Sulfur-containing all-solid-state polymer electrolyte membrane, preparation method and lithium battery

Abstract

The invention provides a sulfur-containing all-solid-state polymer electrolyte membrane, a preparation method thereof and a lithium battery, and belongs to the technical field of lithium metal batteries. The electrolyte membrane is a sulfur-containing solid polymer, and the structural general formula of the polymer is shown in the specification, wherein a, b and c are units of different polymerization, n is a structural unit of the whole polymer, a, b and c are larger than 2 and smaller than 8, and n is larger than 3000 and smaller than 3000. The electrolyte membrane can reduce the Li < + > diffusion energy barrier, widen the electrochemical window, reduce the interface impedance and improve the interface compatibility between the positive and negative electrode materials and the sulfur-containing all-solid-state polymer electrolyte membrane, and the lithium battery assembled by the electrolyte membrane has excellent electrochemical performance and cycle performance.

Description

TECHNICAL FIELD

[0001] The present disclosure belongs to the technical field of lithium metal batteries, and particularly relates to a sulfur-containing all-solid-state polymer electrolyte film, a preparation method thereof, and a lithium battery. BACKGROUND

[0002] Lithium metal batteries have become the core candidate technology in the research and development field of next-generation energy storage devices due to their excellent energy density and excellent long cycle capability. However, in practical applications, the organic liquid electrolyte matched with the lithium metal electrode has a prominent risk of combustion and explosion, and during the charging and discharging cycles of the battery, it can cause severe corrosion of the lithium metal negative electrode and trigger the random growth of lithium dendrites. These problems not only slow down the industrialization progress of lithium metal batteries, but also bring serious safety challenges to their actual service process.

[0003] Compared with traditional liquid electrolytes, solid-state electrolytes have significant technical advantages: their reaction activity with lithium metal is greatly weakened, and they have good inhibitory effect on the growth of lithium dendrites, which can significantly enhance the safety and stability of lithium batteries, and thus become the core path to solve the above technical problems. In recent years, in the field of solid-state electrolyte research for lithium batteries, the relevant materials are mainly divided into two categories: inorganic solid-state electrolytes and polymer solid-state electrolytes. Among them, polymer solid-state electrolytes have more outstanding flexibility, more reliable safety performance and more convenient processing characteristics than inorganic solid-state electrolytes, and are more suitable for the large-scale manufacturing process of batteries, so they occupy an important development position in the solid-state lithium battery technology system.

[0004] However, the existing technical solutions still have obvious shortcomings. For example, traditional solid-state polymer electrolytes represented by polyethylene oxide (PEO) have problems such as low ionic conductivity at room temperature, poor interface combination with electrodes, narrow electrochemical stability window, and easy oxidation and decomposition at high charging voltage, which greatly limit their popularization and application in solid-state lithium batteries. Although researchers have subsequently developed various new electrolyte materials including nitrile-based polymer electrolytes, siloxane-based polymer electrolytes, carbonate-based polymer electrolytes, and vinylidene fluoride-based polymer electrolytes, due to the limitation of the single polymer backbone structure, such electrolytes are always difficult to simultaneously achieve excellent electrochemical performance, reliable mechanical strength and good safety performance, and cannot fully meet the actual application requirements of high-performance lithium batteries. SUMMARY

[0005] The present disclosure aims to at least solve one of the technical problems existing in the prior art, and provides a sulfur-containing all-solid-state polymer electrolyte film, a preparation method thereof, and a lithium battery.

[0006] In one aspect of the present disclosure, a sulfur-containing all-solid-state polymer electrolyte film is provided, the electrolyte film being a sulfur-containing solid-state polymer having a general structure as follows: ; wherein a, b, and c are different polymerized units, and n is a structural unit of the entire polymer, wherein 2 < a, b, c < 8, and 3000 < n < 30000. In another aspect of the present disclosure, a method for preparing the sulfur-containing all-solid-state polymer electrolyte film described above is provided, the method comprising: mixing tripropylene sulfide and divinylbenzene in a mass ratio, and uniformly mixing them through a high-temperature reverse vulcanization reaction and then cooling to room temperature to obtain a polymer solid; dissolving the polymer solid in N-methylpyrrolidone, adding lithium bis(trifluoromethanesulfonyl)imide, and uniformly mixing them under magnetic stirring to obtain a precursor solution; casting the precursor solution in a mold, uniformly spreading it, and performing drying and cutting to obtain the sulfur-containing all-solid-state polymer electrolyte film.

