Sulfur-containing all-solid-state polymer electrolyte membrane for energy storage lithium battery and preparation method thereof

Abstract

The application discloses a kind of sulfur-containing full solid-state polymer electrolyte membrane for energy storage lithium battery and preparation method thereof, belong to polymer electrolyte technical field.The preparation method of sulfur-containing full solid-state polymer electrolyte membrane provided by the application includes uniformly mixing 2,2'-diamino diphenyl disulfide and sulfurized divinyl, and obtaining polymer solid by polymerization reaction;The mixed solution is obtained by dissolving the polymer solid in dimethyl sulfoxide, lithium bis-trifluoromethanesulfonimide is added to the mixed solution and uniformly mixed to obtain a precursor solution;The precursor solution is cast in a mold, and the sulfur-containing full solid-state polymer electrolyte membrane is obtained after vacuum drying.The electrolyte membrane provided by the application solves the technical problems of low ionic conductivity of traditional solid-state electrolyte, insufficient lithium ion migration number, serious interface polarization and weak oxidation resistance through triple mechanism.At the same time, the lithium metal battery assembled by the sulfur-containing full solid-state polymer electrolyte has excellent electrochemical performance and cycle performance.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of polymer electrolytes, and particularly relates to a sulfur-containing all-solid-state polymer electrolyte film for energy storage lithium batteries and a preparation method thereof. BACKGROUND

[0002] Lithium metal batteries have become an ideal choice for energy storage devices due to their outstanding energy density and cycle stability. However, the flammability and severe side reactions with lithium metal of traditional organic liquid electrolytes lead to safety hazards such as electrode corrosion and dendrite uncontrollable growth, which seriously restricts their commercial application. Solid-state electrolytes have become a key path to break through the safety bottleneck because they can inhibit lithium dendrite penetration and reduce the risk of thermal runaway.

[0003] Current solid-state electrolytes are mainly divided into inorganic and polymer systems, among which polymer types are attracting much attention due to their good flexibility and strong processing adaptability. However, traditional polymer electrolyte materials represented by polyethylene oxide (PEO) still face many challenges. For example: the room temperature ionic conductivity is generally low, which is difficult to meet the fast charging demand; the electrode / electrolyte interface contact impedance is large, which leads to increased polarization; the electrochemical stability window is narrow, and oxidation decomposition easily occurs under high voltage conditions; the mechanical strength is insufficient, which is difficult to continuously inhibit lithium dendrite penetration.

[0004] In recent years, various new polymer electrolyte systems such as nitrile, siloxane, carbonate and polyvinylidene fluoride have been developed, but they are often difficult to balance high ionic conductivity, excellent mechanical strength and ideal safety due to the inherent properties of single polymer backbone structure. In view of this challenge, organic polysulfide electrolytes have attracted attention due to their structural characteristics: the polysulfide segment-(S-S) n - with abundant sulfur atoms and lone pair electrons, it forms an efficient lithium ion transport channel, the low electronegativity of sulfur element not only significantly reduces the lithium ion migration energy barrier, improves the ionic conductivity and cycle stability, and the flexible backbone can also effectively improve the interface compatibility, and the unique dynamic S-S bond further endows the material with self-repairing ability, which helps to inhibit the generation of lithium dendrites. However, this type of electrolyte still has limitations in practical application, especially in terms of electrochemical stability under high voltage conditions, inhibition of anion migration to improve lithium ion transference number, strengthening of interface compatibility to reduce polarization, and full play of self-repairing function, which restricts the breakthrough of solid-state lithium batteries in long cycle life and interface stability. SUMMARY

[0005] To overcome the technical problems of low ionic conductivity, insufficient lithium-ion transference number, severe interface polarization, and weak oxidation resistance of traditional solid electrolytes, this invention provides a sulfur-containing all-solid-state polymer electrolyte membrane for energy storage lithium batteries and its preparation method. Through a triple synergistic mechanism of sulfur chain coordination conduction, amino bidentate chelation, and dynamic SS bond repair, it breaks through the bottleneck of interface stability and long cycle life of solid batteries.

[0006] To achieve the above objectives, the present invention employs the following technical solution:

[0007] In a first aspect, the present invention provides a sulfur-containing all-solid polymer electrolyte membrane, which is prepared by hot melting, casting, and evaporation of a sulfur-containing all-solid polymer, wherein the general structural formula of the sulfur-containing all-solid polymer is:

[0008]

[0009] In the formula, n is the degree of aggregation, and 5000≤n≤50000.

