An olive-shaped In2O x Modified lithium-sulfur battery separator and its preparation method and application

Abstract

The present invention belongs to the technical field of lithium-sulfur batteries, and specifically relates to an olive-shaped In2O x Modified lithium-sulfur battery separator and its preparation method and application. The lithium-sulfur battery separator is based on a polypropylene separator and coated with an olive-shaped structure In2O x The composite film formed by stirring with Super-P conductive carbon black is used as the modified layer; the olive-shaped structure In2O x The oxygen concentration in the middle region is lower than that in the two end regions; In2O prepared by hydrothermal calcination process x The material has a high concentration of oxygen vacancies and a unique olive-shaped structure, which enhances electrolyte wettability and helps expose adsorption catalytic sites, inhibiting polysulfide shuttling, improving redox reaction efficiency, and increasing sulfur utilization. The use of the modified separator significantly improves the rate performance and cycle stability of lithium-sulfur batteries.

Description

Technical Field

[0001] The present invention belongs to the technical field of lithium-sulfur batteries, and specifically relates to an olive-shaped In2O x Modified lithium-sulfur battery separator, preparation method and application thereof. Background Art

[0002] Although lithium-sulfur batteries have the advantages of high theoretical specific capacity (1675 mAh / g), high energy density (2600 Wh / kg) and abundant raw materials, the problem of capacity attenuation caused by polysulfide migration has not yet been solved, and there is an urgent need to develop new membrane modification materials to improve electrochemical performance. To solve these problems, researchers have explored a variety of strategies, including cathode modification, anode protection, electrolyte optimization, and functionalized membrane design. Among them, the design of functional membranes to inhibit polysulfide migration and accelerate its conversion has become a key way to improve the performance of lithium-sulfur batteries. Compared with non-polar carbon materials, polar materials (such as metal oxides, sulfides, nitrides and carbides) have been shown to be effective for Li2S n It has strong chemical adsorption and catalytic conversion capabilities. The surface of the metal oxide contains hydrophilic functional groups, and the polar chemical bonds between the metal cations and oxygen anions can provide sufficient polar active sites to anchor Li2S n . As a metal oxide, In2O3 not only has a small resistivity, but also has a high catalytic activity, and is widely used in lithium-sulfur batteries. In2O3 can accelerate the kinetics of sulfur redox reactions and inhibit the shuttle effect, thereby improving battery performance. Recent studies have shown that defect engineering can destroy the charge balance state of the crystal surface and effectively expose active sites. In addition, compared with the absence of defects, the electrons around the defects are rich in activity and can serve as Li2S n The adsorption and catalytic sites of In2O3 can accelerate the conversion of S8 to Li2S, thereby improving the electrochemical performance of lithium-sulfur batteries. Despite this, the defect engineering based on In-based materials in existing research is often limited to the catalytic activity of specific reaction stages, and it is difficult to cover the polysulfide conversion path during the entire discharge process. The corresponding rate performance and cycle performance of lithium-sulfur batteries are still not significantly improved. In2O3 modified diaphragms are difficult to effectively inhibit the polysulfide shuttle effect under lean electrolyte conditions, and the redox kinetics are slow, which seriously restricts the practical application of lithium-sulfur batteries. Summary of the Invention

[0003] The purpose of the present invention is to solve the above problems and provide an olive-shaped In2O x The modified lithium-sulfur battery separator and its preparation method and application solve the problems of low discharge specific capacity and poor cycle performance of existing lithium-sulfur batteries.

[0004] To achieve the above objectives, the first aspect of the present invention provides an olive-shaped In2O x The modified lithium-sulfur battery separator is based on a polypropylene separator and coated with an olive-shaped In2O x The composite film formed by stirring with Super-P conductive carbon black is used as the modification layer; the olive-shaped structure In2O x The oxygen concentration in the middle area is lower than that in the two end areas.

[0005] As a preferred solution, the thickness of the lithium-sulfur battery separator is 43 to 50 μm.

[0006] Furthermore, the olive-shaped structure In2O x The oxygen concentration in the middle area is 20%-40% lower than that in the two end areas.

[0007] Furthermore, the olive-shaped structure In2O x The oxygen vacancies account for 35%-45%.