[0007] Optionally, the mass ratio of the tripropylene sulfide and the divinylbenzene is 1:(1-10).

[0008] Optionally, the temperature of the high-temperature reverse vulcanization reaction is 110-180°C, and the time is 30-120 min.

[0009] Optionally, the length of the lithium bis(trifluoromethanesulfonyl)imide is 40%-80% of the mass sum of the tripropylene sulfide and the divinylbenzene.

[0010] Optionally, the time of the magnetic stirring is 12-48 h, and the temperature of the magnetic stirring is 25-60°C.

[0011] Optionally, the temperature of the drying is 25-160°C, and the time of the drying is 12-48 h. Optionally, the thickness of the sulfur-containing all-solid-state polymer electrolyte film is 45-55 μm, and the diameter is 12-20 mm.

[0012] In another aspect of the present disclosure, a lithium battery is provided, the lithium battery comprising: a positive electrode sheet, a negative electrode sheet, and the sulfur-containing all-solid-state polymer electrolyte film described above.

[0013] Optionally, when the lithium battery is assembled, the sulfur-containing all-solid-state polymer electrolyte film is wetted by an interfacial wetting agent.

[0014] The present disclosure provides a sulfur-containing all-solid-state polymer electrolyte film, a preparation method thereof, and a lithium battery. The electrolyte film is a sulfur-containing solid-state polymer having a general structure as follows: ; wherein a, b, c are different polymerized units, and n is the structural unit of the whole polymer, wherein 2 + diffusion energy barrier, broadens the electrochemical window, reduces the interface impedance, and improves the interface compatibility between the positive and negative materials and the sulfur-containing full solid-state polymer electrolyte film. The lithium battery assembled with the electrolyte film has excellent electrochemical performance and cycle performance. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 is a flowchart of the preparation method of the sulfur-containing full solid-state polymer electrolyte film of the specific embodiment of the present disclosure; Figure 2 is the impedance performance result of Example 1-Example 3 of the present disclosure; Figure 3 is the interface stability result of Example 2 of the present disclosure. DETAILED DESCRIPTION

[0016] In order for those skilled in the art to better understand the technical solutions of the present disclosure, the present disclosure will be further described in detail below in combination with the drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present disclosure and are part of the embodiments of the present disclosure, but not all embodiments. Based on the embodiments of the present disclosure, all other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the present disclosure.

[0017] In one aspect of the present disclosure, a sulfur-containing full solid-state polymer electrolyte film is provided, which is a sulfur-containing solid-state polymer, and the structure of the polymer has the following general formula: ; wherein a, b, c are different polymerized units, and n is the structural unit of the whole polymer, wherein 2 It should be noted that due to the singleness of the existing polymer backbone, the polymer electrolyte cannot have excellent electrochemical performance, good mechanical performance and high safety at the same time. In order to solve the above problems, the present embodiment provides a sulfur-containing full solid-state polymer electrolyte film, and the molecular structure of such electrolyte has a polysulfide chain -(S-S) n-: on the one hand, the chain contains rich lone pair electrons, and the flexible -(S-S) n- structure formed by high-density sulfur atoms can construct a dense "solvation" region to provide sufficient path for lithium ion conduction; on the other hand, the electronegativity of S 2- is lower than that of O 2-The adsorption of lithium ions is weaker, which greatly reduces the diffusion energy barrier of lithium ions and significantly improves the ion migration efficiency, ultimately achieving superior ion conductivity and cycle stability of the electrolyte. In addition, the -(S-S)n- bond has a dual role: first, it can directly act as a lithium ion conduction medium, enabling efficient transmission of lithium ions through the polysulfur chain; second, it can act as a flexible functional group, effectively optimizing the interface compatibility between the positive and negative electrode materials and the sulfur-containing all-solid-state polymer electrolyte membrane.