[0010] A further improvement of the present invention is that the thickness of the sulfur-containing all-solid polymer electrolyte membrane is 55µm±5µm.

[0011] Secondly, the present invention also provides a method for preparing a sulfur-containing all-solid polymer electrolyte membrane, comprising the following steps:

[0012] 2,2'-diaminodiphenyl disulfide was mixed evenly with divinyl sulfide and polymerized to obtain a polymer solid.

[0013] The polymer solid was dissolved in dimethyl sulfoxide to obtain a mixed solution, and lithium bis(trifluoromethanesulfonyl)imide was added to the mixed solution and mixed evenly to obtain a precursor solution;

[0014] The precursor solution was poured into a mold and dried under vacuum to obtain a sulfur-containing all-solid polymer electrolyte membrane.

[0015] A further improvement of the present invention is that the mass ratio of the 2,2'-diaminodiphenyl disulfide to the divinyl sulfide is 1:(1~8).

[0016] A further improvement of the present invention is that the polymerization reaction is carried out in an oil bath at a temperature of 80~160℃ for a reaction time of 30~120min, and the polymer solid is obtained after the reaction is completed and cooled to room temperature.

[0017] A further improvement of the present invention is that the amount of lithium bis(trifluoromethanesulfonyl)imide added is 20% to 80% of the total mass of 2,2'-diaminodiphenyl disulfide and divinyl sulfide.

[0018] A further improvement of the present invention is that lithium bis(trifluoromethanesulfonyl)imide is added to the mixed solution and magnetically stirred at a temperature of 25~60℃ for 12~48h until the mixture is homogeneous and a precursor solution is obtained.

[0019] A further improvement of this invention is that the specific method for pouring the precursor solution into the mold is as follows:

[0020] Slowly pour the precursor solution into the center of the PTFE mold until the PTFE mold is completely filled, then stop pouring.

[0021] The depth of the PTFE mold is 250~350µm.

[0022] A further improvement of the present invention is that the vacuum drying temperature is 25~130℃ and the drying time is 12~24h.

[0023] Thirdly, the present invention also provides an application of a sulfur-containing all-solid polymer electrolyte membrane used in lithium-ion batteries.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] This invention provides a sulfur-containing all-solid-state polymer electrolyte membrane, which synergistically enhances ionic conductivity and Li through a triple mechanism of sulfur chain coordination conduction, amino bidentate chelation, and dynamic SS bond repair. + This increases the transference number and reduces interfacial polarization. First, the lone pair electrons of the sulfur atom interact with Li... + Coordination, making Li + It can perform low-barrier jumps along the highly polar sulfur chain -S-CH2-S-CH2-CH2-SS-, and the dynamic process of disulfide bond breaking and recombination also generates transient diffusion channels. Secondly, the ortho-amino group -NH2 on the benzene ring stabilizes Li through bidentate coordination. + Its chelating energy is stronger than that of the cyano group of traditional polyacrylonitrile, thus reducing the migration activation energy; at the same time, the protonated amino group -NH 3+ This anchors anions, significantly increasing the lithium-ion mobility number to over 0.7. Furthermore, the benzene ring conjugated system of this membrane absorbs oxidative free radicals, resulting in an antioxidant potential window exceeding 4.5V vs. Li. + / Li. In addition, the rigid benzene ring unit endows it with a high tensile strength exceeding 5 MPa, effectively suppressing lithium dendrite penetration; the reversible recombination of dynamic SS bonds repairs cracks generated during charge and discharge, ensuring long cycle life; the amino group reacts with Li metal to form Li3N / Li x The S passivation layer improves lithium metal compatibility, enabling stable operation for over 1000 hours.

[0026] This invention also provides a method for preparing a sulfur-containing all-solid-state polymer electrolyte membrane. By in-situ polymerization of 2,2'-diaminodiphenyl disulfide and divinyl sulfide, a three-dimensional cross-linked network is formed, ensuring the mechanical strength of the electrolyte membrane while simultaneously constructing continuous ion transport channels through the synergistic effect of sulfide bonds and sulfide groups. Secondly, dimethyl sulfoxide is selected as a green solvent to promote uniform dispersion of lithium salt while dissolving the polymer. The resulting homogeneous precursor solution, after vacuum drying, effectively removes residual solvent and maintains a stable pore structure. Simultaneously, the added lithium bis(trifluoromethanesulfonyl)imide, as a highly dissociable lithium salt, forms a strong interaction with the sulfur-containing polymer matrix, improving ionic conductivity and inhibiting anion migration, thereby obtaining a sulfur-containing all-solid-state electrolyte membrane with high ionic conductivity, excellent thermal stability, and good interfacial compatibility. This preparation method is simple and mild, and the resulting electrolyte membrane shows potential for reducing interfacial impedance and inhibiting lithium dendrite growth in solid-state lithium batteries, providing an effective solution for developing energy storage devices with high safety and long cycle life. Attached Figure Description

