Micron-sized antimony compound, and preparation method and use thereof

Abstract

This invention relates to a micron-sized antimony compound, its preparation method, and its uses. The antimony compound comprises Sb₂O₃ and Zn elements; the particle size of the antimony compound is 0.5-10 μm. The preparation method includes mixing zinc salt, antimony salt, 2-methylimidazole, and an organic solvent, followed by a solvothermal reaction to obtain the antimony compound. This invention innovatively uses a solvothermal method to prepare a micron-sized antimony compound and applies it as an inorganic additive in polymer solid electrolytes. It is then combined with a polymer substrate and lithium salt to prepare polymer solid electrolytes, significantly improving the ionic conductivity and safety performance of the polymer solid electrolytes.

Description

Technical Field

[0001] This invention belongs to the field of lithium-ion battery technology, and particularly relates to a micron-sized antimony compound, its preparation method, and its uses. Background Technology

[0002] Lithium-ion batteries, also known as lithium secondary batteries, are rechargeable secondary power sources. They are characterized by high energy density, excellent electrical performance, and the ability to be manufactured in various shapes, making them widely used in mobile phones, electric vehicles, laptops, cameras, and other applications requiring portable power. With the continuous growth in demand from related industries, lithium-ion battery materials and technologies are undergoing rapid development. Improving the safety, energy density, and lifespan of lithium-ion batteries is the development direction for high-performance lithium batteries. Among the core materials and technologies of lithium-ion batteries, the type and performance of the electrolyte system between electrodes have a decisive influence on battery structure and manufacturing technology, internal resistance, charge / discharge current density, charge / discharge cycle characteristics, ionic conductivity, electrochemical window, and overcharge / discharge safety, making it one of the key and core aspects of lithium-ion batteries.

[0003] Liquid electrolytes meet the requirements of low internal resistance and high charging rate for lithium-ion batteries, but severe side reactions occur between the liquid electrolyte and the electrodes, resulting in low capacity and poor cycle stability. Furthermore, liquid electrolytes pose risks such as leakage, leading to poor safety performance. While gel polymer electrolytes can adsorb liquid electrolytes, their safety performance still cannot be guaranteed.

[0004] To completely solve the safety hazards and low ionic conductivity problems associated with liquid electrolytes and gel polymer electrolytes, lithium-ion batteries fabricated using all-solid-state electrolytes represent one of the important development directions for next-generation lithium-ion batteries. Polymer solid-state electrolytes offer advantages such as flexibility, ease of fabrication, low cost, and good safety. Commonly used polymer substrates include PEO and PVDF, but their low ionic conductivity at room temperature hinders their practical application.

[0005] Therefore, modifying it by methods such as blending and doping to improve its ionic conductivity is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a micron-sized antimony compound, its preparation method, and its applications. It innovatively employs a solvothermal method to prepare the micron-sized antimony compound, which is then used as an inorganic additive in polymer solid electrolytes. This compound is then combined with a polymer substrate and lithium salt to prepare the polymer solid electrolyte, significantly improving the ionic conductivity and safety performance of the polymer solid electrolyte.

[0007] To achieve the above-mentioned technical effects, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a micron-sized antimony compound comprising Sb₂O₃ and Zn elements;

[0009] The antimony compound has a particle size of 0.5-10 μm.

[0010] Preferably, the Zn element in the antimony compound has a mass content of 10-30 wt.%.

[0011] Preferably, the antimony compound has an octahedral structure.

[0012] In a second aspect, the present invention provides a method for preparing an antimony compound as described in the first aspect, the method comprising:

[0013] The antimony compound is prepared by mixing zinc salt, antimony salt, 2-methylimidazole and an organic solvent, followed by a solvothermal reaction.

[0014] Preferably, the molar ratio of the zinc salt to the antimony salt is 1:(1-3), more preferably 1:(1-2).

[0015] Preferably, the mass-to-volume ratio of the zinc salt to the solvent is 1:(80-200)g / mL.

[0016] Preferably, the mass ratio of the zinc salt to 2-methylimidazole is 1:(1:2.5).

