionic conductivity, poor interface compatibility, insufficient mechanical strength and serious lithium dendrite growth of the polymer electrolyte, the application realizes two-dimensional MoO 3‑X Modification of filler on polyvinylidene fluoride electrolyte. Through two-dimensional MoO 3‑X The synergistic effect of filler anchoring anions and physical barrier is expected to solve the key problems of lithium ion conduction, interface compatibility and dendrite growth, and provide an effective way for realizing high-energy-density solid-state lithium metal batteries.

Description

Technical Field

[0001] This invention belongs to the field of solid-state lithium metal batteries, and specifically relates to a method based on two-dimensional MoO. 3-X Preparation method of filler polymer electrolyte. Background Technology

[0002] With the rapid development of electric vehicles and portable electronic devices, energy storage systems are placing increasingly stringent demands on battery energy density and safety. However, the energy density of lithium-ion batteries based on existing energy storage mechanisms is gradually approaching their theoretical limits, making it difficult to meet the application requirements of future high-performance energy storage systems. Furthermore, traditional lithium-ion batteries generally use liquid electrolytes, and electrode materials are prone to side reactions with the electrolyte during cycling, leading to shortened battery life. Simultaneously, under extreme conditions such as overcharging and short circuits, liquid electrolytes pose risks of leakage, combustion, and even explosion, severely restricting battery safety performance. Solid-state polymer electrolytes (SPEs), due to their excellent thermal and chemical stability, are considered one of the important development directions for improving battery safety. SPEs can significantly reduce the risk of thermal runaway in batteries, while their dense structure helps suppress lithium dendrite penetration, improves the compatibility of the lithium metal anode, and avoids side reactions between lithium metal and the liquid electrolyte. In addition, SPEs have good flexibility and low production costs, showing promising prospects for large-scale application.

[0003] However, traditional SPEs still face key problems such as low room-temperature ionic conductivity and insufficient mechanical strength, making it difficult to effectively suppress lithium dendrite growth and achieve uniform lithium ion deposition and stripping, thus limiting their practical application in solid-state lithium metal batteries. To address these issues, this invention proposes a composite polymer electrolyte that incorporates two-dimensional MoO₂. 3-X The material modifies the polymer matrix. On the one hand, two-dimensional MoO 3-X As a functional filler, it can significantly improve the mechanical strength of polymer electrolytes and enhance their physical suppression of lithium dendrites; on the other hand, two-dimensional MoO 3-X The interaction between the material and the lithium salt and polymer chains helps promote the dissociation of the lithium salt and the movement of polymer chain segments, thereby improving the overall lithium-ion conductivity of the system. In summary, based on two-dimensional MoO... 3-X Modified composite polymer electrolytes provide a feasible technical path for constructing high-energy-density and high-safety solid-state lithium metal batteries.

[0004] Therefore, this application provides a two-dimensional MoO 3-X The preparation method of filler polymer electrolytes meets the requirements. Summary of the Invention

[0005] The purpose of this application is to provide a two-dimensional MoO2-based... 3-XA method for preparing a filler polymer electrolyte is presented. This polymer electrolyte exhibits good mechanical strength and oxidation resistance, can suppress lithium dendrites and match a high-voltage cathode; in addition, it also has high ionic conductivity and lithium-ion transference number, and the full cell exhibits good cycle stability.

[0006] To achieve the above objectives, this application provides the following technical solution: a method based on two-dimensional MoO 3-X A method for preparing filler polymer electrolytes based on two-dimensional MoO 3-X The preparation method of the filler polymer solid electrolyte, the specific steps are as follows: S1. Add polyvinylidene fluoride and lithium bis(fluorosulfonyl)imide salt to a solvent and heat and stir until completely dissolved to obtain a homogeneous viscous solution; S2. Add two-dimensional MoO to the solution obtained in step S1. 3-X The filler material is heated and stirred to form a viscous suspension. S3. Pour the solution obtained in step S2 into a clean mold, place the mold in an oven, and evaporate the solvent at a certain temperature to obtain a two-dimensional MoO2-based solution. 3-X Polymer electrolyte for filler; S4. Remove the electrolyte obtained in step S3 from the mold, assemble it into a coin cell according to the negative electrode Li, the electrolyte obtained in S3, and the positive electrode, and then encapsulate it to obtain a two-dimensional MoO-based battery. 3-X Lithium metal batteries with filler.