[0027] The accompanying drawings described herein are for illustrative purposes only and are not intended to limit the scope of the invention in any way. Furthermore, the shapes and proportions of the components in the drawings are merely illustrative to aid in understanding the invention and do not specifically limit the shapes and proportions of the components of the invention.

[0028] Figure 1 The XRD pattern of the sulfur-containing all-solid polymer electrolyte membrane prepared in Example 2 of this invention;

[0029] Figure 2 Impedance test diagrams of the polymer electrolyte membranes prepared in Examples 1-3 and Comparative Example 1 of this invention;

[0030] Figure 3(a) is an SEM image of the sulfur-containing all-solid polymer electrolyte membrane prepared in Example 2 of the present invention;

[0031] Figure 3(b) is a SEM image of the polymer electrolyte membrane prepared in Comparative Example 1 of the present invention;

[0032] Figure 4 The rate performance of the polymer electrolyte membranes prepared in Example 2 and Comparative Example 1 of this invention is shown at 25°C. Detailed Implementation

[0033] To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used in the specification and claims are explained and defined in general below. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0034] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.

[0035] In this document, all features defined by numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0036] In this article, unless otherwise specified, “contains,” “includes,” “containing,” “has,” or similar terms cover the meanings of “composed of” and “mainly composed of,” for example, “A contains a” covers the meanings of “A contains a and others” and “A contains only a.”

[0037] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0038] This invention provides a sulfur-containing all-solid polymer electrolyte membrane, which is prepared by hot melting, casting, and evaporation of a sulfur-containing all-solid polymer. The general structural formula of the sulfur-containing all-solid polymer is:

[0039]

[0040] In the formula, n is the degree of aggregation, and 5000≤n≤50000.

[0041] The thickness of the sulfur-containing all-solid polymer electrolyte membrane is 55µm±5µm.

[0042] The sulfur-containing all-solid-state polymer electrolyte membrane of this invention replaces the ion transport function of the liquid electrolyte with its solid-state ion conduction properties, and simultaneously replaces the physical isolation function of the separator with its dense and robust physical structure, achieving a crucial "two-in-one" integration. This integrated design not only simplifies the battery structure, but more importantly, it fundamentally overcomes the technical problems that have constrained the development of traditional and solid-state batteries, such as low ion conductivity, insufficient lithium-ion transference number, severe interface polarization, and weak oxidation resistance. It brings a leap forward in inherent battery safety, significantly extends battery life and a wider operating temperature range, and breaks through the bottlenecks of interface stability and long cycle life in solid-state batteries.

[0043] This invention also provides a method for preparing a sulfur-containing all-solid polymer electrolyte membrane, comprising the following steps:

[0044] 2,2'-Diaminodiphenyl disulfide (DADPS) and divinyl disulfide (DTVS) were mixed evenly and polymerized to obtain a polymer solid.

[0045] The polymer solid was dissolved in dimethyl sulfoxide (DMSO) to obtain a mixed solution. Lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) was added to the mixed solution and mixed evenly to obtain a precursor solution.

[0046] The precursor solution was poured into a mold and vacuum dried to obtain a sulfur-containing all-solid polymer electrolyte membrane, denoted as P(DADPS). x -DTVS y @LiTFSI, where x and y represent the mass ratio of 2,2'-diaminodiphenyl disulfide to divinyl sulfide, i.e., x=1, 1≤y≤8.

[0047] In some embodiments, the mass ratio of the 2,2'-diaminodiphenyl disulfide to the divinyl sulfide is 1:(1~8).

[0048] In some embodiments, 2,2'-diaminodiphenyl disulfide and divinyl sulfide are mixed uniformly at a mass ratio, and then polymerized in an oil bath at a temperature of 80~160°C for 30~120 min. After the reaction is completed, the mixture is cooled to room temperature to obtain a polymer solid. Silicone oil / mineral oil has a high specific heat capacity, which can buffer temperature fluctuations and maintain an accuracy of ±1~2°C, ensuring the controllability of the sulfide exchange reaction. Furthermore, the oil medium achieves three-dimensional homogenization through thermal convection, avoiding localized overheating that could lead to side reactions. Moreover, the oil layer covering the reaction system can block air oxygen and prevent the sulfide from oxidizing to sulfone.