[0018] Notably, the sulfur-containing polymer also has excellent self-repairing ability, which plays a key role in inhibiting lithium dendrite growth, reducing the damage to the electrode interface, and ensuring the stability of long-term cycling of lithium metal batteries. As shown in FIG. 1, in one aspect of the present disclosure, a preparation method S100 of a sulfur-containing all-solid-state polymer electrolyte membrane is provided, specifically comprising the following steps S110-S130: S110, uniformly mix diacetylene trisulfide (DAT) and divinylbenzene (DVB) according to the mass ratio, cool to room temperature after high-temperature reverse vulcanization reaction without initiator at high temperature, and obtain a polymer solid.

[0019] In some preferred embodiments, the mass ratio of diacetylene trisulfide and divinylbenzene is 1:(1-10), for example, 1:1, 1:2, 1:4, 1:6, 1:8, 1:10, etc. can be preferred.

[0020] In other preferred embodiments, the high-temperature reverse vulcanization reaction is in an oil bath environment, the reaction temperature is 110-180°C, for example, 110°C, 130°C, 150°C, 180°C, etc. can be preferred, and the time is 30-120 min, for example, 30 min, 50 min, 80 min, 100 min, 120 min, etc. can be preferred.

[0021] S120, dissolve the obtained polymer solid in N-methyl pyrrolidone (NMP), add lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), and mix uniformly under magnetic stirring to obtain a precursor solution.

[0022] In some preferred embodiments, the length of lithium bis(trifluoromethanesulfonyl)imide is added in an amount of 40%-80% of the mass sum of diacetylene trisulfide and divinylbenzene, for example, 40%, 50%, 60%, 70%, 80%, etc.

[0023] In other preferred embodiments, the time of magnetic stirring is 12-48h, for example, 12h, 16h, 24h, 48h, etc. The temperature of magnetic stirring is 25-60°C, for example, 25°C, 35°C, 45°C, 55°C, 60°C, etc.

[0024] S130, casting the precursor solution in a PTFE mold, making it evenly spread, and then vacuum oven drying to obtain a sulfur-containing all-solid-state polymer electrolyte film P(DATx-DVBy), wherein x, y in the above expression is the mass ratio of dipropylene sulfide and divinylbenzene.

[0025] It should be noted that the specific method of casting the precursor solution in the mold is: slowly pouring the precursor solution at the center position of the PTFE mold until the PTFE mold is fully spread, and then stopping pouring. The depth of the PTFE mold used in step S130 is 300 µm.

[0026] In some preferred embodiments, the thickness of the sulfur-containing all-solid-state polymer electrolyte film is 45-55 µm, for example, 50 µm can be preferred, and the diameter is 12-20 mm, for example, 16 mm can be preferred.

[0027] In other preferred embodiments, the drying temperature is 25-160 °C, for example, 25 °C, 50 °C, 80 °C, 100 °C, 120 °C, 150 °C, 160 °C, etc., and the drying time is 12-48 h, for example, 12 h, 24 h, 36 h, 48 h, etc.

[0028] It should also be understood that the prepared electrolyte film should also be removed from the mold, and the film should be cut into a circular piece of appropriate diameter with a punching machine to obtain a P(DATx-DVBy)@LiTFSI electrolyte film, which is then assembled for battery testing. It should be noted that the P(DATx-DVBy)@LiTFSI electrolyte film should be stored in an argon environment glove box before use, to facilitate subsequent battery assembly. The storage conditions are as follows: water <0.1 ppm, oxygen <0.1 ppm in an argon environment.

[0029] In another aspect of the present disclosure, a lithium battery is provided, which comprises a positive electrode sheet, a negative electrode sheet, and the sulfur-containing all-solid-state polymer electrolyte film described above.

[0030] It should be noted that in the lithium battery of the present embodiment, lithium metal (lithium sheet) is used as the negative active material, and LFP is used as the positive active material. The positive active material, conductive agent acetylene black, and binder PVDF are dissolved in N-methyl pyrrolidone (NMP) at a mass ratio of 8:1:1 to prepare a positive electrode slurry. The positive electrode slurry is coated on an aluminum foil current collector using a 150 µm doctor blade, and then placed in a vacuum drying oven at 120 °C for drying to obtain a positive electrode sheet. Then, the sulfur-containing all-solid-state polymer electrolyte film prepared above is assembled with the positive electrode sheet and the negative electrode sheet to form a coin cell.