[0017] Preferably, the zinc salt comprises any one or a combination of at least two of zinc acetate, zinc nitrate, zinc chloride, zinc sulfate, zinc gluconate, or zinc iodide.

[0018] Preferably, the antimony salt includes any one or a combination of at least two of antimony trichloride, antimony nitrate, or potassium antimony tartrate;

[0019] Preferably, the organic solvent includes any one or a combination of at least two of the following: alcohols, N,N-dimethylformamide, N,N-dimethylacetamide, or N-methylpyrrolidone.

[0020] Preferably, the alcohol compound includes any one or a combination of at least two of methanol, ethanol, or ethylene glycol.

[0021] Preferably, the temperature of the solvothermal reaction is 180-240°C.

[0022] Preferably, the holding time for the solvothermal reaction is 20-26 hours.

[0023] Preferably, the method for mixing zinc salt, antimony salt, and solvent specifically comprises:

[0024] The zinc salt and solvent are first mixed, and then the antimony salt is added for a second mixing.

[0025] Preferably, the first mixing time is 10-14 hours;

[0026] Preferably, the second mixing time is 1-4 hours.

[0027] Thirdly, the present invention provides a polymer solid electrolyte comprising a lithium salt, a polymer substrate, and an antimony compound as described in the first aspect or an antimony compound prepared by the preparation method described in the second aspect.

[0028] Preferably, the mass ratio of the antimony compound to the polymer substrate is (0.05-0.1):1.

[0029] Preferably, the mass ratio of the lithium salt to the polymer substrate is (0.25-0.4):1.

[0030] Preferably, the lithium salt includes fluorinated lithium salt and / or lithium dioxaborate.

[0031] Preferably, the fluorinated lithium salt includes any one or a combination of at least two of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium bis(trifluoromethanesulfonyl)imide, lithium bis(fluorosulfonyl)imide, lithium difluorooxalateborate, or lithium trifluoromethanesulfonate.

[0032] Preferably, the polymer substrate comprises any one or a combination of at least two of polyvinylidene fluoride, polyethylene oxide, thermoplastic polyurethane, polypropylene oxide, polycarbonate, polyvinyl alcohol, polyacrylic acid, polyethyl methacrylate, polymethyl methacrylate, polyacrylonitrile, or polyvinyl chloride.

[0033] Fourthly, the present invention provides a method for preparing a polymer solid electrolyte, the method comprising:

[0034] The polymer solid electrolyte is obtained by mixing lithium salt, polymer substrate and antimony compound.

[0035] Preferably, the preparation method includes:

[0036] S1, a homogeneous mixture is obtained by mixing lithium salt, polymer substrate, antimony compound and organic solvent;

[0037] S2. Solidify the homogeneous mixture obtained in step S1 to obtain the polymer solid electrolyte.

[0038] Preferably, in step S1, the amount of the polymer substrate dissolved in each 100 mL of organic solvent is 6 to 15 g, more preferably 7.5 to 9.5 g.

[0039] Preferably, the curing method described in step S2 is a solution coating method.

[0040] Preferably, the product is dried after curing as described in step S2.

[0041] Fifthly, the present invention provides a lithium-ion battery, the lithium-ion battery comprising a positive electrode, a negative electrode, and a polymer solid electrolyte as described in the third aspect or a polymer solid electrolyte prepared by the preparation method described in the fourth aspect;

[0042] The polymer solid electrolyte is located between the positive electrode and the negative electrode.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] (1) In this invention, micron-sized antimony compounds are used as inorganic additives in polymer solid electrolytes, and then combined with polymer substrates and lithium salts to prepare polymer solid electrolytes, which greatly improves the ionic conductivity and safety performance of polymer solid electrolytes.

[0045] (2) The present invention innovatively uses a solvothermal method to prepare micron-sized antimony compounds. The preparation method is simple, has a short processing time and low cost, and has extremely broad prospects in practical applications. Attached Figure Description

[0046] Figure 1 This is a SEM image of the antimony compound obtained in Example 1 of the present invention;

[0047] Figure 2 The image shows the XRD pattern of the antimony compound prepared in Example 1 of this invention. Detailed Implementation

[0048] To facilitate understanding of the present invention, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be construed as limiting the scope of the invention.

