A sulfur-containing all-solid-state polymer electrolyte film, a preparation method thereof, and a lithium battery

Abstract

The disclosure provides a sulfur-containing all-solid-state polymer electrolyte film and a preparation method thereof and a lithium battery, and belongs to the technical field of lithium metal batteries. + The electrolyte film can reduce the Li + diffusion energy barrier, widen the electrochemical window, reduce the interface impedance, improve the interface compatibility between the positive and negative electrode materials and the sulfur-containing all-solid-state polymer electrolyte film, and the lithium battery assembled with the electrolyte film 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:

[0007] ;

[0008] wherein a, b, c are different polymerized units, and n is the structure unit of the whole polymer, wherein 2

[0009] In another aspect of the present disclosure, a method for preparing the sulfur-containing all-solid-state polymer electrolyte film as described above is provided, the method comprising:

[0010] mixing tripropylene sulfide and divinylbenzene in a mass ratio, and uniformly mixing them by high-temperature reverse vulcanization, and then cooling to room temperature to obtain a polymer solid;

[0011] dissolving the polymer solid in N-methylpyrrolidone, and adding lithium bis(trifluoromethanesulfonyl)imide and uniformly mixing them under magnetic stirring to obtain a precursor solution;

[0012] 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.

[0013] Optionally, the mass ratio of tripropylene sulfide and divinylbenzene is 1:(1-10).

[0014] Optionally, the temperature of the high-temperature reverse vulcanization is 110-180°C, and the time is 30-120 min.

[0015] Optionally, the length of the lithium bis(trifluoromethanesulfonyl)imide is 40%-80% of the mass sum of tripropylene sulfide and divinylbenzene.

[0016] Optionally, the time of the magnetic stirring is 12-48 h, and the temperature of the magnetic stirring is 25-60°C.

[0017] Optionally, the temperature of the drying is 25-160°C, and the time of the drying is 12-48 h.

[0018] Optionally, the thickness of the sulfur-containing all-solid-state polymer electrolyte film is 45-55 μm, and the diameter is 12-20 mm.

[0019] 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 as described above.

[0020] Optionally, the sulfur-containing all-solid-state polymer electrolyte film is wetted by an interfacial wetting agent when the lithium battery is assembled.

[0021] The disclosure provides a sulfur-containing full-solid-state polymer electrolyte film, a preparation method thereof, and a lithium battery. The electrolyte film is a sulfur-containing solid-state polymer, and the general structure of the polymer is as follows:

[0022] ; wherein a, b, and c are different polymerized units, and n is a structural unit of the entire polymer, wherein 2 + The diffusion energy barrier of the electrolyte film is reduced, the electrochemical window is widened, the interface impedance is reduced, and the interface compatibility between the positive and negative electrode materials and the sulfur-containing full-solid-state polymer electrolyte film is improved. The lithium battery assembled with the electrolyte film has excellent electrochemical performance and cycle performance. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is a flowchart of a preparation method of the sulfur-containing full-solid-state polymer electrolyte film of the specific embodiment of the disclosure;

[0024] Figure 2 is the impedance performance result of Example 1-Example 3 of the disclosure;

[0025] Figure 3 is the interface stability result of Example 2 of the disclosure. DETAILED DESCRIPTION

[0026] To enable those skilled in the art to better understand the technical solutions of the disclosure, the 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 disclosure and are part of the embodiments of the disclosure, but not all embodiments. Based on the embodiments of the disclosure, all other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the disclosure.

[0027] In one aspect of the disclosure, a sulfur-containing full-solid-state polymer electrolyte film is provided. The electrolyte film is a sulfur-containing solid-state polymer, and the general structure of the polymer is as follows:

[0028] ;

[0029] wherein a, b, and c are different polymerized units, and n is a structural unit of the entire polymer, wherein 2

[0030] It should be noted that due to the singleness of the existing polymer skeleton, the polymer electrolyte cannot simultaneously have excellent electrochemical performance, good mechanical performance and high safety. In order to solve the above problems, the present embodiment provides a sulfur-containing all-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" area to provide sufficient path for lithium ion conduction; on the other hand, the electronegativity of S 2- is lower than that of O 2- , and the adsorption of lithium ions is weaker, so that the diffusion energy barrier of lithium ions is greatly reduced, and the ion migration efficiency is significantly improved, so that the electrolyte finally has more excellent ion conductivity and cycle stability. In addition, the -(S-S) n- bond also has a dual role: first, it can directly act as a lithium ion conduction medium to complete the efficient transmission of lithium ions through the polysulfide chain; second, it can act as a flexible functional group to effectively optimize the interface compatibility between the positive and negative electrode materials and the sulfur-containing all-solid-state polymer electrolyte film.