[0007] Preferably, in step S1, the mass fraction of the polymer in the solution is 10%-40%, and the mass fraction of the lithium salt is 10%-40%.

[0008] Preferably, in step S1, the solution is one or a mixture of two or more of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, and acetonitrile.

[0009] Preferably, in step S3, the temperature range of the evaporation solution is 60-80 °C.

[0010] Preferably, the two-dimensional MoO2 described in step S2 3-X The material was prepared by mechanical exfoliation.

[0011] Preferably, the polymer electrolyte prepared by the method is a smooth, dense film.

[0012] Preferably, it is used to prepare lithium metal batteries or sodium metal batteries.

[0013] Preferably, based on two-dimensional MoO 3-X Application of filler polymer solid electrolytes in solid lithium metal batteries.

[0014] In summary, the technical effects and advantages of this invention are as follows: 1. In this invention, a simple stirring and solution casting method is used to prepare two-dimensional MoO₂. 3-X The material and lithium salt are uniformly dispersed in the polyvinylidene fluoride polymer matrix, which solves the problems of poor mechanical strength and low ionic conductivity of polymer electrolyte at room temperature.

[0015] 2. In this invention, by introducing two-dimensional MoO 3-X The filler serves two purposes: firstly, it anchors anions, promotes lithium salt dissociation, and increases the concentration of free lithium ions; secondly, it constructs a dense physical barrier in the polymer matrix, improving the polymer's mechanical strength and inhibiting the growth of lithium dendrites.

[0016] 3. This invention has the advantages of simple preparation process and controllable process, and has the application prospect of large-scale production. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a scanning electron microscope image of the polymer electrolyte in Example 1 of the present invention; Figure 2 This is a voltage stability window diagram of the polymer electrolyte in Example 1 of the present invention; Figure 3 The impedance spectrum of the polymer electrolyte in Example 1 of the present invention; Figure 4 This is a lithium-ion transport number graph of the electrolyte in Example 1 of the present invention; Figure 5 This is a charge-discharge curve of the electrolyte at 0.5 C in Example 1 of the present invention. Detailed Implementation

[0019] 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.

[0020] Example 1: A two-dimensional MoO 3-XPreparation method of filler polymer electrolyte, Preparation of two-dimensional vacant molybdenum trioxide nanosheets (S1): 0.5 g of MoO3 was dispersed in 50 mL of a mixed solution of ethanol and water (ethanol to water volume ratio 1:1) and sonicated at room temperature for 6 h. The dispersion was then centrifuged at 4000 rpm for 10 min. The supernatant was collected, and 8 mg of thioacetamide was weighed and mixed with 20 mL of the supernatant, then sonicated at room temperature for 5 h. The resulting solution was mixed with a certain amount of CHCl3, and after standing and separating into layers, the CHCl3 fraction was removed. This process was repeated three times to obtain blue MoO3 nanosheets. 3-x The solution was heated at 50 °C with forced air for 12 h to obtain a powder sample.

[0021] S2 Preparation of polymer electrolyte: Dissolve 400 mg of polyvinylidene fluoride and 267 mg of lithium bis(fluorosulfonyl)imide in 15 mL of N-methylpyrrolidone and stir until completely dissolved to obtain a viscous solution. Add 40 mg of two-dimensional MoO2 to the above solution. 3-x Nanosheets were heated and stirred to form a viscous suspension. The resulting viscous suspension was poured into a clean polytetrafluoroethylene mold and dried in a forced-air oven at 60 °C for 24 h to prepare a polymer electrolyte based on nano-vacancy molybdenum trioxide, denoted as PVMO.

[0022] S3 Preparation of Solid-State Lithium Metal Batteries: Taking a CR2032 coin cell as an example, in a glove box filled with argon gas, the negative electrode (Li) and MoO2-based... 3-x The polymer electrolyte and positive electrode (NCM811) of the nanosheets were assembled in this order and left to stand for 8 h to prepare a two-dimensional MoO2-based polymer electrolyte. 3-X Lithium metal batteries with filler polymer electrolytes.