[0031] It should be further explained that when assembling the battery for cycle testing, an interfacial wetting agent may be preferably added. The interfacial wetting agent is a lithium-ion electrolyte (LiPF6 in EC / DMC) commonly used on the market, and the amount of the interfacial wetting agent added is ≤5μL. The wetting agent mainly wets the porous structure of the electrolyte membrane through capillary action, thereby improving the compatibility of the sulfur-containing all-solid-state polymer electrolyte membrane and the positive and negative electrode materials, accelerating lithium ion conduction, and improving the cycle performance.

[0032] The sulfur-containing all-solid-state polymer electrolyte membrane proposed in this disclosure achieves synergy of four core functions through a three-dimensional network that combines rigidity and flexibility, and dynamic and static properties. This can improve the ionic conductivity and mechanical strength of the electrolyte membrane, as well as the interfacial stability of the battery. Its four core functions are as follows: ① Synergy between ion transport and flexible chain segments: flexible polysulfide segments (-SS- / -S x -) is the main channel for lithium ion conduction. The lone pair of electrons of sulfur atoms and Li + The coordination ability is comparable to that of ether oxygen bonds, and the larger atomic radius reduces the Li + Transition energy barrier. The conformational flexibility of the long sulfur chains further promotes the formation of continuous ion channels, laying the foundation for high ionic conductivity. ② Synergy between self-healing and dynamic bonds: The residual dynamic SS bonds in the network are key to safety. When lithium dendrites grow or mechanical damage occurs, the SS bonds reversibly break and reform, instantly repairing microcracks and physically blocking dendrite penetration. This mechanism significantly improves interfacial stability and battery safety, resolving the dendrite problem in solid-state batteries. ③ Synergy between mechanical strength and rigid skeleton: The rigid benzene rings of DVB serve as crosslinks, endowing the network with high modulus and dimensional stability. Their physical barrier effect synergizes with the chemical self-healing of the SS bonds to dually inhibit dendrite growth. The thermal stability of the benzene rings also enhances overall thermal safety. ④ Synergy between functional integration: The microscopic phase separation of the flexible sulfur chains (ionic conductors) and the rigid aromatic rings (structural support) optimizes the balance between ionic conductivity and mechanical strength. The combination of dynamic SS bonds (intelligent response) and the covalent network (overall stability) achieves a dynamic balance between damage and repair. This multi-scale synergy enables the material to simultaneously meet the stringent requirements of high ionic conductivity, dendrite suppression, self-healing and thermal stability.

[0033] The sulfur-containing all-solid-state polymer electrolyte membrane and its preparation method will be further described below with reference to specific examples: Example 1 This embodiment provides a method for preparing a sulfur-containing all-solid-state polymer electrolyte membrane, comprising the following steps: Step one, mix dithiopropylene (DAT) and divinylbenzene (DVB) uniformly according to the mass ratio of 1:1, and then magnetically stir in an oil bath at a temperature of 130℃ for 60 min. After the reaction at high temperature, cool to room temperature to obtain a polymer solid; dissolve the obtained polymer solid in N-methyl pyrrolidone (NMP), and add 40% mass of LiTFSI and mix uniformly, magnetically stir at room temperature for 24 h to obtain a precursor solution; Step two, cast the precursor solution on the surface of a PTFE mold, and then place the precursor solution in an oven for 24 h after uniformly spreading the precursor solution. The oven ensures a vacuum atmosphere, and the oven temperature is 120℃. The dried polymer electrolyte film is cut into a 16 mm diameter disc by a punching machine to obtain a sulfur-containing all-solid-state polymer electrolyte film P(DAT1-DVB1)@LiTFSI. The obtained sulfur-containing all-solid-state polymer electrolyte film is stored in an argon environment with water <0.1 ppm and oxygen <0.1 ppm.

[0034] Further, as shown in Table 1, the ionic conductivity of the sulfur-containing all-solid-state polymer electrolyte film of Example 1 is 3.20×10 -4 S / cm, the tensile strength is 3.6 MPa, and the Li-Li symmetric polarization voltage is 62 mV.

[0035] Example 2 The embodiment provides a sulfur-containing all-solid-state polymer electrolyte film, which is different from the sulfur-containing all-solid-state polymer electrolyte film of Example 1 only in that dithiopropylene (DAT) and divinylbenzene (DVB) are mixed according to a mass ratio of 1:2 to obtain a sulfur-containing all-solid-state polymer electrolyte film P(DAT1-DVB2)@LiTFSI, and other conditions are the same as those in Example 1.