[0031] Notably, the sulfur-containing polymer also has excellent self-repairing ability, which plays a key role in inhibiting lithium dendrite growth, reducing the damage degree of the electrode interface, and ensuring the stability of the long-term cycle of lithium metal batteries.

[0032] 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 film is provided, which specifically includes the following steps S110-S130:

[0033] S110, uniformly mix dithiobispropylene (DAT) and divinylbenzene (DVB) according to the mass ratio, and cool to room temperature after high-temperature reverse vulcanization reaction at high temperature without initiator to obtain a polymer solid.

[0034] In some preferred embodiments, the mass ratio of dithiobispropylene and divinylbenzene is 1:(1-10), for example, 1:1, 1:2, 1:4, 1:6, 1:8, 1:10, etc. can be preferred.

[0035] 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 30-120min, for example, 30min, 50min, 80min, 100min, 120min, etc. can be preferred.

[0036] S120, dissolving the obtained polymer solid in N-methyl pyrrolidone (NMP) and adding lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and mixing uniformly under magnetic stirring to obtain a precursor solution.

[0037] In some preferred embodiments, the length of lithium bis(trifluoromethanesulfonyl)imide added is 40% to 80% of the mass sum of the two substances of dipropargyl disulfide and divinylbenzene, for example, 40%, 50%, 60%, 70%, 80%, etc.

[0038] In other preferred embodiments, the time of magnetic stirring is 12 to 48 h, for example, 12 h, 16 h, 24 h, 48 h, etc., and the temperature of magnetic stirring is 25 to 60°C, for example, 25°C, 35°C, 45°C, 55°C, 60°C, etc.

[0039] S130, casting the precursor solution in a PTFE mold, making it uniformly 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 dipropargyl disulfide and divinylbenzene.

[0040] 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 stopping pouring. The depth of the PTFE mold used in step S130 is 300 pm.

[0041] In some preferred embodiments, the thickness of the sulfur-containing all-solid-state polymer electrolyte film is 45 to 55 pm, for example, preferably 50 pm, and the diameter is 12 to 20 mm, for example, preferably 16 mm.

[0042] In other preferred embodiments, the drying temperature is 25 to 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 to 48 h, for example, 12 h, 24 h, 36 h, 48 h, etc.

[0043] It should also be understood that the prepared electrolyte film should also be removed from the mold, and the film is cut into a circular sheet of appropriate diameter with a punching machine to obtain a P(DATx-DVBy)@LiTFSI electrolyte film, which is then assembled for battery testing. Note 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.

[0044] Another aspect of the present disclosure provides a lithium battery, which comprises a positive electrode sheet, a negative electrode sheet, and the sulfur-containing all-solid-state polymer electrolyte film described above.

[0045] It should be noted that in the lithium battery of the present embodiment, lithium metal (lithium sheet) is used as the negative active material, LFP is used as the positive active material, and 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 dried in a vacuum drying oven at 120°C 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 obtain a coin cell.

[0046] It should be further noted that an interfacial wetting agent can also be added when assembling the battery for cycle testing. The interfacial wetting agent is a commonly used lithium ion electrolyte (LiPF6 in EC / DMC) on the market, and the amount of the interfacial wetting agent is ≤5 μL. The wetting agent mainly wets the porous structure of the electrolyte film through capillary action, improves the compatibility of the sulfur-containing all-solid-state polymer electrolyte film and the positive and negative electrode materials, accelerates the conduction of lithium ions, and improves the cycle performance.