[0049] In one embodiment, the present invention provides a micron-sized antimony compound comprising Sb₂O₃ and Zn elements;

[0050] The particle size of the antimony compound is 0.5-10 μm, for example, it can be 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, 5.5 μm, 6 μm, 6.5 μm, 7 μm, 7.5 μm, 8 μm, 8.5 μm, 9 μm or 9.5 μm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0051] The antimony compound of the present invention includes Sb2O3 and Zn elements, wherein Zn exists in amorphous or low-crystalline particulate form. Compared with single Sb2O3 particles, the incorporation of Zn elements can form a heterostructure with Sb2O3 and promote the dissociation of lithium salts as a Lewis acid; while the unique octahedral structure can effectively reduce the crystallinity of the polymer substrate and provide channels for lithium ion transport.

[0052] In one embodiment, the Zn content in the antimony compound is 10-30 wt.%, for example, it can be 12 wt.%, 15 wt.%, 17 wt.%, 19 wt.%, 20 wt.%, 22 wt.%, 25 wt.%, 27 wt.%, or 29 wt.%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0053] In one embodiment, the antimony compound has an octahedral structure.

[0054] In another embodiment of the present invention, a method for preparing the antimony compound as described above is provided, the method comprising:

[0055] The antimony compound is prepared by mixing zinc salt, antimony salt, 2-methylimidazole and an organic solvent, followed by a solvothermal reaction.

[0056] This invention innovatively uses a solvothermal method to prepare antimony compounds. Compared with coprecipitation or high-temperature calcination methods, the prepared crystal particles have a unique octahedral crystal structure and form a heterostructure with zinc oxide doping.

[0057] In one embodiment, the molar ratio of the zinc salt to the antimony salt is 1:(1-3), for example, it can be 1:1.2, 1:1.4, 1:1.6, 1:1.8, 1:2, 1:2.2, 1:2.4, 1:2.6 or 1:2.8, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable, preferably 1:(1-2).

[0058] It is worth noting that the present invention controls the molar ratio of zinc salt and antimony salt within the range of 1:(1-3), which is beneficial to the formation of octahedral Sb2O3 crystals. When too much antimony salt is added, the amount of Zn salt as an oxidant is too small, resulting in the formation of some elemental Sb or ZnSb alloy. When too little antimony salt is added, since the main body of the octahedral crystal is Sb2O3, the amount of Sb salt is too small, resulting in a significant reduction in the number of octahedral crystals in the generated material.

[0059] In one embodiment, the mass-to-volume ratio of the zinc salt to the solvent is 1:(80-200) g / mL, for example, it can be 1:100 g / mL, 1:120 g / mL, 1:140 g / mL, 1:160 g / mL, 1:180 g / mL or 1:190 g / mL, etc., but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0060] In one embodiment, the mass ratio of the zinc salt to 2-methylimidazole is 1:(1:2.5), for example, it can be 1:1.2, 1:1.4, 1:1.5, 1:1.6, 1:1.8, 1:2 or 1:2.2, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0061] In one embodiment, the zinc salt includes any one or a combination of at least two of zinc acetate, zinc nitrate, zinc chloride, zinc sulfate, zinc gluconate, or zinc iodide. Typical but not limited combinations include combinations of zinc acetate and zinc nitrate, combinations of zinc nitrate and zinc chloride, or combinations of zinc sulfate and zinc gluconate.

[0062] In one embodiment, the antimony salt includes any one or a combination of at least two of antimony trichloride, antimony nitrate, or potassium antimony tartrate. Typical but not limited combinations include: a combination of antimony trichloride and antimony nitrate, a combination of antimony nitrate and potassium antimony tartrate, or a combination of antimony trichloride, antimony nitrate, and potassium antimony tartrate, etc.

[0063] In one embodiment, the organic solvent includes any one or a combination of at least two of alcohols, N,N-dimethylformamide, N,N-dimethylacetamide, or N-methylpyrrolidone.

[0064] In one embodiment, the alcohol compound includes any one or a combination of at least two of methanol, ethanol, or ethylene glycol.