[0049] In some embodiments, the amount of lithium bis(trifluoromethanesulfonyl)imide added is 20% to 80% of the total mass of 2,2'-diaminodiphenyl disulfide and divinyl sulfide. Within the addition range of 20% to 80%, LiTFSI can form a continuous ion conduction network, significantly improving ion conductivity, while suppressing phase separation and anion aggregation caused by excessive lithium salt, and maintaining mechanical stability.

[0050] In some embodiments, the polymerization reaction is carried out in an oil bath at a temperature of 80~160°C for a reaction time of 30~120 min, and the polymer solid is obtained by cooling to room temperature after the reaction is completed.

[0051] In some embodiments, the precursor solution is slowly poured into the center of the PTFE mold until it is completely filled, and then the pouring is stopped; wherein, before pouring, it is ensured that the precursor solution is mixed evenly; the PTFE mold is placed on a stable tabletop with a depth of 250~350µm.

[0052] In some embodiments, the vacuum drying is carried out in a vacuum oven at a temperature of 25~130℃ for 12~24 hours.

[0053] In some embodiments, the sulfur-containing all-solid polymer electrolyte membrane is stored in an argon atmosphere, where the water content is <0.1 ppm and the oxygen content is <0.1 ppm. This achieves dual targeted protection of the dynamic sulfur bond network and the lithium salt, ensuring the long-term structural integrity and electrochemical stability of the electrolyte membrane.

[0054] The present invention also provides the sulfur-containing all-solid polymer electrolyte membrane for use in lithium-ion batteries, and lithium metal batteries assembled with the electrolyte membrane have excellent electrochemical performance and cycle performance.

[0055] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0056] The following examples use instruments and equipment conventional in the art. Experimental methods in the following examples, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. All raw materials used in the following examples are conventional commercially available products with specifications conventional in the art. In this specification and the following examples, unless otherwise specified, "%" refers to weight percentage, "parts" refers to parts by weight, and "ratio" refers to weight proportion.

[0057] Example 1

[0058] This embodiment provides a method for preparing a sulfur-containing all-solid polymer electrolyte membrane, including the following steps:

[0059] Step 1: Mix DADPS and DTVS at a mass ratio of 1:1 until homogeneous, stir in an oil bath at 150°C for 120 min, react at high temperature and then cool to room temperature to obtain polymer solid.

[0060] Step 2: Dissolve the polymer solid obtained in Step 1 in DMSO, add 40% by mass of LiTFSI and mix well. Stir magnetically at room temperature for 24 hours to obtain the precursor solution.

[0061] Step 3: The precursor solution is cast onto the surface of a PTFE mold with a depth of 300µm to spread the precursor solution evenly. Then, it is dried in a vacuum oven at 120℃ for 16h. The dried polymer electrolyte membrane is cut into 16mm diameter discs using a punching machine to obtain a sulfur-containing all-solid polymer electrolyte membrane, denoted as P(DADPS1-DTVS1)@LiTFSI.

[0062] P(DADPS1-DTVS1)@LiTFSI was stored in a glove box under an argon atmosphere, with water <0.1ppm and oxygen <0.1ppm.

[0063] The P(DADPS1-DTVS1)@LiTFSI prepared in Example 1 was assembled with a positive electrode (lithium nickel cobalt manganese oxide, NCM523) and a negative electrode (lithium metal sheet) to form a CR2025 button cell, and its performance was tested.

[0064] The positive electrode active material NCM523, conductive agent (acetylene black), and binder (polyvinylidene fluoride, PVDF) were dissolved in N-methyl-2-pyrrolidone (NMP) at a mass ratio of 96.8:2.0:1.2 to prepare a positive electrode slurry, and 1% ethylene carbonate (EC) was added to wet the electrode sheet; then the positive electrode slurry was coated onto an aluminum foil current collector and dried under vacuum to obtain the positive electrode sheet.

[0065] Before assembling CR2025 coin cells for cycle testing, ≤5 μL of commercially available electrolyte (LiPF6 in EC / DMC) was dropped onto the surface of the P(S1-PFP1)@LiTFSI electrolyte membrane as an interface wetting agent, allowing it to penetrate to the electrolyte membrane and electrode interface via capillary action. This treatment was only used to improve initial interfacial compatibility during the testing phase. After addition, the membrane was allowed to stand for 5 minutes to allow the solvent to evaporate and form a thin wetting interface.