[0047] The sulfur-containing all-solid-state polymer electrolyte film proposed by the present disclosure realizes the synergy of the four core functions through the "rigid-flexible combination and dynamic-static combination" three-dimensional network, which can improve the ionic conductivity, mechanical strength of the electrolyte film, and the interface stability of the battery. The four core functions are as follows:

[0048] ① Ion transport and flexible chain segment synergy: the flexible polysulfide chain segment (-S-S- / -S x -) formed by the breakage of DAT is the main channel for lithium ion conduction. The coordination ability of sulfur atom lone pair electrons is comparable to that of ether oxygen bond, and the larger atomic radius reduces the Li + + ​Transition energy barrier. The conformational flexibility of long sulfur chains further promotes the formation of continuous ion channels, laying the foundation for high ionic conductivity; ②Self-repair and dynamic bond synergy: the residual dynamic S-S bond in the network is the key to safety. When lithium dendrite growth or mechanical damage occurs, the S-S bond reversibly breaks / recombines, instantly repairing micro-cracks and physically blocking dendrite penetration. This mechanism significantly improves interface stability and battery safety, solving the dendrite problem of solid-state batteries; ③Mechanical strength and rigid skeleton synergy: the rigid benzene ring of DVB as a crosslinking point gives the network high modulus and dimensional stability. Its physical barrier effect synergizes with the chemical self-repair of S-S bonds to double inhibit dendrite growth. The thermal stability of the benzene ring also enhances the overall thermal safety; ④Functional integration synergy: the microphase separation of flexible sulfur chains (ion conductor) and rigid aromatic rings (structural support) optimizes the balance between ionic conductivity and mechanical strength; the combination of dynamic S-S bonds (intelligent response) and covalent networks (overall stability) achieves a dynamic balance of "damage-repair". This multi-scale synergy meets the stringent demands of high ionic conductivity, dendrite inhibition, self-repair, and thermal stability.

[0049] The sulfur-containing all-solid-state polymer electrolyte membrane and the preparation method thereof will be further described below with reference to specific examples:

[0050] Example 1

[0051] The present example provides a preparation method of a sulfur-containing all-solid-state polymer electrolyte membrane, comprising the following steps:

[0052] Step one, mix dithiobis(acrylate) (DAT) and divinylbenzene (DVB) uniformly in a mass ratio of 1:1, and magnetically stir in an oil bath at a temperature of 130°C for 60 min. After 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% by mass of LiTFSI and mix uniformly, magnetically stir at room temperature for 24 h to obtain a precursor solution;

[0053] 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 24 h. The oven ensures a vacuum atmosphere, and the oven temperature is 120°C. The polymer electrolyte membrane after drying is cut into a 16 mm diameter disc by a punching machine to obtain a sulfur-containing all-solid-state polymer electrolyte membrane P(DAT1-DVB1)@LiTFSI. Store the obtained sulfur-containing all-solid-state polymer electrolyte membrane in an argon environment, where the water is <0.1 ppm and the oxygen is <0.1 ppm.

[0054] Further, as shown in Table 1, the ionic conductivity 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.

[0055] Example 2

[0056] The present example provides a sulfur-containing all-solid-state polymer electrolyte film, which is different from example 1 only in that the dithioacetylene (DAT) and divinylbenzene (DVB) are mixed in a mass ratio of 1:2 to obtain a sulfur-containing all-solid-state polymer electrolyte film P(DAT1-DVB2)@LiTFSI, and the rest is the same as example 1.

[0057] Further, as shown in Table 1, the ionic conductivity of the present example 2 is 2.50 x 10 -4 S / cm, the tensile strength is 8.8 MPa, and the Li-Li symmetric polarization voltage is 45 mV.

[0058] Example 3

[0059] The present example provides a sulfur-containing all-solid-state polymer electrolyte film, which is different from example 1 only in that the dithioacetylene (DAT) and divinylbenzene (DVB) are mixed in a mass ratio of 1:4 to obtain a sulfur-containing all-solid-state polymer electrolyte film P(DAT1-DVB4)@LiTFSI, and the rest is the same as example 1.

[0060] Further, as shown in Table 1, the ionic conductivity of the present example 3 is 1.80 x 10 -4 S / cm, the tensile strength is 10.6 MPa, and the Li-Li symmetric polarization voltage is 58 mV.

[0061] Example 4

[0062] Step one, mix dithioacetylene (DAT) and divinylbenzene (DVB) in a mass ratio of 1:6, and stir magnetically in an oil bath at a temperature of 180°C for 90 min. After 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 50% mass of LITFSI and mix uniformly, magnetically stir at 45°C for 16 h to obtain a precursor solution;

[0063] 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 36 h, the oven ensures a vacuum atmosphere, and the oven temperature is 150°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-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 <0.1 ppm, and the oxygen is <0.1 ppm.