[0008] The second aspect of the present invention provides the above olive-shaped structure In2O x The preparation method of the modified lithium-sulfur battery separator comprises the following steps:

[0009] Step 1: Preparation of olive-shaped In2O x :

[0010] (a) uniformly mixing InCl₃·4H₂O, urea, and water to obtain a mixed solution; wherein the molar ratio of InCl₃·4H₂O to urea is 1:4-6;

[0011] (b) subjecting the mixed solution to a hydrothermal reaction to obtain a precipitate;

[0012] (c) After centrifugation, washing and drying, the precipitate is obtained to obtain In2O x Powder precursor;

[0013] (d) In2O x The powder precursor is calcined to obtain olive-shaped In2O x ;

[0014] Step 2: Prepare a uniform slurry:

[0015] Olive-shaped In2O x , Super-P conductive carbon black and a binder are dissolved in N-methylpyrrolidone, and the mixture is uniformly mixed to obtain a mixed slurry;

[0016] Step 3: Coat the mixed slurry on a polypropylene diaphragm and vacuum dry to obtain an olive-shaped In2O x Modified lithium-sulfur battery separator.

[0017] As a preferred embodiment, the preparation method of the lithium-sulfur battery separator meets at least one of the following characteristics:

[0018] The temperature of the hydrothermal reaction is 105-115°C;

[0019] The hydrothermal reaction time is 4-8h;

[0020] The calcination temperature is 650-750℃;

[0021] The calcination time is 4-6h.

[0022] As a preferred embodiment, in the preparation method of the lithium-sulfur battery separator, the olive-shaped structure In2O x The mass ratio of Super-P conductive carbon black and binder is 7-9:1:0.8-1.2.

[0023] As a preferred embodiment, in the above-mentioned method for preparing the lithium-sulfur battery separator, the binder is PVDF, and the concentration of the binder dissolved in N-methylpyrrolidone is 8-10 g / L.

[0024] The third aspect of the present invention provides the above olive-shaped structure In2O x Application of modified lithium-sulfur battery separator in the preparation of button-type lithium-sulfur batteries.

[0025] The prepared button-type lithium-sulfur battery has a discharge capacity of 1293.8 mAh g at 0.1C. -1 , the capacity is maintained at 623 mAh g after 500 cycles at 1C. -1 Under the condition of poor electrolyte (E / S = 10 μl / mg), the capacity retention rate is >80% after 200 cycles at 1C.

[0026] Compared with the prior art, the present invention has at least the following beneficial effects:

[0027] The present invention uses polypropylene diaphragm as substrate, olive-shaped structure In2O x The composite film formed by stirring with Super-P was used as the modification layer; In2O prepared by hydrothermal-calcination process x The material has a high concentration of oxygen vacancies and a unique olive-shaped structure, which enhances electrolyte wettability and helps expose adsorption catalytic sites, inhibiting polysulfide shuttling, improving redox reaction efficiency, and increasing sulfur utilization. The use of the modified separator significantly improves the rate performance and cycle stability of lithium-sulfur batteries.

[0028] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are specifically listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 Olive-shaped In2O prepared in Example 1 x and XRD patterns of its precursors;

[0030] Figure 2 Olive-shaped In2O prepared in Example 1 x and SEM images of precursors with different In / urea ratios;

[0031] Figure 3 Olive-shaped In2O prepared in Example 1 x TEM images of

[0032] Figure 4 Olive-shaped In2O prepared in Example 1 x XPS graph;

[0033] Figure 5 Olive-shaped In2O prepared in Example 1 x EPR diagram;

[0034] Figure 6 Olive-shaped In2O prepared in Example 1 x Digital photos of the flexibility test of the modified lithium-sulfur battery separator;

[0035] Figure 7 Olive-shaped In2O prepared in Example 1 x Electrolyte contact angle test of the modified lithium-sulfur battery separator and the separators of Comparative Examples 1-3;

[0036] Figure 8 The rate performance diagram of the lithium-sulfur battery assembled in Example 1 and Comparative Examples 1 to 3 at different current densities;

[0037] Figure 9 The cycling performance diagram of the lithium-sulfur batteries assembled in Example 1, Comparative Example 2 and Comparative Example 3 at a current density of 1C;

[0038] Figure 10 The cycling performance diagram of the lithium-sulfur batteries assembled in Example 1, Comparative Example 2 and Comparative Example 3 at E / S=10 μl / mg and 1C current density. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solutions and advantages of the present invention more clear, the following is a further detailed description with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. That is, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments.