[0065] In one embodiment, the temperature of the solvothermal reaction is 180-240°C, for example, it can be 185°C, 190°C, 195°C, 200°C, 205°C, 210°C, 215°C, 220°C, 225°C, 230°C or 235°C, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0066] It is worth noting that the temperature range of the solvothermal reaction described in this invention affects the physicochemical properties of the obtained antimony compound. When the solvothermal reaction temperature is too low, the activation energy required for the reaction cannot be reached, which will lead to the occurrence of side reactions and prevent the formation of octahedral Sb2O3. When the solvothermal reaction temperature is too high, the octahedral Sb2O3 formed will undergo structural fragmentation.

[0067] In one embodiment, the holding time for the solvothermal reaction is 20-26 h, for example, it can be 20.5 h, 21 h, 21.5 h, 22.5 h, 23 h, 23.5 h, 24 h, 24.5 h, 25 h or 25.5 h, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0068] In one embodiment, the method of mixing zinc salt, antimony salt, and solvent specifically comprises:

[0069] The zinc salt and solvent are first mixed, and then the antimony salt is added for a second mixing.

[0070] In one embodiment, the first mixing time is 10-14 hours, for example, it can be 10.5 hours, 11 hours, 11.5 hours, 12 hours, 12.5 hours, 13 hours or 13.5 hours, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0071] In one embodiment, the second mixing time is 1-4 hours, for example, it can be 1.5 hours, 2 hours, 2.5 hours, 3 hours or 3.5 hours, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0072] In another embodiment of the present invention, a polymer solid electrolyte is provided, the polymer solid electrolyte comprising a lithium salt, a polymer substrate, and the antimony compound described above or an antimony compound prepared by the above preparation method.

[0073] In one embodiment, the mass ratio of the antimony compound to the polymer substrate is (0.05-0.1):1, for example, it can be 0.06:1, 0.065:1, 0.07:1, 0.075:1, 0.08:1, 0.085:1, 0.09:1 or 0.095:1, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0074] It is worth noting that the amount of antimony compound added affects the ionic conductivity of the polymer solid electrolyte. When the amount of antimony compound added is too small, the improvement on the ionic conductivity of the polymer solid electrolyte is not significant. When the amount of antimony compound added is too large, it cannot be fully mixed with the polymer substrate, resulting in precipitation, which in turn affects the improvement of ionic conductivity.

[0075] In one embodiment, the mass ratio of the lithium salt to the polymer substrate is (0.25-0.4):1, for example, it can be 0.27:1, 0.3:1, 0.31:1, 0.32:1, 0.33:1, 0.34:1, 0.35:1, 0.36:1, 0.37:1, 0.38:1 or 0.39:1, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0076] It is worth noting that when too little lithium salt is added, the ionic conductivity is severely low; when too much lithium salt is added, the polymer is difficult to form a film.

[0077] In one embodiment, the lithium salt includes a fluorinated lithium salt and / or lithium dioxaborate.

[0078] In one embodiment, the fluorinated lithium salt includes any one or a combination of at least two of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium bis(trifluoromethanesulfonyl)imide, lithium bis(fluorosulfonyl)imide, lithium difluorooxalateborate, or lithium trifluoromethanesulfonate. Typical but not limiting combinations include: a combination of lithium hexafluorophosphate and lithium tetrafluoroborate, a combination of lithium bis(trifluoromethanesulfonyl)imide and lithium bis(fluorosulfonyl)imide, or a combination of lithium difluorooxalateborate and lithium trifluoromethanesulfonate, etc.

[0079] In one embodiment, the polymer substrate comprises any one or a combination of at least two of polyvinylidene fluoride, polyethylene oxide, thermoplastic polyurethane, polypropylene oxide, polycarbonate, polyvinyl alcohol, polyacrylic acid, polyethyl methacrylate, polymethyl methacrylate, polyacrylonitrile, or polyvinyl chloride. Typical but not limiting combinations include combinations of polyvinylidene fluoride and polyethylene oxide, thermoplastic polyurethane and polypropylene oxide, or polycarbonate and polyvinyl alcohol, etc.

[0080] In another embodiment of the present invention, a method for preparing the above-mentioned polymer solid electrolyte is provided, the method comprising:

[0081] The polymer solid electrolyte is obtained by mixing lithium salt, polymer substrate and antimony compound.