[0064] Further, as shown in Table 1, the ionic conductivity of the present example 4 is 2.0 x 10-4 S / cm, tensile strength of 12.8 MPa, and Li-Li symmetric polarization voltage of 79 mV.

[0065] Example 5

[0066] Step one, mix DAT and DVB uniformly in a mass ratio of 1:8, and then magnetically stir in an oil bath at a temperature of 110°C for 120 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 60% mass of LiTFSI and mix uniformly, magnetically stir at 55°C for 48 h to obtain a precursor solution;

[0067] Step two, cast the precursor solution on the surface of a PTFE mold, and then place the precursor solution in an oven for 12 h after uniformly spreading the precursor solution, the oven ensures a vacuum atmosphere, and the oven temperature is 160°C; cut the polymer electrolyte film after drying into a 16 mm diameter disc using a punching machine to obtain a sulfur-containing all-solid-state polymer electrolyte film P(DAT1-DVB8)@LiTFSI, and store the prepared sulfur-containing all-solid-state polymer electrolyte film in an argon environment, and the water in the argon environment is <0.1 ppm, and the oxygen is <0.1 ppm.

[0068] Further, as shown in Table 1, the ionic conductivity of the all-solid-state polymer electrolyte film of Example 5 is 0.75 x 10 -4 S / cm, tensile strength of 16.2 MPa, and Li-Li symmetric polarization voltage of 92 mV.

[0069] Example 6

[0070] Step one, mix DAT and DVB uniformly in a mass ratio of 1:10, and then magnetically stir 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% mass of LiTFSI and mix uniformly, magnetically stir at 60°C for 12 h to obtain a precursor solution;

[0071] Step two, cast the precursor solution on the surface of a PTFE mold, and then place the precursor solution in an oven for 48 h after uniformly spreading the precursor solution, the oven ensures a vacuum atmosphere, and the oven temperature is 25°C; cut the polymer electrolyte film after drying into a 16 mm diameter disc using a punching machine to obtain a sulfur-containing all-solid-state polymer electrolyte film P(DAT1-DVB 10 )@LiTFSI, and store the prepared sulfur-containing all-solid-state polymer electrolyte film in an argon environment, and the water in the argon environment is <0.1 ppm, and the oxygen is <0.1 ppm.

[0072] Further, as shown in Table 1, the ionic conductivity of the ion conductive film 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.

[0073] Comparative Example 1

[0074] This comparative example provides an industry standard all-solid-state electrolyte film PEO@LiTFSI, which is prepared as follows:

[0075] 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 coated on a PTFE mold and placed in a 60°C vacuum dryer for 24 hours to dry the solvent, and then the film is removed from the mold and cut into 16 mm diameter discs using a punch machine to obtain a PEO@LiTFSI electrolyte film, which is then assembled for battery testing.

[0076] Further, as shown in Table 1, the ionic conductivity of the ion conductive film 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.

[0077] Table 1 Battery test results of each example and comparative example

[0078]

[0079] 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:

[0080] 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 due to the high DAT ratio providing more flexible sulfide chain segments (-S-S- / -S x -), enhancing the coordination and transition ability of Li⁺. Compared with the comparative example, the radius of sulfur atom is larger than that of oxygen, the Li⁺-S bond is weaker and the chain segment is more flexible (PEO crystalline region inhibits conduction), and the 1:4 ionic conductivity gradually decreases mainly due to the high crosslinking density, which limits the chain segment movement and leads to a decrease in conductivity, but it is still significantly higher than PEO.

[0081] 2. In terms of tensile strength performance: Example 3 > Example 2 > Example 1, which is mainly due to the rigid benzene ring of DVB as a crosslinking point, which improves the network modulus. Compared with the comparative example of 0.8 Mpa, the benzene ring crosslinking network provides rigid support, which is the key to inhibiting physical penetration of lithium dendrites.