[0040] The features and performance of the present invention are further described in detail below with reference to the accompanying drawings and embodiments.

[0041] In the embodiment of the present invention, the concentration of the binder dissolved in N-methylpyrrolidone is 8-10 g / L.

[0042] In the examples and comparative examples of the present invention, the raw materials are commercially available.

[0043] Example 1

[0044] This embodiment provides an olive-shaped In2O x The preparation method of the modified lithium-sulfur battery separator comprises the following steps:

[0045] Step 1: Preparation of olive-shaped In2O x :

[0046] InCl3·4H2O and urea were dissolved in 40 mL of purified water at a molar ratio of 1:5 and stirred for 30 min to prepare a homogeneous mixed solution;

[0047] The mixed solution was added to a 100 mL reactor and reacted at 110 °C for 6 h;

[0048] The obtained white precipitate was washed by centrifugation with ethanol and water, and dried in an oven at 60 °C for 12 h to obtain olive-shaped In2O x Powder precursor;

[0049] The precursor was placed in a quartz boat and calcined at 700 °C for 5 h in a muffle furnace to obtain an olive-shaped In2O x Yellow powder.

[0050] The phase of the prepared material was characterized by X-ray diffractometer (XRD), and its morphology was studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM).

[0051] Figure 1 Olive-shaped In2O prepared in Example 1 x and its precursor XRD patterns, where Figure 1 (a) in the figure: XRD pattern of the precursor; Figure 1 (b) in: In2O x XRD pattern of Figure 1 As shown, Figure 1 The horizontal axis represents the 2θ angle, and the vertical axis represents the intensity. x The diffraction peaks of In(OH)3 basically match the PDF card (ICDD#01-076-1464). x The XRD patterns of 21.4°, 30.5°, and 50.9° correspond to (211), (222), and (440) planes, respectively, which are consistent with the PDF card of standard indium oxide (In2O3ICDD#01-071-2195). No other impurity peaks were found in the sample, indicating that the obtained In2O x The main material in this series of materials is In2O3.

[0052] Figure 2 Olive-shaped In2O prepared in Example 1 x and SEM images of its precursors; the morphologies of the precursors prepared at different molar ratios of InCl3·4H2O and urea were compared; Figure 2 (a): SEM image of the precursor (In: urea = 5:1); Figure 2 (b): SEM image of the precursor (In: urea = 1:1); Figure 2 (c): SEM image of the precursor (In: urea = 1:5); Figure 2 (d) in: In2O x (In: urea = 1:5) SEM image. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to observe the olive-shaped In2O x The morphology of its precursors was characterized, such as Figure 2 (a) and Figure 2 As shown in (b), the product is in the shape of a block, while Figure 2 (c) and Figure 2 As shown in (d), the product presents a unique olive-shaped structure with a length of about 5 μm and a width of about 1000 nm. After calcination and annealing at 700℃ ( Figure 2 In (d)), the material still maintains the olive-shaped main structure, but a large number of agglomerated nanoparticles appear on the originally smooth surface. Figure 3 Olive-shaped In2O prepared in Example 1 x TEM image, where Figure 3 (a) in: In2O x TEM; Figure 3 (b): HRTEM image; Figure 3 (c) in: In2O x SAED pattern; Figure 3 (d)- Figure 3 (f) in: In2Ox Elemental mapping of . High-resolution transmission electron microscopy (HRTEM) image ( Figure 3 (b) in the figure clearly shows lattice fringes with a spacing of 0.28 nm, which is consistent with the (222) crystal plane spacing of In2O3. Figure 3 (c) shows a series of clear diffraction rings, and its characteristic crystal plane index is consistent with the above XRD analysis results. Figure 3 (d)- Figure 3 The elemental mapping image shown in (f) shows that in In2O x The O element in the sample is not evenly distributed, showing an asymmetric state with high content at both ends and low content in the middle. The oxygen concentration in the middle area is 20%-40% lower than that at both ends, indicating that there may be more oxygen vacancies in the middle part of the nanoparticles than at the two ends. Figure 4 Olive-shaped In2O prepared in Example 1 x XPS graph, Figure 4 In the figure, the horizontal axis represents the binding energy and the vertical axis represents the intensity. Figure 4 In (a), the two main peaks at about 444 and 452 eV correspond to In 3+ In 3D 5 / 2 and In 3d 3 / 2 . O 1s spectrum ( Figure 4 Three peaks can be fitted in (b), of which 530.0, and 533.8 eV correspond to lattice oxygen (O L ), and chemically adsorbed oxygen species (O C ). The 532.0 eV corresponds to the oxygen vacancy (O V ), the peak area accounts for 39.7%, indicating that In2O x The material has a high concentration of oxygen vacancies. Figure 5 Olive-shaped In2O prepared in Example 1 x The EPR diagram of In2O x The g value is 2.0036, showing a significant EPR characteristic signal, that is, there are a large number of oxygen vacancies in the system.