[0023] Example 2 Preparation of two-dimensional vacant molybdenum trioxide nanosheets (S1): 0.5 g of MoO3 was dispersed in 50 mL of a mixed solution of ethanol and water (ethanol to water volume ratio 1:1) and sonicated at room temperature for 6 h. The dispersion was then centrifuged at 4000 rpm for 10 min. The supernatant was collected, and 8 mg of thioacetamide was weighed and mixed with 20 mL of the supernatant, then sonicated at room temperature for 5 h. The resulting solution was mixed with a certain amount of CHCl3, and after standing and separating into layers, the CHCl3 fraction was removed. This process was repeated three times to obtain blue MoO3 nanosheets. 3-x The solution was heated at 50 °C with forced air for 12 h to obtain a powder sample.

[0024] S2 Preparation of Polymer Electrolyte: 400 mg of polyvinylidene fluoride and 267 mg of lithium difluorosulfonyl imide were dissolved in 15 mL of N-methylpyrrolidone and stirred until completely dissolved to obtain a viscous solution. 20 mg of two-dimensional MoO2 was added to the above solution. 3-x Nanosheets were stirred to form a viscous suspension. The resulting viscous suspension was poured into a clean polytetrafluoroethylene mold, and the mold was placed in a forced-air drying oven at 60 °C for 24 h to prepare nanosheets based on two-dimensional MoO2. 3-X Polymer electrolyte for fillers.

[0025] S3 Preparation of Solid-State Lithium Metal Batteries: Taking a CR2032 coin cell as an example, in a glove box filled with argon gas, the negative electrode (Li) and MoO2-based... 3-x The polymer electrolyte and positive electrode (NCM811) of the nanosheets were assembled in this order and left to stand for 8 h to prepare a two-dimensional MoO2-based polymer electrolyte. 3-X Lithium metal batteries with filler polymer electrolytes.

[0026] Example 3 Preparation of two-dimensional vacant molybdenum trioxide nanosheets (S1): 0.5 g of MoO3 was dispersed in 50 mL of a mixed solution of ethanol and water (ethanol to water volume ratio 1:1) and sonicated at room temperature for 6 h. The dispersion was then centrifuged at 4000 rpm for 10 min. The supernatant was collected, and 8 mg of thioacetamide was weighed and mixed with 20 mL of the supernatant, then sonicated at room temperature for 5 h. The resulting solution was mixed with a certain amount of CHCl3, and after standing and separating into layers, the CHCl3 fraction was removed. This process was repeated three times to obtain blue MoO3 nanosheets. 3-x The solution was heated at 50 °C with forced air for 12 h to obtain a powder sample.

[0027] Preparation of polymer electrolyte S2: 400 mg of polyvinylidene fluoride and 267 mg of lithium difluorosulfonylimide were dissolved in 15 mL of N-methylpyrrolidone and stirred until completely dissolved to obtain a viscous solution. 60 mg of nano-vacant molybdenum trioxide was added to the above solution, and stirring continued to form a viscous suspension. The resulting viscous suspension was poured into a clean polytetrafluoroethylene mold, and the mold was placed in a forced-air drying oven at 60 °C for 24 h to prepare a two-dimensional MoO2-based polymer electrolyte. 3-X Polymer electrolyte for fillers.

[0028] S3 Preparation of Solid-State Lithium Metal Batteries: Taking the CR2032 coin cell as an example, in an argon-filled glove box, the positive electrode (NCM811), the polymer electrolyte based on nano-gallium oxide, and the negative electrode (Li) were assembled in this order and left to stand for 8 hours to prepare a solid-state lithium metal battery based on two-dimensional MoO. 3-XLithium metal batteries with filler polymer electrolytes.

[0029] Comparative Example 1 This comparative example uses molybdenum trioxide filler without two-dimensional vacancy sites. The specific steps are as follows: S1 dissolved 400 mg of polyvinylidene fluoride and 267 mg of lithium difluorosulfonamide in 15 mL of N-methylpyrrolidone, and heated and stirred until completely dissolved to obtain a viscous solution. The resulting viscous solution was poured into a clean polytetrafluoroethylene mold, and the mold was placed in a forced-air drying oven at 60 °C for 24 h to prepare the polymer electrolyte.

[0030] S2 Preparation of solid-state lithium metal batteries: Taking CR2032 button cell as an example, in a glove box filled with argon gas, the negative electrode (Li), unmodified polymer electrolyte, and positive electrode (NCM811) are assembled in this order and left to stand for 8 hours to prepare a lithium metal battery based on unmodified polymer electrolyte.