[0082] 3、In terms of Li|P(DATx-DVBy)@LiTFSI|Li interface stability: Example 2>Example 3>Example 1, which is mainly related to the synergistic effect of sulfur chain- aromatic ring: ① The DAT sulfur chain ensures Li⁺ conduction and provides dynamic S-S bond repair ability; ② The DVB benzene ring improves mechanical strength and stabilizes the cross-linked network. When 1:2: the sulfur chain density and benzene ring cross-linking degree reach the golden balance, the ionic conductivity meets the application requirements, and the mechanical strength exceeds the yield strength of lithium dendrite (~8 MPa). In addition, the S-S bond is in the best dynamic activity state, and the repair rate is > dendrite damage rate. Physical barrier (rigid aromatic ring) + chemical repair (dynamic S-S bond) significantly delays dendrite growth, and the polarization voltage is stable at 25 mV.

[0083] 4、As Figure 2 shown in the data, in terms of impedance performance: Example 3>Example 2>Example 1, which corresponds to the ionic conductivity data in Table 1 after conversion, impedance is reduced, and ionic conductivity is improved.

[0084] 5、As Figure 3 shown in the data, in terms of interface stability performance: under the test conditions of a current density of 0.2 mA·cm -2 and an area specific capacity of 0.2 mAh·cm -2 at 30°C, the battery using P(DAT1-DVB2)@LiTFSI sulfur-containing all-solid-state polymer electrolyte film can be stably cycled for >300h, and 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 between the -(S-S)x- bond in the polymer backbone and Li metal, which builds an SEI layer that enables stable cycling of the battery. In addition, this polymer electrolyte film is synthesized without initiator, greatly reducing the introduction of impurities, thereby reducing the occurrence of side reactions.

[0085] 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.

[0086] The present disclosure provides a sulfur-containing full-solid-state polymer electrolyte film, a preparation method thereof and a lithium battery, and has the following beneficial effects relative to the prior art: the sulfur-containing full-solid-state polymer electrolyte film provided by the present disclosure replaces the ion transmission function of the liquid electrolyte by its solid-state ion conduction property, and replaces the physical isolation function of the separator by its dense and solid physical structure. This "two-in-one" replacement not only simplifies the battery structure, but more importantly brings about a leap in intrinsic safety, a huge potential for energy density improvement, revolutionary advantages of longer life and a wider working temperature range, and solves the problems of low ion conductivity, poor mechanical properties, poor interface compatibility and poor cycle performance of the full-solid-state battery in the related art.

[0087] It can be understood that the above embodiments are only exemplary embodiments adopted for illustrating the principles of the present disclosure, and 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 to be within the protection scope of the present disclosure.

Claims

1. A sulfur-containing all-solid-state polymer electrolyte membrane, characterized by, The electrolyte film is a sulfur-containing solid-state polymer, and the general structure of the polymer is as follows: ； Wherein, a, b, c are different polymerized units, and n is the structural unit of the whole polymer, wherein 2 2. A method for producing the sulfur-containing all-solid-state polymer electrolyte film according to claim 1, characterized by, The method comprises: Mixing tripropylene sulfide and divinylbenzene in a mass ratio, cooling to room temperature after high-temperature inverse vulcanization reaction, and obtaining 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; Pouring the precursor solution into a mold, uniformly spreading it, drying, and cutting to obtain a sulfur-containing all-solid-state polymer electrolyte film.

3. The method of claim 2, wherein, The mass ratio of tripropylene sulfide and divinylbenzene is 1:(1-10).

4. The method of claim 2, wherein, The temperature of the high-temperature inverse vulcanization reaction is 110-180℃, and the time is 30-120min.

5. The method of claim 2, wherein, The length of lithium bis(trifluoromethanesulfonyl)imide is 40%-80% of the mass of tripropylene sulfide and divinylbenzene.

6. The method of claim 2, wherein, The time of magnetic stirring is 12-48h, and the temperature of magnetic stirring is 25-60℃.

7. The method of claim 2, wherein, The temperature of drying is 25-160℃, and the time of drying is 12-48h.

8. The method of claim 2, wherein, The thickness of the sulfur-containing all-solid-state polymer electrolyte film is 45-55μm, and the diameter is 12-20mm.

9. A lithium battery, characterized by The lithium battery comprises a positive electrode sheet, a negative electrode sheet, and the sulfur-containing all-solid-state polymer electrolyte film of claim 1.

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

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