[0053] Step 2: Preparation of olive-shaped In2O x Modified lithium-sulfur battery separator

[0054] 80 wt% In2O xThe powder, 10 wt% Super P, and 10 wt% PVDF binder were dissolved in NMP solvent and stirred for 4 h to obtain a uniform mixed slurry with a concentration of 93 g / L. The uniform mixed slurry was then coated on a Celgard 2400 (PP) separator and vacuum dried at 35°C overnight. The In2O was obtained by cutting into discs with a diameter of 16 mm. x Modified diaphragm, denoted as In2O x / / PP. The uncoated side is white, the coated side is black, the thickness is 20 μm, Figure 6 It can be seen that the modified membrane still has good flexibility.

[0055] like Figure 7 As shown (PP represents polypropylene membrane, Super P / / PP represents carbon black (Super P) modified membrane, C-In2O3 / / PP represents commercial indium oxide (C-In2O3) modified membrane, In2O x / / PP represents olive-shaped structure In2O x Modified membrane), the olive-shaped In2O prepared in this embodiment x Contact angle test of modified lithium-sulfur battery separator electrolyte, olive-shaped structure In2O x The modified lithium-sulfur battery separator has a smaller electrolyte contact angle, which illustrates the olive-shaped structure of In2O x The modified lithium-sulfur battery separator has good wettability with the electrolyte.

[0056] Comparative Example 1

[0057] This comparative example provides a carbon black (Super P) modified lithium-sulfur battery separator and a preparation method thereof:

[0058] 90 wt% Super P and 10 wt% PVDF binder were dissolved in NMP solvent and stirred for 4 hours to obtain a uniform mixed slurry with a concentration of 93 g / L. The uniform mixed slurry was then coated on a Celgard 2400 (PP) separator and vacuum-dried overnight at 35°C. The resulting discs were cut into 16 mm diameter discs with a coating layer thickness of 20 μm. This resulted in a Super P-modified separator, designated Super P / / PP.

[0059] Comparative Example 2

[0060] This comparative example provides a commercial indium oxide (C-In2O3) modified lithium-sulfur battery separator and its preparation method:

[0061] 80 wt% C-In2O3 powder, 10 wt% Super P, and 10 wt% PVDF binder were dissolved in NMP solvent and stirred for 4 h to obtain a uniform mixed slurry with a concentration of 93 g / L. The uniform mixed slurry was then coated on a Celgard2400 (PP) separator and vacuum-dried overnight at 35°C. The discs with a diameter of 16 mm were cut to obtain a commercial indium oxide (C-In2O3)-modified lithium-sulfur battery separator. The coating layer thickness was 20 μm and was recorded as C-In2O3 / / PP.

[0062] Comparative Example 3

[0063] The separator used in this comparative example was Celgard 2400 polypropylene (PP) without any modification and with a thickness of 25 μm, designated as PP. The positive electrode sheet was prepared by grinding 53 wt% sulfur and 47 wt% Ketjen black (KB) together and then heating at 155°C for 12 hours to produce a sulfur / carbon composite (S / KB). A slurry prepared by mixing S / KB (53%) and a binder, LA 133, in a 9:1 mass ratio with a solvent consisting of ethanol and deionized water (v:v = 1:3) was applied to a carbon-coated aluminum foil. After drying in air for 12 hours and then in a vacuum oven at 50°C for another 12 hours, the foil was cut into discs with a diameter of 12 mm for use as the sulfur positive electrode.