[0066] Example 2

[0067] This embodiment provides a method for preparing a sulfur-containing all-solid polymer electrolyte membrane, including the following steps:

[0068] Step 1: Mix DADPS and DTVS at a mass ratio of 1:2 until homogeneous, stir in an oil bath at 150°C for 120 min, react at high temperature and then cool to room temperature to obtain polymer solid.

[0069] Step 2: Dissolve the polymer solid obtained in Step 1 in DMSO, add 40% by mass of LiTFSI and mix well. Stir magnetically at room temperature for 24 hours to obtain the precursor solution.

[0070] Step 3: The precursor solution is cast onto the surface of a PTFE mold with a depth of 300µm to spread the precursor solution evenly. Then, it is dried in a vacuum oven at 120℃ for 16h. The dried polymer electrolyte membrane is cut into 16mm diameter discs using a punching machine to obtain a sulfur-containing all-solid polymer electrolyte membrane, denoted as P(DADPS1-DTVS2)@LiTFSI.

[0071] P(DADPS1-DTVS2)@LiTFSI was stored in a glove box under an argon atmosphere, with water <0.1ppm and oxygen <0.1ppm.

[0072] The P(DADPS1-DTVS2)@LiTFSI prepared in Example 2 was assembled with positive and negative electrode sheets to form a CR2025 button cell, and its performance was tested.

[0073] like Figure 1 The image shown is the XRD pattern of the sulfur-containing all-solid-state polymer electrolyte membrane prepared in Example 2. Figure 1 The XRD pattern shows broad peaks in the polymer, indicating successful polymer synthesis.

[0074] Example 3

[0075] This embodiment provides a method for preparing a sulfur-containing all-solid polymer electrolyte membrane, including the following steps:

[0076] Step 1: Mix DADPS and DTVS at a mass ratio of 1:4 until homogeneous, stir in an oil bath at 150°C for 120 min, react at high temperature and then cool to room temperature to obtain polymer solid.

[0077] Step 2: Dissolve the polymer solid obtained in Step 1 in DMSO, add 40% by mass of LiTFSI and mix well. Stir magnetically at room temperature for 24 hours to obtain the precursor solution.

[0078] Step 3: The precursor solution is cast onto the surface of a PTFE mold with a depth of 300µm to spread the precursor solution evenly. Then, it is dried in a vacuum oven at 120℃ for 16h. The dried polymer electrolyte membrane is cut into 16mm diameter discs using a punching machine to obtain a sulfur-containing all-solid polymer electrolyte membrane, denoted as P(DADPS1-DTVS4)@LiTFSI.

[0079] P(DADPS1-DTVS4)@LiTFSI was stored in a glove box under an argon atmosphere, with water <0.1ppm and oxygen <0.1ppm.

[0080] The P(DADPS1-DTVS4)@LiTFSI prepared in Example 3 was assembled with positive and negative electrode sheets to form a CR2025 button cell, and its performance was tested.

[0081] Example 4

[0082] This embodiment provides a method for preparing a sulfur-containing all-solid polymer electrolyte membrane, including the following steps:

[0083] Step 1: Mix DADPS and DTVS at a mass ratio of 1:5 until homogeneous, stir in an oil bath at 160°C for 30 minutes, react at high temperature and then cool to room temperature to obtain polymer solid.

[0084] Step 2: Dissolve the polymer solid obtained in Step 1 in DMSO, add 80% by mass of LiTFSI and mix well. Stir magnetically at room temperature for 12 hours to obtain the precursor solution.

[0085] Step 3: Cast the precursor solution onto the surface of a PTFE mold with a depth of 250µm to spread the precursor solution evenly. Then dry it in a vacuum oven at 80℃ for 24h. The dried polymer electrolyte membrane is cut into 16mm diameter discs using a punching machine to obtain a sulfur-containing all-solid polymer electrolyte membrane, denoted as P(DADPS1-DTVS5)@LiTFSI.

[0086] P(DADPS1-DTVS5)@LiTFSI was stored in a glove box under an argon atmosphere, with water <0.1ppm and oxygen <0.1ppm.

[0087] The P(DADPS1-DTVS5)@LiTFSI prepared in Example 4 was assembled with positive and negative electrode sheets to form a CR2025 button cell, and its performance was tested.

[0088] Example 5

[0089] This embodiment provides a method for preparing a sulfur-containing all-solid polymer electrolyte membrane, including the following steps:

[0090] Step 1: Mix DADPS and DTVS at a mass ratio of 1:6 until homogeneous, stir in an oil bath at 80°C for 120 min, react at high temperature and then cool to room temperature to obtain polymer solid.