[0082] In one embodiment, the preparation method includes:

[0083] S1, a homogeneous mixture is obtained by mixing lithium salt, polymer substrate, antimony compound and organic solvent;

[0084] S2. Solidify the homogeneous mixture obtained in step S1 to obtain the polymer solid electrolyte.

[0085] In one embodiment, in step S1, the amount of the polymer substrate dissolved in each 100 mL of organic solvent is 6 to 15 g, for example, 7 g, 8 g, 9 g, 10 g, 12 g or 14 g, etc., but not limited to the listed values. Other unlisted values ​​within the range are also applicable, preferably 7.5 to 9.5 g.

[0086] In one embodiment, the mixing described in step S1 is carried out under stirring.

[0087] In one embodiment, the stirring temperature is 35-45°C, for example, it can be 36°C, 37°C, 38°C, 39°C, 40°C, 41°C, 42°C, 43°C or 44°C, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0088] In one embodiment, the stirring time is 22-26 hours, for example, it can be 22.5 hours, 23 hours, 23.5 hours, 24 hours, 24.5 hours, 25 hours or 25.5 hours, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0089] In one embodiment, the curing method in step S2 is a solution coating method, specifically: applying a homogeneous mixture onto a substrate. Exemplarily, the substrate includes a polytetrafluoroethylene (PTFE) sheet or a tempered glass sheet.

[0090] In one embodiment, the curing process described in step S2 is followed by drying.

[0091] In another embodiment of the present invention, a lithium-ion battery is provided, the lithium-ion battery comprising a positive electrode, a negative electrode and the polymer solid electrolyte described above or the polymer solid electrolyte prepared by the above preparation method;

[0092] The polymer solid electrolyte is located between the positive electrode and the negative electrode.

[0093] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0094] Example 1

[0095] This embodiment provides a method for preparing an antimony compound, the method comprising:

[0096] 1 mmol of zinc acetate, 0.4 g of 2-methylimidazole, 25 mL of methanol, and 5 mL of N,N-dimethylformamide were placed in a reaction vessel and magnetically stirred for 12 h. 1 mmol of antimony chloride was added and the mixture was magnetically stirred for 2 h. The reaction vessel was then placed in a forced-air drying oven and reacted at 210 °C for 24 h. Afterward, the reactants were centrifuged, washed, and dried to obtain the antimony compound.

[0097] Figure 1-2 The images show the SEM and XRD patterns of the antimony compound prepared in this embodiment. As can be seen from the images, the prepared antimony compound has an octahedral structure, and the prepared zinc-doped octahedral antimony compound is completely consistent with the standard spectrum of Sb2O3, proving that Sb2O3 was indeed prepared. The reason why ZnO does not have obvious diffraction peaks is because its low crystallinity is covered by the diffraction peaks of Sb2O3.

[0098] Example 2

[0099] This embodiment provides a method for preparing an antimony compound, the method comprising:

[0100] 0.67 mmol of zinc chloride, 0.4 g of 2-methylimidazole, 25 mL of ethanol, and 5 mL of N,N-dimethylformamide were placed in a reaction vessel and magnetically stirred for 14 h. 1.33 mmol of antimony chloride was added and the mixture was magnetically stirred for 2 h. The reaction vessel was then placed in a forced-air drying oven and reacted at 240 °C for 22 h. Afterward, the reactants were centrifuged, washed, and dried to obtain the antimony compound.

[0101] The antimony compound obtained in this embodiment has an octahedral structure.

[0102] Example 3

[0103] This embodiment provides a method for preparing an antimony compound, the method comprising:

[0104] 0.5 mmol of zinc acetate, 0.4 g of 2-methylimidazole, and 30 mL of N,N-dimethylformamide were placed in a reaction vessel and magnetically stirred for 12 h. 1.5 mmol of antimony chloride was added and the mixture was magnetically stirred for 4 h. The reaction vessel was then placed in a forced-air drying oven and reacted at 180 °C for 26 h. Afterward, the reactants were centrifuged, washed, and dried to obtain the antimony compound.

[0105] The antimony compound obtained in this embodiment has an octahedral structure.