[0064] Cell Assembly: 2032-size coin cells were assembled in an argon-filled glove box. The positive electrode of the coin cell was separated from the lithium metal electrode by a modified separator. 40 μl of electrolyte was added dropwise onto the separator. The electrolyte consisted of 1 mol / L lithium bis(trifluoromethane)sulfonyl imide (LiTFSI) dissolved in a 1 / 1 (v / v) mixture of dimethoxyethane (DME) and dioxolane (DOL), which contained 2 wt% lithium nitrate (LiNO3).

[0065] The assembled batteries were aged for 24 hours using a LAND CT2001a multi-channel battery cycler and cycled at 25°C. The cycle test was conducted in accordance with GB / T 36276-2023 Lithium-ion Batteries for Power Energy Storage, with a charge and discharge cut-off voltage of 1.7-2.8V.

[0066] Figure 8 The figure shows the rate performance of lithium-sulfur batteries assembled in Example 1 and Comparative Examples 1 to 3 at different current densities. Figure 8 The horizontal axis represents the number of cycles, and the vertical axis represents the specific capacity. Figure 8As shown in the figure, the rate performance of the lithium-sulfur batteries assembled in Example 1 and Comparative Examples 1 to 3 at different current densities. As shown in the battery rate performance of Example 1, when the modified diaphragm contains olive-shaped In2O x The lithium-sulfur battery exhibited excellent electrochemical performance, wherein the battery performance of Example 1 was 1293.8, 1150.8, 1051.2, 968.8, 851.5, 748.8, and 569.9 mAh g at 0.1, 0.2, 0.5, 1.0, 2.0, 3.0, and 5.0 C, respectively. -1 , after returning to 0.2 C, In2O x / / PP battery still provides 1083mAh g -1 The specific capacity of the lithium-sulfur battery was 92.4%, and the capacity retention rate was 95%, which was higher than that of other separator batteries (PP: 92.4%, Super P / / PP: 94%, C-In2O3 / / PP: 93.1%). This shows that the lithium-sulfur battery separator prepared by the present invention can improve the discharge specific capacity of lithium-sulfur batteries.

[0067] Figure 9 The cycle performance diagram of the lithium-sulfur battery assembled in Example 1, Comparative Example 2 and Comparative Example 3 at a current density of 1C is shown as follows: Figure 9 As shown, Figure 9 The horizontal axis represents the number of cycles, the vertical axis represents the specific capacity, and the vertical axis represents the Coulombic efficiency. At a 1C rate, the PP separator battery fails after only 72 cycles. Although the C-In2O3 / / PP can be cycled for more than 100 cycles, the capacity is extremely low (initial capacity: 13 mAh g -1 ), while In2O x / / PP battery at 1 C (initial specific capacity 796.6 mAh g -1 ), and still maintained 624.2 mAh g after 500 cycles -1 , attenuation rate 21.6%.

[0068] In2O x The system seems to be more suitable for lean liquid conditions. By comparing the test results, the use of In2O x Cycling performance of batteries with / / PP, C-In2O3 / / PP, and PP separator under lean solution conditions of E / S=10. Figure 10 The cycle performance diagram of the lithium-sulfur battery assembled in Example 1, Comparative Example 2 and Comparative Example 3 at E / S=10 μl / mg and 1C current density. Figure 10 As shown, Figure 10 The horizontal axis represents the number of cycles, the vertical axis represents the specific capacity, and the vertical axis represents the Coulombic efficiency. The initial capacity of the C-In2O3 / / PP battery is extremely low, only 88 mAh g -1, and failed after 50 cycles. Although the PP battery can run 200 cycles, the initial specific capacity (32.5 mAhg -1 ) is too low, and there is basically no possibility of practical application. In contrast, In2O x / / PP battery showed better long-term cycling stability (initial capacity 702.8 mAh g -1 ), the retention capacity after 200 cycles is 569.14 mAh g -1 The attenuation rate is about 19%, which is much more stable than other materials. This further verifies that In2O x It can still provide high catalytic activity under lean solution conditions.