[0091] Step 2: Dissolve the polymer solid obtained in Step 1 in DMSO, add 60% by mass of LiTFSI and mix well. Stir magnetically at 45°C for 48 hours to obtain the precursor solution.

[0092] Step 3: The precursor solution is cast onto the surface of a PTFE mold with a depth of 350µm to spread the precursor solution evenly. Then, it is dried in a vacuum oven at 130℃ for 20h. The dried polymer electrolyte membrane is cut into 16mm diameter discs using a punching machine to obtain a sulfur-containing all-solid polymer electrolyte membrane, denoted as P(DADPS1-DTVS6)@LiTFSI.

[0093] P(DADPS1-DTVS6)@LiTFSI was stored in a glove box under an argon atmosphere, with water <0.1ppm and oxygen <0.1ppm.

[0094] The P(DADPS1-DTVS6)@LiTFSI prepared in Example 5 was assembled with positive and negative electrode sheets to form a CR2025 button cell, and its performance was tested.

[0095] Example 6

[0096] This embodiment provides a method for preparing a sulfur-containing all-solid polymer electrolyte membrane, including the following steps:

[0097] Step 1: Mix DADPS and DTVS at a mass ratio of 1:8 until homogeneous, stir in an oil bath at 150°C for 90 min, react at high temperature and then cool to room temperature to obtain polymer solid.

[0098] Step 2: Dissolve the polymer solid obtained in Step 1 in DMSO, add 20% by mass of LiTFSI and mix well. Stir magnetically at 60℃ for 20h to obtain the precursor solution.

[0099] Step 3: Cast the precursor solution onto the surface of a PTFE mold with a depth of 300µm to spread the precursor solution evenly. Then dry it in a vacuum oven at 25℃ for 12h. The dried polymer electrolyte membrane is cut into 16mm diameter discs using a punching machine to obtain a sulfur-containing all-solid polymer electrolyte membrane, denoted as P(DADPS1-DTVS8)@LiTFSI.

[0100] P(DADPS1-DTVS8)@LiTFSI was stored in a glove box under an argon atmosphere, with water <0.1ppm and oxygen <0.1ppm.

[0101] The P(DADPS1-DTVS8)@LiTFSI prepared in Example 6 was assembled with positive and negative electrode sheets to form a CR2025 button cell, and its performance was tested.

[0102] Comparative Example 1

[0103] Comparative Example 1 provides a method for preparing a PEO@LiTFSI electrolyte membrane, comprising the following steps:

[0104] Step 1: Mix PEO and LiTFSI in a typical mixing ratio of EO:Li + =16:1 (mass ratio of 10:4) dissolved in acetonitrile (ACN) solvent to obtain a mixed solution;

[0105] Step 2: Spread the mixed solution into a PTFE mold and vacuum dry it at 60°C for 24 hours to dry the solvent. Then peel the film off the mold and cut it into 16mm diameter discs using a die-cutting machine to obtain the PEO@LiTFSI electrolyte membrane.

[0106] The PEO@LiTFSI electrolyte membrane prepared in Comparative Example 1 was assembled with positive and negative electrode sheets to form a battery, and its performance was tested.

[0107] Table 1 Performance parameters of sulfur-containing all-solid-state polymer electrolyte membranes prepared in Examples 1-6 and Comparative Example 1

[0108]

[0109] As shown in Table 1, the performance of the electrolyte membranes prepared in Examples 1-6 and Comparative Example 1 was tested. The results of the single-factor comparison (Examples 1-3) test are as follows:

[0110] As shown in Table 1, the electrochemical window follows the order of Example 1 > Example 2 > Example 3. Among them, the DADPS to DTVS mass ratio of 1:1 in Example 1 showed the best performance, which is mainly attributed to the high-density benzene ring conjugated system. This structure can efficiently absorb high-voltage free radicals, thereby maximizing the electrochemical window.

[0111] Table 1 shows that the order of ionic conductivity is Example 2 > Example 1 > Example 3. This phenomenon is mainly determined by the balance between sulfur chain density and polymer chain flexibility. In Example 1, the conductivity is lower when the mass ratio of DADPS to DTVS is 1:1 compared to 1:2 in Example 2. This is mainly because insufficient DTVS results in shorter flexible chain segments, restricting chain movement, but it still meets the basic requirements for solid electrolyte membranes (>10). -5The lower conductivity of Example 1 compared to Example 4 is mainly due to excessive DTVS, which leads to a decrease in sulfur chain density and a sparser conduction pathway.