[0036] Further, as shown in Table 1, the ionic conductivity of the sulfur-containing all-solid-state polymer electrolyte film of Example 2 is 2.50×10 -4 S / cm, the tensile strength is 8.8 MPa, and the Li-Li symmetric polarization voltage is 45 mV.

[0037] Example 3 The embodiment provides a sulfur-containing all-solid-state polymer electrolyte film, which is different from the sulfur-containing all-solid-state polymer electrolyte film of Example 1 only in that dithiopropylene (DAT) and divinylbenzene (DVB) are mixed according to a mass ratio of 1:4 to obtain a sulfur-containing all-solid-state polymer electrolyte film P(DAT1-DVB4)@LiTFSI, and other conditions are the same as those in Example 1.

[0038] Further, as shown in Table 1, the ionic conductivity of the sulfur-containing all-solid-state polymer electrolyte film of Example 3 is 1.80×10 -4 S / cm, the tensile strength is 10.6 MPa, and the Li-Li symmetric polarization voltage is 58 mV.

[0039] Example 4 Step one, mix DAT and DVB uniformly in the mass ratio of 1:6, and then magnetically stir in an oil bath at 180℃ for 90min. After the reaction at high temperature, cool to room temperature to obtain a polymer solid; dissolve the polymer solid in N-methyl pyrrolidone (NMP), add 50% mass of LiTFSI and mix uniformly, and then magnetically stir at 45℃ for 16h to obtain a precursor solution; Step two, cast the precursor solution on the surface of a PTFE mold, and then place the precursor solution in an oven for 36h after uniformly spreading the precursor solution. The oven ensures a vacuum atmosphere, and the oven temperature is 150℃. After drying, the polymer electrolyte film is cut into a 16mm diameter disc by a punching machine to obtain a sulfur-containing all-solid-state polymer electrolyte film P(DAT1-DVB6)@LiTFSI. The prepared sulfur-containing all-solid-state polymer electrolyte film is stored in an argon environment, and the water in the argon environment is <0.1ppm, and the oxygen is <0.1ppm.

[0040] Further, as shown in Table 1, the ionic conductivity of the ion conductive film of Example 4 is 2.0×10 -4 S / cm, the tensile strength is 12.8MPa, and the Li-Li symmetric polarization voltage is 79mV.

[0041] Example 5 Step one, mix DAT and DVB uniformly in the mass ratio of 1:8, and then magnetically stir in an oil bath at 110℃ for 120min. After the reaction at high temperature, cool to room temperature to obtain a polymer solid; dissolve the polymer solid in N-methyl pyrrolidone (NMP), add 60% mass of LiTFSI and mix uniformly, and then magnetically stir at 55℃ for 48h to obtain a precursor solution; Step two, cast the precursor solution on the surface of a PTFE mold, and then place the precursor solution in an oven for 12h after uniformly spreading the precursor solution. The oven ensures a vacuum atmosphere, and the oven temperature is 160℃. After drying, the polymer electrolyte film is cut into a 16mm diameter disc by a punching machine to obtain a sulfur-containing all-solid-state polymer electrolyte film P(DAT1-DVB8)@LiTFSI. The prepared sulfur-containing all-solid-state polymer electrolyte film is stored in an argon environment, and the water in the argon environment is <0.1ppm, and the oxygen is <0.1ppm.

[0042] Further, as shown in Table 1, the ionic conductivity of the ion conductive film of Example 5 is 0.75×10 -4 S / cm, the tensile strength is 16.2MPa, and the Li-Li symmetric polarization voltage is 92mV.

[0043] Example 6 Step one, mix DAT and DVB in the ratio of 1:10 by mass, and stir magnetically in an oil bath at a temperature of 180°C for 30 min. After the reaction at high temperature, cool to room temperature to obtain a polymer solid; dissolve the obtained polymer solid in N-methyl pyrrolidone (NMP), and add 80% by mass of LiTFSI and mix uniformly, magnetically stir at 60°C for 12 h to obtain a precursor solution; Step two, cast the precursor solution on the surface of a PTFE mold, and after the precursor solution is evenly spread, place it in an oven for 48 h. The oven ensures a vacuum atmosphere, and the oven temperature is 25°C. The polymer electrolyte film after drying is cut into a 16 mm diameter disc by a punching machine to obtain a sulfur-containing all-solid-state polymer electrolyte film P(DAT1-DVB 10 )@LiTFSI. The sulfur-containing all-solid-state polymer electrolyte film prepared is stored in an argon environment, and the water in the argon environment is <0.1 ppm, and the oxygen is <0.1 ppm.