[0031] The scanning electron microscope image of the polymer electrolyte prepared in Example 1 is shown below. Figure 1 As shown. From Figure 1 It can be seen that the electrolyte surface is smooth, and MoO 3-x The nanosheets are evenly distributed.

[0032] The linear sweep voltammetric curve of this embodiment 1 is as follows: Figure 2 As shown, the electrochemical stability window is 4.5 V, indicating that the electrolyte can be matched with a high-voltage cathode.

[0033] The impedance spectrum of the electrolyte-assembled stainless steel symmetric cell prepared in Example 1 is as follows: Figure 3 As shown, through the formula The calculated ionic conductivity of the electrolyte is 0.42 mS / cm. -1 Where R is the resistance of the electrolyte obtained from the impedance spectrum (x-axis intercept), L is the thickness of the electrolyte, and S is the contact area between the stainless steel electrode and the electrolyte.

[0034] The impedance spectrum of the electrolyte-assembled coin-type lithium-ion symmetric battery prepared in Example 1 is as follows: Figure 4 As shown, through the formula The lithium-ion transference number of the electrolyte in Example 1 was calculated to be 0.41, where (V is the applied polarization voltage of 0.01 V, I0 and IS are the initial current and steady-state current, and R0 and RS are the initial resistance and steady-state resistance).

[0035] The electrolyte-assembled NCM811 / Li coin cell (CR2032) prepared in Example 1 exhibited a discharge specific capacity of 176.8 mAh g⁻¹ when tested at room temperature and 0.5 C. -1 .

[0036] The electromechanical connection involved in this invention is a common method used by those skilled in the art, and technical inspiration can be obtained through a limited number of experiments. It is common knowledge.

[0037] Components not described in detail in this article are existing technologies.

[0038] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method based on two-dimensional MoO 3-X A method for preparing a filler polymer solid electrolyte, characterized in that, The specific steps are as follows: S1. Add polyvinylidene fluoride and lithium bis(fluorosulfonyl)imide salt to a solvent and heat and stir until completely dissolved to obtain a homogeneous viscous solution; S2. Add two-dimensional MoO to the solution obtained in step S1. 3-X The filler material is heated and stirred to form a viscous suspension. S3. Pour the solution obtained in step S2 into a clean mold, place the mold in an oven, and evaporate the solvent at a certain temperature to obtain a two-dimensional MoO2-based solution. 3-X The polymer electrolyte of the filler; S4. Remove the electrolyte obtained in step S3 from the mold, assemble it into a coin cell according to the negative electrode Li, the electrolyte obtained in S3, and the positive electrode, and then encapsulate it to obtain a two-dimensional MoO-based battery. 3-X Lithium metal batteries with filler.

2. A method based on two-dimensional MoO as described in claim 1 3-X A method for preparing a filler polymer solid electrolyte, characterized in that: In step S1, the mass fraction of the polymer in the solution is 10%-40%, and the mass fraction of the lithium salt is 10%-40%.

3. A method based on two-dimensional MoO as described in claim 1 3-X A method for preparing a filler polymer solid electrolyte, characterized in that: In step S1, the solution is one or a mixture of two or more of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, and acetonitrile.

4. A method based on two-dimensional MoO as described in claim 1 3-X A method for preparing a filler polymer solid electrolyte, characterized in that: In step S3, the temperature range of the evaporation solution is 60-80 ℃.

5. A method based on two-dimensional MoO as described in claim 1 3-X A method for preparing a filler polymer solid electrolyte, characterized in that: The two-dimensional MoO mentioned in step S2 3-X The material was prepared by mechanical exfoliation.

6. The preparation method according to any one of claims 1-5 yielding a two-dimensional MoO2-based product. 3-X Filler polymer solid electrolyte, characterized in that: The polymer electrolyte, prepared by the method described above, is a smooth, dense film.

7. The two-dimensional MoO based invention according to claim 6 3-X The application of filler polymer solid electrolytes is characterized by: Used to manufacture lithium metal batteries or sodium metal batteries.

8. The two-dimensional MoO based invention according to claim 7 3-X The application of filler polymer solid electrolytes is characterized by: Based on two-dimensional MoO 3-X Application of filler polymer solid electrolytes in solid lithium metal batteries.

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