[0112] In addition, such as Figure 2 As can be seen from the impedance test diagrams of Examples 1-3 and Comparative Example 1, their magnitudes are in the order of Comparative Example 1 > Example 3 > Example 1 > Example 2, which is consistent with the inverse relationship of ionic conductivity.

[0113] The tensile strength test results showed that Example 1 > Example 2 > Example 3. This is mainly attributed to the difference in benzene ring density. As a rigid unit, the dense cross-linked structure of the benzene ring significantly improves the mechanical strength of the material.

[0114] In summary, in the single-factor comparison test, Example 2 exhibited superior overall performance, with the highest ionic conductivity, while maintaining high levels of electrochemical window and tensile strength, demonstrating a balance between sulfur chain density and flexible segments. In contrast, although Example 1 was optimal in electrochemical window and tensile strength, its ionic conductivity was slightly lower; Example 3 was weaker than the former two in all three performance aspects.

[0115] A comprehensive analysis of the data in Table 1 shows that Example 2, with its optimal ionic conductivity and balanced overall performance, is currently the best solution. Although the performance of Examples 4-6 is relatively weaker, their electrochemical window, ionic conductivity, and tensile strength are all significantly better than those of Comparative Example 1, fully verifying that the performance of the sulfur-containing all-solid-state polymer electrolyte membrane of the present invention is significantly improved.

[0116] Table 2 Performance parameters of sulfur-containing all-solid-state polymer electrolyte membranes prepared in Examples 1-6 and Comparative Example 1

[0117]

[0118] As shown in Table 2, Li + The ion transference numbers in Examples 1-3 showed the order: Example 2 > Example 3 > Example 1. Example 2 performed best, mainly due to the suitable benzene ring ratio and the protonation of the ortho-NH2 group (-NH2). 3+ It can efficiently fix TFSI - Anions, and the pore structure released by SS bond recombination promotes Li + Selective migration. The lower ion transference number in Example 1 (DADPS to DTVS mass ratio 1:1) compared to Example 2 (DADPS to DTVS mass ratio 1:2) is mainly due to the higher amino group density but excessively rigid chain segments, leading to lower Li after anion anchoring. + Migration was hindered. In Example 3, the reduced benzene ring ratio led to a decrease in amino group density and a weakened anionic anchoring effect, but it still maintained better Li compared to Example 1. +Migration performance.

[0119] Analysis shows that the polarization voltage of the Li-Li symmetric cell in Example 2 (26 mV) is significantly lower than that in Comparative Example 1 (90 mV). This advantage is mainly due to its high lithium-ion transference number (tLi). + The dual effect of >0.7) is as follows: on the one hand, it reduces interfacial impedance and suppresses interfacial polarization by reducing the accumulation of anions at the electrode / electrolyte interface; on the other hand, it promotes uniform migration of lithium ions and effectively alleviates concentration polarization.

[0120] To further verify the effect of P(DADPS1-DTVS2)@LiTFSI on the stability of the lithium metal anode, SEM analysis was performed at 0.1 mA cm⁻¹. -1 The surface morphology of lithium in a Li-Li symmetric cell after 100 cycles at a current density is shown in Figures 3(a) and 3(b). The Li-Li symmetric cell assembled with a P(DADPS1-DTVS2)@LiTFSI electrolyte membrane improves the morphology of the lithium anode after cycling, with almost no Li dendrite formation on the Li surface after cycling. In contrast, the Li-Li symmetric cell assembled with a PEO@LiTFSI electrolyte membrane has a rough lithium electrode surface, severe lithium anode corrosion, and uneven lithium deposition. This result is consistent with the polarization voltage of the symmetric cell.

[0121] Example 2 maintained 88.7% capacity retention after 300 cycles, significantly better than Comparative Example 1's 80.6%. This is mainly attributed to the reversible breakage-recombination characteristics of the dynamic SS bonds, which effectively repair microcracks generated in the electrode material during cycling; the highly efficient free radical absorption capacity of the benzene ring structure significantly improved the material's oxidation resistance (>4.5V); and more importantly, the amino-derived Li3N / LiS passivation layer formed a stable protective layer at the electrode / electrolyte interface, greatly enhancing interface stability. These synergistic effects together construct a multi-layered protection system, thereby ensuring the battery's long cycle life.