[0044] Further, as shown in Table 1, the ionic conductivity of Example 6 is 9.68 x 10 -5 S / cm, the tensile strength is 11.6 MPa, and the Li-Li symmetric polarization voltage is 115 mV.

[0045] Comparative Example 1 This comparative example provides an industry standard all-solid-state electrolyte film PEO@LiTFSI, which is prepared as follows: A commonly used PEO and LiTFSI are dissolved in acetonitrile (ACN) solvent in a typical mixing ratio of EO:Li + = 16:1 (mass ratio of 10:4) to obtain a mixed solution, which is then spread on a PTFE mold and placed in a vacuum dryer at 60°C for 24 h to dry the solvent, and then the film is removed from the mold and cut into a 16 mm diameter disc by a punching machine to obtain a PEO@LiTFSI electrolyte film, which is then assembled for battery testing.

[0046] Further, as shown in Table 1, the ionic conductivity of Comparative Example 1 is 7.6 x 10 -5 S / cm, the tensile strength is 0.8 MPa, and the Li-Li symmetric polarization voltage is 220 mV.

[0047] Table 1 Battery test results of each example and comparative example

[0048] In summary, in combination with Table 1 and Figure 2 , Figure 3 it can be seen that the ionic conductivity performance, tensile strength performance, interface stability and impedance performance of the above examples and comparative examples are as follows: 1. In terms of ionic conductivity performance: Example 1> Example 2> Example 3, and all six examples are better than the comparative example, which is mainly attributed to the fact that the high DAT ratio provides more flexible thioether segments (-SS- / -S x -), enhancing Li⁺ coordination and transition capabilities. Compared to the comparative example, the sulfur atom radius is larger than that of oxygen, resulting in a weaker Li⁺-S bond and a more compliant chain segment (PEO crystalline regions inhibit conduction). While the gradual decrease in 1:4 ionic conductivity is primarily due to the high crosslinking density, which restricts chain segment motion and leads to a decrease in conductivity, it is still significantly higher than PEO.

[0049] 2. In terms of tensile strength performance: Example 3 > Example 2 > Example 1. This is mainly due to the rigid benzene rings of DVB acting as crosslinking points, which improve the network modulus. Compared with the comparative example of 0.8 MPa, the rigid support provided by the benzene ring crosslinking network is the key to inhibiting the physical penetration of lithium dendrites.

[0050] 3. Regarding the stability of the Li|P(DATx-DVBy)@LiTFSI|Li interface, Example 2 > Example 3 > Example 1. This is primarily due to the synergistic effect of the sulfur chains and aromatic rings: ① The DAT sulfur chains ensure Li⁺ conduction and provide dynamic SS bond repair; ② The DVB benzene rings enhance mechanical strength and stabilize the crosslinked network. At a ratio of 1:2, the sulfur chain density and benzene ring crosslinking degree reach a golden balance, ensuring that the ionic conductivity meets application requirements while the mechanical strength exceeds the yield strength of lithium dendrites (~8 MPa). Furthermore, the SS bonds are in an optimally dynamic state, with the repair rate exceeding the dendrite destruction rate. The combination of the physical barrier (rigid aromatic ring) and chemical repair (dynamic SS bonds) significantly slows dendrite growth, resulting in a stable polarization voltage of 25 mV.

[0051] 4. If Figure 2 As shown in the data, in terms of impedance performance: Example 3> Example 2> Example 1, which is consistent with the ionic conductivity data in Table 1 after conversion, the impedance is reduced and the ionic conductivity is improved.