[0106] Example 4

[0107] The only difference between this embodiment and Example 1 is that the molar amount of zinc acetate is 1.33 mmol and the molar amount of antimony chloride is 0.67 mmol. All other conditions are the same as in Example 1.

[0108] Comparative Example 1

[0109] This comparative example provides a method for preparing Sb₂O₃, the method comprising:

[0110] 2 mmol of antimony chloride, 0.4 g of 2-methylimidazole, 25 mL of methanol, and 5 mL of N,N-dimethylformamide were placed in a reaction vessel and magnetically stirred for 12 h. The reaction vessel was then placed in a forced-air drying oven and reacted at 210 °C for 24 h. Afterward, the reactants were centrifuged, washed, and dried to obtain Sb2O3.

[0111] Comparative Example 2

[0112] The only difference between this comparative example and Example 1 is that "1 mmol zinc acetate" is replaced with "1 mmol copper acetate", and all other conditions are the same as in Example 1.

[0113] Comparative Example 3

[0114] The only difference between this comparative example and Example 1 is that "0.4g 2-methylimidazole, 25mL methanol, 5mL N,N-dimethylformamide" is replaced with "0.4g 2-methylimidazole, 30mL water". All other conditions are the same as in Example 1.

[0115] The compounds obtained in the above examples and comparative examples were characterized as materials, and the results are shown in Table 1.

[0116] Table 1

[0117] Particle size (μm) Zn element content (wt.%) Example 1 0.5-3 28.26 Example 2 0.5-3.5 17.11 Example 3 0.5-3.2 12.06 Example 4 0.5-2.8 41.42 Comparative Example 1 0.8-4.5 / Comparative Example 2 0.8-4.1 Cu content: 25.6 Comparative Example 3 0.5-3.8 25.51

[0118] Application Example 1

[0119] This application example provides a method for preparing a polymer solid electrolyte, the method comprising the following steps:

[0120] (1) Dissolve 3g PVDF-HFP in 37mL N,N-dimethylformamide, then add the antimony compound and LiFSI prepared in Example 1, and then stir magnetically at 40°C for 24h to obtain a homogeneous mixture.

[0121] The mass ratio of the antimony compound to the PVDF-HFP is 0.075:1; the mass ratio of the LiFSI to the PVDF-HFP is 0.3:1.

[0122] (2) The homogeneous mixture described in step (1) is coated onto a tempered glass plate using a solution coating method, and then vacuum dried at 80°C for 8 hours. After peeling off the glass plate, it is cut to obtain a polymer solid electrolyte with a diameter of 16 mm.

[0123] Application Example 2-4

[0124] Application Examples 2-4 provide a method for preparing a polymer solid electrolyte. Except for using the antimony compound described in Examples 2-4, the other conditions in the preparation method are the same as in Application Example 1.

[0125] Application Example 5

[0126] The only difference between this application example and application example 1 is that PVDF-HFP is replaced with PVDF-CTFE, while all other conditions are the same as in application example 1.

[0127] Application Example 6

[0128] The only difference between this application example and application example 1 is that the mass ratio of the antimony compound to the PVDF-HFP is 0.05:1, while all other conditions are the same as in application example 1.

[0129] Application Example 7

[0130] The only difference between this application example and application example 1 is that the mass ratio of the antimony compound to the PVDF-HFP is 0.1:1, while all other conditions are the same as in application example 1.

[0131] Application Example 8

[0132] The only difference between this application example and application example 1 is that the mass ratio of the antimony compound to the PVDF-HFP is 0.03:1, while all other conditions are the same as in application example 1.

[0133] Application Example 9

[0134] The only difference between this application example and application example 1 is that the mass ratio of the antimony compound to the PVDF-HFP is 0.15:1, while all other conditions are the same as in application example 1.

[0135] Application Example 10

[0136] The only difference between this application example and application example 1 is that the mass ratio of LiFSI to PVDF-HFP is 0.2:1, while all other conditions are the same as in application example 1.

[0137] Application Example 11

[0138] The only difference between this application example and application example 1 is that the mass ratio of LiFSI to PVDF-HFP is 0.5:1, while all other conditions are the same as in application example 1.