[0122] like Figure 4 The figure shows the rate performance of LFP|P(DADPS1-DTVS2)@LiTFSI|Li and LFP|PEO@LiTFSI|Li batteries prepared by the electrolyte membranes of Example 2 and Comparative Example 1 at 25°C. Figure 4 It can be observed that the discharge capacity of the lithium battery assembled using P(DADPS1-DTVS2)@LiTFSI@LiTFSI is 151 mAh g at 0.1C, 0.2C, and 0.5C. -1 143mAh g -1 and 135mAh g -1The discharge capacity of the lithium metal battery manufactured using PEO@LiTFSI is 93 mAh g at 0.1C, 0.2C, and 0.5C. -1 85mAh g -1 and 69mAh g -1 When the discharge rate decreases to 0.1C, use P(DADPS1-DTVS) 1.5 The discharge capacity of the LiTFSI lithium battery has been increased to 150mAh g. -1 The discharge capacity of the lithium battery using LFP|PEO@LiTFSI|Li only increased to 90mAh g. -1 This indicates that P(DADPS1-DTVS) 1.5 @LiTFSI exhibits excellent rate performance and capacity recovery. This is mainly due to the synergistic enhancement of ion transport kinetics by the sulfur chain dynamic conduction mechanism and amino bidentate chelation; in addition, the wide electrochemical window (>4.5V) and in-situ passivation layer ensure high voltage stability and interfacial compatibility, resulting in less capacity loss during fast charge and discharge.

[0123] The data above indicate that Example 2 has the best overall performance among the current examples. Although its tensile strength and electrochemical window are not optimal, its performance is still greater than the normal use threshold of solid electrolyte membranes.

[0124] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A sulfur-containing all-solid polymer electrolyte membrane, characterized in that, It is prepared by hot melting, casting and evaporation of a sulfur-containing all-solid polymer, wherein the general structural formula of the sulfur-containing all-solid polymer is: In the formula, n is the degree of aggregation, and 5000≤n≤50000.

2. The sulfur-containing all-solid polymer electrolyte membrane according to claim 1, characterized in that, The thickness of the sulfur-containing all-solid polymer electrolyte membrane is 55µm±5µm.

3. A method for preparing a sulfur-containing all-solid polymer electrolyte membrane as described in claim 1, characterized in that, Includes the following steps: 2,2'-diaminodiphenyl disulfide was mixed evenly with divinyl sulfide and polymerized to obtain a polymer solid. The polymer solid was dissolved in dimethyl sulfoxide to obtain a mixed solution, and lithium bis(trifluoromethanesulfonyl)imide was added to the mixed solution and mixed evenly to obtain a precursor solution; The precursor solution was poured into a mold and dried under vacuum to obtain a sulfur-containing all-solid polymer electrolyte membrane.

4. The method for preparing a sulfur-containing all-solid polymer electrolyte membrane according to claim 3, characterized in that, The mass ratio of the 2,2'-diaminodiphenyl disulfide to the divinyl sulfide is 1:(1~8).

5. The method for preparing a sulfur-containing all-solid polymer electrolyte membrane according to claim 3, characterized in that, The polymerization reaction is carried out in an oil bath at a temperature of 80~160℃ for a reaction time of 30~120min. After the reaction is completed, the polymer solid is obtained by cooling to room temperature.

6. The method for preparing a sulfur-containing all-solid polymer electrolyte membrane according to claim 3, characterized in that, The amount of lithium bis(trifluoromethanesulfonyl)imide added is 20% to 80% of the total mass of 2,2'-diaminodiphenyl disulfide and divinyl sulfide.

7. The method for preparing a sulfur-containing all-solid polymer electrolyte membrane according to claim 3, characterized in that, Lithium bis(trifluoromethanesulfonyl)imide was added to the mixed solution and magnetically stirred at a temperature of 25-60°C for 12-48 hours until the mixture was homogeneous to obtain the precursor solution.

8. The method for preparing a sulfur-containing all-solid polymer electrolyte membrane according to claim 3, characterized in that, The specific method for pouring the precursor solution into the mold is as follows: Slowly pour the precursor solution into the center of the PTFE mold until it is completely filled, then stop pouring. The depth of the PTFE mold is 250~350µm.

9. The method for preparing a sulfur-containing all-solid polymer electrolyte membrane according to claim 3, characterized in that, The vacuum drying temperature is 25~130℃, and the drying time is 12~24h.

10. An application of the sulfur-containing all-solid-state polymer electrolyte membrane according to claim 1 or 2, characterized in that, The sulfur-containing all-solid polymer electrolyte membrane is used in lithium-ion batteries.

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