[0052] 5. If Figure 3 As shown in the data, in terms of interface stability performance: Example 2 of the present disclosure is at a temperature of 30°C and uses 0.2 mA·cm -2 The current density and 0.2 mAh·cm -2Under the test condition of the area specific capacity, the battery using P(DAT1-DVB2)@LiTFSI sulfur-containing all-solid-state polymer electrolyte membrane can be stably cycled for >300h, the polarization potential is only 45mV, and the voltage platform is very smooth, which proves that the interface side reaction is less, which is mainly due to the formation of inorganic units (Li2S / Li2S2) and organic units (organic polysulfide) by the contact of the -(S-S)x- bond in the polymer skeleton and Li metal, which builds the SEI layer that makes the battery stable cycle, in addition to this, the polymer electrolyte membrane is synthesized without initiator, greatly reducing the introduction of impurities, thereby reducing the generation of side reactions.

[0053] From the above data, it can be seen that the comprehensive performance of Example 2 is the best, but it is not limited to the data of Example 2, and other data can be preferred according to actual needs.

[0054] The present disclosure provides a sulfur-containing all-solid-state polymer electrolyte membrane, a preparation method thereof and a lithium battery. Compared with the prior art, the present disclosure has the following beneficial effects: the sulfur-containing all-solid-state polymer electrolyte membrane provided by the present disclosure replaces the ion transmission function of the liquid electrolyte through its solid-state ion conduction property, and replaces the physical isolation function of the separator through its dense and solid physical structure. This "two-in-one" replacement not only simplifies the battery structure, but more importantly brings a leap in intrinsic safety, a huge potential for energy density improvement, a revolutionary advantage of longer life and a wider working temperature range, solving the problems of low ionic conductivity, poor mechanical properties, poor interface compatibility and poor cycle performance of the all-solid-state battery in the related art.

[0055] It can be understood that the above embodiments are only exemplary embodiments adopted for illustrating the principles of the present disclosure, but the present disclosure is not limited thereto. Various modifications and improvements can be made by those of ordinary skill in the art without departing from the spirit and essence of the present disclosure, and these modifications and improvements are also considered within the protection scope of the present disclosure.

Claims

1. A sulfur-containing all-solid polymer electrolyte membrane, characterized in that: The electrolyte membrane is a sulfur-containing solid polymer, and the general structural formula of the polymer is as follows: ； Wherein, a, b, c are all units of different polymerizations, and n is the structural unit of the entire polymer, wherein 2<a, b, c<8, 3000<n<30000.

2. A method for preparing the sulfur-containing all-solid polymer electrolyte membrane according to claim 1, characterized in that: The method comprises: Propylene trisulfide and divinylbenzene are mixed uniformly according to a mass ratio, subjected to a high-temperature inverse vulcanization reaction, and then cooled to room temperature to obtain a polymer solid; dissolving the polymer solid in N-methylpyrrolidone, adding lithium bis(trifluoromethanesulfonyl)imide and mixing uniformly under magnetic stirring to obtain a precursor solution; The precursor solution is cast in a mold to be evenly spread, and then dried and cut to obtain a sulfur-containing all-solid polymer electrolyte membrane.

3. The method according to claim 2, characterized in that The mass ratio of the propylene trisulfide to divinylbenzene is 1:(1-10).

4. The method according to claim 2, characterized in that The temperature of the high-temperature inverse vulcanization reaction is 110-180° C., and the time is 30-120 minutes.

5. The method according to claim 2, characterized in that The amount of lithium bis(trifluoromethanesulfonyl)imide added is 40% to 80% of the total mass of the two substances, propylene trisulfide and divinylbenzene.

6. The method according to claim 2, characterized in that The magnetic stirring time is 12-48 hours, and the magnetic stirring temperature is 25-60°C.

7. The method according to claim 2, characterized in that The drying temperature is 25~160℃ and the drying time is 12~48h.

8. The method according to claim 2, characterized in that The sulfur-containing all-solid-state polymer electrolyte membrane has a thickness of 45-55 μm and a diameter of 12-20 mm.

9. A lithium battery, characterized in that: The lithium battery comprises: a positive electrode sheet, a negative electrode sheet and the sulfur-containing all-solid-state polymer electrolyte membrane according to claim 1.

10. The lithium battery according to claim 9, wherein When the assembled lithium battery is subjected to a cycle test, the sulfur-containing all-solid-state polymer electrolyte membrane is wetted by an interfacial wetting agent, and the amount of the interfacial wetting agent added is ≤5 μL.

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