[0139] Comparative Application Examples 1-3

[0140] Comparative Examples 1-3 provide a method for preparing a polymer solid electrolyte, wherein the preparation method is the same as that in Application Example 1, except that the oxides described in Comparative Examples 1-3 are used respectively.

[0141] Performance testing

[0142] (i) The polymer solid electrolyte sheets (CSEs) prepared in the above application examples and comparative application examples were combined with two stainless steel electrodes (SS) to form an SS / CSEs / SS simulated battery for testing. The battery assembly process was carried out in a glove box with water and oxygen content both below 0.1 ppm.

[0143] Electrochemical impedance spectroscopy (EIS) testing was performed using a frequency range of 0.01 Hz to 10 Hz. 6 The electrochemical impedance of the polymer electrolyte sheet was measured at room temperature in the Hz frequency range. The ionic conductivity of the polymer electrolyte sheet was calculated from the impedance data obtained by EIS test. The results are shown in Table 2.

[0144] (ii) The polymer electrolyte sheets (CSEs) prepared in the above examples and comparative examples were combined with lithium iron phosphate (LiFePO4) positive electrode and lithium metal negative electrode to form coin cells and their electrical performance was tested. The battery assembly process was carried out in a glove box with water and oxygen content both below 0.1 ppm.

[0145] The battery was subjected to charge-discharge cycle tests at a rate of 0.5C, and the decay of its discharge capacity was tested. The results are shown in Table 2.

[0146] Table 2

[0147]

[0148]

[0149] The following points can be drawn from Tables 1 and 2:

[0150] (1) The antimony compound obtained in Examples 1-2 of this invention is used to prepare polymer solid electrolyte, which greatly improves the ionic conductivity. Solid lithium-ion batteries can be prepared using it, which improves battery safety and has good cycle stability.

[0151] (2) Based on the combined application examples 1 and 4, it can be seen that when the antimony compound contains a large amount of Zn, it generates too much ZnO during the solvothermal process, resulting in a low ionic conductivity when it is used to prepare polymer solid electrolytes.

[0152] (3) Based on the combined application examples 1 and 8-9, it can be seen that when the amount of antimony compound added is too small, the improvement of the ionic conductivity of the polymer solid electrolyte is not significant; when the amount of antimony compound added is too large, it cannot be fully mixed with the polymer substrate, resulting in agglomeration, which in turn affects the improvement of ionic conductivity and the performance of lithium-ion batteries.

[0153] (4) Based on Application Example 1 and Application Examples 10-11, it can be seen that when the amount of lithium salt added is too small, there are fewer active ions, which leads to a decrease in the ionic conductivity of the polymer solid electrolyte; when the amount of lithium salt added is too large, although it can slightly improve the ionic conductivity of the membrane, it will significantly reduce the mechanical properties of the membrane and affect its cycle stability in the battery.

[0154] (5) Based on the combined application example 1 and the comparative application examples 1-2, it can be seen that compared with pure Sb2O3 or Cu / Sb2O3 compounds, antimony compounds containing Zn have a better synergistic effect, can more effectively improve the crystallization phenomenon of polymers, and provide more active sites to assist the dissociation of lithium salts, which can significantly improve the ionic conductivity of polymer solid electrolytes.

[0155] (6) Based on the combined application example 1 and the comparative application example 3, it can be seen that the composite particles prepared by using a mixture of methanol and DMF as a solvent have higher ionic conductivity and cycle performance than using water as a solvent alone. The main reason is that water as a solvent may partially hydrolyze SbCl3 to produce other byproducts.

[0156] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A polymer solid-state electrolyte, characterized by, The polymer solid-state electrolyte comprises a lithium salt, a polymer base and a micron-sized antimony compound; The mass ratio of the antimony compound to the polymer base is (0.05-0.1):1; The mass ratio of the lithium salt to the polymer base is (0.25-0.4):1; The antimony compound comprises Sb2O3 and Zn element; The particle size of the antimony compound is 0.5-10 μm; The mass content of Zn element in the antimony compound is 10-30 wt.%; The antimony compound is an octahedral structure; The preparation method of the antimony compound comprises: The antimony compound is prepared by mixing zinc salt, antimony salt, 2-methyl imidazole and organic solvent, and then performing a solvothermal reaction.