[0069] The present invention uses commercial Celgard 2400 polypropylene diaphragm as the substrate, and the surface is modified with olive-shaped In2O x Composite film formed by assembling In2O x The special olive-shaped structure has good electrolyte wettability, thereby improving the lithium ion conduction rate. The presence of oxygen vacancies can effectively adsorb polysulfides; the conductivity of Super P can effectively alleviate the olive-shaped structure In2O x The disadvantage of poor conductivity is overcome and the interfacial impedance is improved. The above characteristics of the modified separator give lithium-sulfur batteries excellent rate performance and cycle stability.

[0070] Thanks to the unique asymmetric distribution of oxygen vacancies in the nanostructure, the olive-shaped In2O x The results showed that In2O x The battery is capable of high rate performance (569.9 mAh g at 5C) -1 ) and excellent reversibility and stability (it can be stably operated for 500 times at 1 C, and its capacity remains at 80% of the initial capacity). More notably, in the lean state (sulfur loading 3 mg cm -2 , E / S=10 μl / mg), In2O x The battery's long-cycle performance at 1C decays by only 0.1% per cycle on average. This work provides a theoretical basis for the application of defect engineering in separator design, promoting the practical application of high-energy-density lithium-sulfur batteries.

[0071] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered by the scope of protection of the claims of the present invention.

Claims

1. An olive-shaped In2O x The modified lithium-sulfur battery separator is characterized in that The lithium-sulfur battery separator is based on a polypropylene separator and coated with an olive-shaped In2O x The composite film formed by stirring with Super-P conductive carbon black is used as the modification layer; the olive-shaped structure In2O x The oxygen concentration in the middle area is lower than that in the two end areas; The olive-shaped structure In2O x The oxygen concentration in the middle area is 20%-40% lower than that in the two end areas; The olive-shaped structure In2O x The oxygen vacancies account for 35%-45%.

2. The olive-shaped In2O structure according to claim 1 x The modified lithium-sulfur battery separator is characterized in that The thickness of the lithium-sulfur battery separator is 43-50 μm.

3. The olive-shaped In2O according to any one of claims 1 to 2 x The preparation method of the modified lithium-sulfur battery separator is characterized in that: The following steps are involved: Step 1: Preparation of olive-shaped In2O x : (a) uniformly mixing InCl₃·4H₂O, urea, and water to obtain a mixed solution; wherein the molar ratio of InCl₃·4H₂O to urea is 1:4-6; (b) subjecting the mixed solution to a hydrothermal reaction to obtain a precipitate; (c) After centrifugation, washing and drying, the precipitate is obtained to obtain In2O x Powder precursor; (d) In2O x The powder precursor is calcined to obtain olive-shaped In2O x ; Step 2: Prepare a uniform slurry: Olive-shaped In2O x , Super-P conductive carbon black and a binder are dissolved in N-methylpyrrolidone, and the mixture is uniformly mixed to obtain a mixed slurry; Step 3: Coat the mixed slurry on a polypropylene diaphragm and vacuum dry to obtain an olive-shaped In2O x Modified lithium-sulfur battery separator.

4. The preparation method according to claim 3, characterized in that Satisfy at least one of the following characteristics: The temperature of the hydrothermal reaction is 105-115°C; The hydrothermal reaction time is 4-8h; The calcination temperature is 650-750℃; The calcination time is 4-6h.

5. The preparation method according to claim 3, characterized in that Olive-shaped In2O x The mass ratio of Super-P conductive carbon black and binder is 7-9:1:0.8-1.

2.

6. The preparation method according to claim 5, characterized in that The binder is PVDF, and the concentration of the binder dissolved in N-methylpyrrolidone is 8-10 g / L.

7. The olive-shaped In2O according to any one of claims 1 to 2 x Application of modified lithium-sulfur battery separator in the preparation of button-type lithium-sulfur batteries.

8. The use according to claim 7, characterized in that The prepared button-type lithium-sulfur battery has a discharge capacity of 1293.8 mAh g at 0.1C. -1 , the capacity is maintained at 623 mAh g after 500 cycles at 1C. -1 Under the condition of lean electrolyte E / S = 10 μl / mg, the capacity retention rate is >80% after 200 cycles at 1C.

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