2. The polymer solid-state electrolyte according to claim 1, characterized by, The molar ratio of the zinc salt to the antimony salt is 1:(1-3).

3. The polymer solid-state electrolyte according to claim 2, characterized by The molar ratio of the zinc salt to the antimony salt is 1:(1-2).

4. The polymer solid-state electrolyte of claim 1, wherein The mass-volume ratio of the zinc salt to the solvent is 1:(80-200) g / mL.

5. The polymer solid-state electrolyte of claim 1, wherein The mass ratio of the zinc salt to 2-methyl imidazole is 1:(1:2.5).

6. The polymer solid-state electrolyte of claim 1, wherein The zinc salt comprises any one or a combination of at least two of zinc acetate, zinc nitrate, zinc chloride, zinc sulfate, zinc gluconate or zinc iodide.

7. The polymer solid-state electrolyte of claim 1, wherein The antimony salt comprises any one or a combination of at least two of antimony trichloride, antimony nitrate or potassium antimonyl tartrate.

8. The polymer solid-state electrolyte of claim 1, wherein, The organic solvent comprises any one or a combination of at least two of alcohol compound, N,N-dimethylformamide, N,N-dimethylacetamide or N-methyl pyrrolidone.

9. The polymer solid-state electrolyte of claim 1, wherein, The temperature of the solvothermal reaction is 180-240℃.

10. The polymer solid-state electrolyte of claim 1, wherein, The holding time of the solvothermal reaction is 20-26 h.

11. The polymer solid-state electrolyte of claim 1, wherein, The method for mixing the zinc salt, the antimony salt and the solvent specifically comprises: The zinc salt and the solvent are first mixed, and then the antimony salt is added for second mixing.

12. The polymer solid-state electrolyte of claim 11, wherein, The first mixing time is 10-14 h.

13. The polymer solid-state electrolyte of claim 11, wherein, The second mixing time is 1-4 h.

14. The polymer solid-state electrolyte of claim 1, wherein, The lithium salt comprises fluorine-containing lithium salt and / or lithium bis(oxalato)borate.

15. The polymer solid-state electrolyte of claim 14, wherein, The fluorine-containing lithium salt comprises any one or a combination of at least two of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium bis(trifluoromethylsulfonyl)imide, lithium bis(fluorosulfonyl)imide, lithium difluoro(oxalato)borate or lithium trifluoromethanesulfonate.

16. The polymer solid-state electrolyte of claim 1, wherein The polymer base comprises any one or a combination of at least two of polyvinylidene fluoride, polyethylene oxide, thermoplastic polyurethane, polypropylene oxide, polycarbonate, polyvinyl alcohol, polyacrylic acid, polyethyl methacrylate, polymethyl methacrylate, polyacrylonitrile or polyvinyl chloride.

17. A method of producing a polymer solid-state electrolyte as claimed in any one of claims 1 to 16, characterized by, The preparation method comprises: The polymer solid-state electrolyte is obtained by mixing the lithium salt, the polymer base and the antimony compound.

18. The method of claim 17, wherein, The preparation method comprises: S1, mixing the lithium salt, the polymer base, the antimony compound and the organic solvent to obtain a homogeneous mixture; S2, solidifying the homogeneous mixture obtained in step S1 to obtain the polymer solid-state electrolyte.

19. The method of claim 18, wherein, In step S1, the amount of the polymer base dissolved in 100 mL of the organic solvent is 6-15 g.

20. The method of claim 19, wherein, In step S1, the amount of the polymer base dissolved in 100 mL of the organic solvent is 7.5-9.5 g.

21. The method of claim 18, wherein, In step S2, the solidification is performed by a solution coating method.

22. The preparation method according to claim 18, characterized in that, After the solidification in step S2, drying is performed.

23. A lithium-ion battery, characterized by, The lithium ion battery comprises a positive electrode, a negative electrode and the polymer solid electrolyte according to any one of claims 1-16 or prepared according to the preparation method of any one of claims 17-22; The polymer solid electrolyte is located between the positive electrode and the negative electrode.

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